A review of progress in B cell receptor (BCR) antigen specificity / 细胞与分子免疫学杂志

B cell receptor (BCR) is a key molecule involved in B cell specific recognition and the binding of antigens to produce adaptive humoral immune response. Gene rearrangement and high frequency mutation during B cell differentiation are the main mechanisms of BCR diversification. The enormous diversity and unique molecular structure of BCR determine the diversity and specificity of antigen recognition, shaping complex B cell repertoire with extensive collections of antigen specificities. Therefore, BCR antigen-specific information is vital to understanding the adaptive immune characteristics of different diseases. Our ability to connect BCR repertoire and antigen specificity has been enhanced with the development of B cell related research technologies, such as single cell sorting techniques, high-throughput sequencing (HTS), linking B cell receptor to antigen specificity through sequencing (LIBRA-seq). It could help researchers to better understand humoral immune responses, identify disease pathogenesis, monitor disease progression, design vaccines, and develop therapeutic antibodies and drugs. We summarizes recent studies on antigen-specific BCR of infections, vaccinations, autoimmune diseases and cancer. By analyzing autoantibody sequences of SLE as a case, the identification of autoantigens has become potentially possible due to this characterization.

Activation-induced cytidine deaminase (AID) involved in the regulation of B cell immune senescence / 细胞与分子免疫学杂志

The humoral immune response of B cells is the key to the protection of specific immunity, and immune aging reshapes its production and function. The decreased B cell immune function is an indicator of immune senescence. The impaired humoral immune function mediated by antibody secreted by B cells leads to a decline in the response of elderly individuals to the vaccine. These people are therefore more susceptible to infection and deterioration, and have a higher incidence of tumors and metabolic diseases. Activation-induced cytidine deaminase (AID) is an enzyme that triggers immunoglobulin class conversion recombination (CSR) and somatic high frequency mutation (SHM). It decreases during immune senescence and is considered to be a biomarker of decreased B cell function in aging mice and humans. Understanding the inherent defects of B-cell immune senescence and the regulation mechanism of AID in the aging process can provide new research ideas for the susceptibility, prevention and treatment of diseases in the elderly.

Paraproteínas: claridad en la nebulosa / Paraproteins: a review

Hematological neoplasms are tumors of cells in different states of maturation and differentiation. Since monoclonal gammopathies (MG) refer to B mature lymphocyte neoplasms, lymphogenesis should be well known. We must keep in mind that the last stage of maturation of these lymphocytes is the plasma cell. This is how a MG could appear in the context of a plasma cell neoplasm, such as multiple myeloma or amyloidosis, but also in relation to a lymphoma. A monoclonal peak is produced by mature B lymphocytes or plasma cells that secrete a monoclonal protein (Immunoglobulin), and represents a MG. But it must be emphasized that, in the correct clinical context, a hypogammaglobulinemia can represent a MG as well. Another important point is the understanding and interpretation of requested tests, such as protein electrophoresis (PEP), immunofixation (IFx) or serum free light chains (sFLC). The current MG screening panel includes these three studies (PEF, IFx, sFLC), although a simpler panel measuring PEF and sFLC has also been proposed, but not yet formally validated. Therefore, screening done only with PEP is insufficient.

Ki-67 expression in mature B-cell neoplasms: a flow cytometry study

SUMMARY OBJECTIVE: Ki-67 is a nuclear protein associated with cellular proliferation in normal or leukemic conditions that can help identify more aggressive diseases and is usually evaluated with immunohistochemistry. The aim of this was to assess Ki-67 expression on mature B-cell neoplasms samples with flow cytometry immunophenotyping. METHOD: After surface staining with CD19 and CD45, intracellular staining for Ki-67 was performed in leukemic mature B-cells. Ki-67 expression was evaluated with flow cytometry. RESULTS: Ki-67 expression was higher in mantle cell lymphoma, Burkitt lymphoma, and diffuse large B-cell lymphoma cases. It was also associated with CD38 mean fluorescence intensity. CONCLUSIONS: Ki-67 expression evaluated by flow cytometry can be a useful tool in the diagnosis of mature B-cell neoplasms. More studies are needed to validate Ki-67 assessment with flow cytometry immunophenotyping.

