Proteínas de checkpoint imunológico como novo alvo da imunoterapia contra o câncer: revisão da literatura / Immune checkpoint proteins as new target for cancer immunotherapy: literature review

Uma nova era no tratamento do câncer está surgindo com o uso de anticorpos capazes de inibir pontos de bloqueio do sistema imunológico, chamados de "inibidores de checkpoint". Um novo conceito de "balas mágicas", que no início do século passado foram imaginadas por Paul Ehrlich como capazes de atuar diretamente na destruição de alvos tumorais, é representado agora por anticorpos direcionadas contra moléculas que bloqueiam a atividade antitumoral do sistema imunológico, como o antígeno-4 de linfócito T citotóxico (CTLA-4) e a proteína-1 de morte celular programada (PD-1). Essas novas imunoterapias vêm revolucionando a forma de tratar diferentes tipos de câncer. Nesta revisão selecionamos estudos sobre CTLA-4 e PD-1, seus ligantes em células apresentadoras de antígenos, assim como destacamos a importância da descoberta de antígenos tumorais e o papel do sistema imunológico na imunovigilância tumoral. Nesse estudo são discutidos aspectos relacionados aos efeitos de imunoterapias baseadas no uso de anticorpos monoclonais anti-CTLA-4 e anti-PD-1/ PD-L1, como o risco de serem estimuladas respostas direcionadas a tecidos saudáveis e outros efeitos adversos, bem como o uso de terapias combinadas que podem contribuir para melhorar a eficiência do tratamento do câncer.

A new era in cancer treatment is emerging with the use of antibodies directed against immune checkpoint proteins, known as "checkpoint inhibitors". A novel concept of "magic bullets", concepted by Paul Ehrlich at the beginning of the last century, as being capable of acting directly on the destruction of tumor targets, is now represented by antibodies directed against molecules which block the antitumor activity of the immune system, such as Cytotoxic T Lymphocyte Antigen-4 (CTLA-4) and Programmed Cell Death Protein-1 (PD-1). These new immunotherapies have revolutionized the treatment of different cancer types. Studies on CTLA-4, PD-1, and their ligands in antigen presenting cells are discussed in this review. The importance of tumor antigen discovery and the role of the immune system in immune surveillance of tumors were highlighted. Also in the present study, aspects related to the effects of immunotherapies based on the use of anti-CTLA-4 and anti-PD-1/ PD-L1 monoclonal antibodies are described, such as the risk of stimulating responses to normal tissues and other adverse effects, as well as the use of combination therapies which can improve the efficacy of cancer treatment.

Results of Questionnaire Survey of Current Immune Monitoring Practice of Transplant Clinicians and Clinical Pathologists in Korea: Basis for Establishment of Harmonized Immune Monitoring Guidelines / 대한이식학회지

Detection of significant alloimmune response, which affects graft function and survival by effective immune monitoring, is critical for treatment decision making. However, there is no consensus regarding immune monitoring (IM) for kidney transplantation (flow KT) in Korea. The IM protocol may be affected by the level of immunological risk, the methods of desensitization and the availabilities of resources such as laboratory support and cost of tests. Questionnaire surveys designed to identify the current practices regarding immune monitoring of KT among transplant clinicians and clinical pathologists in Korea and eventually provide a basis for the establishment of harmonized immune monitoring guidelines in KT were administered as part of a Korean Society for Transplantation Sponsored Research Project. The survey results revealed significant variations in IM protocols and interpretation of tests affecting treatment decisions between institutes. Moreover, the results revealed a need to expand the histocompatibility tests into high resolution HLA typing in multiple loci and non-HLA antibody tests that facilitate the epitope analysis and eventually virtual crossmatching. The results of the questionnaire survey from clinical pathologists are addressing the urgent need for the standardization of interpretation and harmonization of results reporting in single antigen bead based HLA antibody identification. Finally, communication between clinicians and clinical pathologists to meet the clinical expectations regarding various immune monitoring tests is needed.

