ANTI-P1 ACTIVITY IN PIGEON BREEDERS' SERUM.

Antibodies against the P₁ antigen of the P blood group system have been found in 34% of P₂ pigeon breeders' sera and in only 6% of the control group. In pigeon breeders, this anti-P₁ activity correlates with immunization to pigeon serum and can consistently be removed by absorption with pigeon erythrocytes, serum or droppings. It is concluded that P₁ or a related antigen is present in the pigeon blood and droppings and that heavy exposure to pigeon dust, as may occur in pigeon breeders, is one of the factors capable of inducing IgM antibodies to P₁ antigen. The clinical importance of this finding remains to be defined. [ABSTRACT FROM AUTHOR]