A study on a possibility of predicting early relapse in XXXX using a ND-O-BSA based ELISA.

@entity1 @entity3761 @entity281 @entity4430 @entity1201
Serological methods have been used for detecting infection with @entity4430 . We have applied a serological test to explore the possibility it could detect a bacterial relapse among @entity1 who have been cured with chemotherapy. More specifically we used an indirect enzyme-linked immunosorbant assay (ELISA) using the natural disaccharide (ND) of the phenolic glycolipid antigen of @entity4430 linked to bovine serum albumin as antigen. Antibody levels were measured in sera from normal controls, active @entity1201 cases, cured @entity1201 @entity1 , and relapsing @entity1201 @entity1 . We correlated antibody levels with the type of @entity1201 , the bacterial index, and with relapse among @entity1201 @entity1 . In our hands, the ND-ELISA, when applied to screening for infection with @entity4430 , had excellent sensitivity, specificity, positive and negative predictive values, and both a low false positive rate and a low false negative rate. Antibody levels gradually increased among active @entity1 from the tuberculoid to the lepromatous end of the @entity1201 spectrum. There was a year-by-year fall in antibody levels in @entity1 responding to chemotherapy. Antibody levels and the bacterial index were correlated using the Spearman's rank correlation method. Serial antibody levels were measured in 666 @entity1201 @entity1 after being cured with @entity3761 monotherapy. Over a three year follow up, 95 multibacillary patients became antibody positive and 12 of them had bacterial relapses of their disease. In contrast, among 335 cases that remained antibody negative, only one relapse was seen. Among 44 paucibacillary cured @entity1 who became antibody positive, there was one relapse. There were 192 such @entity1 who remained antibody negative and one relapsed. The risk of relapse is 6.7 times higher among cured multibacillary @entity1 compared to cured paucibacillary @entity1 . Overall, the cumulative relapse rate among antibody positive cases was 13.7%, compared to 0.4% among antibody negative @entity1 . We conclude that the ND-ELISA is a useful tool both for screening for @entity281 with @entity4430 and for predicting a relapse in cured @entity1 , particularly in cured multibacillary @entity1 .