Polyclonal anti T-lymphocyte antibody therapy monitoring in kidney transplant recipients: comparison of CD3+ T cell and total lymphocyte counts / Monitoramento da terapia com anticorpo policlonal antilinfócitos T em transplantados renais: comparação da contagem de células T CD3+ e de linfócitos totais

ABSTRACT Objective: To investigate the correlation between total lymphocyte and CD3+ T cell counts in peripheral blood in renal transplant patients treated with anti-thymocyte globulin, and discuss related outcomes. Methods: A single-center, retrospective study involving 226 patients submitted to kidney transplant between 2008 and 2013, and treated with anti-thymocyte globulin for induction or treatment of cellular rejection. Doses were adjusted according to CD3+ T cell or total lymphocyte counts in peripheral blood. Results: A total of 664 paired samples were analyzed. The Spearman's correlation coefficient was 0.416 (p<0.001) for all samples combined; the overall Kappa coefficient was 0.267 (p<0.001). Diagnostic parameters estimated based on total lymphocyte counts were also calculated using the number of CD3+ T cells (gold standard), with a cut off of >20 cells/mm3. Conclusion: Total lymphocyte and CD3+ T cell counts in peripheral blood are not equivalent monitoring strategies in anti-thymocyte globulin therapy.

RESUMO Objetivo: Investigar a correlação entre a contagem de linfócitos totais e células T CD3+ no sangue periférico em receptores de transplante renal submetidos a tratamento com globulina antitimocitária, e discutir resultados relacionados. Métodos: Estudo retrospectivo de centro único envolvendo 226 pacientes submetidos a transplante renal entre 2008 e 2013 e tratados com globulina antitimocitária, para fins de indução ou tratamento de rejeição celular. As doses foram ajustadas de acordo com a contagem de células T CD3+ ou linfócitos totais no sangue periférico. Resultados: No total, 664 amostras pareadas foram analisadas. O coeficiente de correlação de Spearman para as amostras em geral foi de 0,416 (p<0,001) e o coeficiente Kappa, de 0,267 (p<0,001). Os parâmetros diagnósticos estimados com base na contagem de linfócitos totais foram recalculados, empregando-se o número de células T CD3+ (padrão-ouro) e adotando-se o ponto de corte >20 células/mm3. Conclusão: A contagem de linfócitos totais no sangue periférico não substitui a contagem de células T CD3+ enquanto estratégia de monitorização da terapia à base de globulina antitimocitária.

Clinical correlates of pp65 antigenemia monitoring in the first months of post kidney transplant in patients undergoing universal prophylaxis or preemptive therapy

Abstract Introduction: Human cytomegalovirus is a major cause of morbidity in kidney transplant patients. Objectives: We aimed to study viral replication and serological response in the first months post kidney transplant in patients undergoing universal prophylaxis or preemptive therapy and correlate the findings with the clinical course of Human cytomegalovirus infection. Patients and methods: Independent from the clinical strategy adopted for managing Human cytomegalovirus infection, prophylaxis versus preemptive therapy, the pp65 antigenemia assay and serological response were assessed on the day of transplantation, and then weekly during the first three months of post-transplant. Results: From the 32 transplant recipients, 16 were positive for pp65 antigenemia, with a similar incidence rate in each group. There were no positive results in the first three weeks of monitoring; the positivity rate peaked at week eight. There was a trend for a higher and earlier frequency of positivity in the universal prophylaxis group in which the course of the Human cytomegalovirus infection was also more severe. Despite the differences in clinical picture and in the initial immunosuppressant schedule, the serological response was similar in both groups. Conclusion: Routine monitoring during the first three post-transplant months has a positive impact on the early detection of Human cytomegalovirus viral replication allowing for timely treatment in order to reduce morbidity of the disease. The strategy of universal therapy employing intravenous ganciclovir was associated to a worse clinical course of the Human cytomegalovirus infection suggesting that the use of >10 cells/2 × 105 leukocytes as a cut-off in this setting may be inappropriate.

