Evaluation of polymerase chain reaction in nerve biopsy specimens of patients with Hansen's disease

• Published in: Journal of the neurological sciences 2017-09, Vol.380, p.187-190
• Main Authors: Tiwari, Vandana, Malhotra, Kiranpreet, Khan, Kainat, Maurya, Pradeep K., Singh, Ajai Kumar, Thacker, Anup Kumar, Husain, Nuzhat, Kulshreshtha, Dinkar
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; AFB negative; Aged; Biopsy; Female; Humans; Leprosy - complications; Leprosy - genetics; Leprosy - pathology; Male; Middle Aged; Mononeuropathies - etiology; Mycobacterium leprae - genetics; Nerve biopsy; Peripheral Nerves - pathology; Polymerase Chain Reaction; Probable leprosy; Pure neuritic leprosy; Retrospective Studies; Young Adult
• ISSN: 0022-510X; 1878-5883
• DOI: 10.1016/j.jns.2017.07.038

Pure neuritic variety of leprosy (PNL) presents as peripheral neuropathy with absent skin lesions and negative skin smears. Diagnosing PNL is an uphill task as most of these patients have nonspecific changes on nerve biopsy. In such circumstances, additional molecular diagnostic tools like polymerase chain reaction (PCR) has proven to be useful in diagnosing leprosy. The present study was planned to evaluate the role of PCR in nerve biopsy specimens of patients with PNL. Patients attending the neuromuscular clinic from January 2013 to June 2014 with mononeuropathy multiplex underwent detailed diagnostic evaluation to ascertain the cause of neuropathy. Patients where this evaluation failed to establish an etiology underwent a nerve biopsy. Nerve biopsy was done in 52 patients, of which 35 were diagnosed as pure neuritic leprosy. Definite leprosy with positive wade fite staining for lepra bacilli was seen in 13 patients and 22 biopsies revealed a probable leprosy without lepra bacilli being identified. PCR for M. leprae was positive in 22 patients (62%). 12 of the 13 cases with definite leprosy on histopathology were PCR positive while in the AFB negative group, PCR was positive in 10 cases. PCR had a sensitivity of 92.3%, specificity of 54.5%. The positive and negative predictive value of PCR was 54.5% and 92.3% respectively. PCR helps in diagnosing PNL in doubtful cases. A positive PCR increases the sensitivity of detection of M. leprae especially in cases of probable PNL group where AFB cannot be demonstrated on histopathology. •Diagnosing pure neuritic leprosy (PNL) is an uphill task.•We proposed to use molecular methods (polymerase chain reaction) as an additional investigation to diagnose PNL.•PCR increased the sensitivity of detection of M. leprae especially in probable PNL where AFB was not seen on histopathology.