Pseudomonas aeruginosa may cause serious infections in most human tissues/organs. Its adherence to them is mediated by a battery of adhesins including the PA-I and PA-II lectins, which are produced in this bacterium in high quantities. PA-I binds to the D-galactose of the erythrocyte glycosphingolipids exhibiting highest affinities for B and Pk (followed by P1) antigens, while PA-II preferentially binds to the L-fucose of H, A and B antigens. Intact P. aeruginosa cells also exhibit a clear Pk and P1 over p preference. Such affinities for the most common human ABH and P system antigens may underlie the widespread tissue infectivity and pathogenicity of this bacterium.

A 43-year-old Arab woman was found to be negative for the high incidence AnWj antigen and her serum contained anti-AnWj. Two of her seven siblings were also AnWj-negative, which provides evidence for the first time that the AnWj-negative phenotype may be an inherited character. Blood groups of the family, in which the parents of the proposita are consanguineous, show that AnWj is not part of the ABO, Rh, MNSs, Kell, Duffy, Kidd, Xg and, notably, Lutheran blood group systems and neither is it X or Y linked.

Women with the rare blood group p are known to have an increased rate of abortions. The case of a 36-year-old woman is presented who had had 7 spontaneous abortions in the first trimester and no live child. When treated by plasma exchange begun early in pregnancy and continued until the 29th week, she delivered a normal child. Time to begin, amount and length of time necessary to continue plasma exchange in these patients are considered. In addition, the question of which fraction of the anti-PP(1)P^k could be responsible for abortion is discussed. To our knowledge, this is the first case of a woman of p phenotype with no live children but with multiple abortions treated by this method, which should be seriously considered in similar cases.

A newborn infant of genotype P2p suffering from ABO-like hemolytic disease was born to a mother of the very rare genotype pp. The disease was severe enough to require exchange transfusions with pp blood. The mother and other members of the family with the same rare pp blood provided compatible donor blood for transfusions of the mother herself and for replacement transfusion of her affected infant. The mothers serum contained IgM molecules and also IgG molecules capable of crossing the placenta to induce a hemolytic process on the infant's red blood cells. The genotype of the P1 negative father was very likely P2P2 so that the genotype of the affected infant had to be P2p. A search of the literature revealed an earlier report from Japan in which the genotype of the P1 positive father was P1P2. As was to be expected the genotype of this affected infant was P2p.

The galactose-binding lectins PA-1 and soybean may facilitate the determination of Pk and p red cells.