Increased Circulating T Lymphocytes Expressing HLA-DR in Kidney Transplant Recipients with Microcirculation Inflammation

We consecutively enrolled 82 kidney transplant recipients (KTRs) with stable renal function and 24 KTRs who underwent indication biopsy to compare the histological grading of renal allografts with the activity of circulating T lymphocyte subsets and monocytes determined by flow cytometry, which were obtained at 2 weeks after kidney transplantation (KT) and at the time of indication biopsy, respectively. The sum of the scores of glomerulitis (g) + peritubular capillaritis (ptc), inflammation (i) + tubulitis (t), interstitial fibrosis (ci) + tubular atrophy (ct), and fibrointimal thickening (cv) + arteriolar hyaline thickening (ah) was used to assign a histological grade to the renal allograft samples. The frequencies of CD4⁺HLA-DR⁺/CD4⁺ T cells and CD8⁺HLA-DR⁺/CD8⁺ T cells were significantly increased in KTRs with a microcirculation inflammation (MI) sum score ≥ 1 when compared with KTRs with an MI sum score = 0 as well as stable KTRs. In these 2 subsets, only CD4⁺HLA-DR⁺/CD4⁺ T cells were positively correlated with MI sum scores. Analysis using the receiver operating characteristic (ROC) curve showed that antibody-mediated rejection (AMR) could be predicted with a sensitivity of 80.0% and a specificity of 94.7%, using a cutoff value of 29.6% frequency of CD4⁺HLA-DR⁺/CD4⁺ T cells. MI was significantly associated with an increased frequency of activated T lymphocytes expressing human leukocyte antigen-antigen D related (HLA-DR). Further studies should focus on validating the utility of circulating CD4⁺HLA-DR⁺/CD4⁺ T cells as a noninvasive, immunologic monitoring tool for the prediction of AMR.

Immunological Prediction of Cytomegalovirus (CMV) Replication Risk in Solid Organ Transplantation Recipients: Approaches for Regulating the Targeted Anti-CMV Prevention Strategies / 감염과화학요법

The current cytomegalovirus (CMV) prevention strategies in solid organ transplantation (SOT) recipients have contributed towards overcoming the detrimental effects caused by CMV lytic infection, and improving the long-term success rate of graft survival. Although the quantification of CMV in peripheral blood is the standard method, and an excellent end-point for diagnosing CMV replication and modulating the anti-CMV prevention strategies in SOT recipients, a novel biomarker mimicking the CMV control mechanism is required. CMV-specific immune monitoring can be employed as a basic tool predicting CMV infection or disease after SOT, since uncontrolled CMV replication mostly originates from the impairment of immune responses against CMV under immunosuppressive conditions in SOT recipients. Several studies conducted during the past few decades have indicated the possibility of measuring the CMV-specific cell-mediated immune response in clinical situations. Among several analytical assays, the most advancing standardized tool is the QuantiFERON®-CMV assay. The T-Track® CMV kit that uses the standardized enzyme-linked immunospot assay is also widely employed. In addition to these assays, immunophenotyping and intracellular cytokine analysis using flow cytometry (with fluorescence-labeled monoclonal antibodies or peptide-major histocompatibility complex multimers) needs to be adequately standardized and validated for potential clinical applications.

The Specific Roles of Vitamins in the Regulation of Immunosurveillance and Maintenance of Immunologic Homeostasis in the Gut

Vitamins are micronutrients which are essential for the maintenance of biological responses including immune system. Hence, vitamin deficiency increases a risk of infectious, allergic, and inflammatory diseases. Accumulating evidence has recently revealed the molecular and cellular mechanisms of vitamin-mediated regulation in the active and quiescent immune responses. In this review, we focus on the immunologic roles of vitamins in the regulation of homeostasis and surveillance in the gut.

Clinical significance of immunologic monitoring in septic patients / 中华烧伤杂志

Sepsis induced by burns, trauma, and surgical stress, remains a major cause of death of patients in ICUs. A growing number of evidence shows that sepsis may result in dysfunction of innate and adaptive immune system, including the abnormal disorder of immune response of T lymphocytes, regulatory T lymphocytes, and dendritic cells, resulting in a state of immune depression. It is of great significance that dynamic monitoring of immune function and the related indicators might help to assess the risk of secondary infection, the prognosis of septic patients, and to guide the treatment of severe sepsis.