RESUMO OBJETIVO: Ki-67 é uma proteína nuclear associada à proliferação celular em condições normais ou leucêmicas que pode ajudar a Identificar doenças mais agressivas. Este marcador é geralmente avaliado com imuno-histoquímica. O objetivo deste estudo foi avaliar a expressão de Ki-67 em amostras de neoplasias de células B maduras com imunofenotipagem por citometria de fluxo. MÉTODO: Após marcação de superfície com CD19 e CD45, foi realizada marcação intracelular para Ki-67 em células B maduras leucémicas. A expressão de Ki-67 foi avaliada por citometria de fluxo. RESULTADOS: A expressão de Ki-67 foi maior em células de linfomas de manto, linfoma de Burkitt e linfoma difuso de grandes células B. Também houve associação de Ki-67 à intensidade de fluorescência média de CD38. CONCLUSÃO: A expressão de Ki-67 avaliada por citometria de fluxo pode ser útil no diagnóstico de neoplasias de células B maduras. São necessários mais estudos para validar a avaliação de Ki-67 com Imunofenotipagem por citometria de fluxo.

Correlation between cellular expression of complement regulatory proteins with depletion and repopulation of B-lymphocytes in peripheral blood of patients with rheumatoid arthritis treated with rituximab / Correlação entre expressão celular de proteínas reguladoras do complemento com a depleção e repopulação de linfócitos B no sangue periférico de pacientes com artrite reumatoide tratada com rituximabe

Abstract Objectives: To correlate the basal expression of complement regulatory proteins (CRPs) CD55, CD59, CD35, and CD46 in B-lymphocytes from the peripheral blood of a cohort of 10 patients with rheumatoid arthritis (RA) initiating treatment with rituximab (RTX) with depletion and time repopulation of such cells. Methods: Ten patients with RA received two infusions of 1 g of RTX with an interval of 14 days. Immunophenotypic analysis for the detection of CD55, CD59, CD35, and CD46 on B-lymphocytes was carried out immediately before the first infusion. The population of B-lymphocytes was analyzed by means of basal CD19 expression and after 1, 2, and 6 months after the infusion of RTX, and then quarterly until clinical relapse. Depletion of B-lymphocytes in peripheral blood was defined as a CD19 expression <0.005 × 109/L. Results: Ten women with a median of 49 years and a baseline DAS28 = 5.6 were evaluated; 9 were seropositive for rheumatoid factor. Five patients showed a repopulation of B-lymphocytes after 2 months, and the other five after 6 months. There was a correlation between the basal expression of CD46 and the time of repopulation (correlation coefficient = −0.733, p = 0.0016). A similar trend was observed with CD35, but without statistical significance (correction coefficient = −0.522, p = 0.12). Conclusion: The increased CD46 expression was predictive of a faster repopulation of B-lymphocytes in patients treated with RTX. Studies involving a larger number of patients will be needed to confirm the utility of basal expression of CRPs as a predictor of clinical response.

Resumo Objetivos: Correlacionar a expressão basal das proteínas reguladoras do complemento (PRC) CD55, CD59, CD35 e CD46 nos linfócitos B do sangue periférico de uma coorte de 10 pacientes com artrite reumatoide (AR) iniciando tratamento com rituximabe (RTX) com a depleção e tempo de repopulação dessas células. Métodos: Dez pacientes com AR receberam duas infusões de 1 g de RTX com intervalo de 14 dias. Análises imunofenotípicas para detecção de CD55, CD59, CD35 e CD46 nos linfócitos B foram feitas imediatamente antes da primeira infusão. A população de linfócitos B foi analisada por meio da expressão de CD19 basal e após um, dois e seis meses após a infusão de RTX e então trimestralmente até a recaída clínica. Depleção de linfócitos B no sangue periférico foi definida como expressão de CD19 < 0,005 × 109/l. Resultados: Dez mulheres com mediana de 49 anos e DAS 28 basal de 5,6 foram avaliadas; nove eram soropositivas para o fator reumatoide. Cinco pacientes apresentaram repopulação de linfócitos B após dois meses e as outras cinco aos seis meses. Houve correlação entre a expressão basal de CD46 e o tempo de repopulação (coeficiente de correlação -0,733, p = 0,0016). Tendência semelhante foi observada com CD35, porém sem significância estatística (coeficiente de correção 0,522, p = 0,12). Conclusão: Expressão aumentada de CD46 foi preditora de repopulação mais rápida de linfócitos B em pacientes tratados com RTX. Estudos com um número maior de pacientes serão necessários para confirmar a utilidade da expressão basal das PRC como preditora de resposta clínica.

