Serological response of leprosy patients to Mycobacterium leprae specific and mycobacteria specific antigens: possibility of using these assays in combinations.

The serological response of 147 leprosy patients to 3 mycobacterial antigens, PGL-I, 35 kDa (Mycobacterium leprae-specific) and LAM (which is a common mycobacterial antigen) were analysed. A stronger serological response was seen amongst the MB patients than the PB patients in all the assays. The 3 antibody levels correlated positively with each other in both MB and PB cases. An overlap of seropositivity was seen between anti-PGL-I and anti-LAM (p > 0.05). A progressive increase in seropositivity and a significant difference of absorbance or titre in antibody levels in all 3 assays over increasing grades of BI were seen in the MB patients (p < 0.05). A significant difference in seropositivity between untreated and treated groups of patients was observed for anti PGL-I (p < 0.05) and antiLAM (p < 0.01) antibodies. The sensitivity, specificity and efficiency of antiPGL-I (50%; 99%; 70%), antiLAM (43%; 95%; 64%) and anti35 kDa (66%; 100%; 80%) assays taken individually were less than that of combinations of antiPGL-I/anti-35 kDa (74%; 99%; 84%) or antiPGL-I/anti-35 kDa/antiLAM (80%; 94%; 86%). The difference in the efficiency of both sets of combination of assays were not statistically significant (p > 0.05).