Characterization of the activation status of T lymphocyte subpopulations in peripheral blood from localized and diffused cutaneous leishmaniasis patients at the University of Gondar Hospital, Ethiopia

Abstract

Cutaneous leishmaniasis (CL) is the most common clinical form of leishmaniasis and remains a major public health problem worldwide. In the Ethiopian setting, reports regarding the human immune response against CL infection are limited. Therefore, this study aimed to determine T lymphocyte subpopulations’ frequency, activation, and proliferation status from peripheral blood of LCL and DCL patients at the University of Gondar Hospital. An institutional based cross-sectional study was conducted on 22 confirmed CL patients attending the Leishmania Research and Treatment Center (LRTC) of the University of Gondar Hospital from January to June 2017. As a control, 14 healthy participants were recruited from Voluntary Counseling and Testing (VCT) clinics of selected health centers. Blood samples were stained, and surface marker expression was evaluated by flow cytometry. Statistical analysis was performed using Kruskal-Wallis followed by Dunn’s multiple comparisons test and the differences were considered statistically significant when the P-values were < 0.05. In this study, all the results are expressed as medians with inter-quartile range (IQR). Both DCL and LCL subjects showed an increased expression of CD38 and HLA-DR markers on T cell subsets compared to control groups. A significant reduction in the frequency of CD8+ T cells was observed in the DCL as compared to the LCL patients (P = 0.04). The co-expression of CD38 and HLA-DR markers on CD4+ and CD8+ T cells was significantly higher among DCL patients when compared with health controls (HC) (P = 0.04) and (P = 0.01), respectively. In contrast, the proliferation marker Ki-67 expression by activated cells did not show significant differences between the CL cases and HC (p > 0.05). The expression levels of activation markers are associated with the LCL and DCL clinical forms of L. aethiopica caused CL. The presence of elevated levels of activated non-proliferating immune cells in DCL cases, as well as reduced numbers of CD8 T cells is consistent with a mechanism of T-cell activation followed by anergy and/or apoptosis.