Expression of BAFF and BR3 in patients with systemic lupus erythematosus

The objective of this study was to examine the relationship between the expression of B cell activating factor (BAFF) and BAFF receptor in patients with disease activity of systemic lupus erythematosus (SLE). Real-time RT-PCR was used to examine BAFF mRNA expression in peripheral blood monocytes of active and stable SLE patients and healthy controls. The percentage of BAFF receptor 3 (BR3) on B lymphocytes was measured by flow cytometry. Soluble BAFF levels in serum were assayed by ELISA. Microalbumin levels were assayed by an automatic immune analysis machine. BAFF mRNA and soluble BAFF levels were highest in the active SLE group, followed by the stable SLE group, and controls (P<0.01). The percentage of BR3 on B lymphocytes was downregulated in the active SLE group compared with the stable SLE group and controls (P<0.01). BAFF mRNA levels and soluble BAFF levels were higher in patients who were positive for proteinuria than in those who were negative (P<0.01). The percentage of BR3 on B lymphocytes was lower in patients who were positive for proteinuria than in those who were negative (P<0.01). The BAFF/BR3 axis may be over-activated in SLE patients. BAFF and BR3 levels may be useful parameters for evaluating treatment.

Frequency and Clinical Characteristics of Intrachromosomal Amplification of Chromosome 21 in Korean Childhood B-lineage Acute Lymphoblastic Leukemia

BACKGROUND: Intrachromosomal amplification of chromosome 21 (iAMP21) is known to be associated with poor prognosis in B-cell ALL (B-ALL). To determine the frequency and clinical characteristics of iAMP21 in Korean B-ALL patients, we performed FISH and multiplex ligation-dependent probe amplification (MLPA) analyses. METHODS: A total of 102 childhood B-ALL patients were screened with ETV6-RUNX1 FISH probes (Abbott Molecular, USA). The presence of an iAMP21 was confirmed by using MLPA P327 iAMP21-ERG probemix (MRC Holland, The Netherlands). RESULTS: iAMP21 was detected in one of the screened B-ALL patients (1/102 patients, 1.0%) who presented the ALL immunophenotype and complex karyotype at initial diagnosis. The patient relapsed twice after bone marrow transplantation. MLPA showed 12.5-Mb and 4.28-Mb regions of amplification and deletion, respectively. CONCLUSIONS: The frequency of iAMP21 is considerable in Korean pediatric patients. Our report suggests that iAMP21 in childhood B-ALL has very unfavorable impact on patient's prognosis. Additional methods such as MLPA analysis is essential to rule out patients with equivocal interphase FISH results.

Novel identification and characterisation of Transient receptor potential melastatin 3 ion channels on Natural Killer cells and B lymphocytes: effects on cell signalling in Chronic fatigue syndrome/Myalgic encephalomyelitis patients

BACKGROUND: Transient receptor potential melastatin 3 (TRPM3) cation channels are ubiquitously expressed by multiple cells and have an important regulatory role in calcium-dependent cell signalling to help maintain cellular homeostasis. TRPM3 protein expression has yet to be determined on Natural Killer (NK) cells and B lymphocytes. Multiple single nucleotide polymorphisms have been reported in TRPM3 genes from isolated peripheral blood mononuclear cells, NK and B cells in Chronic fatigue syndrome/Myalgic encephalomyelitis (CFS/ME) patients and have been proposed to correlate with illness presentation. The object of the study was to assess TRPM3 surface expression on NK and B lymphocytes from healthy controls, followed by a comparative investigation examining TRPM3 surface expression, and cytoplasmic and mitochondrial calcium influx in CD19+ B cells, CD56bnght and CD56dim cell populations from CFS/ME patients. RESULTS: TRPM3 cell surface expression was identified for NK and B lymphocytes in healthy controls (CD56bright TRPM3 35.72 % ± 7.37; CD56dim 5.74 % ± 2.00; B lymphocytes 2.05 % ± 0.19, respectively). There was a significant reduction of TRPM3 surface expression on CD19+ B cells (1.56 ± 0.191) and CD56bright NK cells (17.37 % ± 5.34) in CFS/ME compared with healthy controls. Anti-CD21 and anti-IgM conjugated biotin was cross-linked with streptavidin,and subsequently treatment with thapsigargin. This showed a significant reduction in cytoplasmic calcium ion concentration in CD19+ B lymphocytes. CD56bright NK cells also had a significant decrease in cytoplasmic calcium in the presence of 2-APB and thapsigargin in CFS/ME patients. CONCLUSIONS: The results from this preliminary investigation identify, for the first time, TRPM3 surface expression on both NK and B lymphocytes in healthy controls. We also report for the first time, significant reduction in TRPM3 cell surface expression in NK and B lymphocytes, as well as decreased intracellular calcium within specific conditions in CFS/ME patients. This warrants further examination of these pathways to elucidate whether TRPM3 and impaired calcium mobilisation has a role in CFS/ME.

