Can anti-PGL-I antibody isotypes differentiate leprosy contacts and leprosy patients?

BACKGROUND: Serological tests for antibody measurement in leprosy have a series of limitations in discriminating contacts and patients. The present paper intends to evaluate if association of more than one antibody isotype in serum samples may be a useful tool in leprosy diagnosis. METHODS: This study evaluated 395 leprosy contacts and 71 leprosy index cases living in endemic municipalities in Northeastern Brazil. The participants were evaluated according to their anti-phenolic glycolipid antigen-I isotype (PGL-I) profile. Serum anti-PGL-I IgM, IgG, and IgA were measured by indirect ELISA. RESULTS: A strong association was found for antibody positivity in MB leprosy index cases. The odds ratios were 6.11 (95% CI 3.08 - 12.16) for IgM, 3.31 (1.66 - 6.61) for IgG, and 16.97 (8.39 - 34.2) for IgA. For IgM associated with one or more isotypes, the OR was 21.0 (95% CI 10.11 - 43.64), and for IgG + IgA, the OR was 17.58 (6.23 - 49.54). The highest diagnostic sensitivity of 76.0% (95% CI 61.8 - 86.9) was observed for IgM, and the lowest value was 24.1% (13.0 - 38.2), which was observed for IgG + IgA isotypes. Regarding presumptive positive predictive values, the lowest value was obtained for IgM at 24.7% (95% CI 18.1 - 32.3), and the highest values were observed for IgM+ one or more isotypes and for IgG + IgA isotype at 60.0% (44.3 - 74.3) and 66.7% (41.0 - 86.7), respectively. CONCLUSIONS: The present work demonstrated that by associating two or more positive antibody isotypes, the risk of facing a real case of leprosy may increase.

Salivary anti-PGL-1 IgM may indicate active transmission of Mycobacterium leprae among young people under 16 years of age

Abstract Considering that the main route of Mycobacterium leprae transmission is the upper respiratory tract, detection of salivary antibodies can be a useful tool for diagnosing early infection. The study aimed to analyze salivary anti-PGL-1 IgA and IgM antibodies in 169 children aged 4-16 years old, who lived nearby or inside the house of multibacillary or paucibacillary leprosy patients in two endemic cities in Alagoas State - Brazil. Salivary anti-PGL-1 antibodies were quantified by modified ELISA method. The frequency of contact and clinical form of the index case were significantly associated with salivary antibody levels. High frequency of IgM positivity strongly suggests active transmission of M. leprae in these communities. We suggest in the present work that salivary anti-PGL IgA and IgM are important biomarkers to be used for identifying communities with probable active transmission of M. leprae.

Salivary anti-PGL-1 IgM may indicate active transmission of Mycobacterium leprae among young people under 16 years of age.

Considering that the main route of Mycobacterium leprae transmission is the upper respiratory tract, detection of salivary antibodies can be a useful tool for diagnosing early infection. The study aimed to analyze salivary anti-PGL-1 IgA and IgM antibodies in 169 children aged 4-16 years old, who lived nearby or inside the house of multibacillary or paucibacillary leprosy patients in two endemic cities in Alagoas State - Brazil. Salivary anti-PGL-1 antibodies were quantified by modified ELISA method. The frequency of contact and clinical form of the index case were significantly associated with salivary antibody levels. High frequency of IgM positivity strongly suggests active transmission of M. leprae in these communities. We suggest in the present work that salivary anti-PGL IgA and IgM are important biomarkers to be used for identifying communities with probable active transmission of M. leprae.

Anti-PGL1 salivary IgA/IgM, serum IgG/IgM, and nasal Mycobacterium leprae DNA in individuals with household contact with leprosy.

OBJECTIVES: Leprosy household contacts represent a group at high risk of developing the disease. The aim of this study was to detect Mycobacterium leprae subclinical infection in this group through serological and molecular parameters. METHODS: Serum anti-PGL1 IgG/IgM and salivary anti-PGL1 IgA/IgM was investigated using an ELISA, and nasal carriage of M. leprae DNA was detected by PCR, in leprosy household contacts of paucibacillary (PB) and multibacillary (MB) household leprosy patients (n=135), their index cases (n=30), and in persons living in a low endemic city (n=17). RESULTS: Salivary anti-PGL1 IgA and IgM and serum anti-PGL1 IgG showed good correlation comparing contacts and index cases (p<0.01, p<0.005, and p<0.0001, respectively). This was not observed for serum anti-PGL1 IgM (p>0.05). A high frequency of anti-PGL1 IgM positivity was found in IgG-negative samples (p<0.0001). For IgG-positive samples, IgM antibodies were also positive in most of the samples. None of the 17 volunteers living in a low endemic city presented seropositivity for IgG; however, two of them showed positivity for anti-PGL1 IgM. M. leprae DNA was found in the nasal swabs of nine out of the 85 MB household leprosy contacts (10.6%) and in three out of the 50 PB household leprosy contacts (6.0%). CONCLUSION: We strongly suggest that serum IgG/IgM and salivary anti-PGL1 IgA/IgM measurements are used to follow leprosy household contacts.

Secondary leprosy infection in a patient with psoriasis during treatment with infliximab.

Tumor necrosis factor α antagonists are proven to be effective for the treatment of chronic inflammatory conditions, such as psoriasis. A major concern for patients is the risk of acquiring granulomatous infectious diseases caused by the immunosuppressive effects of the drugs. We report a 60-year-old man with psoriasis who underwent infliximab treatment for 2 years and developed secondary leprosy, presenting extensive erythematous and infiltrated plaques on the trunk and limbs with loss of sensitivity (thermal, pain and tactile). The skin lesion biopsy showed perivascular epithelioid granulomas, nodular dermal aggregates of foamy macrophages and bundles of acid-fast bacilli. The clinical picture associated with histopathologic evaluation suggested borderline lepromatous leprosy. Before infliximab treatment, the patient had a positive tuberculin skin test and underwent chemoprophylaxis treatment for latent tuberculosis. Although the tuberculin reactivity suggests a strong correlation with a latent Mycobacterium tuberculosis infection, the possibility of infections by other mycobacteria, such as Mycobacterium leprae, should not be discarded.