Smooth muscle antibody in Burkitt's lymphoma and in nasopharyngeal carcinoma.

Smooth muscle antibodies (SMA) with specificity for actin, were found with a higher frequency in sera from Burkitt's lymphoma (BL) and nasopharyngeal carcinoma (NPC) patients than in sera from matched controls. No correlation could be found between SMA and anti-Epstein-Barr virus (EBV) antibody titres. There was no parallelism, in individual sera, between the finding of SMA and the occurrence of cold lymphocytotoxins, aother antibody activity found with an abnormally high frequency among BL and NPC patients. The reason why actin, a weak antigen in experimental animals, may become immunogenic in humans remains unexplained.