Discovery of 4 exonic and 1 intergenic novel susceptibility loci for leprosy.

Seven new risk coding variants have been identified through an exome-wide association study (EWAS), which studied the contributions of protein-coding variants to leprosy susceptibility. But some potential susceptibility loci were not studied in the previous EWAS study because of the project consideration. Seventeen unstudied potential susceptibility loci of the previous EWAS were validated in 3169 cases and 9814 controls in this study. Four disease-associated exonic loci were identified: rs671 in ALDH2 (P = 2.0 × 10-20 , odds ratio [OR] = 1.35), rs13259978 in SLC7A2 (P = 1.74 × 10-8 , OR = 1.28), rs925368 in GIT2 (P = 9.18 × 10-17 , OR = 1.44), and rs75680863 in TCN2 (P = 8.37 × 10-21 , OR = 0.74). Potentially implicating ZFP36L1 as a new susceptibility gene, 1 intergenic single nucleotide polymorphism (SNP), rs1465788 (P = 7.81 × 10-6 , OR = 0.88), was also suggested to be associated with leprosy. A luciferase reporter assay showed that the rs1465788 risk allele notably decreased the transcription activity of the flanking sequence. These findings suggest the possible involvement of lipid metabolism, NF-κB homeostasis and macrophage antimicrobial pathways in leprosy pathogenesis.

Drug resistance in Mycobacterium leprae from patients with leprosy in China.

BACKGROUND: Previous studies of drug resistance have shown that mutations in the drug resistance-determining region (DRDR) in the Folp1, RpoB and GyrA genes of Mycobacterium leprae are responsible for resistance to dapsone, rifampin and ofloxacin, respectively. AIM: To investigate the prevalence of mutations in genes associated with drug resistance in M. leprae isolates from patients with leprosy in Shandong Province. METHODS: The DRDR in the FolP1, RpoB and GyrA genes was analysed by direct sequencing of the PCR product from 85 isolates of M. leprae sampled from patients with leprosy in Shandong, China. RESULTS: Sequencing results were obtained for FolP1, RpoB and GyrA in 67, 57 and 81 of the 85 samples, with mutation rates of 1.5% (1/67), 8.8% 5/57 and 25.9% (21/81). Three multidrug-resistant samples were found among the new cases: one had a mutation in both Folp1 and RpoB, while the other two had a mutation in both RpoB and GyrA. CONCLUSIONS: Primary resistance appears to be to either single drugs or combinations of two drugs. The resistance rate to dapsone seems to be low. To our knowledge, this is the first case of multidrug-resistant M. leprae from China.

HLA-B*13:01 and the dapsone hypersensitivity syndrome.

BACKGROUND: Dapsone is used in the treatment of infections and inflammatory diseases. The dapsone hypersensitivity syndrome, which is associated with a reported mortality of 9.9%, develops in about 0.5 to 3.6% of persons treated with the drug. Currently, no tests are available to predict the risk of the dapsone hypersensitivity syndrome. METHODS: We performed a genomewide association study involving 872 participants who had received dapsone as part of multidrug therapy for leprosy (39 participants with the dapsone hypersensitivity syndrome and 833 controls), using log-additive tests of single-nucleotide polymorphisms (SNPs) and imputed HLA molecules. For a replication analysis, we genotyped 24 SNPs in an additional 31 participants with the dapsone hypersensitivity syndrome and 1089 controls and performed next-generation sequencing for HLA-B and HLA-C typing at four-digit resolution in an independent series of 37 participants with the dapsone hypersensitivity syndrome and 201 controls. RESULTS: Genomewide association analysis showed that SNP rs2844573, located between the HLA-B and MICA loci, was significantly associated with the dapsone hypersensitivity syndrome among patients with leprosy (odds ratio, 6.18; P=3.84×10(-13)). HLA-B*13:01 was confirmed to be a risk factor for the dapsone hypersensitivity syndrome (odds ratio, 20.53; P=6.84×10(-25)). The presence of HLA-B*13:01 had a sensitivity of 85.5% and a specificity of 85.7% as a predictor of the dapsone hypersensitivity syndrome, and its absence was associated with a reduction in risk by a factor of 7 (from 1.4% to 0.2%). HLA-B*13:01 is present in about 2 to 20% of Chinese persons, 1.5% of Japanese persons, 1 to 12% of Indians, and 2 to 4% of Southeast Asians but is largely absent in Europeans and Africans. CONCLUSIONS: HLA-B*13:01 was associated with the development of the dapsone hypersensitivity syndrome among patients with leprosy. (Funded by the National Natural Science Foundation of China and others.).

Autoantibodies and related immunity of leprosy patients from leprosarium in Taiwan.

Autoantibodies and related immunological examinations were measured in 60 leprosy patients from a leprosarium in Taiwan. Thirty-one lepromatous type, 24 tuberculoid type and 5 borderline type patients were identified. The measured autoantibodies included antinuclear antibodies, anti-nDNA, anti-cardiolipin and rheumatoid factor. Serum protein electrophoresis and immunofixation were also performed to detect the monoclonal and polyclonal status of immunoglobulins. Circulating immune complex and complements were also quantitated. Delayed type skin tests were performed during patients' visits. A higher frequency of autoantibodies, especially the antinuclear antibodies and anticardiolipin antibodies, were detected in lepromatous type patients. Higher levels of circulating immune complex and frequency of polyclonal and monoclonal gammopathy were also noted in lepromatous type patients. Anergy skin tests were only noted in lepromatous type patients. It was concluded that the more impared cell-mediated immunity in leprosy patients, with lepromatous type in particular, the greater the production of autoantibodies.