B cells expressing IL-10 mRNA modulate memory T cells after DNA-Hsp65 immunization

In DNA vaccines, the gene of interest is cloned into a bacterial plasmid that is engineered to induce protein production for long periods in eukaryotic cells. Previous research has shown that the intramuscular immunization of BALB/c mice with a naked plasmid DNA fragment encoding the Mycobacterium leprae 65-kDa heat-shock protein (pcDNA3-Hsp65) induces protection against M. tuberculosis challenge. A key stage in the protective immune response after immunization is the generation of memory T cells. Previously, we have shown that B cells capture plasmid DNA-Hsp65 and thereby modulate the formation of CD8+ memory T cells after M. tuberculosis challenge in mice. Therefore, clarifying how B cells act as part of the protective immune response after DNA immunization is important for the development of more-effective vaccines. The aim of this study was to investigate the mechanisms by which B cells modulate memory T cells after DNA-Hsp65 immunization. C57BL/6 and BKO mice were injected three times, at 15-day intervals, with 100 µg naked pcDNA-Hsp65 per mouse. Thirty days after immunization, the percentages of effector memory T (TEM) cells (CD4+ and CD8+/CD44high/CD62Llow) and memory CD8+ T cells (CD8+/CD44high/CD62Llow/CD127+) were measured with flow cytometry. Interferon γ, interleukin 12 (IL-12), and IL-10 mRNAs were also quantified in whole spleen cells and purified B cells (CD43−) with real-time qPCR. Our data suggest that a B-cell subpopulation expressing IL-10 downregulated proinflammatory cytokine expression in the spleen, increasing the survival of CD4+ TEM cells and CD8+ TEM/CD127+ cells.

Estigma e discriminação: experiências de mulheres HIV positivo nos bairros populares de Maputo, Moçambique / Stigma and discrimination: the experiences of HIV-positive women in poor neighborhoods of Maputo, Mozambique / Estigma y discriminación: las experiencias de las mujeres VIH positivas en los barrios populares de Maputo, Mozambique

A epidemia de HIV/AIDS é um sério problema de saúde pública em Moçambique, que convive com altas taxas de prevalência do HIV. O impacto da epidemia é agravado pelo forte estigma que atinge as pessoas soropositivas. O objetivo deste estudo foi investigar, com base em uma perspectiva socioantropológica, a experiência de mulheres HIV positivo nos bairros populares de Maputo e como lidam com o estigma e a discriminação. Foram realizadas entrevistas semiestruturadas com dez mulheres HIV positivo, residentes nos bairros populares de Maputo. Os resultados mostram como a desigualdade de gênero atua de forma importante na construção da vulnerabilidade das mulheres ao HIV, assim como em sua estigmatização e discriminação. No enfrentamento do estigma, as mulheres procuram preservar o sigilo do diagnóstico buscando apoio na reunião em grupos de pares HIV positivo. É fundamental que se implementem políticas públicas voltadas para o empoderamento das mulheres e redução do estigma associado ao HIV/AIDS.

The HIV/AIDS epidemic is a serious public health problem in Mozambique. The country has high prevalence rates, and the epidemic's impact is aggravated by the stigma affecting HIV-positive persons. This study takes a socio-anthropological perspective to analyze the experience of HIV-positive women in poor neighborhoods of Maputo and the ways they cope with stigma and discrimination. Semi-structured interviews were conducted with 10 HIV-positive women. The results show how gender inequalities increase women's vulnerability to HIV and contribute to their stigmatization and discrimination. In dealing with stigma, women try to keep their diagnosis confidential, seeking support in group meetings with others living with HIV. Public policies should focus on women's empowerment and the reduction of HIV/AIDS-related stigma.

