Identifying Leprosy and Those at Risk of Developing Leprosy by Detection of Antibodies against LID-1 and LID-NDO

Abstract

Leprosy is caused by Mycobacterium leprae infection and remains a major public health problem in many areas of the world. Challenges to its timely diagnosis result in delay in treatment, which is usually associated with severe disability. Although phenolic glycolipid (PGL)-I has been reported as auxiliary diagnostic tool, currently there is no serological assay routinely used in leprosy diagnosis. The aim of this study was to evaluate the effectiveness of two related reagents, LID-1 and LID-NDO, for the detection of M. leprae infection. Sera from 98 leprosy patients, 365 household contacts (HHC) and 98 endemic controls from Rio Grande do Norte, Brazil, were evaluated. A subgroup of the HHC living in a hyperendemic area was followed for 7–10 years. Antigen-specific antibody responses were highest in multibacillary (MB) at the lepromatous pole (LL/BL) and lowest in paucibacillary (PB) at the tuberculoid pole (TT/BT). A positive correlation for both anti-LID-1 and anti-LID-NDO antibodies was found with bacterial burden (LID-1, r = 0.84, p<0.001; LID-NDO, r = 0.82, p<0.001), with higher sensitivity than bacilloscopy. According to Receiver Operating Curve, LID-1 and LID-NDO performed similarly. The sensitivity for MB cases was 89% for LID-1 and 95% for LID-NDO; the specificity was 96% for LID-1 and 88% for LID-NDO. Of the 332 HHC that were followed, 12 (3.6%) were diagnosed with leprosy in a median time of 31 (3–79) months after recruitment. A linear generalized model using LID-1 or LID-NDO as a predictor estimated that 8.3% and 10.4% of the HHC would become a leprosy case, respectively. Together, our findings support a role for the LID-1 and LID-NDO antigens in diagnosing MB leprosy and identifying people at greater risk of developing clinical disease. These assays have the potential to improve the diagnostic capacity at local health centers and aid development of strategies for the eventual control and elimination of leprosy from endemic areas.

ELISA-based assay of immunoglobulin G antibodies against mammalian cell entry 1A (Mce1A) protein: a novel diagnostic approach for leprosy

“…Previous studies have suggested that the true prevalence of leprosy is underestimated because of diagnostic limitations inherent to large-scale control programs aimed at eventual disease elimination ( Amorim et al 2016 , WHO 2016 ). Thus, we evaluated the potential of a Mce1A-dependent antibody response against M. leprae as an alternative method for diagnosing leprosy.…”

“…The diagnosis of leprosy is based on clinical examination, bacilloscopy of the dermal lymph, and histopathology of skin lesion biopsies ( WHO 2016 ). Although bacilloscopy and histopathology are highly specific, these techniques show low sensitivity ( Amorim et al 2016 ). Moreover, negative results do not exclude the diagnosis of leprosy ( MS 2002 ).…”

Persistência da hanseníase em redes de convívio domiciliar: sobreposição de casos e vulnerabilidade em regiões endêmicas no Brasil

“…O estudo da hanseníase em uma perspectiva além do indivíduo acometido deve considerar o reconhecimento de possíveis RCD como elemento importante para melhor compreensão da dinâmica de transmissão e da adoção de ações oportunas de vigilância e controle. Ressalta-se, portanto, a necessidade de ampliar o foco das ações para os casos entre os contatos fora do domicílio, em especial nas áreas de maior endemicidade 3,18,19,20 . No entanto, os dados deste estudo sugerem que a experiência do adoecimento entre pessoas de uma mesma RCD parece não ser suficiente para desdobrar em ações de atenção e cuidado longitudinal, na perspectiva da integralidade do cuidado e da redução da carga da doença 21 .…”

Epidemiological and space aspects of the schools of the National Leprosy Campaign: the case of Sobral – Ceará, Brazil

“…From the distribution of the endemicity rate of new leprosy cases registered in 2016, it was verified that 29.2% of Sobral's neighborhoods have a hyperendemic profile for leprosy, which makes the resident population with the potential to develop M. leprae, and reinforces the need for the development of strategic actions of active search, combat and control, since the number of cases registered in passive search may be greater when performing active search actions27 .Brazil has a heterogenic spatial distribution of cases of leprosy, guided by the economic social level. Southern states with greater socioeconomic development do not reach high levels or hyperendemicity of leprosy.…”