Plasma exchange in severe erythema nodosum leprosum.

Four patients with severe erythema nodosum leprosum were treated by plasma exchange and/or fresh frozen plasma infusions after failure of classical therapy. After the procedures, the patients improved rapidly; with a follow-up between 4 and 7 years after the last plasma exchange, no clinical relapse was noted. The replacement fluids were variable; the most beneficial procedure seemed to be plasma exchange replaced with fresh frozen plasma. Elimination of circulating immune complexes, replacement of a lacking plasma factor are possible mechanisms of action. Plasma exchange may also work like a regulator of immune mechanisms, since it has been shown that there is a depression of suppressor cells in erythema nodosum leprosum.