Changes in expression of signal transduction proteins in T lymphocytes of patients with leprosy.

Advanced stages of mycobacterial diseases such as leprosy and tuberculosis are characterized by a loss of T-cell function. The basis of this T-cell dysfunction is not well understood. The present report demonstrates major alterations in the expression of signal transduction molecules in T cells of leprosy patients. These alterations were most frequently observed in lepromatous leprosy (LL) patients. Of 29 LL patients, 69% had decreased T-cell receptor zeta-chain expression, 48% had decreased p56(lck) tyrosine kinase, and 63% had a loss of nuclear transcription factor NF-kappaB p65. An electrophoretic mobility shift assay with the gamma interferon core promoter region revealed a loss of the Th1 DNA-binding pattern in LL patients. In contrast, tuberculoid leprosy patients had only minor signal transduction alterations. These novel findings might improve our understanding of the T-cell dysfunction observed in leprosy and other infectious diseases and consequently might lead to better immunologic evaluation of patients.

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-1 beta 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-CD3 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.