Serological anti PGL I and anti LID-1 profile in paraguayan patients infected with Mycobacterium leprae and household contacts

Abstract

Background: Hansen's Disease is chronic and can cause severe motor disorders, due to lack of treatment or late diagnosis. The prevalence in Paraguay has remained the same for decades. Seroreactivity to specific antigens of M. leprae (PGL I and LID-1); may indicate an increased risk of developing the disease, especially in contacts. Aim: To evaluate the level of antibodies using an in-house ELISA test for different target populations. Methods: Descriptive observational cross-sectional study, in which sera from 28 patients at the time of diagnosis and 22 household contacts who attended the National Leprosy Control Program of Paraguay between 2018 and 2023 were analyzed. Additionally, sera from 11 healthy volunteers of middle to high socioeconomic status from non-endemic areas were also analyzed. Results: Seroreactivity to PGL I was 89.5% and 66.6% of multibacillary (MB) and paucibacillary (PB) patients, respectively. In household contacts (HC), 40% of multibacillary contacts (HCMB) and 42.9% of paucibacillary contacts (HCPB) were seroreactive. Regarding LID-1, 78.9% in MB, 44.4% in PB and 16.6% in HCPB. A significant correlation (p<0.0001) was observed with the smear index. Screening of anonymized sera of patients without a clinical history of leprosy (n=81) has detected 12.3% positivity for PGL I; all residents of the capital and surrounding departments. Screening of sera from a blood bank (n=100) in Asunción detected a seroreactivity of 6.7% against LID-1. Conclusion: The use of the in house ELISA could benefit leprosy surveillance in Paraguay.