Blood group, secretor status, and susceptibility to infection by Neisseria gonorrhoeae.

To determine whether the presence or absence of anti-B isohaemagglutinin in individuals of blood group B increases their susceptibility to gonococcal infections 567 new patients attending a sexually transmitted disease clinic were screened for blood group and secretor status. Of the patients with blood group B, 20.1% had gonorrhoea and 12% had not. A higher percentage (20.9%) of patients with no anti-B isohaemagglutinin had gonorrhoea compared with those without (12.1%). There was, however, no synergy between the absence of anti-B isohaemagglutin and nonsecretion of water-soluble blood group B antigen. Further research is needed to determine the underlying host-parasite interactions responsible for the increased susceptibility to gonorrhoea in these individuals.