Immunoprofile of reactions in leprosy.

The immunologic profile during erythema nodosum leprosum (ENL) revealed increased percentage and absolute count of B-lymphocytes, in addition to considerably lowered levels of complement component C3. Serum immunoglobulins--IgG, IgA, and IgM--were significantly raised after subsidence of ENL, whereas upgrading reaction showed an increase of absolute count of total T lymphocytes and percentage and count of B-lymphocytes. In addition, a raised serum IgM level was noted after regression of ENL. Downgrading reaction demonstrated a decreased percentage of early T-lymphocytes and raised the absolute count of B-lymphocytes. Serum IgA levels were found to be increased after amelioration of ENL.