Monitoring of the efficacy of multidrug therapy (MDT) by polymerase chain reaction (PCR) and Mycobacterium leprae particle agglutination (MLPA) test in leprosy patients

Abstract

This study was undertaken to monitor the efficacy of multidrug therapy (MDT) in leprosy patients using polymerase chain reaction (PCR) to detect the M. leprae DNA from nasal swab specimens and Mycobacterium leprae particle agglutination (MLPA) test to determine the titer of lgM anti-phenolic glycolipid-I (PGL-I) antibodies. The follow up was performed every 3 months in paucibacillary (TT and BT types) patients for a period of 12 months and in multibacillary (BL and LL types) patients for 27 months. Fifty-two previously untreated leprosy patients (31 TT, 5 BT, 11 BL and 5 LL type) were included in this study. Before treatment, using the PCR technique, the TT, BT, BL and LL types respectively showed 7/31 (22.6%), 4/5 (80.0%), 11/11 (100.0%) and 5/5 (100.0%) PCR positive. All of the paucibacillary and all of the multibacillary patients became PCR negative respectively at 9 and 27 months after MDT treatment. Furthermore, using the MLPA test, the TT, BT, BL and LL types respectively showed 14/31 (45.1%), 4/5 (80.0%), 11/11 (100.0%) and 5/5 (100.0%) MLPA positive before treatment. All the paucibacillary and 13 of 16 multibacillary patients became MLPA negative at 12 and 18 months after treatment. And 3 of 16 multibacillary patients remained MLPA positive till 7 months observation. In conclusion, the PCR and MLPA test might be of benefit to monitor the efficacy of MDT in leprosy patients.