Abnormal expression of b10 cell frequencies: possible relation to pathogenesis and disease severity of aplastic anemia

SUMMARY OBJECTIVE: Aplastic anemia (AA) is an immune-mediated disease that destroys hematopoietic cells through activated T lymphocytes. B lymphocyte-mediated humoral immunity also plays an important role in the pathogenesis of AA. Regulatory B cell (Breg) subpopulation, which is defined as "B10", secretes interleukin 10 (IL-10). The objective of our experiment was to investigate whether the scale-down proportion of B10 cells in AA patients may play a key role in the pathogenesis. METHODS: A total of 38 AA patients (14 SAA patients and 24 NSAA patients) and 20 healthy control subjects were included. All subjects did not suffer from autoimmune diseases or any other diseases affecting the immune system, such as infectious diseases. Bone marrow mononuclear cells (PBMCs) were isolated and analyzed by Flow cytometry (FCM) and Immunofluorescence double-labeling assay. The relationship between the relative proportions of B10 and ProB10 and their associations to AA, as well as disease severity, were assessed by common clinical indicators and then examined. RESULTS: Our analyses revealed AA patients had significantly lower proportions of peripheral B10 and B10pro compared to healthy controls. SAA patients had a substantially lower percentage of B10 cells and B10pro cells compared to NSAA patients. In addition, B10 cells and B10pro cells were negatively correlated with absolute neutrophil counts, hemoglobin levels and platelet, and absolute reticulocyte counts in AA patients. CONCLUSIONS: The present study attempted to elucidate the potential role of the scale-down proportion of B10 cells in the pathogenesis of AA.

RESUMO OBJETIVO: A anemia aplástica (AA) é uma doença imunomediada que destrói células hematopoiéticas por meio dos linfócitos T ativados. A imunidade humoral mediada por linfócitos B também desempenha um papel importante na patogênese da AA. A subpopulação de células B reguladoras (Breg), que é definida como "B10", secreta interleucina 10 (IL-10). No experimento, investigou-se se a proporção reduzida de células B10 nos pacientes de AA pode desempenhar um papel-chave na patogênese. MÉTODOS: Um total de 38 pacientes de AA (14 pacientes de anemia aplástica grave e 24 pacientes de anemia aplástica não grave) e 20 indivíduos de controle saudáveis foram incluídos. Todos os indivíduos não sofriam de doenças autoimunes ou de quaisquer outras doenças que afetam o sistema imunológico, tais como doenças contagiosas. As células mononucleares da medula óssea (PBMCs) eram isoladas e analisadas por citometria de fluxo (FCM) e ensaio de dupla marcação por imunofluorescência. A relação entre as proporções relativas de células B10 e as células ProB10 e as suas associações à AA, assim como a gravidade da doença avaliada por indicadores clínicos comuns, foram examinadas. RESULTADOS: Nossas análises revelaram que os pacientes de AA têm proporções significativamente menores de células B10 e células ProB10 periféricas em comparação com indivíduos de controle saudáveis. Os pacientes de anemia aplástica grave tiveram uma percentagem substancialmente menor de células B10 e células B10pro em comparação com pacientes de anemia aplástica não grave. Além disso, as células B10 e B10pro foram negativamente correlacionadas com contagens absolutas de neutrófilos, níveis de hemoglobina e plaquetas e contagem de reticulócitos absolutos nos pacientes de AA. CONCLUSÕES: Além disso, o estudo presente tentou elucidar o papel imunorregulatório potencial das células B10 na patogênese da AA e fornecer uma nova estratégia para a aplicação de imunoterapia baseada na célula B para tratar a AA no futuro.

Regulatory B Cells Are Inversely Associated with Disease Activity in Rheumatoid Arthritis

PURPOSE: The function of regulatory B lymphocytes is known to be abnormal in inflammatory diseases. However, a recent study indicates that IL-10+ B cells seem to be expanded in rheumatoid arthritis (RA). Therefore, the state of IL-10+ B cells in the peripheral blood from RA patients and healthy controls were investigated. MATERIALS AND METHODS: CD19+ cells in peripheral blood mononuclear cells were purified from blood samples of RA patients and age and gender-matched healthy controls, and stimulated with CD40 ligand and CpG for 48 hours. Then, intracellular IL-10 in CD19+ cells was analyzed using flow cytometry. RESULTS: There was no significant difference in the proportion of IL-10+ B cells between 10 RA patients and 10 healthy controls (RA, 0.300+/-0.07 vs. healthy control 0.459+/-0.07, p=0.114). The proportion of induced IL-10+ B cells to total B cells in RA patients was significantly higher than those in controls (RA, 4.44+/-3.44% vs. healthy control 2.44+/-1.64%, p=0.033). However, the proportion of IL-10+ B cells to total B cells correlated negatively with disease activity in RA patients (r=-0.398, p=0.040). Erythrocyte sedimentation rate or C-reactive protein or medication was not associated with the proportion of IL-10+ B cells. CONCLUSION: The proportion of induced IL-10+ B cell increased in RA patients compared to healthy control, however, negatively correlated with disease activity in RA.