El VIH/SIDA es un problema de salud pública grave en Mozambique, que convive con altas tasas de prevalencia del VIH. El impacto de la epidemia se ve agravada por el fuerte estigma que afecta a las personas con VIH. El objetivo de este estudio fue investigar, desde una perspectiva antropológica, la experiencia de las mujeres VIH positivas en los barrios populares de Maputo y cómo enfrentan el estigma y la discriminación. Se realizaron entrevistas semi-estructuradas con 10 mujeres VIH positivas que viven en barrios pobres de Maputo. Los resultados muestran cómo la desigualdad de género juega un papel importante en la construcción de la vulnerabilidad de las mujeres frente al VIH, así como en la estigmatización y discriminación. Para hacer frente el estigma, las mujeres buscan preservar la confidencialidad del diagnóstico y buscar apoyo en la reunión de grupos de pares con VIH. Es imprescindible implementar políticas públicas enfocadas al empoderamiento de las mujeres y a la reducción del estigma asociado con el VIH/SIDA.

Seroprevalence and seroincidence of Leptospira infection in dogs during a one-year period in an endemic urban area in Southern Brazil

INTRODUCTION: Leptospirosis is a zoonosis that affects both humans and animals. Dogs may serve as sentinels and indicators of environmental contamination as well as potential carriers for Leptospira. This study aimed to evaluate the seroprevalence and seroincidence of leptospirosis infection in dogs in an urban low-income community in southern Brazil where human leptospirosis is endemic. METHODS: A prospective cohort study was designed that consisted of sampling at recruitment and four consecutive trimestral follow-up sampling trials. All households in the area were visited, and those that owned dogs were invited to participate in the study. The seroprevalence (MAT titers ≥100) of Leptospira infection in dogs was calculated for each visit, the seroincidence (seroconversion or four-fold increase in serogroup-specific MAT titer) density rate was calculated for each follow-up, and a global seroincidence density rate was calculated for the overall period. RESULTS: A total of 378 dogs and 902.7 dog-trimesters were recruited and followed, respectively. The seroprevalence of infection ranged from 9.3% (95% CI; 6.7 - 12.6) to 19% (14.1 - 25.2), the seroincidence density rate of infection ranged from 6% (3.3 - 10.6) to 15.3% (10.8 - 21.2), and the global seroincidence density rate of infection was 11% (9.1 - 13.2) per dog-trimester. Canicola and Icterohaemorraghiae were the most frequent incident serogroups observed in all follow-ups. CONCLUSIONS: Follow-ups with mean trimester intervals were incapable of detecting any increase in seroprevalence due to seroincident cases of canine leptospirosis, suggesting that antibody titers may fall within three months. Further studies on incident infections, disease burden or risk factors for incident Leptospira cases should take into account the detectable lifespan of the antibody. .

Early surgical complications after gastric by-pass: a literature review / Complicações cirúrgicas precoces após bypass gástrico: revisão da literatura

INTRODUCTION: Gastric bypass is today the most frequently performed bariatric procedure,but, despite of it, several complications can occur with varied morbimortality. Probably all bariatric surgeons know these complications, but, as bariatric surgery continues to spread, general surgeon must be familiarized to it and its management. Gastric bypass complications can be divided into two groups: early and late complications, taking into account the two weeks period after the surgery. This paper will focus the early ones. METHOD: Literature review was carried out using Medline/PubMed, Cochrane Library, SciELO, and additional information on institutional sites of interest crossing the headings: gastric bypass AND complications; follow-up studies AND complications; postoperative complications AND anastomosis, Roux-en-Y; obesity AND postoperative complications. Search language was English. RESULTS: There were selected 26 studies that matched the headings. Early complications included: anastomotic or staple line leaks, gastrointestinal bleeding, intestinal obstruction and incorrect Roux limb reconstruction. CONCLUSION: Knowledge on strategies on how to reduce the risk and incidence of complications must be acquired, and every surgeon must be familiar with these complications in order to achieve an earlier recognition and perform the best intervention. .

INTRODUÇÃO: O bypass gástrico é hoje o procedimento bariátrico mais realizado, mas, apesar disso, várias complicações podem ocorrer com variada morbimortalidade. Provavelmente todos os cirurgiões bariátricos conhecem essas complicações, mas como a cirurgia bariátrica continua a se espalhar, o cirurgião geral deve estar familiarizado com essas complicações e seu manuseio. As complicações do bypass gástrico podem ser divididas em dois grupos: as precoces e tardias, tendo em conta o período de duas semanas após a operação. Este artigo irá focar as precoces. MÉTODO: Foi realizada revisão da literatura utilizando as bases Medline/PubMed, Cochrane Library, SciELO, e informações adicionais sobre sites institucionais de interesse cruzando os descritores: bypass gástrico AND complicações; seguimento AND complicações; complicações pós-operatórias AND anastomose, Roux-en-Y; obesidade AND complicações pós-operatórias. A língua usada para a busca foi o inglês. RESULTADOS: Foram selecionados 26 artigos que combinavam com os descritores. As complicações imediatas foram: fístula na linha de grampeamento, sangramento gastrointestinal, obstrução intestinal e reconstrução incorreta da alça em Roux. CONCLUSÃO: O conhecimento sobre as estratégias de como reduzir o risco e incidência das complicações deve ser adquirido ao longo do tempo, e cada cirurgião deve estar familiarizado com essas complicações, a fim de reconhecê-las precocemente e realizar a melhor intervenção. .

