The immunogenetics of multiple sclerosis. The frequency of HLA-alleles class 1 and 2 is lower in Southern Brazil than in the European population / Imunogenética na esclerose múltipla. A frequência dos alelos HLA classe 1 e 2 no sul do Brasil são menores que da população Europeia

ABSTRACT Objective To study the HLA of class 1and 2 in a multiple sclerosis (MS) population to verify the susceptibility for the disease in the Southern Brazil. Methods We analyzed patients with MS and controls, by direct sequencing of the genes related to HLA DRB1, DQB1, DPB1, A, B and C alleles with high resolution techniques. Results We found a lower frequency of all HLA alleles class 1 and 2 in MS and controls comparing to the European population. Several alleles had statistical correlation, but after Bonferroni correction, the only allele with significance was the HLA-DQB1*02:03, which has a positive association with MS. Conclusions Our data have different frequency of HLA-alleles than the previous published papers in the Southeast Brazil and European population, possible due to several ethnic backgrounds.

RESUMO Objetivo Estudo do HLA classes 1 e 2 em pacientes com esclerose múltipla (EM) a fim de verificar a susceptibilidade para a doença em uma população do Sul do Brasil. Métodos Foram analisados por sequenciamento direto de alta resolução os genes relacionados com os HLA DRB1, DQB1, DPB1, A, B e C em casos de EM comparados com uma população controle normal. Resultados Foi encontrado uma frequência menor dos alelos dos HLA classe 1 e 2 nos casos de EM e controles quando comparado com a população Europeia. Diversos alelos mostraram correlação estatística, mas depois da correção de Bonferroni, somente o alelo do HLA-DQB1*02:03 foi positivo para a EM. Conclusões Encontramos frequência diferente dos alelos do HLA relatados previamente nos Sudeste do Brasil e Europeus, possivelmente devido a origem étnica diferente da população estuda.

Lack of association between alopecia areata and HLA class I and II in a southeastern Brazilian population

Abstract: Background: Alopecia areata (AA) is a common disorder of unknown etiology that affects approximately 0.7% to 3.8% of patients among the general population. Currently, genetic and autoimmune factors are emphasized as etiopathogenic. Studies linking Human Leukocyte Antigens (HLA) to AA have suggested that immunogenetic factors may play a role in the disease's onset/development. Objectives: To investigate an association between AA and HLA class I/II in white Brazilians. Methods: Patients and control groups comprised 33 and 112 individuals, respectively. DNA extraction was performed by column method with BioPur kit. Allele's classification was undertaken using the PCR-SSO technique. HLA frequencies were obtained through direct counting and subjected to comparison by means of the chi-square test. Results: Most patients were aged over 16, with no familial history, and developed partial AA, with no recurrent episodes. Patients showed a higher frequency of HLA-B*40, HLA-B*45, HLA-B*53 and HLA-C*04 compared with controls, although P was not significant after Bonferroni correction. Regarding HLA class II, only HLA-DRB1*07 revealed statistical significance; nevertheless, it featured more prominently in controls than patients (P=0.04; Pc=0.52; OR=0.29; 95%; CI=0.07 to 1.25). P was not significant after Bonferroni correction. Conclusions: The development of AA does not seem to be associated with HLA in white Brazilians, nor with susceptibility or resistance. The studies were carried out in populations with little or no miscegenation, unlike the Brazilian population in general, which could explain the inconsistency found.