Chronic psychological stress and its impact on the development of aggressive breast cancer / Estresse psicológico crônico e seu impacto no desenvolvimento de neoplasia mamária agressiva

Objective To investigate the clinicopathological findings of women diagnosed with breast cancer and study the impact of chronic psychological stress on the pathological characteristics of these tumors.Methods We investigated a cohort composed of women diagnosed with breast cancer and divided into two groups. One group was categorized as presenting with chronic psychological stress (by using the Self-Reporting Questionnaire − SRQ-20). Another group of women with breast cancer, but with no previous history of chronic psychological stress, comprised the Control Group. Clinical and pathological data were assessed.Results Women presenting with a history of chronic distress were significantly overweight when compared to the Control Group. Furthermore, it was observed that these stressed women also had a significant percentage of aggressive breast cancer subtype, the HER2 amplified tumor, which could be putatively associated with the loss of immunosurveillance.Conclusion Our findings suggested an interaction among chronic psychological stress, overweight, and the development of more aggressive breast tumors.

Objetivo Investigar os achados clínico-patológicos de mulheres diagnosticadas com câncer de mama e estudar o impacto do estresse psicológico crônico nas características patológicas desses tumores.Métodos Investigamos uma coorte composta por mulheres diagnosticadas com câncer de mama divididas em dois grupos. O primeiro foi classificado pela apresentação de estresse psicológico crônico (por meio do Self-Reporting Questionnaire− SRQ-20). Outro grupo de mulheres com câncer de mama, mas sem história prévia de estresse psicológico crônico, foi denominado Grupo Controle. Os dados clínicos e patológicos foram avaliados.Resultados As mulheres com histórico de estresse crônico apresentaram-se significativamente acima do peso quando comparadas com o Grupo Controle. Além disso, verificou-se que estas mulheres estressadas apresentaram um porcentual significativo de um subtipo de câncer de mama agressivo, o HER2, o que poderia estar associado à possível perda da imunovigilância.Conclusão Nossos resultados sugeriram uma ligação entre o estresse psicológico crônico, o excesso de peso e o desenvolvimento de tumores de mama com maior agressividade.

Cytomegalovirus infection in renal transplantation: clinical aspects, management and the perspectives / Infecção pelo citomegalovírus no transplante de rim: aspectos clínicos, manejo e perspectivas

Cytomegalovirus infection is one of most frequent infectious complications after renal transplantation, and can be classified as primo-infection, when the transmission occurs through the graft, or reactivation, when the recipient is cytomegalovirus seropositive. After transplantation, cytomegalovirus can appear as an infection, when the patient presents with evidence of viral replication without symptoms or disease, which has two clinical spectra: typical viral syndrome or invasive disease, which is a less common form. Their effects can be classified as direct, while the disease is developed, or indirect, with an increase of acute rejection and chronic allograft dysfunction risks. Diagnosis must be made based on viremia by one of the standardized methods: antigenemia or PCR, which is more sensitive. The risk factors related to infection after transplantation are the serologic matching (positive donor and negative recipient) and anti-lymphocyte antibody drugs. One of the strategies to reduce risk of disease should be chosen for patients at high risk: preemptive treatment or universal prophylaxis. Recent clinical research has described ganciclovir resistance as an emergent problem in management of cytomegalovirus infection. Two types of mutation that cause resistance were described: UL97 (most frequent) and UL54. Today, sophisticated methods of immunologic monitoring to detect specific T-cell clones against cytomegalovirus are used in clinical practice to improve the management of high-risk patients after renal transplantation.

A infecção pelo citomegalovírus é uma das principais complicações após o transplante de rim, podendo ser classificada em primoinfecção, quando a transmissão ocorre por meio do enxerto, ou em reativação, quando o receptor é soropositivo. Do ponto de vista clínico, pode se apresentar como infecção, na ausência de sintomas, ou como doença, com dois diferentes espectros: a síndrome viral típica ou, menos comumente, a doença invasiva. Os efeitos podem ser diretos, que é o desenvolvimento da doença, ou indiretos, como aumento no risco de rejeição aguda e de disfunção crônica do enxerto. O diagnóstico deve ser feito por pesquisa de viremia por meio de um dos dois métodos padronizados: antigenemia ou PCR − sendo essa última a mais sensível. Os fatores de risco relacionados com a infecção após o transplante são o match sorológico (doador positivo e receptor negativo) e o uso de anticorpos antilinfócitos. Uma das estratégias de redução de risco de doença deve ser escolhida após o transplante nos pacientes de alto risco: tratamento preemptivo ou profilaxia. Recentemente, linhas de pesquisa clínica têm apontado a resistência ao ganciclovir como um problema emergente no manejo da infecção pelo citomegalovírus. Duas formas de mutação que causam resistência são descritas: UL97, que é a mais frequente, e a UL54. Atualmente, sofisticados métodos de monitorização imunológica, como a detecção de clones específicos de células T contra o citomegalovírus podem ser utilizados na prática clínica para o melhor manejo após o transplante renal dos pacientes de alto risco.

