Population survey to determine risk factors for Mycobacterium leprae transmission and infection

Background: Not every leprosy patient is equally effective in transmitting Mycobacterium leprae. We studied the spatial distribution of infection (using seropositivity as a marker) in the population to identifity which disease characteristics of leprosy patients are important in transmission. Methods: Clinical data and blood samples for anti-M.leprae ELISA were collected during a cross-sectional survey on five Indonesian islands highly endemic for leprosy. A geographic information system (GIS) was used to define contacts of patients. We investigated spatial clustering of patients and seropositive people and used logist regression to determine risk factors for seropositivity. Results: Of the 3986 people examined for leprosy, 3271 gave blood. Seroprevalence varied between islands (1.7-8.7%) and correlated significantly with leprosy prevalence. Five clusters of patients and two clusters of seropositives were detected. In multivariate analysis, seropositivity significantly differed to be the best discriminator of contact groups with higher seroprevalence: contacts of seropositive patients had an adjusted odds ratio (aOR) of 1.75 (95% CI: 0.92-3,31). This increased seroprevalence was strongest for contact groups living _< 75 metres of two seropositive patients (aOR:3.07;95%CI:1.74-5.42). Conclusions: In this highly endemic area for leprosy, not only household contacts of seropositive patients, but also persons living in the vicinity of seropositive patient were more likely to harbour antibodies against M.leprae. Through measuring the serological status of patients and using a broader definition of contacts, higher risk groups can be more specifically identified

Risk factores for developing leprosy -A population-based cohort study in Indonesia

This study identified risk factors for developing leprosy through yearly incidence rates in five island populations. Personal factors, like age, sex, household size and the presence of M.leprae-specific antibodies as well as contact were studied. Of the 94 index patients (patients diagnosed in 2000) 43 (46%) were classified as multibacillary (MB), 17 (19%) were seropositive and 6 (7%) presented M.leprae DNA in nasal swabs as determined by polumerase chain reaction (PCR). All PCR positive patients were also seropositive. Forty-four of the 4903 persons initially without symptoms of leprosy developed leprosy in almost four years follow-up, giving an incidence rate of 2.98 per 1000 person-years. Men had a 2.2 times higher risk (95% Confidence Interval [CI]: 1.2-4.1) to developd leprosy than women. Persons living in households of more than 7 household members. Persons who were seropositive in 2000 had a 3.7 times higher risk (95% CI:1.1-12.4) than seronegative persons. Household contacts of MB patients had an adjusted hazard ratio (aHR) of 4.6 (95% CI:1.6-12.9) and household contacts of PCR positive patients an aHR of 9.36 (95% CI: 2.5-34.9) compared to non-contacts. Patients with PCR positive nasal swabs, suggesting nasal excretion of M.leprae, are probably the patients with the highest transmission patential. Since all index patients who were PCR positive were also seropositive, serology semms an adequate tool to identify these patients. Preventing seropositive persons to become seropositive patients and thus the main source of infection may break the chain of transmission

Immunological crossreactivity of the Mycobacterium leprae CFP-10 with its homologue in Mycobacterium tuberculosis

Mycobacterium tuberculosis culture filtrate protein-10 (CFP-10) (Rv3874) is considered a promising antigen for the immunodiagnosis of tuberculosis (TB) together with early secreted antigens of M. tuberculosis (ESAT-6). Both ESAT-6 and CFP-10 are encoded by the RD1 region that is deleted from all tested M. bovis bacille Calmette-Guérin (BCG) strains but present in M. leprae, M. tuberculosis, M. bovis, M. kansasii, M. africanum and M. marinum. In this study, the homologue of CFP-10 in M. leprae (ML0050) is identified and characterized. Interferon-gamma production in response to this homologue by T cells from leprosy patients, TB patients and unexposed controls shows that CFP-10 of M. leprae is a potent antigen that crossreacts with CFP-10 of M. tuberculosis at the T-cell level. This crossreactivity has implications for the use of CFP-10 of these mycobacterial species as diagnostic tool in areas endemic for both the diseases.

Thalidomide therapy. An open trial

In an open trial, 35 patients suffering from a variety of dermatologic conditions were treated with thalidomide. The drug was shown to be a valuable addition to the therapeutic armamentarium; however, the occurrence of a peripheral neuropathy will limit its use just as its teratogenic side effects have done for many years.

Immune complexes in leprosy patients from an endemic and a nonendemic area and a longitudinal study of the relationship between complement breakdown products and the clinical activity of erythema nodosum leprosum

The sera from leprosy patients living in Surinam (endemic) and 41 leprosy patients living in The Netherlands (nonendemic) were tested for circulating immune complexes (CIC) with the Clq-binding assay and the conglutinin-binding assay and for complement.

Immunofluorescence studies across the leprosy spectrum

Forty biopsies from skin lesions of untreated (24) and treated (16) leprosy patients, representing the whole leprosy spectrum, were examined by means of immunofluorescence (IF) methods. Only few or no cells staining with FTC-labelled antihuman immunoglobulin antisera were found in the lesional skin of all patients examined. Sparse IgM-deposits along the basement membrane of the epidermis were observed in a few borderline lepromatous and lepromatous patients. Complement deposits along the basement membrane of the epidermis and in the vessel walls were found in tuberculoïd as well as in lepromatous patients. Complement and in a lesser number IgG-deposits were observed around sweat glands and sometimes around sweat gland ducts and other skin appendages. Autofluorescing macrophages were noted in patients at the lepromatous side of the leprosy spectrum; approximately half of these patients showed complement deposits in an around these cells.

Immunofluorescence studies in reactional leprosy with relevance to treatment

Twenty-three biopsies of skin lesions of patients with various types of leprosy, showing a recent reaction, were examined by means of immunofluorescence (IF) methods. The patients were divided into two groups according to the number of inflammatory cells, staining with various FTC-labelled anti-immunoglobulin antisera, in representative areas of the biopsies. It was found that the presence of these cells was correlated with a good response to thalidomide treatment.