Desensitization using IVIG alone for living-donor kidney transplant: impact on donor-specific antibodies / Dessensibilização usando somente IgIV para transplante renal com doador vivo: impacto nos anticorpos específicos contra o doador

Abstract Introduction: Sensitization to human leukocyte antigen is a barrier to. Few data have been published on desensitization using polyvalent human intravenous immunoglobulin (IVIG) alone. Methods: We retrospectively reviewed the of 45 patients with a positive complement-dependent cytotoxicity crossmatch (CDCXM) or flow cytometry crossmatch (FCXM) against living donors from January 2003 to December 2014. Of these, 12 were excluded. Patients received monthly IVIG infusions (2 g/kg) only until they had a negative T-cell and B-cell FCXM. Results: During the 33 patients, 22 (66.7%) underwent living donor kidney transplantation, 7 (21.2%) received a deceased donor graft, and 4 (12.1%) did not undergo transplantation. The median class I and II panel reactive antibodies for these patients were 80.5% (range 61%-95%) and 83.0% (range 42%-94%), respectively. Patients (81.8%) had a positive T-cell and/or B-cell CDCXM and 4 (18.2%) had a positive T-cell and/or B-cell FCXM. Patients underwent transplantation after a median of 6 (range 3-16). The median donor-specific antibody mean fluorescence intensity sum was 5057 (range 2246-11,691) before and 1389 (range 934-2492) after desensitization (p = 0.0001). Mean patient follow-up time after transplantation was 60.5 (SD, 36.8) months. Nine patients (45.0%). Death-censored graft survival at 1, 3, and 5 years after transplant was 86.4, 86.4, and 79.2%, respectively and patient survival was 95.5, 95.5, and 83.7%, respectively. Conclusions: Desensitization using IVIG alone is an effective strategy, allowing successful transplantation in 87.9% of these highly sensitized patients.

Resumo Introdução: Sensibilização HLA é uma barreira ao transplante em pacientes sensibilizados. Há poucos dados publicados sobre dessensibilização utilizando somente imunoglobulina intravenosa humana polivalente (IgIV). Métodos: Revisamos retrospectivamente prontuários de 45 pacientes com prova cruzada positiva por citotoxicidade dependente do complemento (CDCXM) ou citometria de fluxo (FCXM) contra doadores vivos, de Janeiro/2003-Dezembro/2014. Destes, excluímos 12. 33 pacientes receberam infusões mensais de IgIV (2 g/kg) apenas até apresentarem FCXM células T e B negativa. Resultados: Durante dessensibilização, 22 pacientes (66,7%) realizaram transplante renal com doador vivo, 7 (21,2%) receberam enxerto de doador falecido, 4 (12,1%) não realizaram transplante. A mediana do painel de reatividade de anticorpos classes I e II para estes pacientes foi 80,5% (intervalo 61%-95%) e 83,0% (intervalo 42%-94%), respectivamente. 18 pacientes (81,8%) apresentaram CDCXM célula T e/ou B positiva; 4 (18,2%) apresentaram FCXM célula T e/ou B positiva. Pacientes realizaram transplante após mediana de 6 (intervalo 3-16) infusões. A mediana da somatória da intensidade média de fluorescência do anticorpo específico contra o doador foi 5057 (intervalo 2246-11.691) antes e 1389 (intervalo 934-2492) após dessensibilização (p = 0,0001). O tempo médio de acompanhamento do paciente pós transplante foi 60,5 (DP, 36,8) meses. Nove pacientes (45,0%) não apresentaram rejeição e 6 (27,3%) apresentaram rejeição mediada por anticorpos. Sobrevida do enxerto censurada para óbito em 1, 3, 5 anos após transplante foi 86,4; 86,4; 79,2%, respectivamente, e sobrevida do paciente foi 95,5; 95,5; 83,7%, respectivamente. Conclusões: Dessensibilização utilizando apenas IgIV é uma estratégia eficaz, permitindo transplante bem-sucedido em 87,9% destes pacientes altamente sensibilizados.

Polimorfismo de los antígenos leucocitarios humanos en receptores cubanos de trasplante relacionado de progenitores hematopoyéticas / Polymorphism of human leukocyte antigens in Cuban recipients of related hematopoietic stem cell transplants

