Use of fine needle aspirate from peripheral nerves of pure-neural leprosy for cytology and PCR to confirm the diagnosis: A pilot study.

ABSTRACT

Background: The diagnosis of pure neural leprosy (PNL) remained subjective because of over-dependence of clinical expertise and a lack of simple yet reliable diagnostic tool. The criteria for diagnosis, proposed by Jardim et al., are not routinely done by clinicians in developing country as it involves invasive nerve biopsy and sophisticated anti-PGL-1 detection. We conducted a study using fi ne needle aspiration cytology (FNAC) coupled with Ziehl Neelsen staining (ZN staining) and Multiplex- Polymerase Chain Reaction (PCR) specifi c for M. leprae for an objective diagnosis of pure neural leprosy (PNL), which may be simpler and yet reliable. Aim: The aim of the study is to couple FNAC with ZN staining and multiplex PCR to diagnose pure neural leprosy patients rapidly, in simpler and yet reliable way. Methods: Thirteen patients of PNL as diagnosed by two independent consultants were included as case, and 5 patients other than PNL were taken as control in the study. Fine needle aspiration was done on the affected nerve, and aspirates were evaluated for cytology, ZN staining and multiplex- PCR. Results: Out of the 13 cases where fi ne needle aspiration was done, M. leprae could be elicited in the nerve tissue aspirates in 5 cases (38.4%) with the help of conventional acid-fast staining and 11 cases (84.6%) with the help of multiplex PCR. On cytological examination of the aspirates, only 3 (23%) cases showed specifi c epithelioid cells, whereas 8 (61.5%) cases showed non-specifi c infl ammation, and 2 (15.3%) cases had no infl ammatory cells. Conclusion: Our study demonstrates that in the fi eld of laboratory diagnosis of PNL cases, FNAC in combination with ZN staining for acid-fast bacilli (AFB) and Multiplex-PCR can provide a rapid and defi nitive diagnosis for the majority of PNL cases. FNAC is a less-invasive, outdoor-based and simpler technique than invasive nerve biopsy procedure. Thus, this study may enlighten the future path for easy and reliable diagnosis of PNL.