Functional disruption of human leukocyte antigen II in human embryonic stem cell

BACKGROUND: Theoretically human embryonic stem cells (hESCs) have the capacity to self-renew and differentiate into all human cell types. Therefore, the greatest promise of hESCs-based therapy is to replace the damaged tissues of patients suffering from traumatic or degenerative diseases by the exact same type of cells derived from hESCs. Allo-graft immune rejection is one of the obstacles for hESCs-based clinical applications. Human leukocyte antigen (HLA) II leads to CD4+ T cells-mediated allograft rejection. Hence, we focus on optimizing hESCs for clinic application through gene modification. RESULTS: Transcription activator-like effector nucleases (TALENs) were used to target MHC class II transactivator (CIITA) in hESCs efficiently. CIITA(-/-)hESCs did not show any difference in the differentiation potential and self-renewal capacity. Dendritic cells (DCs) derived from CIITA(-/-)hESCs expressed CD83 and CD86 but without the constitutive HLA II. Fibroblasts derived from CIITA(-/-)hESCs were powerless in IFN-γ inducible expression of HLA II. CONCLUSION: We generated HLA II defected hESCs via deleting CIITA, a master regulator of constitutive and IFN-γ inducible expression of HLA II genes. CIITA(-/-)hESCs can differentiate into tissue cells with non-HLA II expression. It's promising that CIITA(-/-)hESCs-derived cells could be used in cell therapy (e.g., T cells and DCs) and escape the attack of receptors' CD4+ T cells, which are the main effector cells of cellular immunity in allograft.

Identification of differentially expressed genes in gauze-exposed omentum of dogs using differential display RT-PCR

Molecular mechanisms governing peritonitis caused by the presence of aseptic gauze have remained unclear. To identify the genes involved, sterile gauze-exposed omentum was collected at 0, 6, 12, 24, and 48 h intervals, and analyzed by differential display RT(reverse transcription)-PCR. Among over 1,200 bands, 230 bands were found differentially expressed. These bands represented the fragment sizes of approximately 200 to 1,500 bp. The eight fragments were expressed differentially in the treatment group but not in the control. The sequences of two bands were similar to those of genes associated with the inflammatory process and a band was related to repair and regeneration process. Another one was related with spermatogonia and the rest four were unknown. Additionally, amplicons corresponding to the full-length sequences of two inflammatory gene fragments were synthesized by rapid amplification of cDNA end PCR. One showed 99% similarity to the major histocompatibility complex class II dog leukocyte antigen-DR beta chain and the other was canis familiaris proteasome beta type 3. Results of the present study suggested that sterile gauze induced the differential expression of genes in the omentum involved in inflammation and healing process.

HLA among Brazilian patients with spontaneous chronic urticaria and positive autologous serum skin test / HLA em brasileiros com urticária crônica espontânea e teste cutâneo do soro autólogo positivo

BACKGROUND: An association between class I and II alleles of the major histocompatibility complex and idiopathic chronic urticaria has previously been observed in different populations, but there are still no studies on Brazilian populations in this regard. OBJECTIVE: The involvement of the major histocompatibility complex classes I and II (loci A, B and DR) in Brazilian patients with idiopathic chronic urticaria and a positive autologous serum skin test was investigated and compared with a healthy population group. METHODS: DNA was extracted from the blood of 42 patients with idiopathic chronic urticaria and major histocompatibility complex classes I and II alleles were determined using the polymerase chain reaction and a laboratory test for oligonucleotide hybridization using a single-filament probe. The frequencies of these alleles in patients with chronic urticaria were compared with the frequencies in 1000 genetically unrelated voluntary blood donors from the same region of Brazil. The diagnosis of idiopathic chronic urticaria was based on the patients' clinical history and routine laboratory tests. Only the patients with positive autologous serum skin test were selected. The allele distribution resulted from the patient and control groups were analyzed using odds ratios and 95% confidence intervals. RESULTS: No statistically significant differences were found between the positive autologous serum skin test patients with chronic urticaria and the control group. CONCLUSIONS: We found that in this population group, there was no specific association between the HLA alleles studied and chronic urticaria. We believe that further population studies are needed in order to investigate the possible existence of this association.

