Presence of M-leprae in tissues in slit skin smear negative multibacillary(MB) patients after WHO-MBR

This study looked for M. leprae in the lymph node, nerve and skin of multib acillary (MB) leprosy patients who become slit skin smear negative after th e completion of WHO-MBR. Twenty-five WHO-MBR-treated multibacillary leprosy patients were studied; borderline lepromatous (BL) leprosy (n = 11) and le promatous (LL) leprosy (n = 14)). Fifteen patients had reaction (erythema n odosum leprosum II, upgrading reaction 4) either at presentation or during therapy. All patients attained slit skin smear negativity after WHO-MBR (ra nge 24-39 months. Sixteen (64%) patients with multibacillary leprosy showed fragmented bacilli in skin and nerve biopsy or lymph node aspirates after WHO-MBR. Lymph node aspirates alone revealed M. leprae in seven patients, f ollowed by nerve in two and skin in one patient. Four cases showed M. lepra e at all sites followed by nerve and skin or lymph node in one case each. A pretreatment bacteriological index (BI) of 4+ or more was significantly as sociated with the presence of M. leprae at the end of treatment. Also, sign ificantly more lymph node aspirates contained M. leprae in comparison with nerve or skin biopsies. All seven cases in whom treatment was extended beyo nd 24 months showed M. leprae in tissues even after attaining slit smear ne gativity. In conclusion, M. leprae persist in tissues after 2 years of WHO- MBR and patients with an initial BI of 4+ or more need to be closely follow ed up after stopping MDT.