Alterations to antigen-specific immune responses before and after multidrug therapy of leprosy Aline Araújo Freitas a , Regiane Morillas Oliveira a , Emerith Mayra Hungria a , Ludimila Paula Vaz Cardoso a , Ana Lúcia Osório Maroccolo Sousa a , Maurício Barcelos Costa a , Steven G. Reed b , Malcolm S. Duthie b , Mariane Martins Araújo Stefani a, ⁎ a Tropical Pathology and Public Health Institute, Federal University of Goias, Goiania, Brazil b Infectious Disease Research Institute, Seattle, WA, USA abstract article info Article history: Received 25 March 2015 Received in revised form 23 June 2015 Accepted 29 June 2015 Available online 2 July 2015 Keywords: Leprosy Diagnosis Serology Cellular immunity Multidrug therapy This study evaluated the impact of leprosy multidrug therapy (MDT) on cell-mediated immunity (CMI) and an- tibody responses at diagnosis in untreated paucibacillary (PB) (n = 15) and multibacillary (MB) patients (n = 15) using a panel of Mycobacterium leprae recombinant antigens (rMLs) (CMI: 46f, ML0276, ML2055, leprosy IDRI diagnostic 1 [LID-1], and ML2629, as negative control; serology: LID-1, 46f, 92f, and 33f, as negative control, and phenolic glycolipid I [PGL-I]) and at 2 time points after MDT (PB: 8–20 months; MB: 4–22 months). At diag- nosis, PB patients produced interferon gamma (IFNγ), and MB patients exhibited low/absent response. Shortly after MDT, IFNγ production in PB patients declined except for LID-1; MB patients produced IFNγ to LID-1. Almost 2 years after MDT, IFNγ levels declined in PB and MB patients. Most untreated PB patients were seronegative to PGL-I and rML, remaining so after MDT. Most untreated MB patients were seropositive to all antigens, and IgG to rMLs declined after MDT. Reduction in antigen-specific CMI in PB and in antibody response in MB patients may help monitor MDT effectiveness. © 2015 Elsevier Inc. All rights reserved. 1. Introduction Leprosy is a chronic disease caused by Mycobacterium leprae that can cause irreversible peripheral nerve damage (Lockwood, 2002). Despite the effectiveness of multidrug therapy (MDT), leprosy incidence ap- pears not to have changed significantly, and 215,656 newly diagnosed cases were still reported in 2013. Brazil reported 31,044 new leprosy cases in this time period, ranking second in overall leprosy incidence to only India (WHO, 2014). Leprosy presents a wide and complex spectrum of bacteriologic, clinical, and histopathologic signs that are dependent on the host im- mune response. Paucibacillary (PB) leprosy patients present absent bac- terial indices (BI), few localized skin and neurological lesions, strong specific cell-mediated immunity (CMI), and low/absent antibody pro- duction. Multibacillary (MB) disease is characterized by high BI, multi- ple disseminated skin lesions, weak/absent M. leprae–specific CMI, and high titers of specific antibodies (Scollard et al., 2006). MDT currently consists of 6 doses with rifampicin and dapsone for PB leprosy and 12 doses with rifampicin, dapsone, and clofazimine for MB patients. Rifampicin is taken once monthly, but the other drugs are scheduled dif- ferently (WHO, 2009). Upon MDT completion, patients are considered cured; however, even after MDT, some patients develop leprosy reac- tions (www.who.int/lep, 2014). Early diagnosis and treatment before the onset of clinical manifestations are considered key to reduce M. leprae transmission and to prevent deformities and disabilities (Scollard, 2008; WHO, 2013). Currently, the diagnosis of leprosy relies on the recognition of the clinical manifestations. Spurred by the decoding of the M. leprae ge- nome, research efforts have pushed toward the identification of M. leprae proteins suitable for the development of appropriate laborato- ry tests. For serology-based tests, the leprosy IDRI diagnostic 1 (LID-1) fusion protein (combining ML0405 and ML2331 in a single product) has been well recognized by IgG antibodies of MB patients from multiple leprosy-endemic areas (Duthie et al., 2008b). Our recent data demonstrated that LID-1 can also induce IFNγ production in whole blood assays (WBAs) of PB leprosy patients and healthy household contacts regularly exposed to M. leprae (Oliveira et al., 2014). While diagnostic and prognostic tests are needed to monitor preven- tive and therapeutic strategies for leprosy, the impact of MDT on M. leprae–specific cell-mediated immune responses is unknown. This study evaluated the impact of MDT on the serological and cellular immune responses against a panel of M. leprae recombinant antigens (rMLs). 2. Patients and methods 2.1. Study groups This longitudinal and prospective study evaluated newly diagnosed, untreated leprosy patients at the time of diagnosis (pre-MDT group) Diagnostic Microbiology and Infectious Disease 83 (2015) 154–161 ⁎ Corresponding author. Tel.: +55-62-3209-6111; fax: +55-62-3209-6363. E-mail address: mmastefani@gmail.com (M.M.A. Stefani). http://dx.doi.org/10.1016/j.diagmicrobio.2015.06.021 0732-8893/© 2015 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Diagnostic Microbiology and Infectious Disease journal homepage: www.elsevier.com/locate/diagmicrobio