Longitudinal analysis of anti-PGL-I Ig antibody levels.

<p>Anti-PGL-I antibodies for all contacts of leprosy patients who developed leprosy during the study (<b>A</b>; n = 25) and contacts who remained free of leprosy disease (<b>B</b>; n = 199) and 4 contacts who developed MB leprosy (<b>C</b>; n = 4) were determined by ELISA using natural disaccharide of PGL-I linked to HSA (ND-O-HSA). Sera were tested at three follow-up time points; FU1: 2 years after intake, FU2: 4 years after intake, FU3: 6 years after intake. Optical density readings were performed at 450nm (OD₄₅₀) and corrected for background levels. Anti-PGL-I Ab levels at the time point of leprosy diagnosis are indicated with black circles (<b>A</b> and <b>C</b>). The cut-off for positivity is indicated by the dashed horizontal lines.