Analysis of antigens of Mycobacterium leprae by interaction to sera IgG, IgM, and IgA response to improve diagnosis of leprosy.

Till 2010, several countries have declared less than one leprosy patient among population of 10,000 and themselves feeling as eliminated from leprosy cases. However, new leprosy cases are still appearing from all these countries. In this situation one has to be confident to diagnose leprosy. This review paper highlighted already explored antigens for diagnosis purposes and finally suggested better combinations of protein antigens of M. leprae versus immunoglobulin as detector antibody to be useful for leprosy diagnosis.

Serological detection of leprosy employing Mycobacterium leprae derived serine-rich 45 kDa, ESAT-6, CFP-10 and PGL-I: a compilation of data from studies in Indian populations.

This article is a compilation of our findings recorded in the recent past where we have investigated the serological performance of Mycobacterium leprae antigens like-serine-rich 45 kDa protein (45 kD), early secretary antigenic target-6 (ESAT-6), culture filtrate protein-10 (CFP-10) and phenolic glycolipid-I (PGL-I) for detection (employing antibody detecting ELISA) of leprosy patients, particularly those belonging to the paucibacillary (PB) group. All of these antigens were capable of detecting, by themselves the majority (82-100%) of multibacillary (MB) patients. However, with respect to PB patients, only 18-47% (i.e. less than half) of the cases could be detected. Based on the results of serological assays for each of the four antigens separately a combinatorial approach was performed for these antigens, which increased the sensitivity for detection of PB patients to 73%, giving 36% improvement over conventional PGL-I based ELISA. Thus, the multi-antigenic serological approach is worthwhile for its establishment for detection of leprosy patients. Since ESAT-6 and CFP-10 are secreted proteins by nature, antibodies against them are worth exploring for detection of early infections and for monitoring of treatment efficiency. Nevertheless, efforts towards identification of more new antigens with serological potential are still desirable in order to further improve the detection rate of leprosy.

Classification of leprosy into multibacillary and paucibacillary groups: an analysis.

Classification of leprosy patients into multibacillary and paucibacillary determines the duration of their treatment. Misclassification leads to increased risk of relapse due to insufficient treatment if a multibacillary patient is classified as paucibacillary. This also prolongs the time the patient is infective. Over the years, the criteria used for classification (for treatment purpose) of leprosy patients have changed significantly from bacterial index measuring approach through number of skin lesions. The reliability of both of these criteria has been questioned. Several studies have shown that the presence of antibodies to the Mycobacterium leprae-specific antigens correlates with the bacterial load of a leprosy patient. Further, there are reports where results of serology and bacteriological approaches have been found to agree substantially. Thus, serology seems to be a worthwhile convenient alternative tool for classification of leprosy into multibacillary or paucibacillary. Nevertheless, in view of the limitations of various classification criteria, follow-up studies are called for to understand the efficiency of various approaches in preventing relapse after treatment. The method ensuring the lowest rate of relapse could be adopted for future use in classifying these patients.

Detection of antibodies against Mycobacterium leprae culture filtrate protein-10 in leprosy patients.

The prevalence of IgG antibodies against Mycobacterium leprae recombinant culture filtrate protein-10 (rCFP-10) was investigated in serum samples from 56 leprosy patients, 15 tuberculosis (TB) patients, 14 other skin-diseased patients and 20 healthy subjects. On classifying the patients into bacterial index (BI)-positive and BI-negative groups, the assay showed 83.3 % (15/18) sensitivity for detection of BI-positive leprosy patients. On the other hand, the sensitivity for detection of BI-negative patients was 18.4 % (7/38). None of the 15 TB patients and 14 other skin-diseased patients was positive; however, only one out of 20 healthy individuals was positive, indicating that antibody response to culture filtrate protein-10 (CFP-10) was highly specific (98.0 %; 48/49). Statistically, the performance of the CFP-10-based assay was found to be comparable (P>0.05) with that of an anti-phenolic glycolipid-I (PGL-I) antibody-detecting assay. Thus, M. leprae CFP-10 is potentially a specific antigen for measuring antibody response in BI-positive leprosy patients. Being a secreted antigen, CFP-10 may act as a marker for the viability of M. leprae inside the host, and hence its serological potential is worth exploring for application in monitoring the response of patients with BI-positive leprosy (a highly infectious form) during the course of chemotherapy. When comparing the bacteriological and serological results, an agreement of 82.1 % showed that seropositivity to M. leprae CFP-10 corresponded well with bacteriological criteria. Hence, CFP-10 seems to be a suitable antigen for classification of leprosy patients into BI-positive and BI-negative groups.

Detection of Mycobacterium leprae DNA for 36kDa protein in urine from leprosy patients: a preliminary report.

We have searched for Mycobacterium leprae DNA for 36kDa protein in urine using a M. leprae specific PCR technique. A limited number of 16 patients (of which 11 belonged to lepromatous leprosy and five to tuberculoid leprosy) and eight healthy individuals were included for the present study. The number of urine samples positive by PCR were 36.4% (4/11) in lepromatous patients and 40% (2/5) in tuberculoid patients. None of the samples from healthy individuals was positive. To our knowledge, the results indicate, for the first time, the presence of M. leprae DNA in urine from leprosy patients. Another important finding obtained out of the study is that amongst treated patients 66.6% (4/6) were positive whereas amongst untreated only 20% (2/10) were positive. From the present indicative data it appears that treatment improves the PCR results with urine as a sample. Thus, the approach could prove to be useful for monitoring the treatment response of individual patients and needs to be further evaluated with a large number of patients.

Detection of Mycobacterium leprae DNA for 36kDa protein in urine from leprosy patients: a preliminary report

Pesquisamos o DNA do Mycobacterium leprae para proteína 36 kDa na urina usando a técnica do PCR específica para M. leprae. Um número limitado de 16 pacientes (dos quais 11 tinham hanseníase multibacilar e cinco hanseníase paucibacilar) e oito indivíduos saudáveis foram incluídos neste estudo. O número de amostras de urina positivas pelo PCR foi de 36,4% (4/11) em pacientes com hanseníase multibacilar e 40% (2/5) em pacientes com hanseníase paucibacilar. Nenhuma das amostras de indivíduos saudáveis foi positiva. Até onde chega o nosso conhecimento, os resultados indicam, pela primeira vez, a presença de DNA do M. leprae na urina de pacientes com hanseníase. Outro fato importante obtido através do exame é que entre os pacientes tratados 66.6% (4/6) eram positivos enquanto entre os não tratados somente 20% (2/10) foram positivos. Pelos presentes dados indicativos parece que o tratamento melhora os resultados do PCR em amostra de urina. Assim, o acesso a estes dados prova ser útil no monitoramento da resposta ao tratamento de pacientes individuais e precisa ser melhor avaliado com um grande número de pacientes.

Progress towards development of immunoassays for detection of Mycobacterium leprae infection, employing 35kDa antigen: an update.

The 35 kDa antigen of Mycobacterium leprae is a membrane component that contains both B and T-cell stimulating epitopes. Monoclonal antibodies, primarily specific to M. leprae, have been developed against this antigen. Moreover, this antigen has been genetically engineered. Using recombinant 35 kDa antigen and/or a monoclonal antibody against an epitope on 35 kDa, a variety of antibody/antigen detecting tests have been described for detection of M. leprae infection. 35 kDa protein also stimulates peripheral blood mononuclear cells (PBMCs) from the majority of paucibacillary (PB) patients. Approaches using combined antibody and T cell are discussed.