Quantitative Real-Time Polymerase Chain Reaction for Detection of Mycobacterium leprae DNA in Tissue Specimens from Patients with Leprosy

In leprosy, early diagnosis is crucial to prevent transmission and onset of disabilities of the disease. The purpose of this study was to determine usefulness of quantitative real-time polymerase chain reaction (PCR) in clinically diagnosed cases of leprosy. Thirty-two leprosy cases were included. The real-time PCR was performed using commercial kit targeting Mycobacterium leprae-specific insertion sequence element. The slit skin smear was positive in two (22.2%) borderline tuberculoid (BT) patients, five (83.3%) borderline lepromatous (BL) patients, and seven (50%) lepromatous leprosy (LL). The positivity of quantitative real-time PCR in BT, BL, LL, and pure neuritic leprosy were 77.8%, 83.3%, 100%, and 33.3%, respectively. Using histopathology as the gold standard, sensitivity of quantitative real-time PCR was 93.1%, and specificity was 100%. The DNA load was higher in LL (3,854.29/10(6) cells), followed by BL (140.37/10(6) cells), and BT (2.69/10(6) cells). Because of the high sensitivity and specificity of real-time PCR, our study strongly suggests the use of real-time PCR as a diagnostic tool for leprosy.

Automated summary

This study aimed to evaluate the usefulness of quantitative real-time polymerase chain reaction (PCR) in the clinical diagnosis of leprosy. The results showed that the sensitivity of quantitative real-time PCR for leprosy was 93.1%, and the specificity was 100%. Therefore, the use of real-time PCR as a diagnostic tool for leprosy is strongly recommended.