Blood groups, salivary secretion and other immunologic variables in rheumatic fever and rheumatic heart disease.

A total of 100 patients and carefully matched controls were studied in relation to six genetic systems (ABO, MN, Rh, haptoglobin, ABH secretion and amylase types), as well as for serum and saliva antibody and ABH antigen levels. The differences observed between patients and controls were generally small and statistically non-significant, the previously reported association between haptoglobin types and reactions to streptococcus infections being not confirmed here. The A/O, B/O and secretor/non-secretor relative incidences, however, occurred in the expected direction considering previous investigations.