Increased CD5+ B-cells are associated with autoimmune phenomena in lepromatous leprosy patients

Leprosy is a chronic slowly progressive infection caused by Mycobacterium leprae that primarily affects the skin and peripheral nerves. Lepromatous leprosy is characterized by absence of T-cell responses to M. leprae and advanced clinical disease. It is frequently associated with the presence of autoantibodies, which might be related to CD19⁺CD5⁺ and CD19⁺CD5^- B lymphocyte percentages. Therefore, the aim of this study was to evaluate the percentages of CD19⁺CD5⁺ and CD19⁺CD5^- B cell subsets as well as the total B cells in lepromatous leprosy patients.

Twenty lepromatous leprosy patients and ten healthy subjects served as control were included in this study. Venous blood samples were analyzed by flow cytometry to determine the B cell subsets and total B cell percentages.

Compared to healthy controls, the percentages of CD19⁺CD5⁺ B cell subset and total B cells were found to be significantly higher in the patient group. While, the percentage of CD19⁺CD5^- B cell subset was found to be higher in the patient group than the control without any significantly difference. Regarding the eye affection, the percentage of total B cells was observed to be significantly higher in affected patients compared to the non-affected group.

The observed significant increases in CD19⁺CD5⁺ and total B cell percentages in patients with lepromatous leprosy suggests a possible role of these cells in the disorganized protective immune response as well as the development of eye complications in these patients.