PCR and in-situ hybridization for diagnosis of leprosy

Abstract

Objective: To assess the diagnostic value of Polymerase Chain Reaction (PCR) and in situ hybridization. Methods: This prospective study was carried out in 22 patients (< 15 yr of age) of leprosy. Clinical examination of each case was done and skin smear for AFB was prepared. Biopsy of lesion site was taken for histopathological examination, in situ hybridization and PCR. Results: The histopathological examination confirmed the clinical diagnosis in 27.2% cases only. In situ hybridization showed a positivity of 42.8% in early (I/BT) and 46.7% in BB/BL group. In situ hybridization thus enhanced the diagnosis by 18.1%. PCR targeting 36 kDa gene of M. leprae was performed on 15 cases. In these 15 cases, histopathology confirmed the diagnosis in 4 cases (26.6%) and PCR confirmed the diagnosis in 10 cases (66.6%), thus enhancing the diagnosis by 40%. Conclusion: 36 kDa PCR and in situ hybridization enhance the diagnosis of leprosy when compared to routine histopathology. They are important diagnostic tools for definitive diagnosis in early and doubtful cases of leprosy.