Complement levles in relation to certain antibodies in polytransfused thalassaemic patients.

Polytransfused patients are exposed to a variety of antigenic stimuli which may eventually trigger autoimmune reactions. The relation of serum complement to the occurrence of various antibodies has been investigated in a group of 75 polytransfused thalassaemic patients. The incidence of the antibodies studied was as follows: anti-HBs 77%, anti-Gm 64%, rheumatoid factor 31%, antinuclear 13%, anti-smooth muscle 47%. Anti-perietal cell, anti-thyroid and anti-kidney were only rarely found and antimitochondrial antibodies were never detected. Total hemolytic complement was low in 6 and incidentally decreased in 21 patients. A positive correlation was found between low serum complement and presence of rheumatoid factor. The high incidence of anti-smooth muscle antibodies seems to be unrelated to liver disease.