Use of PCR for Diagnosis of Post-Kala-Azar Dermal Leishmaniasis

Abstract

Microscopy and PCR were compared for use in the diagnosis of post-kala-azar dermal leishmaniasis (PKDL) in 63 patients. Aspirates of lymph nodes (samples from 52 patients), skin (23 samples), and bone marrow (18 samples) were used. For 11 patients lymph node aspiration could be repeated 6 months after they recovered from PKDL. During active PKDL, PCR 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. PCR was always positive when parasites were seen by microscopy. When the results obtained with lymph node and skin aspirates from the same patient (n = 16) were compared, there was complete agreement. Bone marrow samples were negative by microscopy and PCR for 16 patients and positive by both methods for 1 patient; for one sample only the PCR was positive. 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 microscopy, 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 controls were all PCR positive. Cross-reactions with Mycobacterium leprae could be ruled out. In conclusion, PCR with inguinal lymph node or skin aspirates is suitable for confirming the clinical diagnosis of PKDL. In some patients, lymph node aspirates are probably preferred because aspiration of material from the skin may leave scars.

Post-kala-azar dermal leishmaniasis in the Sudan: clinical presentation and differential diagnosis

“…10 In another study by our group, 30% of smears were positive by microscopy and 83% by PCR. 11 These findings show that PKDL should be considered a distinct pathological entity which is the result of dissemination of parasites to the skin and the host's developing immune response to parasite antigens after successful treatment for kala-azar.…”

A simple and sensitive test for field diagnosis of post kala-azar dermal leishmaniasis.

“…Our study has shown that the immunochromatographic strips impregnated with k39 antigen provided a simple and reliable diagnostic test for PKDL. The sensitivity of detection was higher than that in procedures requiring high technical expertise such as immunohistochemistry 5 or PCR 7 . The test appeared to be suitable for use in endemic as well as non‐endemic regions of the country.…”

“…As a result, PKDL is easily confused with a number of dermatological conditions, of which leprosy is the most important 4 . In recent years, improved sensitivity and specificity for the diagnosis of PKDL has been reported by use of anti‐ L. donovani monoclonal antibodies, Western blotting and polymerase chain reaction (PCR) 5–7 …”

Leishmaniasis in the Sudan: a literature review with emphasis on clinical aspects

“…Using an immunoperoxidase technique and anti‐ L. donovani monoclonal antibody, they achieved high sensitivity with microscopy. Using slit skin smears of PKDL patients, Leishmania DNA was detected in 19 of 23 samples by PCR, whereas with microscopy parasites were only found in seven ( Osman et al . 1998a ).…”

“… Endemic and epidemic areas of visceral and cutaneous leishmaniasis in the Sudan (adapted from Osman 1998 ). …”