Introducción: El trasplante relacionado de células progenitoras hematopoyéticas (TCPH) es una alternativa terapéutica curativa para los pacientes con ciertos tipos de hemopatías o de inmunodeficiencias, en la que se selecciona como donante a un familiar del receptor. Objetivo: Caracterizar el sistema de antígenos leucocitarios humanos (HLA) en receptores de TCPH relacionado. Métodos: Se realizó un estudio descriptivo y transversal en el departamento de Histocompatibilidad del Instituto de Hematología e Inmunología desde enero 2013 hasta diciembre de 2015. Se tipificaron 75 genes HLA mediante la técnica de reacción en cadena de la polimerasa con cebadores de secuencia específico, de baja resolución a 117 pacientes con criterio de TCPH. Para el análisis inmunogenético se empleó el programa Arlequín 3.5.2.2. Resultados: Fueron más frecuentes los genes HLA-A*02, HLA-B*35, HLA-DQB1*03, HLA-DRB1*03 y HLA-DRB1*04, los haplotipos de dos loci HLA-A*02 B*35, HLA-DQB1*03 DRB1*04 y el haplotipo extendido HLA-A*03 B*07 DQB1*06 DRB1*15. Conclusiones: Los genes del sistema HLA en pacientes cubanos candidatos a TCPH relacionado presentaron frecuencias similares a las descritas en poblaciones generales de Cuba y el mundo, aunque con características distintivas en algunos genes y haplotipos(AU)

Introduction: Related hematopoietic progenitor cell (TCPH) transplantation is a curative therapeutic alternative for patients with certain types of hemopathies or immunodeficiencies, in which a recipient family member is selected as a donor. Objective: To characterize the human leukocyte antigen (HLA) system in related TCPH receptors. Methods: A descriptive and cross-sectional study was conducted in the Histocompatibility department of the Institute of Hematology and Immunology from January 2013 to December 2015. 75 HLA genes were typed using the polymerase chain reaction technique with specific sequence primers, from Low resolution to 117 patients with TCPH criteria. For the immunogenetic analysis, the Harlequin 3.5.2.2 program was used. Results: The genes HLA-A * 02, HLA-B * 35, HLA-DQB1 * 03, HLA-DRB1 * 03 and HLA-DRB1 * 04, the haplotypes of two HLA-A * 02 B * 35 loci were more frequent , HLA-DQB1 * 03 DRB1 * 04 and the extended haplotype HLA-A * 03 B * 07 DQB1 * 06 DRB1 * 15. Conclusions: The genes of the HLA system in Cuban patients related to TCPH presented frequencies similar to those described in general populations of Cuba and the world, although with distinctive characteristics in some genes and haplotypes(AU)

HLA alleles in renal transplant recipients with nonmelanoma skin cancer in southeastern Brazil

Abstract: Background: Renal transplant recipients are submitted to immunosuppression to avoid graft rejection, which makes them susceptible to various conditions. Furthermore, these individuals present malignant tumors more frequently than the general population, including nonmelanoma skin cancer. The individual genetic basis that acts in the pathogenesis of cutaneous cancer may present a protection or susceptibility factor for disease development. One of these factors is the HLA complex. Objective: To investigate HLA alleles association to the occurrence of nonmelanoma skin cancer in renal transplant recipients from São Paulo State. Methods: A total of 213 patients (93 renal transplant recipients with nonmelanoma skin cancer and 120 renal transplant recipients without nonmelanoma skin cancer) were evaluated by retrospective and cross-sectional study. Epidemiological, clinical and HLA typing data were found in databases. HLA class I (A, B) and class II (DR) alleles were compared to establish their association with nonmelanoma skin cancer. Results: Comparing renal transplant recipients with and without nonmelanoma skin cancer, the HLA-B*13 allele was associated with higher risk of developing nonmelanoma skin cancer while B*45 and B*50 alleles were associated with protection. Study limitations: The HLA A, B and DR alleles identification for the kidney transplantation routine is done by low and medium resolution techniques that do not allow discrimination of specific alleles. Conclusion: The involvement of HLA alleles in nonmelanoma skin cancer in renal transplant recipients was confirmed in this study. Renal transplant recipients with HLA-B*13 showed higher risk for developing a skin cancer (OR= 7.29) and should be monitored for a long period of time after transplantation.

Haplotipo HLA infrecuente en un estudio familiar de histocompatibilidad para trasplante de células progenitoras hematopoyéticas / Non frequent HLA haplotype in a family-based histocompatibility study for hematopoietic stem cell transplantation

Ante una indicación de trasplante de células progenitoras hematopoyéticas se realiza la tipificación de los antígenos HLA de clase I y clase II al receptor y sus posibles donantes. En el departamento de Histocompatibilidad del Instituto de Hematología e Inmunología de La Habana se realizó un estudio familiar de histocompatibilidad a una paciente diagnosticada de leucemia linfoide aguda Ph+. La paciente y el padre presentaron el haplotipo HLA-A*03:01 B*39:10 C*12:03 DRB1*15:03 DQB1*06:02, que se identificó en el abuelo paterno, aunque por técnicas de baja resolución. A su vez, en el hermano y la madre también se tipificó un haplotipo compuesto por estos mismos alelos HLA-A, B, C, DRB1 y DQB1; y que se detectó en baja resolución en el abuelo materno. Sorprendentemente la paciente era HLA idéntica a la madre, cuando se esperaría que solo compartieran la mitad de los genes HLA. El hecho de que el haplotipo objeto de estudio apareciera en ambos padres de la paciente, quienes provenían de familias sin vínculos de parentesco conocido en al menos dos generaciones pasadas, puede considerarse un evento poco probable. Las investigaciones inmunogenéticas que están basadas en la tipificación HLA, no solo contribuyen a la selección de la mejor pareja donante receptor, sino que permiten a caracterizar el patrimonio genético del país(AU)