FUNDAMENTOS: A associação entre os alelos do MHC classe I e II e a urticária crônica idiopática tem sido previamente constatada em diferentes populações, sendo que na população brasileira ainda não existem estudos a este respeito. OBJETIVOS: Foi estudado o envolvimento do MHC classe I e II (locci A, B e DR) em pacientes brasileiros com urticária crônica idiopática e teste cutâneo do soro autólogo positivo, comparando-se com um grupo populacional saudável. MÉTODOS: O DNA foi extraído do sangue de 42 pacientes com urticária crônica idiopática e o MHC classe I e II determinado por reação em cadeia da polimerase e teste laboratorial de hibridização de oligonucleotídeo com sonda de filamento único. A freqüência destes alelos em pacientes com urticária crônica idiopática foi comparada com a de 1000 doadores de sangue voluntários e geneticamente não relacionados, da mesma região do Brasil. O diagnóstico de urticária crônica idiopática foi baseado na história clínica do paciente e exames laboratoriais de rotina; foram selecionados apenas os pacientes com teste cutâneo do soro autólogo positivo. O resultado da distribuição alélica entre o grupo de pacientes e o grupo controle foi analisado através do odds rate com o cálculo do intervalo de confiança de 95% (95% IC). RESULTADOS: Não foram encontradas diferenças com significância estatística entre os pacientes com urticária crônica teste cutâneo do soro autólogo positivos e o grupo controle. CONCLUSÕES: Verificamos que neste grupo populacional estudado não houve associação específica entre os alelos HLA estudados e a urticária crônica; acreditamos na necessidade de outros estudos populacionais, para podermos verificar a possível existência desta associação.

Molecular analysis of human leukocyte antigen class I and class II allele frequencies and haplotype distribution in Pakistani population.

AIM: Distribution of HLA class I and II alleles and haplotype was studied in Pakistani population and compared with the data reported for Caucasoid, Africans, Orientals and Arab populations. MATERIALS AND METHODS: HLA class I and II polymorphisms in 1000 unrelated Pakistani individuals was studied using sequence-specific primers and polymerase chain reaction and assay. RESULTS: The most frequent class I alleles observed were A*02, B*35 and CW*07, with frequencies of 19.2, 13.7 and 20%, respectively. Fifteen distinct HLA-DRB1 alleles and eight HLA-DQB1 alleles were recognized. The most frequently observed DRB1 alleles which represented more than 60% of the subjects were DRB1 *03, *07, *11 and *15. The rare DRB1 alleles detected in this study were HLADRB1 *08 and *09, having frequencies of 0.9 and 1.7%, respectively. In addition, at DRB1-DQB1 loci there were 179 different haplotypes and 285 unique genotypes and the most common haplotype was DRB1*15-DQB1*06 which represented 17% of the total DRB1-DQB1 haplotypes. In our population, haplotype A*33-B*58-Cw*03 comprised 2.8% of the total class I haplotypes observed. This haplotype was seen only in the oriental populations and has not been reported in the African or European Caucasoid. CONCLUSION: Our study showed a close similarity of HLA class I and II alleles with that of European Caucasoid and Orientals. In Pakistani population, two rare loci and three haplotypes were identified, whereas haplotypes characteristic of Caucasians, Africans and Orientals were also found, suggesting an admixture of different races due to migration to and from this region.

Correlation between histocompatibility antigens and recurrent aphthous stomatitis in the brazilian population / Estudo da associação entre antígenos de histocompatibilidade e estomatite aftoide recorrente em população brasileira

Recurrent aphthous stomatitis is a common oral mucosa disorder that affects 20 percent of the world's population, characterized by recurring painful ulcers in the mouth. The diagnosis is primarily based on the patient's clinical history. Inheritance may pose as a risk factor for the disease; however, the studies available are inconclusive as to the results attained, and they vary according to the population studied. AIM: to typify class I and class II HLA molecules and to assess how frequent these molecules are present in the Brazilian population with Recurrent Aphthous Stomatitis, compared to healthy controls. MATERIALS AND METHODS: In this prospective, cross-sectional and investigative study, thirty one patients with diagnostic hypothesis of recurrent aphthous stomatitis were seen from February of 2004 to May of 2006. We obtained the DNA from those patients who matched the inclusion criteria and typified their HLA by PCR. RESULTS: In those patients with Recurrent Minor Aphthous Stomatitis we found statistically significant occurrences of HLA-A33 and HLA-B35. CONCLUSION: HLA-A33 and HLA-B35 may be associated with recurrent minor aphthous stomatitis in the Brazilian's population.