B cell-associated immune profiles in patients with end-stage renal disease (ESRD)

Most of the previous studies on immune dysregulation in end-stage renal disease (ESRD) have focused on T cell immunity. We investigated B cell subpopulations in ESRD patients and the effect of hemodialysis (HD) on B cell-associated immune profiles in these patients. Forty-four ESRD [maintenance HD patients (n = 27) and pre-dialysis patients (n = 17)] and 27 healthy volunteers were included in this study. We determined the percentage of B cell subtypes, such as mature and immature B cells, memory B cells, and interleukin (IL)-10+ cells, as well as B cell-producing cytokines (IL-10, IL-4 and IL-21) by florescent activated cell sorting (FACS). B cell-associated gene expression was examined using real-time PCR and B cell producing cytokines (IL-10, IL-4 and IL-21) were determined using an enzyme-linked immunosorbent assay (ELISA). The percentage of total B cells and mature B cells did not differ significantly among the three groups. The percentages of memory B cells were significantly higher in the pre-dialysis group than in the HD group (P 0.05) between the two subgroups within the ESRD group, but the serum IL-10 concentration was significantly lower in the pre-dialysis group (P < 0.01). The results of this study demonstrate significantly altered B cell-associated immunity. Specifically, an imbalance of immature and memory B cells in ESRD patients was observed, with this finding predominating in pre-dialysis patients.

Three-way Translocation of MLL/MLLT3, t(1;9;11)(p34.2;p22;q23), in a Pediatric Case of Acute Myeloid Leukemia / 대한진단검사의학회지

The chromosome band 11q23 is a common target region of chromosomal translocation in different types of leukemia, including infantile leukemia and therapy-related leukemia. The target gene at 11q23, MLL, is disrupted by the translocation and becomes fused to various translocation partners. We report a case of AML with a rare 3-way translocation involving chromosomes 1, 9, and 11: t(1;9;11)(p34.2;p22;q23). A 3-yr-old Korean girl presented with a 5-day history of fever. A diagnosis of AML was made on the basis of the morphological evaluation and immunophenotyping of bone marrow specimens. Flow cytometric immunophenotyping showed blasts positive for myeloid lineage markers and aberrant CD19 expression. Karyotypic analysis showed 46,XX,t(1;9;11)(p34.2;p22;q23) in 19 of the 20 cells analyzed. This abnormality was involved in MLL/MLLT3 rearrangement, which was confirmed by qualitative multiplex reverse transcription-PCR and interphase FISH. She achieved morphological and cytogenetic remission after 1 month of chemotherapy and remained event-free for 6 months. Four cases of t(1;9;11)(v;p22;q23) have been reported previously in a series that included cases with other 11q23 abnormalities, making it difficult to determine the distinctive clinical features associated with this abnormality. To our knowledge, this is the first description of t(1;9;11) with clinical and laboratory data, including the data for the involved genes, MLL/MLLT3.

IL-10 is Predominantly Produced by CD19(low)CD5(+) Regulatory B Cell Subpopulation: Characterisation of CD19 (high) and CD19(low) Subpopulations of CD5(+) B cells

IL-10 production by CD19(+)CD5(+) B cells was investigated, by determining the expression levels of CD19, a classical B cell marker. Peripheral mononuclear cells were stained with fluorescence-conjugated anti-CD5, anti-CD19, anti-IL-10, and Annexin V. Interestingly, IL-10-producing B cells were found to be localised within the CD19(low)CD5(+) B cell subset. Apoptotic changes were also observed mainly in CD19(low) cells among B cells. Thus, CD5(+) B cells should be classified as CD19(high) and CD19(low) cells, and the immunological significance of CD19 for the IL-10 production by CD5(+) B cells requires further studies.

Distribution of Antigenic Aberration in the Bone Marrow of Acute Leukemia in Complete Remission / 대한진단검사의학회지

