Smooth muscle antibody inBurkitt's lymphoma andinnasopharyngeal carcinoma

SUMMARY Smoothmuscle antibodies (SMA) with specificity for actin, were foundwith a higher frequencyinsera fromBurkitt's lymphoma(BL) and nasopharyngeal carcinoma (NPC)patients thaninserafrom matched controls. No correlation could be found between SMAand anti-Epstein-Barr virus (EBV) antibody titres. There was no parallelism, in individual sera, between the findingof SMAand the occurrence of cold lymphocytotoxins, another antibody activity found withan abnormally high frequency among BLand NPC patients. The reason why actin, a weakantigen in experimental animals, may becomeimmunogenic in humansremains unexplained. INTRODUCTION In 1968, antibodies were described in patients with chronic active hepatitis which reacted in indirect immunofluorescence with smooth muscle (Johnson, Holborow & Glynn, 1965) and a variety ofother tissues (Farrow, Holborow & Brighton, 1971; Gabbiani et al., 1973; Fagraeus, The& Biberfeld, 1973; Biberfeld, Fagraeus & Brighton, 1974; Fagraeus, Lidman