Anti-mycobacterial antibodies in saliva.

Modified techniques for the fluorescent leprosy antibody absorption (FLA-ABS) test and the enzyme-linked immunosorbent assay (ELISA) using phenolic glycolipid-l (PG) antigen of M. leprae were employed for detecting anti-M. /eprae antibodies in sera and saliva from the patients with leprosy , household contacts and inhabitants in leprosy endemic areas . The FLA-ABS test with saliva was positive in 20 (58 . 8 % ) of the 34 household contacts , 92 (39 % ) of the 236 schoolchi ldren and 3 7 (38 . 1 % ) of the 97 adu lts who had social contacts with le­ prosy , but negative in the 23 patients with pulmonary tuberculosis . Serological specific ity of sal ivary anti-M. leprae antibodies detected in the specimens of saliva from the schoolchi ld­ ren was checked by cross-reactions and additional absorption tests . Only 7 out of the 55 spe­ cimens of saliva showing a positive FLA-ABS test were cross-reactive with some species of mycobacteria . Positive reactions against M. /eprae were not influenced at all by additional absorptions with cross-reacting mycobacteria , but became negative after an additional ab­ sorption with M. leprae. Therefore , the modified technique of FLA-ABS test was found specific to M. leprae and useful for detecting subclinical leprosy infection . The PG-ELISA activity was most frequently found in the serum and sal ivary IgA from the patients with le­ prosy , the percentage of positive reactions in saliva being comparable to that of FLA-ABS test . The PG-ELISA using anti-IgA-enzyme conjugate was negative in the specimens of sal i­ va from the patients with tuberculosis and the schoolchi ldren who had no suspicious symp­ tom nor FLA-ABS reactiv ity , but was positive in 3 ( 1 1 . 1 % ) of the 27 specimens of saliva from the schoolchildren who had suspicious symptoms and/or FLA-ABS reactivity and in 1 7 ( 1 7 . 5 % ) of the 97 specimens of sal iva from the adults who had social contacts with leprosy . Therefore , the PG-ELISA with sa l iva was a l so found specific to M. /eprae and useful for de­ tecting the secretory type of anti -PG atibodies . A significant difference in the percentage of positive reactions between FLA-ABS and PG-ELISA was discussed from a point of view concerning specific epitopes of M. /eprae .