Immunosuppression Has Long-Lasting Effects on Circulating Follicular Regulatory T Cells in Kidney Transplant Recipients

Background: FoxP3⁺ follicular regulatory T cells (Tfr) have been identified as the cell population controlling T follicular helper (Tfh) cells and B cells which, are both involved in effector immune responses against transplanted tissue.

Methods: To understand the biology of Tfr cells in kidney transplant patients treated with tacrolimus and mycophenolate mofetil (MMF) combination immunosuppression, we measured circulating (c)Tfh and cTfr cells in peripheral blood by flow cytometry in n = 211 kidney transplant recipients. At the time of measurement patients were 5–7 years after transplantation. Of this cohort of patients, 23.2% (49/211) had been previously treated for rejection. Median time after anti-rejection therapy was 4.9 years (range 0.4–7 years). Age and gender matched healthy individuals served as controls.

Results: While the absolute numbers of cTfh cells were comparable between kidney transplant recipients and healthy controls, the numbers of cTfr cells were 46% lower in immunosuppressed recipients (p < 0.001). More importantly, in transplanted patients, the ratio of cTfr to cTfh was decreased (median; 0.10 vs. 0.06), indicating a disruption of the balance between cTfr and cTfh cells. This shifted balance was observed for both non-rejectors and rejectors. Previous pulse methylprednisolone or combined pulse methylprednisolone + intravenous immunoglobulin anti-rejection therapy led to a non-significant 30.6% (median) and 51.2% (median) drop in cTfr cells, respectively when compared to cTfr cell numbers in transplant patients who did not receive anti-rejection therapy. A history of alemtuzumab therapy did lead to a significant decrease in cTfr cells of 85.8% (median) compared with patients not treated with anti-rejection therapy (p < 0.0001). No association with tacrolimus or MMF pre-dose concentrations was found.

Conclusion: This cross-sectional study reveals that anti-rejection therapy with alemtuzumab significantly lowers the number of cTfr cells in kidney transplant recipients. The observed profound effects by these agents might dysregulate cTfr functions.

Interstitial Lung Disease-Complicated Anti-MDA5 Antibody in Clinically Amyopathic Dermatomyositis Patients: Report of Two Cases With Distinct Clinical Features

Two patients presented simultaneously to our hospital with distinct clinical features associated with the presence of anti-MDA5 antibodies: the first one was admitted for a skin rash resembling to a toxic epidermal necrosis (Lyell syndrome) and the second one presented with pulmonary manifestations attributed to a diffuse fibrosing interstitial pneumonitis on chest CT-scan. In addition to the skin lesions involving 40% of the body surface area, the first patient developed a rapid diffuse interstitial pneumonitis with respiratory distress justifying the initiation of a systemic immunosuppressive treatment. However, she died 3 weeks after her admission from mesenteric thrombosis associated with septic shock. The second patient respiratory condition worsened despite an intensive immunosuppressive treatment with high doses of intravenous methylprednisolone and cyclophosphamide and plasmapheresis, and required lung transplantation. Anti-MDA5 antibody titer declined and disappeared on anti-rejection treatment. These two cases underline the diagnostic conundrum and the therapeutic difficulties in patients with anti-MDA5 antibodies and clinically amyopathic dermatomyositis (CADM) or interstitial lung disease (ILD), who may undergo rapidly-progressive and fatal outcome. Presence of anti-MDA5 antibodies should always be suspected when confronted to CADM patients with cutaneous ulcerations or ILD to allow a rapid and adapted treatment initiation.