A Estomatite Aftoide Recorrente é uma doença oral com incidência em 20 por cento da população mundial, caracterizada por úlceras mucosas de caráter recidivante. O diagnóstico baseiase principalmente na história clínica do paciente. Hereditariedade pode ser um fator de risco para doença, entretanto, os estudos disponíveis não são conclusivos quanto aos resultados obtidos, variando segundo a população estudada. OBJETIVO: Tipificar moléculas HLA de classe I e de classe II e avaliar a frequência destas moléculas em pacientes brasileiros, portadores de Estomatite Aftoide Recorrente, comparando com grupo controle. MATERIAL E MÉTODO: Este trabalho possui um desenho prospectivo, transverso e investigativo. Foram estudados 31 pacientes com suspeita diagnóstica de Estomatite Aftoide Recorrente no período de fevereiro de 2004 a maio de 2006. Os pacientes foram submetidos a protocolo de exames e, daqueles que obedeceram aos critérios de inclusão, foi extraído o DNA e realizada a tipificação HLA por Reação de Polimerização em Cadeia. RESULTADO: Nos pacientes portadores de Estomatite Aftoide Recorrente do tipo minor encontramos as frequências HLA A33 e B35 estatisticamente significantes. CONCLUSÃO: As frequências HLA-A33 e HLA-B35 podem estar associadas à Estomatite Aftoide Recorrente minor na população brasileira.

Association study between the -62A/T NFKBIL1 polymorphism and obsessive-compulsive disorder / Estudo de associação entre o polimorfismo -62A/T NFKBIL1 e o transtorno obsessivo-compulsivo

OBJECTIVE: Evidence from family and molecular genetic studies support the hypothesis of involvement of immunologic mechanisms in the pathophysiology of obsessive-compulsive disorder. The nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-like 1 (NFKBIL1) has been suggested as a modulator of the immunological system. Given the importance of NFKBIL1 in the immunological response, the present study investigated the -62A/T polymorphism (rs2071592), located in the promoter region of its gene (NFKBIL1), as a genetic risk factor for the development of obsessive-compulsive disorder. METHOD: The -62A/T NFKBIL1 polymorphism was investigated in a sample of 111 patients who met DSM-IV criteria for obsessive-compulsive disorder and 272 healthy age- and gender-matched controls. RESULTS: There were no differences in genotypic distributions between patients and controls (χ2 = 0.98; 2 d.f.; p = 0.61). DISCUSSION: Despite these negative findings, more comprehensive polymorphism coverage within the NFKBIL1 is warranted in larger samples. Populations with different ethnic backgrounds should also be studied. CONCLUSION: The results of the present investigation do not provide evidence for the association between the -62A/T NFKBIL1 polymorphism and obsessive-compulsive disorder in this Brazilian sample.

OBJETIVO: Evidências advindas de estudos de família e de genética molecular têm dado suporte à hipótese do envolvimento de mecanismos imunológicos na fisiopatologia do transtorno obsessivo-compulsivo. Tem sido sugerido que o potencializador do fator nuclear do polipeptídeo kappa light em células-B inibidoras-like 1 (NFKBIL1) é um modulador do sistema imunológico. Dada a importância do NFKBIL1 na resposta imunológica, o presente estudo investigou o polimorfismo -62A/T (rs2071592), localizado na região promotora de seu gene, como fator de risco genético para o desenvolvimento do transtorno obsessivo-compulsivo. MÉTODO: O polimorfismo -62A/T do gene do NFKBIL1 foi investigado em uma amostra de 111 pacientes com o diagnóstico de transtorno obsessivo-compulsivo, de acordo com os critérios do DSM-IV, e 272 controles saudáveis emparelhados por idade e gênero. RESULTADOS: Não houve diferenças na distribuição genotípica entre pacientes e controles (χ2 = 0,98; 2 d.f.; p = 0,61). DISCUSSÃO: Apesar dos resultados negativos, estudos compreendendo mais polimorfismos no gene do NFKBIL, em amostras maiores, são necessários. Populações com diferentes origens étnicas também precisam ser avaliadas. CONCLUSÃO: Os resultados da presente investigação não evidenciam associação entre o polimorfismo -62A/T do gene do NFKBIL1 e o transtorno obsessivo-compulsivo nesta amostra brasileira.

