Use of anti-PGL-1 antibodies to monitor therapy regimes in leprosy patients.

The suitability of IgM antibodies to PGL-1 for monitoring the response to multidrug therapy (MDT) was sequentially tested by ELISA in 105 leprosy patients, and bacterial indexes (BI) were also determined. Patients were divided into 3 groups: group 1, 34 multibacillary (MB) patients treated for 12 months with MDT-MB; group 2, 33 MB patients treated for 24 months with MDT-MB, and group 3, 38 paucibacillary (PB) patients treated for 6 months with MDT-PB. Untreated MB patients exhibited higher antibody levels (mean +/- SEM): group 1 (6.95 +/- 1.35) and group 2 (12.53 +/- 2.02) than untreated PB patients (1.28 +/- 0.35). There was a significant difference (P < 0.01) in anti-PGL-1 levels in group 1 patients: untreated (6.95 +/- 1.35) and treated for 12 months (2.78 +/- 0.69) and in group 2 patients: untreated (12.53 +/- 2.02) and treated for 24 months (2.62 +/- 0.79). There was no significant difference between untreated (1.28 +/- 0.35) and treated (0.62 +/- 0.12) PB patients. Antibody levels correlated with BI. The correlation coefficient (Pearson's r) was 0.72 before and 0.23 (P < 0.05) after treatment in group 1 and 0.67 before and 0.96 (P < 0.05) after treatment in group 2. BI was significantly reduced (P < 0.01) after 12 and 24 months on MDT (group 1: 1.26-0.26; group 2: 1.66-0.36). Our data indicate that monitoring anti-PGL-1 levels during MDT may be a sensitive tool for evaluating treatment efficacy. These data also indicate that the control of leprosy infection can be obtained with 12 months of MDT in MB patients.