Leprosy reactions in postelimination stage: the Bangladesh experience.

BACKGROUND: Leprosy reactions are immunologically mediated conditions and a major cause of disability before, during and after multidrug therapy (MDT). Little data have been published on the epidemiology of leprosy reactions in Bangladesh. OBJECTIVES: To describe the pattern and prevalence of leprosy reactions in the postelimination stage. METHODS: A descriptive retrospective cross-sectional study was carried out in Chittagong Medical College Hospital using the registered records of patients in the period between 2004 and 2013. RESULTS: Of the 670 patients with leprosy, 488 (73.38%) were males and 182 (27.37%) were females. The prevalence of reaction was in 300 (44.78%) patients with a male:female ratio of 3.55 : 1. The age-specific cumulative reaction cases at >40 years were 115 (38.33%) among all age groups. The prevalence of reaction was found to be in 166 (55.33%) patients for the reversal reaction, 49 (16.57%) for the erythema nodosum leprosum (ENL) and 85 (28.33%) for the neuritis. Borderline tuberculoid was most common (106, 35.33%)in the reversal reaction group, while lepromatous leprosy was most common (37, 12.33%) in ENL group. More than half of the patients (169, 56.33%) had reactions at the time of presentations, while 85 (28.33%) and 46 (15.33%) patients developed reaction during and after MDT, respectively. The reversal reaction group presented with ≥six skin lesions in 96 (57.83%) patients and ≥two nerve function impairments (NFIs) in 107 (64.46%) patients. The ENL was present chiefly as papulo-nodular lesions in 45 (91.84%) patients followed by pustule-necrotic lesions in four (8.16%), neuritis in 33 (67.35%), fever in 24 (48.98%), lymphadenitis in six (12.24%), arthritis in five (10.20%) and iritis in two (4.08%). Bacterial index ≥3 had been demonstrated in 34 (60.71%) patients in ENL group. CONCLUSION: The incidence of leprosy reaction seemed to be more than three times common in borderline tuberculoid (52.33%) group than in lepromatous leprosy (14%) group. Reactions with NFI and disability still occur among multibacillary patients during and after MDT. Early detection and management of leprosy reaction are very important in preventing disability and deformity, and patients should be educated to undergo regular follow-up examinations. Developing reinforced new therapies to curb leprosy reactions is crucial for improving leprosy healthcare services.

Delayed-type hypersensitivity, mycobacterial vaccines and protective immunity.

There is a longstanding debate over the implications of natural and vaccine-induced delayed type hypertensivity for protective immunity to mycobacterial infections. The identification of correlates of vaccine-induced protective immunity should help explain the inconsistent behaviour of BCG vaccines in different populations and assist in efforts to devise improved vaccines. More than 70,000 subjects in Karonga District, northern Malawi were skin tested with soluble antigens of the tubercle and leprosy bacilli, and then followed up for five years for tuberculosis and leprosy incidence. Incidence rate ratios were calculated to compare subjects with different levels of prior skin test sensitivity, after controlling for the effects of age, sex and previous BCG vaccination. BCG vaccination protected against leprosy without persistent delayed-type hypersensitivity to tuberculin or to soluble antigens of the leprosy bacillus. In subjects who had not received BCG, hypersensitivity to tuberculin or to antigens of the leprosy bacillus was associated with strong protection against leprosy. In BCG-vaccinated and unvaccinated subjects, there was a J-shaped relation between hypersensitivity to tuberculin and subsequent rates of tuberculosis, with lowest rates associated with low grade sensitivity (induration 1-10 mm). This study shows that delayed-type hypersensitivity to mycobacterial antigens has different implications for tuberculosis and leprosy: low-level hypersensitivity (probably attributable to environmental mycobacteria) is associated with protection, but persistent vaccine-associated hypersensitivity to mycobacterial antigens is not a correlate of vaccine-derived protection against mycobacterial diseases.

Skin-test sensitisation by tubercle bacilli and by other mycobacteria in Ethiopian school-children.

Quadruple skin-testing with a range of 22 new tuberculins and PPD-RT23 was carried out on 665 school-children without BCG scars and 666 with BCG scars, in and around the towns of Butajira and Hosana in Shoa district of Ethiopia. Marked differences in patterns of sensitisation were distinguished between the 5 schools visited. In general, Mycobacterium chitae, M. diernhoferi, M. kansasii and M. vaccae were common sensitising agents in all schools, M. avium subspecies brunense, M. gilvum, M. rhodesiae and M. xenopi were absent, and the remaining species investigated were variably present between the schools. Contact with M. tuberculosis and M. leprae appeared greatest in Hosana and the possibility of sensitisation by M. ulcerans around the village of Enseno was discovered. The data also provided indirect evidence of the value of BCG in Shoa district. An interesting observation was the very variable enhancing effect that BCG vaccination had on sensitisation to individual fast growing species.