Association of Cytotoxic T Lymphocyte Antigen-4 Gene Polymorphisms and HLA Class II Alleles with the Development of Type 1 Diabetes in Korean Children and Adolescents

We studied the association of cytotoxic T lymphocyte antigen-4 gene (CTLA4) polymorphisms with the development of type 1 diabetes (T1D) in Korean children and adolescents. A total of 176 Korean subjects (92 females and 84 males) with childhood-onset T1D were studied. The A/G polymorphism at position 49 in CTLA4 exon 1 and the C/T polymorphism at position -318 in the CTLA4 promoter were analyzed by PCR-RFLP methods. The genotype and allele frequencies of the CTLA4 polymorphisms in the T1D patients were not different from those in the controls. These polymorphisms were not associated with the clinical characteristics or the development of autoimmune thyroid disease in the T1D patients. The frequency of the A allele was significantly higher in the patients that did not have two out of the three susceptible HLA-DRB1 alleles, which were DRB1*0301, *0405 and *09012, compared to the controls (P<0.05). These results suggest that CTLA4 polymorphisms do not directly confer any susceptibility to T1D. However, a CTLA4-mediated susceptibility effect on the development of T1D might be significant in children and adolescents that do not have susceptible HLA class II alleles.

HLA profile in patients with AIDS and tuberculosis

Studies carried out in various populations have reported an association between some HLA specificities and susceptibility to tuberculosis. We investigated the class I and class II HLA profile in Brazilian patients of various ethnic backgrounds who had AIDS and tuberculosis. Twenty-two adult patients with AIDS and tuberculosis (Group I), 103 patients with AIDS without tuberculosis (Group II) and 423 healthy individuals not infected with HIV (Group III) were evaluated. Diagnosis of HIV infection was made by ELISA, confirmed by a gelatin particle agglutination test. Diagnosis of tuberculosis was made based on clinical/radiological presentation and direct bacilloscopy or clinical specimen cultures. Class I antigens were typed by microlymphotoxicity. Class II alleles were characterized by the polymerase chain reaction (PCR). Differences in frequency of HLA specificities between groups were found in the following antigens/alleles: Group I x Group II: HLA-A31 - p=0.026; HLA-B41 - p= 0.037; HLA-DRB1*10 - p=0.037; HLA-DQB1*5 - p=0.009. Group I x Group III (control): HLA-A31 - p = 0.000008; odds ratio (OR)=31.75; HLA-B41 - p=0.003; HLA-DQB1*5 - p=0.02. HLA-A31 and HLA-B41 antigens and the HLA-DRB1*10 and HLA-DQB1*05 alleles were over-represented in patients with AIDS and tuberculosis (Group I), suggesting that these HLA molecules are associated with susceptibility to tuberculosis in Brazilian patients with AIDS.