The CD4 slope can be a predictor of immunologic recovery in advanced HIV patients: a case-control study

BACKGROUND/AIMS: Advanced human immunodeficiency virus (HIV) infection, despite sustained viral suppression by highly active antiretroviral therapy (HAART), is a risk factor for poor immunologic recovery. However, some patients with advanced infection do show immunologic recovery. In this study, predictive factors of immunologic recovery were analyzed in advanced HIV patients showing sustained viral suppression. METHODS: A case-control study was conducted in HIV-infected adult patients with HIV-1 RNA or = 500/mm3 at 4 years with HAART). To analyze the CD4 T cell kinetics, the CD4 slope (monthly changes in the CD4 T cell count) was estimated for each patient using a linear regression between the CD4 T cell count and the time since HAART initiation. RESULTS: Of 102 eligible patients, 73 had advanced HIV, and 33 (45.2%) showed immunologic recovery. The median CD4 slopes (cells/mm3 per month) during 0 to 6 and 0 to 12 months of HAART in the 73 advanced patients were significantly higher in responders than in non-responders (0 to 6 months, 38.6 vs. 22.8; 0 to 12 months, 24.5 vs. 13.5). Multivariate analyses showed opportunistic infections at the start of HAART (adjusted odds ratio [OR], 0.28) and a CD4 slope > or = 20 during 0 to 12 months of HAART (adjusted OR, 10.10) were independently associated with immunologic recovery. CONCLUSIONS: The CD4 slope can be an early predictor of long-term immunologic recovery in advanced HIV patients.

Usefulness of the ImmuKnow Assay in a Case of Suspected Acute Rejection after Liver Transplantation / 대한이식학회지

We report on the usefulness of the ImmuKnow assay in a case of suspected acute cellular rejection after liver transplantation. A 58-year-old male with hepatocellular carcinoma and liver cirrhosis caused by chronic hepatitis C had undergone tumorectomy 2 months previously. Following surgery, the underlying cirrhosis and hepatic encephalopathy were aggravated. The patient had been listed for liver transplantation and underwent cadaveric donor liver transplantation. Approximately 11 days after discharge, the patient developed mild fever and diarrhea and was rehospitalized. A liver biopsy showed histologic features associated with cellular rejection. According to the histopathologic diagnosis, the dosage of tacrolimus was increased from 5 to 7 mg twice daily. After changing the dose, aspartate aminotransferase and alanine aminotransferase were elevated, findings not corresponding to the former diagnosis. Hepatitis C virus (HCV) quantitative assay and ImmuKnow assay were performed for further evaluation. High HCV viral load and a very low ATP level detected using the ImmuKnow assay were suggestive of recurrent HCV rather than acute cellular rejection. Two weeks after reducing the immunosuppressant dosage and treating with antiviral therapy using ribavirin, the patient showed clinical improvement with a decrease in HCV viral load and a normal ATP level. Due to overlapping histologic features, acute cellular rejection can be difficult to distinguish from recurrent HCV. As in this case, the ATP level detected using the ImmuKnow assay is considered a reliable marker of cellular immune status. Immune monitoring of transplant patients may assist in making a differential diagnosis and in minimizing the adverse events of immunosuppression.