Evaluation of Antibody Response to Polysaccharide Vaccine and Switched Memory B Cells in Pediatric Patients with Inflammatory Bowel Disease

BACKGROUND/AIMS: Inflammatory bowel disease (IBD) is a chronic disease of the gastrointestinal tract, whose etiologies are still unknown. This study was performed to evaluate the humoral immune response in terms of B cell functions in selected IBD patients. METHODS: Eighteen pediatric patients with IBD, including 12 cases of ulcerative colitis (UC) and six with Crohn disease (CD), were enrolled in this study. The pneumococcal vaccine was injected in all patients, and the IgG antibody level to the polysaccharide antigen was measured before and 4 weeks after injection. The B cell switch-recombination process was evaluated. RESULTS: Five patients with IBD (three CD and two UC) had defects in B cell switching, which was significantly higher than in controls (p=0.05). Ten patients had a specific antibody deficiency and exhibited a higher frequency of bacterial infection than the healthy group. The mean increased level of IgG after vaccination was lower in IBD patients (82.9+/-32.5 microg/mL vs 219.8+/-59.0 microg/mL; p=0.001). Among the patients who had an insufficient response, no significant difference in the number of switched memory B-cell was observed. CONCLUSIONS: A defect in B lymphocyte switching was observed in pediatric IBD patients, and especially in those patients with CD. Owing to an increased risk of bacterial infections in those patients with antibody production defects, pneumococcal vaccination could be recommended. However, not all patients can benefit from the vaccination, and several may require other prophylactic methods.

Overexpression of Fc receptor-like 1 associated with B-cell activation during hepatitis B virus infection

The role of B cells in the pathogenesis of hepatitis B virus (HBV) infection has not been explored in depth. In the present study, the activation status of B cells from peripheral blood of healthy controls (N = 20) and patients with acute hepatitis B (AHB, N = 15) or chronic hepatitis B (CHB, N = 30) was evaluated by measuring the expression levels of B-cell activation markers CD69 and CD86, using quantitative real-time PCR and flow cytometry. Moreover, the potential mechanism underlying B-cell activation during HBV infection was further investigated by analyzing the expression profile of FCRL1, an intrinsic activation molecule of B cells. An elevation in the levels of B-cell activation markers including CD69 and CD86 was observed in the AHB patients (44.31 ± 9.27, 27.64 ± 9.26%) compared to CHB patients (30.35 ± 11.27, 18.41 ± 6.56%, P < 0.05), which was still higher than healthy controls (12.23 ± 7.84, 8.22 ± 3.43%, P < 0.05). Furthermore, the expression of FCRL1 was found to be similar to B-cell activation markers, which was highest in AHB patients (70.15 ± 17.11%), lowest in healthy donors (36.32 ± 9.98%, P < 0.05) and half-way between these levels in patients with CHB (55.17 ± 12.03%, P < 0.05). The results were positively associated with aberrant B-cell activation. These data suggest that B cells can play a role in HBV infection, and therefore more effort should be devoted to exploring their functions.

The role of promoter methylation in Epstein-Barr virus (EBV) microRNA expression in EBV-infected B cell lines

Epstein-Barr virus (EBV) microRNAs (miRNAs) are expressed in EBV-associated tumors and cell lines, but the regulation mechanism of their expression is unclear yet. We investigated whether the expression of EBV miRNAs is epigenetically regulated in EBV-infected B cell lines. The expression of BART miRNAs was inversely related with the methylation level of the BART promoter at both steady-state and following 5-aza-2'-deoxycytidine treatment of the cells. The expression of BHRF1 miRNAs also became detectable with the demethylation of Cp/Wp in latency I EBV-infected cell lines. Furthermore, in vitro methylation of the BART and Cp promoters reduced the promoter-driven transactivation. In contrast, tricostatin A had little effect on the expression of EBV miRNA expression as well as on the BART and Cp/Wp promoters. Our results suggest that promoter methylation, but not histone acetylation, plays a role in regulation of the EBV miRNA expression in EBV-infected B cell lines.

