Lepromatous and tuberculoid leprosy: Clinical presentation and cytokine responses

Objective. This study analyzes the major clinical characteristics of patients with active leprosy in relation to the in vitro immune response to the T-lymphocyte activator anti-CD3. Methods. Thirty-eight patients with an established diagnosis of leprosy were classified according to the Ridley and Jopling table. Peripheral blood mononuclear cells from both lepromatous leprosy (LL) and tuberculoid leprosy (TL) patients and healthy controls were used to evaluate lymphocyte proliferation; immunoenzymatic assays were used to evaluate cytokine production (IL-1, IL-2, IL-4, IL-6, IL-10, IFN-gamma). Results. Peripheral blood mononuclear cells from both LL and TL patients displayed blastogenic responses to anti-CD3. The cytokines IL-1 beta, IL-6, IL-10, and IFN-gamma were detected in culture supernatants. Endogenous production of IL-18 was significantly higher in cell cultures from patients with the lepromatous form of the disease compared to those with tuberculoid leprosy. Production of IL-6 in response to anti-CD3 was observed in a significantly higher proportion of LL than TL patients (P = 0.0025). Gamma-interferon production did not differ between TL and LL, but a direct correlation was observed between time of multidrug treatment and IFN production in vitro (P = 0.016). Interleukin-10 was detected in culture supernatants of lymphocytes activated by anti-CDS from both patient groups, but not from healthy controls. Conclusions. The findings of this study suggest that patients with the two distinct forms of leprosy are capable of responding to a polyclonal T-lymphocyte stimulus such as anti-CD3 and provide evidence suggestive of alterations in the immune responses mediated by cytokines that may contribute to the spectrum of disease and response to treatment.