O impacto da fibrose cística no perfil imunológico de pacientes pediátricos / The impact of cystic fibrosis on the immunologic profile of pediatric patients

OBJETIVO: Comparar o estado imunológico de 44 pacientes pediátricos com fibrose cística (FC)a umgrupo-controle formado por 16 indivíduos saudáveis. MÉTODOS: Foram selecionados para o estudo pacientes com FC com idade entre 3 e 12 anos, apresentando um escore clínico moderado e bom. Foram avaliados a glutationa eritrocitária, a produção de espécies reativas de oxigênio, citocinas (TNF-α, IFN-γ, IL-8, IL-6, IL-10) em culturas de células mononucleares do sangue periférico em condições espontâneas e estimuladas por BCG ou PHA, a concentração sérica de TGF-β2, IgA, IgG, IgM, IgE e IgA salivar. RESULTADOS :A produção espontânea de TNF-α, IL-6 e IL-10, a produção de IL-6 estimulada por PHA e TGF-β2, IgA e IgG séricas aumentaram em amostras de pacientes com FC. Indivíduos saudáveis tiveram uma produção mais elevada de TNF-α em resposta a BCG. CONCLUSÃO: Apesar de os pacientes com FC parecerem clinicamente estáveis, os resultados de seus exames de sangue periférico mostraram que houve um impacto sobre o sistema imunológico.

OBJECTIVE: To compare the immunologic state of 44 pediatric patients with cystic fibrosis (CF) with a control group consisting of 16 healthy individuals. METHODS: CF patients aged 3 to 12 years with moderate to good clinical score were selected for the study. Erythrocytic glutathione, production of reactive oxygen species, cytokines (TNF-α, IFN-γ, IL-8, IL-6, IL-10) in peripheral blood mononuclear cells cultures under spontaneous and BCG- or PHA-stimulated conditions, serum concentrations of TGF-β2, IgA, IgG, IgM, IgE, and salivary IgA were evaluated. RESULTS: The spontaneous production of TNF-α, IL-6, and IL-10, the PHA-stimulated production of IL-6, and the serum TGF-β2, IgA, and IgG were increased in samples from CF patients. Healthy subjects had a higher production of TNF-α in response to BCG. CONCLUSION: Although CF patients appearedclinically stable, the results of their peripheral blood examinations demonstrated an impact on the immune system.

Cytomegalovirus Infections in Solid Organ Transplantation: A Review / 감염과화학요법

Cytomegalovirus (CMV) continues to have a tremendous impact in solid organ transplantation despite remarkable advances in its diagnosis, prevention and treatment. It can affect allograft function and increase patient morbidity and mortality through a number of direct and indirect effects. Patients may develop asymptomatic viremia, CMV syndrome or tissue-invasive disease. Late-onset CMV disease continues to be a major problem in high-risk patients after completion of antiviral prophylaxis. Emerging data suggests that immunologic monitoring may be useful in predicting the risk of late onset CMV disease. There is now increasing interest in the development of an effective vaccine for prevention. Novel antiviral drugs with unique mechanisms of action and lesser toxicity are being developed. Viral load quantification is now undergoing standardization, and this will permit the generation of clinically relevant viral thresholds for the management of patients. This article provides a brief overview of the contemporary epidemiology, clinical presentation, diagnosis, prevention and treatment of CMV infection in solid organ transplant recipients.

Immunologic monitoring in kidney transplant recipients

Transplant biopsy has always been the gold standard for assessing the immune response to a kidney allograft (Chandraker A: Diagnostic techniques in the work-up of renal allograft dysfunction-an update. Curr Opin Nephrol Hypertens 8:723-728, 1999). A biopsy is not without risk and is unable to predict rejection and is only diagnostic once rejection has already occurred. However, in the past two decades, we have seen an expansion in assays that can potentially put an end to the "drug level" era, which until now has been one of the few tools available to clinicians for monitoring the immune response. A better understanding of the mechanisms of rejection and tolerance, and technological advances has led to the development of new noninvasive methods to monitor the immune response. In this article, we discuss these new methods and their potential uses in renal transplant recipients.

