Comparative study of anti-PGL-1, anti-35 kDa and anti-lipoarabinomannan assays for serodiagnosis of leprosy.

Three antibody assays (anti-PGL-1, anti-35 kDa and anti-LAM) were used to determine the levels of antibodies in the sera of untreated leprosy patients. All the three assays showed higher levels of antibodies in BL/LL patients as compared to I and TT/BT patients, as well as healthy controls. BL/LL patients showed positivity of 100%, 84.2% and 78.9% by anti-PGL-1, anti-35 kDa and anti-LAM assays respectively. All the three assays were negative for leprosy in healthy controls. Anti-PGL-1 assay was positive in 20% of TT/BT patients and 17.9% of I patients. Anti-35 kDa assay was negative in all the TT/BT patients and positive in 7.14% of I patients. Anti-LAM assay was positive in 13.3% of TT/BT patients and in 10.7% of I patients. Hence, while these assays are valuable in diagnosing BL/LL patients, their usefulness in diagnosing I, BT or TT leprosy is limited.