Major histocompatibility complex class II polymorphisms and risk of cervical cancer in Puerto Rican women

Association between HLA antigens and cervical squamous cell carcinoma has been described in several populations. To verify whether HLA-DRB1 and DQB1 diversity is related to cervical cancer in Puerto Rican women, 40 cases and 50 controls were HLA typed. DRB1*16 (POR=2.89) and DRB1*11 (POR=1.74) were positively associated with cervical cancer. A negative association was found with DRB1*01 (POR=0.52), DRB1*04 (POR=0.60), DRB1*14 (POR=0.33), DRB1*15 (POR=0.65), DQB1*04 (POR=0.33), DQB1*05 (POR=0.64) and DQB1*06 (POR=0.65). We suggest that HLA Class H polymorphisms are involved in genetic susceptibility to cervical cancer in Puerto Rican women. These results should be confirmed in studies with larger sample size to preclude the possibility of false positive observations.

Association between HLA class II alleles and autoimmune hepatitis type 1 in Thai patients.

OBJECTIVE: To investigate the association between HLA class II alleles and autoimmune hepatitis (AIH) type I in Thai patients. MATERIAL AND METHOD: The clinical data of 50 autoimmune hepatitis patients type I (AIH) at Siriraj hepatitis clinic were analysed, 37 of whom were tested for HLA class II genotyping using polymerase chain reaction and sequence-specific oligonucleotide technique (PCR-SSO). RESULTS: AIH is an uncommon chronic hepatitis in Thailand with females predominant. The HLA DRB1*0301, and DQA1*0101 were significantly associated with AIH patients when compared to controls; (OR = 3.92 [1.18-13.30], p 0.021, OR = 2.31 [1.13-4.73], p 0.019, respectively). When 18 patients with "definite" AIH were analysed, only HLA DRB1*0301 was still significantly associated with AIH (OR = 5.22, 95%CI = 1.28-20.92, p 0.015). CONCLUSION: HLA genotyping has shown that HLA DRB1*0301 and HLA DQA1*0101 were significantly associated with AIH.

Distribuição e freqüência de alelos e haplotipos HLA em brasileiros com diabetes melito tipo 1 / Distribution and frequency of HLA alleles and haplotypes in brazilians with type 1 diabetes mellitus

A predisposição genética ao diabetes melito tipo 1 (DM1) é associada a múltiplos genes do sistema de histocompatibilidade humano (HLA) de classe II. Em caucasianos, os antígenos HLA-DR3 e -DR4 são associados à susceptibilidade e o -DR2, à proteção. No Brasil, um país constituído por grande miscigenação entre caucasianos europeus, índios nativos e negros africanos, a base genética do DM1 tem sido pouco estudada. O objetivo desse trabalho foi apresentar uma revisão crítica dos artigos indexados nos bancos de dados MEDLINE e LILACS-BIREME sobre a associação do HLA com DM1 em brasileiros. Todos os oito estudos encontrados foram realizados no sudeste do país. A susceptibilidade imunogenética para o DM1 em brasileiros foi associada com os alelos HLA-DRB1*03, -DRB1*04, -DQB1*0201, -DQB1*0302 e a proteção com os alelos -DQB1*0602 e -DQB1*0301 e os antígenos -DR2 e -DR7. Por ser o Brasil constituído por grande miscigenação, não se pode extrapolar para todo o país estudos realizados em apenas uma região. Faz-se necessário pesquisar populações de várias regiões, analisando sua diversidade alélica para identificar novas associações ou reforçar aquelas já existentes. Esse conhecimento contribuirá para futuras intervenções profiláticas e terapêuticas nos grupos de brasileiros com maior risco de desenvolver DM1.

Ovar-Mhc - ovine major histocompatibility complex: structure and gene polymorphisms

