Amorim FM, Nobre ML, Nascimento LS, Miranda AM, Monteiro GRG, Freire-Neto FP, Queiroz MDCP, Queiroz JW, Duthie MS, Costa MR, Reed SG, Johnson WD, Dupnik KM, Jeronimo SMB. Differential immunoglobulin and complement levels in leprosy prior to development of reversal reaction and erythema nodosum leprosum. PLoS neglected tropical diseases. 2019 Dec;13(13). e0007089. PMID: 30689631 [PubMed] PMCID: PMC6366718
Leprosy is a treatable infectious disease caused by Mycobacterium leprae. However, there is additional morbidity from leprosy-associated pathologic immune reactions, reversal reaction (RR) and erythema nodosum leprosum (ENL), which occur in 1 in 3 people with leprosy, even with effective treatment of M. leprae. There is currently no predictive marker in use to indicate which people with leprosy will develop these debilitating immune reactions. Our peripheral blood mononuclear cell (PBMC) transcriptome analysis revealed that activation of the classical complement pathway is common to both RR and ENL. Additionally, differential expression of immunoglobulin receptors and B cell receptors during RR and ENL support a role for the antibody-mediated immune response during both RR and ENL. In this study, we investigated B-cell immunophenotypes, total and M. leprae-specific antibodies, and complement levels in leprosy patients with and without RR or ENL. The objective was to determine the role of these immune mediators in pathogenesis and assess their potential as biomarkers of risk for immune reactions in people with leprosy.