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

IL-10 dependent modulatory effect of regulatory B10 cells on local scar formation following Roux-en-Y choledochojejunostomy in a novel rat model

Choledochojejunostomy has been common surgical treatment of biliary tract disease. Scar formation at anastomotic often results in postoperative complications associated with bleak post-operative recovery, in which local inflammation may be a potential target to modulate local scar formation. This study investigated the effect of regulatory B10 cells on local scar formation through interleukin-10 signal pathway following Roux-en-Y choledochojejunostomy (RCJS) in a novel rat model. Sprague-Dawley (SD) rats with RCJS were randomly divided into blank group, experimental group, IL-10 blocking group, control group, and received different interventions and duration. Injected through dorsal vein of penis, rats in different groups were treated respectively according to scheme. These interventions were performed during surgery, on 1st day, and 2nd day after surgery. Related indexes, including blood examination, specimen tissue of anastomotic detection, were recorded and compared in different interventional groups. Rats in experimental groups had more rapid recovery in liver function and inflammatory index, and higher in IL-10 level. Flow cytometry analysis showed that rats in experimental groups had highest content of B10 cells and lowest content of CD4+CD25- T cells in peripheral blood. Wider anastomotic by macroscopical observation, and slighter proliferation of collagen fiber and smooth muscle fiber, lower α-SMA and TGF-β1 levels by pathological staining were detected in experimental groups. Higher expression of the IL-10 gene and lower expression of TGF-β1 at anastomotic were detected in experimental groups. B10 cells may relieve local inflammation of anastomotic following RCJS in rats through IL-10-dependent modulatory effect, and improve local scar formation.

Influence of Housing Temperature and Genetic Diversity on Allogeneic T Cell-Induced Tissue Damage in Mice

The objective of this study was to determine how housing temperature and genetic diversity affect the onset and severity of allogeneic T cell-induced tissue damage in mice subjected to reduced intensity conditioning (RIC). We found that adoptive transfer of allogeneic CD4+ T cells from inbred donors into sub-lethally irradiated inbred recipients (I→I) housed at standard housing temperatures (ST; 22-24 °C) induced extensive BM and spleen damage in the absence of injury to any other tissue. Although engraftment of T cells in RIC-treated mice housed at their thermo-neutral temperature (TNT; 30-32 °C) also developed similar BM and spleen damage, their survival was markedly and significantly increased when compared to their ST counterparts. In contrast, the adoptive transfer of allogeneic T cells into RIC-treated outbred CD1 recipients failed to induce disease in any tissue at ST or TNT. The lack of tissue damage was not due to defects in donor T cell trafficking to BM or spleen but was associated with the presence of large numbers of B cells and myeloid cells within these tissues that are known to contain immunosuppressive regulatory B cells and myeloid-derived suppressor cells. These data demonstrate, for the first time, that housing temperature affects the survival of RIC-treated I→I mice and that RIC-conditioned outbred mice are resistant to allogeneic T cell-induced BM and spleen damage.

Cyclosporine Monotherapy in Pediatric Patients With Non-severe Aplastic Anemia: A Retrospective Analysis

Objective

The management of children with non-severe aplastic anemia (NSAA) is undefined and the efficacies and benefits of immunosuppressive therapy remain inconsistent. The study aimed to investigate the efficacy of Cyclosporine (CsA) monotherapy for pediatric NSAA.

Methods

Clinical data of children with NSAA who had been treated with CsA monotherapy at the outpatient department of Beijing Children's Hospital, Capital Medical University, National Children's Medical Center from January 2017 to March 2021 was collected retrospectively. Patients who had been treated <1 years until the end of follow-up were excluded. Transfusion-independent NSAA was further divided into moderate NSAA and mild NSAA according to the degree of cytopenia. Progression was defined as the development of transfusion-dependent AA or SAA and relapse was considered when treatment failed after initial response.