The major histocompatibility complex (MHC) in sheep, Ovar-Mhc, is poorly characterised, when compared to other domestic animals. However, its basic structure is similar to that of other mammals, comprising class I, II and III regions. Currently, there is evidence for the existence of four class I loci. The class II region is better characterised, with evidence of one DRA, four DRB (one coding and three non-coding), one DQA1, two DQA2, and one each of the DQB1, DQB2, DNA, DOB, DYA, DYB, DMA, and DMB genes in the region. The class III region is the least characterised, with the known presence of complement cascade (C4, C2 and Bf), TNFalpha and CYP21 genes. Products of the class I and II genes, MHC molecules, play a pivotal role in antigen presentation required for eliciting immune responses against invading pathogens. Several studies have focused on polymorphisms of Ovar-Mhc genes and their association with disease resistance. However, more research emphasis is needed on characterising the remaining Ovar-Mhc genes and developing simplified and cost-effective methods to score gene polymorphisms. Haplotype screening, employing multiple markers rather than single genes, would be more meaningful in MHC-disease association studies, as it is well known that most of the MHC loci are tightly linked, exhibiting very little recombination. This review summarises the current knowledge of the structure of Ovar-Mhc and polymorphisms of genes located in the complex.

Association of BoLA-DRB3.2 alleles with tick (Boophilus microplus) resistance in cattle

Losses caused by bovine tick burdens in tropical countries have a tremendous economic impact on production systems. Besides reducing production, this parasite can cause death in the most susceptible animals. The use of commercial acaricides has been the major method of control, but their misuse has led to tick resistance to many chemicals. More recently, vaccines have been used in some countries without solving the problem completely. An alternative could be the development of resistant animals and the use of genetic markers and candidate genes that could help with the enormous task of selecting resistant animals. The bovine lymphocyte antigen genes (BoLA) have been shown to be associated with some parasitic infestations and disease incidence. Thus, the objective of the present study was to determine the association of BoLA-DRB3.2 alleles with tick resistance in cattle. The study was conducted on 231 F2 (Gyr x Holstein) animals that were artificially infested with 10,000 tick larvae. Log of tick count +1 was used as the dependent variable in a mixed animal model with allele substitution effects in addition to fixed effects of year and season at tick count, sex of calves, age of animal at tick count, hair type (short-straight, short-curl, long-straight, and long-curl), coat color (white, >75% white, 50- 75% white, and 25-50% white), and additive genetic, permanent environmental and residual effects as random. Females showed fewer ticks than males. Animals with short-straight hair were more resistant to tick infestation than animals with long-curl hair, and animals with whiter coat color also had fewer ticks. An association between BoLA alleles and lower tick number was found for alleles DRB3.2 *18, *20 and *27 at the 5% significance level. Also, one allele (DRB3.2*16) showed an association at the 10% level. Allele *27 was the most frequent in the population (30.7%), followed by alleles *16 (10.8%), *20 (8.7%) and *18 (2.4%)...

Delayed allograft rejection by the suppression of class II transactivator

We examined the effect of class II transactivator (CIITA) down-modulation on allograft rejection. To inhibit the function of CIITA, we constructed a series of CIITA mutants and found one exhibiting the dominant-negative effect on the regulation of major histocompatibility complex (MHC) class II expression. To test whether the CIITA dominant-negative mutant reduces immunogenecity, CIITA-transfected melanoma cells were injected into allogeneic host and assessed for immune evading activity against host immune cells. We demonstrated that the CIITA dominant-negative mutant allowed tumor nodules to develop earlier in the lung than control by this tumor challenge study. Furthermore, skin grafts deficient for CIITA also survived longer than wild-type in allogeneic hosts. Both the tumor challenge and skin graft studies suggest the inhibition of CIITA molecules in donor tissue would be beneficial to the control of allo-response.

Estudo de associação entre antígenos leucocitários humanos e doença de Jorge Lobo / Study of the association between human leukocyte antigens and Jorge Lobo's disease

A doença de Jorge Lobo é uma micose cutânea/subcutânea de evolução crônica, causada pelo fungo Lacazia loboi. Devido às características epidemiológicas e poucos estudos relacionados aos aspectos imunológicos dessa doença, o objetivo do trabalho foi investigar uma possível associação das especificidades HLA de classe II em 21 pacientes portadores da doença de Jorge Lobo, comparando com indivíduos sadios de mesma etnia. As tipificações HLA foram realizadas pelo método de PCR-SSP. O resultado não revelou qualquer tipo de associação entre os antígenos HLA e doença de Jorge Lobo. Embora sem significância estatística, foi observada a diminuição da freqüência do antígeno HLA-DR7 no grupo dos pacientes em relação aos controles (0 por cento x 18 por cento), sugerindo uma associação negativa (protetora) entre HLA-DR7 e doença de Jorge Lobo. Contudo, estudos devem ser continuados, objetivando melhor entendimento nos mecanismos envolvidos na suscetibilidade e/ou proteção dessa doença.

