PHD SCHOLAR Sanjay Gandhi PostGrad. Inst. of Med. Sci. Lucknow, Uttar Pradesh, India
Introduction/Rationale: Macrophages contribute to both acute and chronic renal allograft injury. M2 macrophages are alternatively activated by exposure to cytokines. CD163 is a marker of M2 macrophages. We performed this study to evaluate the urinary soluble CD163 (usCD163) and peripheral blood total and monocyte-derived microparticles (MMPs) in antibody-mediated rejection (ABMR) to analyze their role as a non-invasive biomarker in renal allografts .
Methods: The study included fifty patients presented with renal allograft dysfunction on for-cause renal allograft biopsy. Twenty patients with stable graft function (SGF) and twenty age, sex matched healthy controls (HC) and ten follow-up patients of ABMR were also included in the study. usCD163 level was estimated by ELISA as per manufacturer’s protocol and circulating MMPs were quantified as PE-CD14+/APC-AV+ by flow cytometry.
Results: The mean age of participants was 37.3±8.8yrs.The mean level of urinary sCD163 in ABMR was 0.7±0.6 ng/ml, 0.06±0.05 ng/ml in SGF, 0.01±0.06 ng/ml in HC and 0.19±0.12 ng/ml in follow up patients. Total MPs MMPs were also elevated in ABMR as compared to SGF, HC and follow-up controls with a mean of 26%, 13.4%, 10.6% and 14.9% of total MPs respectively. The usCD163 levels significantly correlated with serum creatinine (r=0.372, p=0.008) and MMPs (r=0.308, p=0.035).
Conclusion: We found significantly elevated urinary sCD163 levels and circulating MMPs in ABMR.A decrease in both were observed after the immunosuppression administration in follow-up patients .Urinary sCD163 can be investigated as a non-invasive biomarker of injury in renal allografts. Our findings suggest an important role of macrophage activation in ABMR and it could be a potential therapeutic target in these patients.
