IgE antibodies against piperazine and N-methyl-piperazine in two asthmatic subjects.

The presence of specific IgE antibodies against conjugates between human serum albumin and piperazine, a compound previously known to cause occupational asthma, and N-methyl-piperazine, respectively, was demonstrated by RAST, RAST inhibition and skin prick tests in 2 asthmatic subjects occupationally exposed to these agents.