Effects of ischemia/reperfusion on beta cells of pancreas and protective effects of melatonin treatment / Efectos de la isquemia/reperfusión sobre células beta del páncreas y efectos protectores del tratamiento de melatonina

Oxygen free radicals are considered to be important components involved in the pathophysiological tissue alterations observed during ischemia-reperfusion (I/R). In this study, we investigated the putative protective effects of melatonin treatment on pancreatic I/R injury. Sprague Dawley male rats were subjected to 30 min of pancreatic pedicle occlusion followed by 90 min reperfusion. Melatonin (10 mg/kg. s.c) was administrated 30 min prior to ischemia or I/R application. At the end of the reperfusion periods, rats were decapitated. Pancreatic samples were taken for transmission electron microscopy. The results indicated that ischemia created b cell damage as evidenced by dilatation between the nucleus inner and outer membrane and degeneration on islets of Langerhans cells, was reversed by melatonin treatment. As melatonin administration reversed these microscopic damage, it seems likely that melatonin protects pancreatic tissue against oxidative damage.

Los radicales libres del oxígeno son considerados como uno de los componentes más importantes que participan en las alteraciones fisiopatológicas del tejido durante la isquemia-reperfusión (I/R). En este estudio, se investigó el supuesto efecto protector del tratamiento de melatonina sobre la lesión pancreática I/R. Ratas Sprague Dawley machos fueron sometidas a 30 minutos de oclusión del pedículo pancreático seguido de 90 minutos de reperfusión. La melatonina (10 mg/kg) fue administrada 30 minutos antes de la isquemia o de la aplicación I/R. Al finalizar los periodos de reperfusión, las ratas fueron decapitadas. Fueron tomadas muestras pancreáticas para el análisis en microscopía electrónica de transmisión. Los resultados indicaron que la isquemia ocasionó daño en las células beta demostrado por la dilatación entre el núcleo interior y la membrana exterior y la degeneración de los islotes de células pancreáticas, los que fueron revertidos por el tratamiento de melatonina. Como la administración de melatonina revirtió estos daños microscópicos, parece probable que ella proteja al tejido pancreático contra el daño oxidativo.

Immunoglobulin VH Chain Gene Analysis of Peripheral Blood IgM-Producing B Cells in Patients with Kawasaki Disease

PURPOSE: Kawasaki disease is a systemic vasculitis, and its etiology and pathogenesis are still not clear. Our study was undertaken to investigate the characteristics of the activation of B cells in the peripheral blood of Kawasaki disease (KD) patients and evidence of stimulation by superantigens. MATERIALS AND METHODS: Blood samples were obtained from three patients (2 males, 1 female) with KD, who were admitted to our Hospital, Seoul, Korea. The mean age was 1.2 years. Distribution of B cells was studied in the acute and subacute phases of KD patients. From the RNA of B cells, we obtained complementary DNA (cDNA) and performed polymerase chain reaction (PCR). To determine the oligoclonal expansion of immunoglobulin M (IgM) VH family, we cloned and sequenced the PCR products from each group and analyzed DNA. RESULTS: In the peripheral blood of acute phase patients, T cells were significantly decreased (p < 0.05), whereas B cells were significantly increased (p < 0.05). When the first PCR was done on the B cell chains, VH1 to VH6 were all found to be expressed. The number of micro gene clones obtained from 3 patients was 312, and they belonged to VH3, VH4 and VH5 family. M99686 germ line was most frequently used and the next most frequently used, were X92224/J, L21967 and L21964. A similar order was seen in patients. Among the clones, 20 sets of clones showed the same base sequence and this was frequent between VH2 and VH5. There was one set, which showed almost the same base sequence between different patients, and the homology was 99.5%. Twenty sets of clones that had the same base sequence showed high similarity to the germ line (94 - 100%). Among these, the clones that utilized the M99686 germ line were 4 sets which were most frequent. The 3-dimensional structure of one of these clones showed typical beta, sheet structure of immunoglobulin chains. CONCLUSION: The IgM transcripts expressed by the B cells in the peripheral blood of KD patients in the acute phase of the disease clearly showed an oligoclonal expansion, suggesting that KD is caused not by stimulation of a superantigen, but rather by a conventional antigen.

