In Reply:-As Kindler and Bircher correctly point out, immunoglobulin E and immunoglobulin G antibodies to protamine were not measured, and, therefore, the precise mechanism underlying our observations remains uncertain. Although I did not have control subjects, I do not think the protamine with concentrations between 10 and 100 micro gram/ml used in our report induced irritative skin responses. Weiler et al. reported that out of 85 patients who were skin tested with 0.001-0.1 mg/ml protamine, only 3 were positive, and the protamine concentration at which these 3 patients showed positive reactions was 0.1 mg/ml.
Makoto Takenoshita, M.D., Department of Anesthesiology, Osaka University Medical School, 2-2, Yamadaoka, Suita City, Osaka 565, Japan.
(Accepted for publication August 6, 1996.)