An evaluation of the Maillard-Gagliardo complement fixation test in leprosy; a review of 100 cases.

The results of a modified Middlebrook-Dubos hemagglutination test in leprosy were reported recently from this laboratory (4). Old Tuberculin 4X Lederle was employed in that test to sensitize the sheep red blood cells. In a series of 261 cases it was observed that titers above those found in controls occurred in 231 cases, or 88.5 per cent. In 1951 Maillard and Gagliardo (1) described a complement-fixation test in which there were used sheep red cells sensitized with old tuberculin, and, as complement, reconstituted dried, frozen guinea-pig serum. These authors concluded that their test gave better quantitative results than were obtained by the Middlebrook hemagglutination test. No positive titers were obtained in the 48 normal controls which they . studied. Maillard (2) later used his test to study the sera of 24 leprosy patients of this institution, from all of whom tuberculosis had been excluded. Reaction titers were obtained in 23 of these 24 sera. The purpose of the present paper is to report an evaluation of the Maillard-Gagliardo complement-fixation test in a larger group of leprosy patients. The Maillard technique (3) was employed, and 100 sera were tested; 90 of them were from lepromatous cases, and 10 from cases of the tuberculoid type. Sera from 20 persons without leprosy were used as controls. Tuberculosis had been excluded in all cases. The Maillard test is characterized by a hemolytic reaction which results from the fixation of a complement by an antigen-antibody system. The specific complex is presumably formed at the cell surface; then, in the presence of complement, there occurs lysis of erythrocytes which is similar to lysis by specific hemolysin. The binding of the specific antibody as well as the complement to the surface of the blood cells is apparently determined by preliminary coating of the cell surface with antigen. The titer of the antiserum is described as the hightest dilution in which there is a constant degree of hemolysis (50 %) with a constant dose of complement (4 units). RESULTS