Next generation sequencing: new tools in immunology and hematology

One of the hallmarks of the adaptive immune system is the specificity of B and T cell receptors. Thanks to somatic recombination, a large repertoire of receptors can be generated within an individual that guarantee the recognition of a vast number of antigens. Monoclonal antibodies have limited applicability, given the high degree of diversity among these receptors, in BCR and TCR monitoring. Furthermore, with regard to cancer, better characterization of complex genomes and the ability to monitor tumor-specific cryptic mutations or translocations are needed to develop better tailored therapies. Novel technologies, by enhancing the ability of BCR and TCR monitoring, can help in the search for minimal residual disease during hematological malignancy diagnosis and follow-up, and can aid in improving bone marrow transplantation techniques. Recently, a novel technology known as next generation sequencing has been developed; this allows the recognition of unique sequences and provides depth of coverage, heterogeneity, and accuracy of sequencing. This provides a powerful tool that, along with microarray analysis for gene expression, may become integral in resolving the remaining key problems in hematology. This review describes the state of the art of this novel technology, its application in the immunological and hematological fields, and the possible benefits it will provide for the hematology and immunology community.

Low-cost assays for monitoring HIV infected individuals in resource-limited settings.

Use of a combination of CD4 counts and HIV viral load testing in the management of antiretroviral therapy (ART) provides higher prognostic estimation of the risk of disease progression than does the use of either test alone. The standard methods to monitor HIV infection are flow cytometry based for CD4+ T cell count and molecular assays to quantify plasma viral load of HIV. Commercial assays have been routinely used in developed countries to monitor ART. However, these assays require expensive equipment and reagents, well trained operators, and established laboratory infrastructure. These requirements restrict their use in resource-limited settings where people are most afflicted with the HIV-1 epidemic. With the advent of low-cost and/or low-tech alternatives, the possibility of implementing CD4 count and viral load testing in the management of ART in resource-limited settings is increasing. However, an appropriate validation should have been done before putting them to use for patient testing.

Monitoreo inmunológico: el comienzo de una nueva era en trasplantes / Inmune monitoring: the start of a new age in transplantation

La necesidad de ajustar la inmunosupresión en forma individualizada ha estimulado la emergencia de técnicas que permiten predecir eventos clínicos como rechazo agudo o tolerancia. Esta revisión analiza, considerando principalmente el trasplante renal, las limitantes actuales de la inmunosupresión para concluir que una terapia individualizada permitiría mejorar la sobrevida de pacientes y órganos trasplantados en el largo plazo. En segundo lugar describe los métodos diagnósticos que en forma más consistente han demostrado tener valor predictivo con importancia clínica. Entre ellos se cuentan ensayos funcionales, determinación de anticuerpos específicos y linfocitos reactivos contra el donante, así como el análisis de marcadores a nivel de proteínas o genómicos. Los avances logrados auguran el comienzo de una nueva eraen trasplantes.

Organ transplantation is often related to higher survival and lower morbidity than conservative treatments. Nevertheless, survival and morbidity could be optimized tailoring the immunosupression to the particular needs of each individual patient. The requirement to optimize immunosupression makes necessary to improve the immunologic assessment and therefore has promoted the development of new immunological diagnostic tools. This review addresses first the need to tailor immunosupression, and then focuses in the value of anti HLA antibodies, alloreactive T cells, phenotypic analysis of lymphocytes and cytokines, repertoire analysis and genetic approaches, as well as in vivo studies. Further validation and standardization of these tests are needed in order to enter the routine clinical practice. Accomplishment of these goals would signal the beginning of a new era in transplantation.

Dendritic Cells-based Vaccine and Immune Monitoring for Hepatocellular Carcinoma

Human tumors, including those of the hepatobiliary system, express a number of specific antigens that can be recognized by T cells, and may provide potential targets for cancer immunotherapy. Dendritic cells (DCs) are rare leucocytes that are uniquely potent in their ability to capture, process and present antigens to T cells. The ability to culture sufficient numbers of DCs from human bone marrow or blood progenitors has attracted a great deal of interest in their potential utilization in human tumor vaccination. CD34+ peripheral blood stem cells (PBSCs) were obtained from a patient with a hepatocellular carcinoma. The PBSCs were cultured in the X-VIVO 20 medium supplemented with the Flt-3 Ligand (FL), GM-CSF, IL-4 and TNF-alpha for 12 days. The morphology and functions of the cells were examined. The generated cells had the typical morphology of DCs. When the DCs were reinjected into the same patient, an augmentation of the cytotoxic T lymphocyte (CTL) activity was observed. Concomitantly, an increase in the natural killer (NK) cell activity was also detected in the patient. These results suggest that DCs-based cancer immunotherapy may become an important treatment option for cancer patients in the future.