The influence of innate and adaptative immune responses on the differential clinical outcomes of leprosy.
Leprosy is a chronic infectious disease caused by Mycobacterium leprae. According to official reports from 121 countries across five WHO regions, there were 213 899 newly diagnosed cases in 2014. Although leprosy affects the skin and peripheral nerves, it can present across a spectrum of clinical and histopathological forms that are strongly influenced by the immune response of the infected individuals. These forms comprise the extremes of tuberculoid leprosy (TT), with a M. leprae-specific Th1, but also a Th17, response that limits M. leprae multiplication, through to lepromatous leprosy (LL), with M. leprae-specific Th2 and T regulatory responses that do not control M. leprae replication but rather allow bacterial dissemination. The interpolar borderline clinical forms present with similar, but less extreme, immune biases. Acute inflammatory episodes, known as leprosy reactions, are complications that may occur before, during or after treatment, and cause further neurological damages that can cause irreversible chronic disabilities. This review discusses the innate and adaptive immune responses, and their interactions, that are known to affect pathogenesis and influence the clinical outcome of leprosy.
Department of Medicine, Molecular Biology Laboratory, University Hospital, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.
Adriana Barbosa de Lima
AB
Fonseca
Department of Medicine, Molecular Biology Laboratory, University Hospital, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.
Marise do Vale
MD
Simon
Department of Medicine, Molecular Biology Laboratory, University Hospital, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.
Rodrigo Anselmo
RA
Cazzaniga
Department of Medicine, Molecular Biology Laboratory, University Hospital, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.
Tatiana Rodrigues
TR
de Moura
Department of Medicine, Molecular Biology Laboratory, University Hospital, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.|Instituto de Investigação em Imunologia, Institutos Nacionais de Ciência e Tecnologia, CNPq, São Paulo, SP, Brazil.
Roque Pacheco
RP
de Almeida
Infectious Disease Research Institute, Seattle, USA.
Malcolm S
MS
Duthie
Infectious Disease Research Institute, Seattle, USA.
Steven G
SG
Reed
Department of Medicine, Molecular Biology Laboratory, University Hospital, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil. ameliaribeirodejesus@gmail.com.|Instituto de Investigação em Imunologia, Institutos Nacionais de Ciência e Tecnologia, CNPq, São Paulo, SP, Brazil. ameliaribeirodejesus@gmail.com.
Amelia Ribeiro
AR
de Jesus
D056704:Adaptive Immunity; D054884:Host-Pathogen Interactions / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate; D007918:Leprosy / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology; D018448:Models, Immunological; D016896:Treatment Outcome
Clinical presentation; Immune pathogenesis; Immunology; Innate immunity; Leprosy