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An example of auto-anti-Kpb in a Kp(a+b-) patient is described. The antibody present in the patient's serum and in eluates from her red cells was IgG. It did not bind complement, and did not cause in vivo hemolysis. 9 months after recognition of the autoimmune state the direct antiglobulin test had become negative and anti-Kpb was no longer detectable. It is postulated that autoimmunity involving the Kell blood group may be precipitated by antigens or enzymes of microbial origin.

Th polyagglutinability is characterized by the agglutination of the red blood cells (RBC) by Arachis hypogaea, Medicago disciformis, Vicia cretica but, in contrast to the T phenomenon, not by Glycine max (Glycine soja). Because Th transformation of RBC has been obtained in vitro, the mechanism of Th polyagglutinability expression has been studied and reproduced experimentally. An enzyme with neuraminidase specificity has been isolated from the culture supernatant of Corynebacterium aquaticum, and further characterized (MW = 55,600 kDa, pH = 5.5, Km = 0.138 microM, Kcat = 0.22 micrograms). Reversely, Th transformation of RBC could be obtained by using other neuraminidases but in very mild conditions of hydrolysis. From our results, it can be concluded that by the release of less than 20 micrograms of sialic acid per 10(10) RBC, Th reactivity can be induced whereas hydrolysis of greater amounts of sialic acid (greater than 20 micrograms/10(10) RBC) give the classical T polyagglutinability.

The second example of anti-K22 was found, like the first, in an Iranian Jew living in Israel. The consanguineous parents of the propositus were both K+k+, and investigation of the family suggested that K22 is controlled by the Kell locus; K travelling with K22 and k with K-22.

The Yta and Ytb allelic frequencies were determined by examining the red cells of 1683 blood samples from Israeli Jews, Arabs, and Druse with anti-Yta and -Ytb. The Ytb allelic frequencies ranged between 0.1005 and 0.1522 in the Jewish communities and were 0.1294 and 0.1429 in the Arab and Druse communities, respectively. These are the highest Ytb allelic frequencies observed so far in any population tested, so the Yt blood group system can be used as a genetic marker in these populations. No factors were recognized that may have influenced the selection for the Ytb allele.