The serum proteins of 67 patients with chronic schistosomiasis and of 37 controls were studied by paper electrophoresis. Compared to the controls, slight but significant changes consisting of decrease of serum albumin and increase of gamma globulin were found in the infected group. The changes were more pronounced in patients with hepatosplenomegaly than in those without hepatosplenomegaly, but the differences were not significant. No significant relationship was found between the protein abnormalities and the hepatic functional impairment determined by the bromsulfalein retention test. The protein abnormalities had no relation to previous treatment with antimonial agents. The changes were significantly more marked in patients who had an abnormal cephalin flocculation test than in those whose cephalin flocculation test was normal. The gamma globulin was significantly higher in those sera that produced a large amount of precipitate (2+ to 4+) in the circumoval precipitation test than in those that produced either no or a small amount of precipitate (0 to 1+). However, no correlation between the circumoval precipitation test and the cephalin flocculation test was found.
These findings indicate that decrease of serum albumin and increase of serum gamma globulin represent a protein response by the human host to chronic infection with Schistosoma mansoni. In view of the known hepatic involvement which occurs in this disease it would seem reasonable to suspect that the protein changes result from this involvement. However, in the present study they could not be correlated at an acceptable level of confidence either with abnormal bromsulfalein retention or with hepatosplenomegaly. The evidence presented supports the view that these changes are due substantially to an immunologic mechanism. This mechanism probably produces a group of antibodies, one of which is the circumoval precipitin.
Medical Service, San Patricio Veterans Administration Hospital, and Department of Medicine, University of Puerto Rico School of Medicine, San Juan, Puerto Rico.
Medical Research Laboratory, San Patricio Veterans Administration Hospital, San Juan, Puerto Rico.