BACKGROUND: The aberrant, leukemia-associated antigen expression patterns allow us to discriminate leukemic blasts from normal precursor cells. Our major goal was to determine a guideline for the detection of minimal residual disease using CD20+/CD34+ and myeloid Ag+/CD19+ combination in the bone marrow of acute leukemia in complete remission (CR) after chemotherapy. METHODS: Bone marrow samples from 117 patients with acute leukemia in complete remission after chemotherapy and from 22 healthy controls were immunophenotyped by triple staining and measured by flow cytometry. RESULTS: The CD20+/CD34+ cells in the large lymphocyte gate (R1) ranged from 0% to 3.24% (0.8+/-0.82%, P=0.000) in CD20+/CD34+ B-lineage ALL CR (N=31), from 0.03% to 4.2% (0.7+/-0.83%, P=0.000) in CD20-/CD34- B-lineage ALL CR (N=66), from 0.1% to 0.96% (0.45+/-0.32%, P=0.016) in T-ALL CR (N=10), and from 0.02% to 0.48% (0.18+/-0.15%, P=0.776) in AML CR (N=10). The CD13,33+/CD19+ cells in R1 gate ranged from 0% to 2.69% (0.37+/-0.48%, P<0.001) in CD13,33+/CD19+ B-lineage ALL CR (N=31), from 0% to 1.8% (0.31+/-0.28%, P<0.001) in CD13,33-/CD19+B-lineage ALL CR (N=65), from 0.02% to 0.64% (0.29+/-0.22%, P=0.071) in T-ALL CR (N=9), and from 0% to 0.17% (0.07+/-0.09%, P=0.341) in AML CR (N=3). CONCLUSIONS: Using an immunophenotypic method for the detection of early relapse or minimal residual disease of B-lineage ALL bone marrow in CR after chemotherapy, different cutoff values should be applied according to antigen combination and gating. When the proportion of aberrant antigen combination was less than 5% in large lymphocyte gate, the results should be interpreted with caution.

Characteristics of Acute Myeloid Leukemia without HLA-DR Expression / 대한진단검사의학회지

BACKGROUND: HLA-DR negativity is known to be useful for distinguishing acute promyelocytic leukemia (APL) from other subtypes of AML, but non-APL cases without HLA-DR antigen expression have been reported. The purpose of this study was to evaluate and compare the characteristics of APL, HLA-DR negative non-APL, and HLA-DR positive non-APL cases. METHODS: A total of 114 cases of AML admitted at Ewha Womans University, Mokdong Hospital between March 1997 and June 2006 were included in this study. A diagnosis of AML was made based on the results of morphology, cytochemistry, immunophenotype, cytogenetics, and/or fluorescence in situ hybridization. RESULTS: Among the 114 AML patients, HLA-DR antigen was not expressed in 39 (34%), including 24 non-APL (62%) and 15 APL patients (38%). The HLA-DR negative non-APL group showed higher leukocyte counts and positive rate of CD19 expression than did APL group (P<0.05). The remaining laboratory findings were not statistically different between the HLA-DR negative non-APL and APL groups. CD34 expression was more frequent in the HLA-DR positive non-APL group than in the HLA-DR negative non-APL group and APL group. Of the 24 patients with HLA-DR negative non-APL, 7 patients had disseminated intravascular coagulation and 2 patients showed morphologic features similar to those of APL. CONCLUSIONS: CD19 expression and leukocyte count may be helpful for differentiating HLA-DR negative non-APL from APL. However, the final diagnosis and classification should be confirmed by cytogenetic or molecular studies.

Proportions of Cells Expressing CD38-/CD34+, CD38+/CD34+, CD19+/CD34+, or CD13,33+/CD34+ in the Regenerating Bone Marrows During Complete Remission of Acute Leukemia or After Bone Marrow Transplantation / 대한진단검사의학회지

BACKGROUND: The hemopoietic stem cells increase in number during the regeneration after chemotherapy or bone marrow transplantation (BMT). Although the proportion of hemopoietic stem cells and their differentiation have been studied by immunophenotyping using the flow cytometry, no substantial research efforts have been directed toward the regenerating marrow. We attempted to discover the proportions of undifferentiated stem cells, committed stem cells, B cell precursors, and myeloid precursors in the regenerating bone marrows during complete remission (CR) and after engraftment of BMT. METHODS: Bone marrow samples from 82 patients with acute leukemia in CR and from 25 patients after BMT engraftment, along with 22 control samples, were used to find the numbers of CD38-/CD34+, CD38+/CD34+, CD19+/CD34+, and CD13,33+/CD34+ cells in the large lymphocyte gate by flow cytometry. We cross-analyzed our results in terms of groups: CR, BMT, and initial diagnosis groups. We performed significance tests on age, relapse, chromosomal abnormalities, clinical outcomes, and initial immunophenotypes of the leukemic cells. RESULTS: The proportions of CD38-/CD34+, CD38+/CD34+, CD19+/CD34+, and CD13,33+/CD34+ cells are more highly distributed in acute B-lymphoblastic leukemia than the normal group and also in the CR than the BMT group. CD19+/CD34+ cells were increased in the relapse group and CD38+/ CD34+, CD19+/CD34+, and CD13,33+/CD34+ cells were increased in the group with chromosomal abnormality. The results were irrelevant to the initial immunophenotype of the leukemic blasts. CONCLUSIONS: The increases of the markers spanned too widely to apply one specific cutoff value to analyze them. They seemed to be the results of normal regeneration, irrelevant to relapse or initial immunophenotype of leukemic blasts.