Relationship of transitional regulatory B and regulatory T cells and immunosuppressive drug doses in stable renal transplant recipients

Abstract

Objectives Regulatory B cells (Bregs) and T cells (Tregs) are thought to be involved in the regulation of graft acceptance in renal transplant recipients. However, mechanisms that affect Breg differentiation and interaction with Tregs are rather unclear. Methods Using eight‐color‐fluorescence flow cytometry, Tregs and CD19+ CD24hiCD38hi Bregs were analyzed in whole blood samples of 80 stable kidney transplant recipients, 20 end‐stage renal disease (ESRD) patients and 32 healthy controls (HC). In addition, differentiation of Bregs and Tregs was studied in different micromilieus using cocultures with strongly enriched B‐lymphocytes and autologous peripheral blood mononuclear cells stimulated with CpG and phytohemagglutinin. Results Bregs were higher in HC than in ESRD patients and lowest in transplant recipients. Bregs were higher early as compared to late posttransplant. Posttransplant, high Bregs were associated with higher glomerular filtration rate (GFR) and lower C‐reactive protein (CRP). Higher doses and blood levels of ciclosporine, tacrolimus, and mycophenolate mofetil as well as higher doses of steroids were not associated with low Bregs. In contrast, most Treg subsets were lower when blood levels of ciclosporine, tacrolimus, and mycophenolate mofetil were higher. Tregs were not associated with Bregs, GFR, CRP plasma levels, and occurrence of rejection or infection. In vitro, differentiation of Bregs was strongly dependent on T cell support and was blocked by excessive or lacking T‐cell help. Tregs were not associated with Breg numbers in vitro. Conclusion Bregs appear to be insensitive to high doses of posttransplant immunosuppressive drugs. The protracted Breg decrease posttransplant might be caused by impaired T cell support attributable to immunosuppressive drugs.

Evaluation of Regulatory B Cell Subpopulations CD24++CD38++, CD24++CD27+, Plasmablasts and Their Correlation with T Regs CD3+CD4+CD25+FOXP3+ in Dialysis Patients and Early Post-Transplant Rejection-Free Kidney Recipients

“…No correlation was found between the frequencies and absolute numbers of tBregs and Tregs in dialysis patients, either before or after transplantation. Ibrahim et al [ 24 ] and Piloni et al [ 29 ] reported similar results. However, it is important to note that Piloni’s study focused on lung transplantation and not on kidney transplantation.…”

“…Our results are in contrast to those of Shabir et al [ 27 ], who found no association between tBregs frequency and eGFR 12 months after transplantation. However, Imrahim EH et al [ 24 ] found that only the frequency of tBregs was associated with the eGFR, although not significantly, but not the absolute number. We found a significant correlation between the eGFR and the frequency of plasmablasts, suggesting that only the frequency of plasmablasts and both the frequency and absolute number of tBregs are associated with renal function.…”

“…Chung et al [ 23 ] found that tacrolimus and mycophenolate mofetil reduced the frequency and number of immature B cells in in vitro cultures, which may explain our findings of a reduction in tBregs due to general immunosuppressive therapy. Ibrahim et al [ 24 ] observed quantitative changes in tBregs. They studied the cell population over a longer period and found that tBregs decreased in less than a year in 45 patients in their cohort.…”

Induction of Long-Lasting Regulatory B Lymphocytes by Modified Immune Cells in Kidney Transplant Recipients

“…29 Rebollo-Mesa et al, in the Genetic Analysis of Molecular Biomarkers of Immunologic Tolerance (GAMBIT) study, observed a slightly higher proportion of TrBs in patients receiving reduced or no corticosteroids, but this result was not fully explained by reduction of immunosuppression. 30 We have recently shown that higher TrB percentages were not associated with lower immunosuppression, 31 and already in our first analysis, we found that on day 135 after transplantation, before steroids were stopped in three of four group C patients, the median TrB percentage was already 9% (range 2%-20%), which was considerably higher than in transplanted controls. 6 In the current analysis, TrB percentages in MICtreated patients were 75-fold higher than TrB percentages in patients with minimal immunosuppression (LTS-mi) and seven-fold higher than TrB percentages in operationally tolerant patients without MIC treatment, clearly showing that the increase in TrBs cannot be explained by immunosuppression reduction alone.…”

Immune Profiling of Peripheral Blood Mononuclear Cells at Pancreas Acute Rejection Episodes in Kidney-Pancreas Transplant Recipients

“…This approach has also lead to novel insights in other solid organs transplants, such as kidney (2)(3)(4)(5), liver (6), heart (7), and lung transplantation (8,9). There have been several studies highlighting the relevance of subsets of T cells and B cells on the outcome of organ transplantation (4,5,10,11). This understanding of transplant immunology has led to the development of strategies to mitigate immunosuppression side effects, by identification of donorspecific B and T cells prior to transplantation and adjusting immunosuppression accordingly (12), or through the treatment with regulatory cell therapies (13).…”