Relationship Between sCD163 and mCD163 and Their Implication in the Detection and Typing of Leprosy

BACKGROUND: Leprosy is a chronic contagious disease caused by Mycobacterium lepraea. CD163 is a monocyte trans-membrane glycoprotein receptor (mCD163) that sheds from the cell surface and circulates as a soluble (serum) form (sCD163). Changes in the mCD163 and sCD163 levels could mirror the categorization of inflammatory procedure, demonstrating a possible use of CD163 as a diagnostic indicator of inflammation. OBJECTIVE: To investigate the possible role of CD163 (sCD163 and mCD163) in leprosy pathogenesis and to assess whether CD163 is a helpful inflammatory marker of leprosy development and typing. PATIENTS AND METHODS: This case control study included 70 leprosy patients and 30 healthy controls. Leprosy patients were classified according to the Madrid criteria (1953) into: tuberculoid leprosy (TT), border-line leprosy (BL), and lepromatous leprosy (LL). For all participants, complete blood count (CBC), serum CD163 using ELISA and monocytes positive for CD163 using flow cytometry were done. RESULTS: Leprosy patients had significantly low WBCs and platelet counts (p<0.001) and had significantly higher sCD163 (p=0.025) and mCD163 (p=0.042) that were highest in LL followed by BL, then TT patients (p<0.001). There was a significant positive correlation between mCD163 and sCD163 levels in leprosy patients (r=0.896, p<0.001). ROC analysis revealed a significant role of serum sCD163 and of mCD163 positive monocytes in the detection (p<0.001) and typing of leprosy (p=0.002 and p<0.001, respectively). CONCLUSION: Both sCD163 and mCD163 positive monocytes may have an active role in leprosy pathogenesis. They could be potential biomarkers for leprosy detection and typing.