When a hematopoietic stem cell transplantation is indicated, the HLA class I and class II antigens are typed in the recipient and its possible donors. In the Histocompatibility department of the Institute of Hematology and Immunology of Havana, a family-based histocompatibility study was performed to a patient diagnosed with Ph+ acute lymphoid leukemia. The patient and the father presented the haplotype HLA-A*03:01 B*39:10 C*12:03 DRB1*15:03 DQB1*06:02, which was also identified in the paternal grandfather by low resolution techniques. In turn, a haplotype, composed of the same HLA-A, B, C, DRB1 and DQB1 alleles, was typed in the mother and the sibling and it was detected in low resolution in the maternal grandfather. Surprisingly, the patient was HLA identical to the mother, when they would be expected to share only half of the HLA genes. The fact that the haplotype under study appeared in both parents of the patient, who came from families without known ties of kinship in at least two past generations, can be considered an unlikely event. Immunogenetic investigations based on HLA typing, not only contribute to the selection of the best recipient donor pair, but also allow characterizing the nation's genetic heritage(AU)

Simplifying celaac disease predisposing hla-dq lleles determination by the reaal time pcr method / Simplificação da detecção dos alelos HLA-DQ predisponentes para doença celíaca pelo método de PCR em tempo real

Background Celiac disease is an autoimmune enteropathy triggered by the ingestion of gluten in genetically susceptible individuals. Genetic susceptibility is associated with two sets of alleles, DQA1*05 - DQB1*02 and DQA1*03 - DQB1*03:02, which code for class II MHC DQ2 and DQ8 molecules, respectively. Approximately 90%-95% of celiac patients are HLA-DQ2 positive, and half of the remaining patients are HLA-DQ8 positive. In fact, during a celiac disease diagnostic workup, the absence of these specific DQA and DQB alleles has a near perfect negative predictive value. Objective Improve the detection of celiac disease predisposing alleles by combining the simplicity and sensitivity of real-time PCR (qPCR) and melting curve analysis with the specificity of sequence-specific primers (SSP). Methods Amplifications of sequence-specific primers for DQA1*05 (DQ2), DQB1*02 (DQ2), and DQA1*03 (DQ8) were performed by the real time PCR method to determine the presence of each allele in independent reactions. Primers for Human Growth Hormone were used as an internal control. A parallel PCR-SSP protocol was used as a reference method to validate our results. Results Both techniques yielded equal results. From a total of 329 samples the presence of HLA predisposing alleles was determined in 187 (56.8%). One hundred fourteen samples (61%) were positive for a single allele, 68 (36.3%) for two alleles, and only 5 (2.7%) for three alleles. Conclusion Results obtained by qPCR technique were highly reliable with no discordant results when compared with those obtained using PCR-SSP. .

Contexto Doença celíaca é uma enteropatia autoimmune desencadeada pela ingestão de gluten em indivíduos geneticamente suscetíveis. Essa suscetibilidade genética está associada a dois conjuntos de alelos, DQA1*05 - DQB1*02 e DQA1*03 - DQB1*03:02, que codificam moléculas MHC de classe II DQ2 e DQ8, respectivamente. Aproximadamente 90%-95% dos pacientes celíacos são HLA-DQ2 positivos, e metade dos restantes são HLA-DQ8 positivos. No diagnóstico da doença celíaca, a ausência desses alelos DQA e DQB específicos possui um elevado valor preditivo negativo. Objetivo Nosso objetivo foi melhorar a detecção de alguns alelos predisponentes para doença celíaca, combinando a simplicidade e sensibilidade da técnica de PCR em tempo real (qPCR) e análise da curva de melting com a especificidade dos primers de sequência específica. Métodos Primers de sequência específica para DQA1*05 (DQ2), DQB1*02 (DQ2), e DQA1*03 (DQ8) foram usados para testar a presença de cada alelo em reações independentes. Primers para Hormônio de Crescimento Humano foram usados como controle interno. Em paralelo, foi usado um protocolo de PCR-SSP como um método de referência para validar nossos resultados positivos. Resultados Das 329 amostras testadas, 187 (56.8%) foram positivas para os alelos HLA predisponentes, usando as duas técnicas. Essas 187 amostras positivas foram subdivididas em 114 (61.0%) positivas para apenas um alelo, 68 (36.3%) para dois alelos e apenas 5 (2.7%) para os três alelos. Conclusão Os resultados obtidos pela técnica de qPCR mostraram-se altamente confiáveis, sem resultados discordantes quando comparados àqueles obtidos pelo método PCR-SSP. .

