PGL-I antigen and antibody detection in leprosy patients: evolution under chemotherapy.

Multibacillary (MB) and paucibacillary (PB) leprosy patients were tested for circulating phenolic glycolipid-I (PGL-I) antigen and antibodies before treatment. In the 27 MB patients tested, 27 (100%) were antigen positive with levels ranging from 50 to 5000 ng/ml, and 26 (96%) were antibody positive with titers ranging from 1000 to 64,000. Although the antigen and antibody levels were much higher in MB than in PB patients, we could not demonstrate a correlation between the number of acid-fast bacilli/mg of skin biopsy and these two parameters in 14 MB patients. After starting daily multidrug therapy, 10 MB patients were monitored monthly. As much as 88.75% +/- 10.8% of the PGL-I antigen was cleared from the bloodstream after 1 month while the anti-PGL-I antibody remained stable. This rapid decrease in the PGL-I antigen level strongly suggests the usefulness of this test for monitoring MB patients under chemotherapy.