Results

A total of 95 pediatric patients with NSAA were enrolled in this study with 49 (51.6%) patients confirmed as mild NSAA, 38 (40%) as moderate NSAA and 8 (8.4%) as transfusion-dependent NSAA. The median treatment time of CsA was 22 (12–44) months. The overall response rate (ORR) was 57.9%, with 30.5% CR and 27.4% PR. Unexpectedly, patients with mild NSAA acquired lowest ORR (46.9%), then patients with moderate NSAA (63.2%), while 8 patients who were transfusion-dependent all had an active response to CsA. The granulocyte and megakaryocyte response was 46.9 and 55.8% respectively, while the erythrocyte response rate was as low as 22.5%. Univariate analyses revealed that patients with lower platelet count and higher interleukin 10 level predict an active response to CsA while higher level of fetal hemoglobin (HbF) tended to be a negative factor. Data of Treg cells before and after 1 year's treatment was available in a total number of 40 patients. Paired comparison found that the percentage of Treg cells in CD4+ T cells was decreased after 1 year's treatment of CsA (6.78 ± 2.72 vs. 5.23 ± 2.06, P = 0.001),both in responders and non-responders. The degree of decline in Treg cells between two distinctive response groups had no significant difference (P>0.05). With a median follow-up time of 22 months, 10.9% of responders relapsed and maintained NSAA while 27.5% of non-responders progressed to SAA or became transfusion-dependent. The overall progression rate was 11.6%.

Conclusion

CsA monotherapy had heterogeneous effects in the treatment of children NSAA Treatment approaches should be hierarchical and individual in clinical. Patients with lower platelet count and higher interleukin 10 level predicted an active response to CsA. While higher level of fetal hemoglobin (HbF) tended to be a negative factor. The percentage of Treg cells in CD4+ T cells was decreased broadly after treatment.

Deficit of circulating CD19+ CD24hi CD38hi regulatory B cells in severe aplastic anaemia

Immune aplastic anaemia (AA) is caused by cytotoxic T lymphocytes (CTLs) that destroy haematopoietic stem and progenitor cells. Enhanced type 1 T helper (Th1) responses and reduced regulatory T cells (Tregs) are involved in the immune pathophysiology. CD24^hiCD38^hi regulatory B cells (Bregs) suppress CTLs and Th1 responses, and induce Tregs via interleukin 10 (IL‐10). We investigated circulating B‐cell subpopulations, including CD24^hiCD38^hi Bregs, as well as total B cells, CD4⁺ T cells, CD8⁺ T cells and natural killer cells in 104 untreated patients with severe and very severe AA, aged ≥18 years. All patients were treated with standard immunosuppressive therapy (IST) plus eltrombopag. CD24^hiCD38^hi Bregs were markedly reduced in patients with AA compared to healthy individuals, especially in very severe AA, but residual Bregs remained functional, capable of producing IL‐10; total B‐cell counts and the other B‐cell subpopulations were similar to those of healthy individuals. CD24^hiCD38^hi Bregs did not correlate with responses to IST, and they recovered to levels present in healthy individuals after therapy. Mature naïve B‐cell counts were unexpectedly associated with IST response. Markedly reduced CD24^hiCD38^hi Bregs, especially in very severe AA, with recovery after IST suggest Breg deficits may contribute to the pathophysiology of immune AA.

Low frequency of IL-10-producing B cells and high density of ILC2s contribute to the pathological process in Graves' disease, which may be related to elevated-TRAb levels

IL-10-producing B Cells (B10) is a functionally defined regulatory B-cell subset. It plays an important role in the control of inflammation and autoimmune diseases, although it is present at low numbers in peripheral blood. Graves' disease is an autoimmune disease characterized by the production of autoantibodies such as TRAb. ILC2s maintains Th2 polarization state by producing type-II cytokines. It is not clear whether the level of autoantibody is related to ILC2s and B10 cells in Graves' disease. In this study, we analyzed the frequencies of B10, Treg cells and ILC2s, as well as the expression of related cytokines in peripheral blood from patients with Graves' disease and evaluated the correlation between B10 cell numbers and autoantibodies level. Our data showed that the frequency of B10 or Treg cells was significantly decreased in peripheral blood mononuclear cells from Graves' disease patients, while the percentage of ILC2s cells was increased; the levels of cytokine IL-5, IL-13 and related transcription factor RORα were up-regulated. Autoantibodies analysis also showed that high level of TRAb was accompanied by low rates of B10 cells in patients, there was a negative correlation trend. In addition, the analytical data from mouse disease models also showed similar results. It indicates that B10 cells may affect the production of TRAb by negative regulation of Th2 cells, while ILC2s can promote the production of autoantibodies such as TRAb by maintaining the dominant response state of Th2 cells.