Interlaboratory Comparison of the Results of Lifecodes LSA Class I and Class II Single Antigen Kits for Human Leukocyte Antigen Antibody Detection

BACKGROUND: Although single antigen bead assays (SAB) are approved qualitative tests, the median fluorescence intensity (MFI) values obtained from SAB are frequently used in combination with quantitative significances for diagnostic purposes. To gauge the reproducibility of SAB results, we assessed the interlaboratory variability of MFI values using identical kits with reagents from the same lot and the manufacturer's protocol. METHODS: Six serum samples containing HLA-specific antibodies were analyzed at five laboratories by using Lifecodes LSA Class I and Class II SAB kits (Immucor, USA) from the same lot, according to the manufacturer's protocol. We analyzed the concordance of qualitative results according to distinct MFI cutoffs (1,000, 3,000, 5,000, and 10,000), and the correlation of quantitative MFI values obtained by the participating laboratories. The CV for MFI values were analyzed and grouped by mean MFI values from the five laboratories ( or =10,000). RESULTS: The categorical results obtained from the five laboratories exhibited concordance rates of 96.0% and 97.2% for detection of HLA class I and class II antibodies, respectively. The Pearson correlation coefficients for MFI values of class I and class II antibodies were between 0.947-0.991 and 0.992-0.997, respectively. The median CVs for the MFI values among five laboratories in the lower MFI range (<1,000) were significantly higher than those for the other MFI ranges (all P<0.01). CONCLUSIONS: Analysis of SAB performed in five laboratories using identical protocols and reagents from the same lot resulted in high levels of concordance and strong correlation of results.

Discrepancies in HLA typing: use of different methods to confirm doubtful or inconclusive results / Discrepâncias na tipagem HLA: diferentes métodos para confirmar resultados duvidosos ou inconclusivos

The major histocompatibility complex (MHC) is a set of genes found on the short arm of chromosome 6. MHC molecules in human beings are known as human leukocyte antigens (HLA). HLA polymorphism can be determined by serological and molecular typing methods, which may yield discordant results. The present analysis performed HLA typing of samples with discordant results by PCR-SSP and PCR-SSO, so that typing discrepancies could be clarified. The cross-sectional study analyzed 33 samples from individuals included in an HLA-disease association study. Discrepant alleles were observed in 6 of 33 samples. Discordant samples were retyped using One Lambda Micro SSP™, Dynal RELI™ SSO and Luminex™ SSO assays for HLA class I (HLA-A, HLA-B) and class II (HLA-DRB1) molecules. The three methods produced concordant results after HLA retyping. Human error occurred in interpreting the initial results, which led to discrepancies in the results obtained. The participation of experienced professionals and the availability of at least two different methods to confirm doubtful or inconclusive results are mandatory for effective HLA typing.

O complexo principal de histocompatibilidade (MHC) é um conjunto de genes encontrados no braço curto do cromossomo 6. Em humanos, as moléculas de MHC são conhecidas como antígenos leucocitários humanos (HLA). Polimorfismo HLA pode ser determinado por métodos de tipagem sorológica e molecular que são susceptíveis de produzir resultados discordantes. Este estudo teve como objetivo realizar a tipagem HLA de amostras com resultados discordantes por PCR-SSP e-SSO e para esclarecer discrepâncias de digitação. Este estudo transversal analisou 33 amostras de indivíduos incluídos em um estudo de associação HLA-doença. Alelos discrepantes foram observados em seis das 33 amostras. Amostras discordantes foram retyped usando One Lambda Micro SSP™, Dynal RELI™ SSO Luminex e ensaios ™ SSO para HLA de classe I (HLA-A, HLA-B) e classe II (HLA-DRB1) moléculas. Todos os três métodos apresentaram resultados concordantes após HLA redigitação. Houve erro humano na interpretação dos resultados iniciais o que levou a uma discrepância entre os resultados obtidos. Concluiu-se que a participação de profissionais experientes e com a disponibilidade de pelo menos dois métodos diferentes para confirmar os resultados duvidosos ou inconclusivos são essenciais para a tipagem de HLA eficaz.

Vascular histocompatiblity after implantation of an arsenic-coated stent / 中国组织工程研究

