USE OF PCR FOR DIAGNOSIS OF POST-KALA-AZAR DERMAL LEISHMANIASIS

Microscopy and PCR were compared for use in the diagnosis of post-kala -azar dermal leishmaniasis (PKDL) in 63 patients. Aspirates of lymph n odes (samples from 52 patients), skin (23 samples), and bone marrow (1 8 samples) were used, For 11 patients lymph node aspiration could be r epeated 6 months after they recovered from PKDL, During active PKDL, P CR was positive for 42 of 52 (80.8%) lymph node aspirates and 19 of 23 (82.7%) skin aspirates, whereas microscopy was positive for only 9 of 52 (17.3%) lymph node aspirates and 7 of 23 (30.4%) skin aspirates. P CR was always positive when parasites were seen by microscopy, When th e results obtained with lymph node and skin aspirates from the same pa tient (n = 16) were compared, there was complete agreement. Bone marro w samples were negative by microscopy and PCR for 16 patients and posi tive by both methods for 1 patient; for one sample only the PCR was po sitive. PCR confirmed the co-occurrence of visceral leishmaniasis and PKDL in one patient and confirmed the suspicion of this co occurrence in the other patient. After recovery, no parasites were found by micro scopy, but 2 of 11 (18.2%) samples were still positive by PCR, Thirty negative controls were all found to be PCR negative, and 15 positive c ontrols were all PCR positive. Cross-reactions with Mycobacterium lepr ae could be ruled out. In conclusion, PCR with inguinal lymph node or skin aspirates is suitable for confirming the clinical diagnosis of PK DL, In some patients, lymph node aspirates are probably preferred beca use aspiration of material from the skin may leave scars.