The diagnostic value of IgM to natural trisaccharide phenylpropionyl bovine serum albumin in leprosy patients: a preliminary report from Taiwan.

An evaluation was made of the serum anti-phenolic-glycolipid-I (PGL-I) IgM levels of leprosy patients in the Taiwan area by enzyme-linked immunosorbent assay (ELISA) with a specific synthetic PGL-I antigen and natural trisaccharide phenylpropionyl bovine serum albumin (NT-P-BSA). Fifty-five blood samples were collected from 24 tuberculoid and 31 lepromatous leprosy patients and 21 healthy age- and sex-matched subjects. Among these groups, lepromatous patients had the highest levels of IgM and anti-NT-P-BSA IgM with a good correlation between these two levels (p less than 0.01). Tuberculoid patients also had higher levels than normal subjects. Wide variation in the standard deviation and decreased levels within the cutoff value of some lepromatous patients may be due to various periods of anti-leprosy treatment. Serial anti-NT-P-BSA IgM assessments in response to anti-leprosy treatment may provide more information and serve as a guideline for therapy.

Effect of three-year multidrug therapy in multibacillary leprosy patients.

The feasibility and effects of a 3-year treatment using rifampicin (RFP), clofazimine (B663) and dapsone (DDS) in multibacillary leprosy patients in Yangzhou Prefecture and Dongtai County (1983-1986) are reported. Among 591 active multibacillary leprosy patients in the two areas, 569 (96.30%) were treated with this regimen. Of 303 cases available for analysis, 196 (64.7%) cases showed negative skin smears and clinical inactivity. The rest showed different degrees of improvement. The average reduction of BI was 0.78. The intensity and frequency of ENL and neuritis decreased markedly with treatment. The main side-effects were pigmentation and ichthyosiform changes of the skin, but these did not influence treatment.

Evaluation of humoral immunity on leprosy patients in Taiwan: a preliminary report.

Twenty-four tuberculoid (T)-type and 31 lepromatous (L)-type leprosy patients from Taiwan Provincial Lo-Sheng Leprosarium were enrolled in this study. Twenty-six age- and sex- matched normal subjects were also studied as a control group. The evaluation of their general and specific humoral immunity included B-cell subpopulations, 3 major classes of immunoglobulin (G, A and M) and antibodies in the IgG class against lepromin suspension and Bacillus Calmette-Guerin (BCG) sonicate. T-type patients showed a larger B-cell percentage than L-type patients (p less than 0.01). In general, patients with leprosy, both T and L types, had higher serum immunoglobulin levels than the control group. T-type patients showed greater antibody levels than the control group (p less than 0.05 for anti-lepromin and p less than 0.0001 for anti-BCG). L-type patients demonstrated a higher anti-BCG IgG level than the control group (p less than 0.0001). The level of anti-BCG IgG was more frequently above the cutoff level than that of anti-lepromin IgG in leprosy patients (p less than 0.01 for T, p less than 0.005 for L). In conclusion, humoral immunity is not impaired in leprosy patients. Discrepancies for T- and L-type patients among B-cell subpopulation, serum immunoglobulin levels and specific antibody levels reflect different aspects of cell-mediated immunity impairment. Though leprosy patients had elevated anti-BCG IgG levels, it is impossible to differentiate L- and T-type patients; specific antigens are needed for serodiagnosis of leprosy patients in Taiwan.

Enzyme-linked immunosorbent assay with BCG sonicate antigen for diagnostic potential of mycobacterial infection in Taiwan.

The diagnostic potential of enzyme-linked immunosorbent assay (ELISA) with Bacillus Calmette-Guerin (BCG) sonicate antigen for detection of mycobacterial infections, including pulmonary tuberculosis and leprosy, has been evaluated in Taiwan area. One hundred blood samples were collected from 74 active and 26 inactive pulmonary tuberculosis patients of the Taiwan Provincial Tuberculosis Control Bureau. Another 50 samples were collected from 24 lepromatous, 23 tuberculoid and 3 borderline leprosy patients at the Taiwan Provincial Lo-Sheng Leprosarium. The IgG anti-BCG sonicate levels were compared among patients with tuberculosis, active or inactive, patients with leprosy, and healthy individuals. Patients with tuberculosis, both active and inactive, and those with leprosy had higher BCG sonicate antibody levels and frequencies above cutoff value than healthy subjects (for BCG-sonicate antibody, p less than 0.05 for inactive tuberculosis, p less than 0.0001 for others; for frequency above cutoff, p less than 0.001 for inactive tuberculosis, p less than 0.0001 for others). Among the three groups of patients, significant differences were noted in anti-BCG sonicate antibody level, and there was no difference of frequency above the cutoff value (i.e. inactive tuberculosis had lower level than active tuberculosis and leprosy, p less than 0.005). In conclusion, ELISA with BCG sonicate antigen could serve as a diagnostic aid for mycobacterial infection in Taiwan. However, it was not possible to differentiate disease activity in tuberculosis, or to discriminate infectious species of mycobacteria. Purified mycobacterial antigens should be tried in further research to improve the specificity and sensitivity in serodiagnosis with ELISA.