ANTI–P 1 ANTIBODY PRODUCTION AFTER THE CASONI SKIN TEST

Abstract
Thirty‐five patients’ blood was P1 grouped at the time of Casoni skin testing. Nine were found to be P1‐negative and were tested for anti‐P1 antibodies immediately, and after 10 days. Eight of the nine (only two of whom had malignant conditions) developed antibodies to P1 substance. Four other patients with anti‐P1 antibody are discussed; in these cases no previous Casoni test can be implicated. It may be that these are examples of naturally occurring antibodies.