HLA class II (DRB1, DQA1 and DQB1) allele and haplotype frequencies among HIV-infection discordant Thai couples.

We investigated the association of HLA-DRB1, -DQA1 and -DQB1 alleles and haplotypes in 33 Thai HIV discordant couples. A significantly lower frequencies of DRB1*14 (3.0% vs 11.3%, p = 0.048) and DQA1*0103 (0.0% vs 5.63%, p = 0.042) alleles were found in the seropositive individuals when compared with HIV-negative controls. In contrast, there was no significant difference in HLA-DQB1* allele frequencies. The haplotype analysis revealed that DRB1*1501-DQA1*0102-DQB1*0601 (7.6% vs 0.0%, p = 0.002), DRB1*0405-DQA1*0302-DQB1*0401 (7.6% vs 1.3%, p = 0.024) and DRB1*1401-DQA1*0104-DQB1*05031 (6.1% vs 0.0%, p = 0.007) were found to be significantly higher frequencies when compared between HIV seronegative partners and HIV negative controls, but DRB1*1501-DQA1*0102-DQB1*0502 (0.0% vs 8.1%, p = 0.01) was significantly lower. The DRB1*1602-DQA1*0101-DQB1*0502 (4.6% vs 0.0%, p = 0.024) haplotype was found to be significantly higher frequencies in HIV seropositive individuals when compared to HIV negative controls but the DRB1*1502-DQA1*0101-DQB1*0501 (1.5% vs 8.1%, p = 0.049) haplotype was lower.

Is There Any Relationship Between Human Leucocyte Antigen Class II and Chronic Urticaria? (Chronic Urticaria and HLA Class II)

Human Leukocyte Antigen (HLA) typing of large groups of patients with various autoimmune diseases has demonstrated that some HLA alleles occur at higher frequencies in specific diseases than in the general population. Chronic urticaria has been shown to have an autoimmune basis by a previous study which found an association between chronic urticaria and specific HLA groups. We investigated the HLA subtypes of Turkish chronic urticaria patients. For this purpose 42 Turkish patients with chronic urticaria and 115 healthy controls were typed for HLA-DR and DQ by PCR-SSP (Polymerase Chain Reaction Sequence Specific Primers) low resolution DNA technique. We found an increased frequency of DR4 (42.9%, p=0.01) in chronic urticaria patients in comparison with that in healthy controls. This study supports the hypothesis that HLA alleles may be involved in the pathogenesis of chronic urticaria and that they appear to be directly involved in the initiation of the immune response.

HLA class II genotyping in chronic hepatitis B infection.

OBJECTIVES: To analyze the role of HLA genotypes in persistence of chronic hepatitis B in Western India. METHODS: HLA genotyping for class II-DR was done in 26 subjects having chronic hepatitis B infection (HBsAg positive) and in 100 healthy controls. Statistics were done using Halden's modification of Woolf's formula. RESULT: Significant association of chronic hepatitis B infection was found for class II-DR antigens DRB1*15XX (57.6 vs. 25%) and DRB1*11XX (23 vs. 4%). DRB1*13XX (0 vs. 19%) was negatively associated with chronic hepatitis B infection. CONCLUSION: HLA phenotype, which varies with different regions, is one of the factors in persistence of hepatitis B infection. Our study supports negative association of DRB1*13XX to persistence of HBV. Also there may be role of DRB1*11XX and DRB1*15XX in persistence of HBV and development of chronic HBV hepatitis.