Assessment of anti-phenolic glycolipid-I IgM levels using an ELISA for detection of M. leprae infection in populations of the South Pacific Islands

Anti-phenolic glycolipid-I (PGL-I) IgM levels were determined in 96% of the general population of the Southern Marquesas and Maupiti, remote islands of French Polynesia, where the average annual detection rates of leprosy during the past 30 years have been 57.1 and 4.4 per 100,000, respectively. The seropositivity in these two areas was 4.3% and 4.2%, respectively. No significant difference (p > 0.05) was found between either these two figures or between the percentages of persons with high (≥ 0.500 OD) anti-PGL-I IgM levels (9.2%) and 5.3%). In the two islands, the age distributions of anti-PGL-I IgM anti-PGL-I IgM were very similar; the percentage of positive responders was higher in females than in males and higher in adolescents than in adults. These results suggest that the usefulness of the determination of anti-PGL-I IgM levels by ELISA, using the synthetic trisaccharide as antigen, for detecting Mycobacterium leprae infection in leprosy control programs is extremely doubtful.