Immunoglobulin VH Chain Gene Analysis of Peripheral Blood IgM-Producing B Cells in Patients with Kawasaki Disease

PURPOSE: Kawasaki disease is a systemic vasculitis, and its etiology and pathogenesis are still not clear. Our study was undertaken to investigate the characteristics of the activation of B cells in the peripheral blood of Kawasaki disease (KD) patients and evidence of stimulation by superantigens. MATERIALS AND METHODS: Blood samples were obtained from three patients (2 males, 1 female) with KD, who were admitted to our Hospital, Seoul, Korea. The mean age was 1.2 years. Distribution of B cells was studied in the acute and subacute phases of KD patients. From the RNA of B cells, we obtained complementary DNA (cDNA) and performed polymerase chain reaction (PCR). To determine the oligoclonal expansion of immunoglobulin M (IgM) VH family, we cloned and sequenced the PCR products from each group and analyzed DNA. RESULTS: In the peripheral blood of acute phase patients, T cells were significantly decreased (p < 0.05), whereas B cells were significantly increased (p < 0.05). When the first PCR was done on the B cell chains, VH1 to VH6 were all found to be expressed. The number of micro gene clones obtained from 3 patients was 312, and they belonged to VH3, VH4 and VH5 family. M99686 germ line was most frequently used and the next most frequently used, were X92224/J, L21967 and L21964. A similar order was seen in patients. Among the clones, 20 sets of clones showed the same base sequence and this was frequent between VH2 and VH5. There was one set, which showed almost the same base sequence between different patients, and the homology was 99.5%. Twenty sets of clones that had the same base sequence showed high similarity to the germ line (94 - 100%). Among these, the clones that utilized the M99686 germ line were 4 sets which were most frequent. The 3-dimensional structure of one of these clones showed typical beta, sheet structure of immunoglobulin chains. CONCLUSION: The IgM transcripts expressed by the B cells in the peripheral blood of KD patients in the acute phase of the disease clearly showed an oligoclonal expansion, suggesting that KD is caused not by stimulation of a superantigen, but rather by a conventional antigen.

Resposta imune celular no câncer de mama / Cellular immune response in breast cancer

O câncer de mama é uma doença de grande impacto social. Seu tratamento e prognóstico dependem de variáveis, tais como: tamanho tumoral, grau histológico, estado linfonodal, entre outras. A resposta imune do hospedeiro tem o objetivo de destruir as células tumorais, porém vários fatores atuam levando ao escape dessas células neoplásicas. O grau de infiltração de linfócitos poderia ser um dos fatores implicados no prognóstico. Este artigo tem como objetivo a revisão do papel da resposta imunológica no câncer de mama.

Breast cancer is a disease with great social repercussions. The treatment and the prognosis depend on serial factors, as: tumoral size, histologycal grade and lymph nodes status. The host immunitary response aims to remove neoplasic cells, but some interferent factors might allow embolization and metastatization. It should be postulated that the lymphocit function could be act as a prognostic. This review focus the role of the immune response en breast cancer.

BAFF: Una citoquina reguladora de linfocitos B implicada en autoinmunidad y cáncer linfoide / BAFF: A regulatory cytokine of B lymphocytes involved in autoimmunity and lymphoid cancer

BAFF (B cell activating factor belonging to the TNF family) is a cytokine implicated in the survival and maturation of peripheral B lymphocytes and T and B cell activation. BAFF binds to three different receptors: TACI, BCMA and BAFF-R, whose expression is restricted to B and T lymphocytes. BAFF and BAFF-R-deficient mice show a dramatic loss of peripheral B lymphocytes and a severely reduced immune response. In contrast, an enhanced BAFF expression leads to B cell hyperplasia and autoimmunity in mice. In vivo, administration of soluble decoy receptors for BAFF effectively decreases disease progression in various autoimmune mouse models. These evidences render BAFF as a potentially new therapeutic target. Elevated BAFF levels have been detected in the serum of patients with autoimmune diseases, such as Systemic Lupus Erythematosus, rheumatoid arthitis, Sjõgren's syndrome, lymphoid cancers and HIV infection. In addition to BAFF receptors, malignant B cells abnormally express BAFF, which attenuates apoptosis through both autocrine and paracrine pathways. The data suggest that an increase in the expression of BAFF induces an enhanced B and T cell activation and the survival of pathologically active B cells. In this article, we review and discuss the participation of BAFF and its receptors in the immune response and its involvement in immunodeficiency, autoimmunity, infections and lymphoid cancers as well as the currently investigated therapies using BAFF antagonists in the treatment of these diseases.