Background: Tumor necrosis factor-alpha (TNF) is an important mediator of immunologic responses to chronic infections.
Method: Sera from 25 patients with acute reactions (6 with type 1 upgrading, 8 with type 1 downgrading, and 11 with type 2 reaction) were assayed for TNF before treatment and after clinical remission of the acute episode. The results were compared with serum TNF levels in healthy controls and fresh pauci- and multibacillary leprosy patients.
Results: TNF levels in acute reactions were higher than in the control groups (significant only in upgrading reaction). In type 1 reaction, serum TNF concentrations fell to approximately the levels of the control patients following treatment and clinical remission. In type 2 reaction, however, levels of TNF were seen to rise further (became statistically significant) as a result of therapy induced clinical remission.
Conclusions: The rise in TNF-alpha level in reactions in leprosy is significant and indicates its active role in immunopathogenesis. The corresponding decline in TNF-alpha levels seen following regression of type 1 (lepra) reactions was not observed in the case of type 2 (ENL) reaction. This probably reflects the enhancement of cellular immunity in such cases and/or an attempt by the immunologic process to overcome specific inhibitors.