BACKGROUND:Arsenic trioxide is considered to inhibit the proliferation of vascular smooth muscle cel s and promote cel apoptosis. Therefore, we wondered whether the arsenic can inhibit the hyperplasia of vascular smooth muscle cel s, an arsenic-coated stent can be compatible with the vascular tissue, and a better vascular intimal coverage as early as possible can reduce intimal hyperplasia. OBJECTIVE:To observe the vascular histocompatibility of the arsenic-coated stent. METHODS:Fourteen white rabbits were randomized into two groups and respectively subject to the implantation of arsenic-coated 316 L stainless steel stents and bare 316 L stainless steel stents into the abdominal aorta. After 28 days, the distal and proximal parts of the vessel at the implantation site were ligated and the ligated vessel was taken for hematoxylin-eosin staining and light microscope observation. RESULTS AND CONCLUSION:(1) Gross observation:the vessel at the stent site was a little larger than the adjacent vessels in the outer diameter, which was expanded but had no visible thrombus. After cutting the stent, the neointima formed smoothly on the stent surface. (2) Light microscope observation:the stent was located in the middle of the vessel, the medial smooth muscle was pressed, and vascular intimal smooth muscle hyperplasia was found around the stent, thereby thickening the vascular intima. The vascular neointima formed and covered the stent, and there was a thin black layer between the stent and the vascular tissue, which consisted of arsenic and its compounds. These findings suggest that the arsenic-coated stents can be covered with vascular tissues, possessing good vascular histocompatibility.

A Successful Bilateral Lung Transplantation in a Patient with High Panel Reactive Antibody and Positive Cross Matching

A 44-year-old pregnant female patient gave stillbirth while being treated for pneumonia. She developed acute respiratory failure, which resulted in mechanical ventilator support. Diagnostic lung biopsy revealed a cryptogenic organizing pneumonia. The patient's condition deteriorated and a venous-venous extracorporeal membrane oxygenation was placed. She was listed for lung transplantation. Because of her worsening condition lung transplantation was performed despite positive cross matching result. She was treated with rituximab, intravenous immunoglobulin, and plasmapheresis and recovered without event. There is no sign of rejection at the time of last follow-up.

Evaluation of Flow Cytometric Crossmatch Results in Comparison with Donor-specific Antibodies Detected by Luminex-PRA Tests in Organ Transplantation Patients / 대한이식학회지

BACKGROUND: Two of the most sensitive methods for detecting donor-specific HLA antibodies (DSAs) are solid phase panel reactive antibody (PRA) assay using Luminex platform (Luminex-PRA), and a cell-based flow cytometric crossmatch (FCXM) test. We evaluated FCXM results in relation to DSAs detected by the Luminex-PRA method in solid organ transplantation candidates or post-transplant follow-up patients. METHODS: A total of 171 donor-recipient pairs were evaluated by Luminex-PRA (LIFECODES Class I and Class II ID kits; Gen-Probe, USA) and FCXM (T- and B-cells) tests. DSA levels were analyzed using a sum of median fluorescence intensity (MFI) values, and FCXM results were analyzed using MFI ratios. RESULTS: Class I and II DSAs were detected in 11.7% (20/171) and 11.1% (19/171) of tested sera, respectively. T-FCXM was negative in 97.4% (147/151) of Class I DSA negative sera, and B-FCXM was negative in 99.3% (137/138) of Class I and II DSA negative sera. T-FCXM was positive in 91.7% (11/12) of sera with moderate to strong Class I DSAs and B-FCXM was positive in 88.9% (16/18) of sera with moderate to strong Class II and/or Class I DSAs in the evaluation of sensitivities of FCXM in relation to DSA. There were significant correlations between FCXM ratios and DSA levels for both T-FCXM (P=0.008) and B-FCXM (P97%) and the sensitivities of T- and B-FCXM were satisfactory (>88%) in detecting moderate to strong DSAs.

Importance of killer immunoglobulin-like receptors in allogeneic hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation is the treatment of choice for many hematologic diseases, such as multiple myeloma, bone marrow aplasia and leukemia. Human leukocyte antigen (HLA) compatibility is an important tool to prevent post-transplant complications such as graft rejection and graft-versus-host disease, but the high rates of relapse limit the survival of transplant patients. Natural Killer cells, a type of lymphocyte that is a key element in the defense against tumor cells, cells infected with viruses and intracellular microbes, have different receptors on their surfaces that regulate their cytotoxicity. Killer immunoglobulin-like receptors are the most important, interacting consistently with human leukocyte antigen class I molecules present in other cells and thus controlling the activation of natural killer cells. Several studies have shown that certain combinations of killer immunoglobulin-like receptors and human leukocyte antigens (in both donors and recipients) can affect the chances of survival of transplant patients, particularly in relation to the graft-versusleukemia effect, which may be associated to decreased relapse rates in certain groups. This review aims to shed light on the mechanisms and effects of killer immunoglobulin-like receptors - human leukocyte antigen associations and their implications following hematopoietic stem cell transplantation, and to critically analyze the results obtained by the studies presented herein.

