Cellular analysis of cutaneous leishmaniasis lymphadenopathy: insights into the early phases of human disease

Abstract

Lymphadenopathy is an early clinical sign in cutaneous leishmaniasis (CL), caused by Viannia parasites, and may help to understand the initial host response to these species of Leishmania. We report on characteristics of cells obtained from lymph nodes from cutaneous leishmaniasis patients with lymphadenopathy without ulceration (early phase, N = 21) or lymphadenopathy and ulceration (late phase, N = 29). Early-phase patients exhibited a higher proportion of neutrophils, eosinophils, and CD8+ T cells. Conversely, CD19+ B lymphocytes and plasma cells were more frequently observed in late-phase patients. The signal for IL-10 was significantly higher in late-phase patients; signals for IFN-gamma or IL-4 were similar in both groups. These data reinforce observations of an initial mixed Th1-Th2 profile as well as the early role of the CD8 T cell in cutaneous leishmaniasis. Additionally, there is a chronologic relationship between ulcer development and B-cell increase. IL-10 also increases at a late stage and may be important in limiting tissue damage.