GENERATION OF NEW REGULATORY T CELLS AND INCREASED IL-10 LEVELS IN SYSTEMIC SCLEROSIS PATIENTS TREATED WITH AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION

Abstract

Background: Systemic Sclerosis (SS) is an autoimmune disease characterized by immune dysregulation, vascular damage, and fibrosis of the skin and internal organs. Autologous Hematopoietic Stem Cell Transplantation (AHSCT) has been used as a therapeutic option for patients with severe and progressive forms of the disease. Immunological monitoring studies demonstrate that AHSCT generates a more self-tolerant lymphocyte repertoire, increases immunoregulatory mechanisms, and promotes a more anti-inflammatory immune profile in patients with autoimmune disorders. However, these investigations require further detailing. Methods: In this study, we evaluated the frequency of Naïve Regulatory T Cells (Tregs), serum levels of Inflammation and immunoregulation-related cytokines and clinical data. Peripheral Blood Mononuclear Cell (PBMC) samples from 14 SSc patients were evaluated by flow cytometry. Frequency was evaluated on Treg expressing CD3, CD4, CD25, CD45RA, and FOXP3. Serum samples were assessed for TNF-, IFN-, IFN-, CCL2, CCL3, IL-1, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-13, IL-17, IL-21, IL-31, IL-33 by multiplex assay. Results: Most participants were female (78%) with a median age (range) of 32 (16‒59) years. Skin fibrosis assessed by mRSS improved from median (range) 27 (11‒41) at baseline to 18 (9‒32) at 12-months and 16 (6‒31) at 24-months after AHSCT. Forced vital capacity and DLCO percentages remained stable after AHSCT. The frequency of naive Tregs (CD45RA+FoxP3highCD4+) decreased at 3 and 24-months post-transplantation compared to baseline (p < 0.05). However, there was a significant increase in their frequency at 36- and 42-months compared to 3-months after AHSCT (p < 0.05). When comparing the levels serum cytokines, there was a decrease in IFN- levels at 12-months (p < 0.05) and CCL-2 and IL-8 decreased at 24-months (p < 0.05). Serum levels of TNF-α, IL-13, IL-31, and IL-33 remained unchanged after transplantation in SSc patients. Of all serum cytokines analyzed, only the anti-inflammatory molecule IL-10 showed an increase at 12 (p < 0.05) and 24 (p < 0.01) months compared to baseline; there was also an increase from 12- to 24-months (p < 0.01). Conclusion: The results showed an increase in naive regulatory T cells, indicating the generation of new regulatory cells. Notably, serum levels of key proinflammatory cytokines such as IFN-γ, CCL-2, and IL-8 showed significant reductions post-transplantation, while serum levels of IL-10, a crucial immunoregulatory cytokine, significantly increased. This suggests that AHSCT can modulate the inflammatory milieu and improve immunoregulatory mechanisms, contributing to the clinical improvements observed in these patients.