Tipificación molecular de los antígenos leucocitarios humanos, estado del arte y perspectivas para los transplantes de células madre en Costa Rica: [revisión] / Molecular typing of human leukocyte antigens, state of the art and perspectives for stem cell transplantation in Costa Rica: [review]

El sistema de antígenos leucocitarios (human leukocyte antigen) es el más polimórfico en el ser humano. Su función la realiza regulando la respuesta inmune mediante su unión a moléculas como el receptor de células T, participando en la presentación de antígenos y el reconocimiento de lo propio en el organismo. Su papel central en la respuesta inmune así como su polimorfismo convierten a estos genes en un factor fundamental en la terapia con trasplantes, siendo su importancia máxima en los trasplantes de células progenitoras hematopoyéticas. Consecuentemente, la tipificación de estos antígenos en los estudios de compatibilidad ha sido desarrollada de manera paralela y en las últimas décadas se ha avanzado grandemente en su comprensión y caracterización. Varias metodologías moleculares son las que predominan actualmente para la tipificación de los antígenos de histocompatibilidad leucocitarios. La información obtenida de estas caracterizaciones ha permitido la aparición de bancos de donantes de células madre y unidades de cordón umbilical, los cuales amplían la probabilidad de encontrar un donador compatible para el paciente. Los programas de trasplante de células madre hematopoyéticas en nuestro país requieren de un avance en las tecnologías disponibles para tipificación de estas moléculas, así como de la instauración de un registro nacional de donantes basado en su tipificación molecular. El presente trabajo tiene por objetivo presentar el estado del conocimiento actual sobre los antígenos leucocitarios humanos, su genética, su tipificación, sus utilidades y protocolos a seguir en la tecnología de los transplantes de células madre.

The Human Leukocyte Antigen genetic system is the most polymorphic in humans. It plays a central role on immune response regulation by its interaction with molecules like the T-cellreceptor, participating in the antigen presentation process and self-recognition. This role addedto its polymorphism make the human leukocyte antigens a fundamental factor for transplantation, especially when it comes to hematopoietic stem cell transplants. Consequently, techniques for human leukocyte antigen typing for compatibility studies have experienced great development over the last decades. Various molecular typing methodologies currently predominate for this characterization. Information obtained with these technologies has prompted the development of stem cell adult donor registries and cord blood banks which raise the probability of finding a suitable compatible donor for patients in need of transplantation. Stem Cell Transplantation Programs in Costa Rica urgently need the updating to molecular typing technologies for patientdonor compatibility studies. Moreover, the creation of a National Stem Cell Donor Registry and the pursuing of the public Cord Blood Bank need to be addressed. The present review aims to present state-of-the-art concepts and knowledge on human leukocyte antigen genetics, typingstrategies and protocols, and applications on stem cell transplantation. Additionally, perspectives for Costa Rican development on these areas are given.

Sequencing analysis of exons 1,5, 6, 7 of HLA-Cw gene located outside of the routine testing region and its application in clinical matching / 中华检验医学杂志

Objective To study the molecular genetic polymorphism of exons 1,5, 6, 7 of HLA-C gene in Chinese population and evaluate the significance of additional sequencing based typing at exons 1,5, 6, 7 of HLA-Cw gene in clinical HLA matching, Methods A total of 324 individuals were typed at exons 2,3, 4 of HLA-C gene by sequence-based typing. If ambiguities appeared outside of exons 2 -4, we designed a total of 5 in-house sequencing primers and optimized the sequencing reaction, additional sequencing based typing at exons 1,5, 6, 7 was performed to solove the emerging ambiguities. Results In the three hundred and twenty-four samples typed by PCR-SBT at exons 2, 3 and 4 of HLA-Cw gene, 23.8 % (77/324) of the typed samples were assigned the conclusive genotype in four digital level 76. 2% (247/324) of the typed samples were given with the ambiguous allele combination results, in which 73 kinds of ambiguous allele combinations were detected. Increasing the additional sequencing analysis at exons 1, 5, 6, 7 of HIA-C gene, ten frequent ambiguities including Cw* 030201/030202, Cw* 070201/0750, Cw* 040101/0409N/0430, Cw* 0403/0409N/0430, Cw* 080101/0822 could be distinguished. ConclusionsIncreasing the sequencing anlysis at exons 1, 5, 6 and 7 of HLA-Cw gene will help to make clear the ambiguous SBT results and also improve the accuracy of HLA-Cw typing. It shows important significance in clinical histoeompatibility matching.

National external quality assessment for HLA low-resolution molecular typing: 2005 -2008 activities / 中华检验医学杂志

Objective National external quality assessment (EQA) results from 2005 to 2008 for HLA class Ⅰ (A, B) and class Ⅱ (DRB1) low-resolution DNA typing were summarized with the goal of exploring strategies to assure and improve HLA DNA typing performance in clinical testing. Methods HLA allele results from the four consecutive years EQA events were analysed. Different kinds of errors were described and classified, and the possible causes were discussed. Results Participant laboratories were increasing in the four consecutive years with the number of 22, 28, 47 and 61 in 2005, 2006, 2007 and 2008,respectively. 2 844 HLA DNA typings were returned from the participants during the 4 years EQA surveys, and overall 30 errors (1.05%) were identified. These 30 errors were classified into two major types of errors including 25 technical genotyping errors and 5 human errors. The proportion of laboratory participants which made mistakes was 13. 6%, 10. 7%, 10. 6% and 16.4% in 2005, 2006, 2007 and 2008, respectively. Conclusions Above 10% of participant laboratories exhibited errors in the four consecutive years HLA molecular typing EQA surveys. Relevant important attentions should be greatly paid to clinical HLA molecular typing test.

