Role of myeloid-derived suppressor and Th17/Treg cells in post-COVID-19 Rhino-Orbital mucormycosis cases.

Rhino-Orbital-Cerebral Mucormycosis (ROCM) cases increased sharply in India during the second COVID-19 wave. Due to uncontrolled hyperglycemia, prolonged steroid use, and high ferritin levels, the immune system was dysregulated throughout this surge. Our study examined post-COVID-19 ROCM patients' T regulatory cell (Treg), T helper 17 cell (Th17) and Myeloid derived suppressor cell (MDSC) levels before and after three months of treatment. T cell activation and MDSC profile were measured in peripheral blood from 20 post-COVID-19 mucormycosis patients and 20 age-matched controls. Compared to controls, cases had significantly greater Th17 cells (CD4IL-23R) before and after treatment ( < 0.05), with no significant change between pre- and post-treatment. In pretreatment cases, Treg cells (CD4CD25FoxP3) were lower than controls, but dramatically increased ( < 0.05) following treatment. Further, these patients had significantly higher rates of monocytic (m) MDSCs (CD14HLA-DR) compared to healthy persons ( < 0.05). Interestingly, after three months of treatment, mMDSC levels dropped to levels similar to healthy controls. Similarly, ROCM patients had higher levels of granulocytic (g) MDSCs (HLA-DRCD33CD11bCD66) than healthy controls, although these levels normalized after three months. Patients had considerably greater expression levels of RORγt, TGF-β, and IL-10 mRNA before therapy compared to healthy controls. FoxP3 and Arg-1 mRNA expression was lower in pretreatment patients than in healthy people. After treatment, these individuals' IL-10, FoxP3, and Arg-1 mRNA expression increased. MDSCs may play a role in mucormycosis immunological dysregulation, suggesting that restoring balance may improve patient outcomes.