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. [1]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.)

Weiler JM, Gellhaus MA, Carter JG, Meng RL, Benson PM, Hottel RA, Schillig KB, Vegh AB, Clarke WR: A prospective study of the risk of an immediate adverse reaction to protamine sulfate during cardiopulmonary bypass surgery. J Allergy Clin Immunol 1990; 85:713-9.