Study on HLA matching in sensitized recipients of renal allografts and its clinical application / 中华器官移植杂志

Objective To evaluate the clinical application of HLA matching in highly sensitized recipients of renal allografts.Methods Recipient's panel reactive antibody (PRA) was detected by using ELISA test with Lambda antigen tray (LAT).Donor and recipient HLA classⅠtyping was performed with special monoclonal tray,and HLA classⅡgene typing with micro-sequence specific primers (Micro-SSP).Results There were 104 recipients with anti-HLA class-ⅠIgG antibody,76 with anti-HLA class-ⅡIgG antibody,and 44 with both anti-HLA class-1 and anti HLA class-ⅡIgG antibody respectively in 136 sensitized recipients.HLA class-ⅠIgG antibody positive rate was 11%-97 %,with an average of 49.6%?23.8%;The common public epitopes antibody was not found in each recipient of 13 cases with PRA＜20%,but was found in I2 recipients in 44 cases with PRA be- tween 20%-50%,and 39 recipients in 47 cases with PRA＞50%.HLA class-ⅡIgG antibody posi- tive rate was 17%-100%,with an average of 28.2%?63.8%.The number of cases of 0,1,2,3, 4 MM was 7 (5.1%),26 (19.1%),47 (34.6%),39 (28.7%) and 17 (12.5%) respectively by the standard of conventional HLA antigen matching;however the number of the recipients with 0,1, 2,3 MM was 31 (22.8%),53 (39.0%),36 (26.5%) and 16 (11.7%) respectively according to the rule of HLA CREGs matching and none with 4 MM.Rates of acute rejection in sensitized recipi- ents with 2MM and 3MM HLA-CREGs were 25.0% and 37.5% respectively and were significantly higher than those with 0MM (P＜0.05,＜0.05 respectively).Kidney year-survival was decreased when the number of MM of HLA CREGs matching increased.Conclusion The HLA CREGs matching can improve the ratio of well-matched significantly.Good HLA matching can reduce the incidence of acute rejection in sensitized recipients and increase the survival rate of grafts.

HLA Typing Proficiency Survey in Korea, 2003-2004 / 대한진단검사의학회지

BACKGROUND: HLA proficiency survey in Korea started in 1996 and the results of the survey were last reported in 1999. In this report, we summarized the results of the survey performed in recent 2 years. METHODS: A total of four proficiency surveys were performed, in which 54-59 laboratories participated. Each survey included 3 tests for HLA class I (serology and DNA) and class II (DNA) typing and 6 for HLA crossmatch test (3 cells x 2 sera). RESULTS: Overall concordance of serologic typing was 99.5% (436/438) for HLA-A, 95.7% (419/438) for HLA-B, and 94.8% (199/210) for HLA-C. The antigens assigned incorrectly by more than 5% of the participating laboratories were B54 (10.3%), B55 (10.3%), B27 (5.4%), Cw6 (22.9%), and C-blank (5.7%). Overall concordance rates of DNA typing were 99.7% (393/394) for HLA-A, 99.8% (415/416) for HLA-B, 100% (156/156) for HLA-C. Correct assignment of HLA-DRB1 and -DQB1 was reportred by 99.7% (98.1-100%) and 99.2% (88.9-100%) for generic and 99.2% and 98.1% (80-100%) for allelic level, respectively. Most laboratories (93.5-97.9%) were using sensitive methods of crossmatch such as T-long, T-AHG, and flowcytometry. The proportion of laboratories evaluated as unacceptable was on the average 3.1% of total laboratories. CONCLUSIONS: The rate of correct identification of HLA antigens was higher this time than in the previous survey in 1999. The rate of unacceptable crossmatch was also low enough to be satisfactory. It is thought that the proficiency survey has contributed to the high quality of HLA tests in the participating laboratories and should be continued to maintain the proficiency in Korea.

Results of the HLA Typing Proficiency Survey in Korea, 2000-2002 / 대한진단검사의학회지

BACKGROUND: HLA proficiency survey was started in 1996 in Korea, and the results of the 1996-1998 surveys were reported previously. Here, we report the results of the surveys performed in recent three years (2000-2002). METHODS: Six surveys were carried out with the participation of 52-54 laboratories. For each survey, 3 peripheral blood samples and 2 sera were distributed for 3 HLA class I serology, 3 HLA class I DNA, 3 HLA class II DNA, 6 HLA crossmatch, and 3 PRA tests. RESULTS: Overall consensus of serologic typing was similar to the results of the previous survey: HLA-A 93.5%, HLA-B 88.3%, and HLA-A, B 82.7%. There were an increasing number of the laboratories that were using DNA typing for HLA-DR (51 laboratories, 94%) and HLA-A and B (26 laboratories, 48%). Overall consensus of DNA typing was very high: HLA-A 100%, HLA-B 99.1%, HLAC 97.9%, HLA-DRB1 low/high resolution 99.2/99.0%, HLA-DQB1 low/high resolution 99.3/97.5%. HLA crossmatch (T cells) was reported by 44-49 laboratories, and the use of sensitive methods was increased: AHG 33 laboratories and flow cytometry 7 laboratories. For incompatible (positive) crossmatches, 4.9% (0-14.3%) of cytotoxicity tests and 7.1% (0-16.7%) of flow tests were reported as negative. PRA was reported by 5 laboratories only. CONCLUSIONS: The use of DNA tests for HLA typing and AHG or flow cytometry methods for HLA crossmatch tests has much increased compared to the previous report. A continuous survey program would play an important role in the standardization and maintenance of laboratory proficiency in histocompatibility testing in Korea.

Early survival analysis and tissue typing of 9 cases of cardiac transplantation / 中华器官移植杂志

Objective To evaluate the matching degree of donor's and receptor's tissue typing and analyze the relationship between the degree and the early survival of cardiac transplantation with donor's and receptor's tissue typing of 9 cases of cardiac transplantation. Methods In accordance with the international standard, donor's and receptor's blood type, HLA antibody, lymphocytotoxicity and panel reactive antibody were determined in 9 cases of cardiac transplantation, and the donor's and receptor's matching degree evaluated by methods of amino acid triplets and cross-reactive group. Results Of 9 cases, 6 survived while 3 died. Of the 3 dead cases, 2 came respectively from the two best comprehensively evaluated matching cases and two worst, and postoperative biopsy showed that there was no rejection in either survival cases or the dead cases. Conclusion With the effective immunosuppressant, the HLA typing doesn't affect the early survival.

Two-Year Study on the HLA Typing Proficiency Survey in Korea, 1996-1998 / 대한임상병리학회지

BACKGROUND: To standardize the histocompatibility testing among different laboratories, we have developed and performed a proficiency survey (external quality control) program in HLA typing with participation of nationwide HLA laboratories in Korea. METHODS: During a two-year period, four trials of proficiency survey were performed with 35-39 participating laboratories. Test number and items included in each survey were 3 HLA class Iantigen typings, 2 class II DNA typings, and 6 HLA crossmatch tests (3 cells x 2 sera). RESULTS: HLA class I serological typing was performed on a total of 12 whole blood specimens representing 7 HLA-A and 17 HLA-B antigens. More than 90% of the laboratories correctly identified 7 HLA-A (A2, A3, A11, A24, A26, A30, A33) and 13 HLA-B antigens (B7, B8, B13, B14, B27, B35, B48, B51, B52, B54, B58, B60, B61). Lower consensus (<90%) was obtained for B62, B67, B75, and B15 (B*1511). Considerable difference in antigen detection rate was observed between different commercial trays used. HLA class II DNA typing was performed on a total of 8 DNA specimens representing 13 HLA-DRB1 and 11 DQB1 alleles. For HLA-DRB1 typing (16-26 laboratories), correct assignment rate was very high (98%) for generic level, but lower (80%) for allele level. For DQB1 typing (5-8 laboratories), 100% consensus was obtained for allelic level. With respect to HLA crossmatching, detection rate of incompatibility was very low in the 1st trial. HLA crossmatch workshop on the standardization of typing methods was performed after the 1st trial, and thereafter the number of laboratories using sensitive methods were increased and the detection rate of incompatible crossmatch was much improved (1st 29-46%, 2nd 78-97%). CONCLUSIONS: Through these HLA typing proficiency surveys, standardization of test methods and improvement of typing results were obtained. A continuous survey program would play an important role for improving success rate of organ transplantations in Korea.

Clinical use of cross reactive groups matching in highly sensitized recipients of kidney recipients / 中华器官移植杂志

Objective To investigate the clinical significance of cross reactive groups (CREG) matching in highly sensitized recipients of kidney recipients by testing their serum PRA levels and specificity.Methods The dynamic PRA levels and the specificity were determined. CREG matching was used to select the best donors. Results The preoperative PRA levels in 60 kidney recipients heightened simply or mixedly. Acccording to CREG matching with 0 to 1 MM, 2 MM and 3 to 4 MM, the average recovery time of postoperative creatinine was 6.5 , 7.0 and 12.7 days respectively and the number of the patients with delayed graft function was 0, 7 and 3 respectively.Conclusion There was a great applied value to raise survival rate of patients or allografts for highly sensitized recipients of kidney recipients by CREG matching, to select donors with compatible HLA phenotype or more compatible, to shun the specific antigen of pre existing HLA antibody in recipients and to strictly prohibit HLA repeat mismatches for those retransplantation recipients.