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Previous issue date: 2017-04-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A hansen?ase ? uma doen?a de evolu??o espectral causada pelo Mycobacterium
leprae. Pacientes podem apresentar desde les?es ?nicas, com pequena carga bacilar
(paucibacilares - PB) a les?es disseminadas e alta carga bacteriana (multibacilares -
MB). Os primeiros apresentam uma forte resposta imune celular e os ?ltimos uma
resposta predominantemente humoral. O Brasil ? o segundo pa?s em n?mero de
casos, com ?reas hiperend?micas em diversos estados, incluindo o Rio Grande do
Norte. A alta morbidade da doen?a est?, em parte, relacionada a ocorr?ncia de
rea??es hans?nicas: a rea??o reversa (RR) e o eritema nodoso hans?nico (ENH).
Essas ocorrem predominantemente em pacientes MB. Nosso objetivo foi determinar
o papel de c?lulas B e de anticorpos na patog?nese da hansen?ase e das rea??es
hans?nicas. Para isto, o trabalho foi subdividido em dois estudos: 1. Determina??o do
perfil de anticorpos espec?ficos utilizando os ant?genos recombinantes LID-1 e LIDNDO
ao longo do espectro cl?nico da hansen?ase e em comunicantes; 2. An?lise de
altera??es envolvidas na regula??o da produ??o de anticorpos em c?lulas B de
pessoas com diferentes formas cl?nicas. Neste ?ltimo foram avaliadas: a frequ?ncia
de diferentes subpopula??es de c?lulas B, a express?o de CD32 e CD21 nestas
c?lulas, subclasses de imunoglobulinas presentes no sangue, complexos imunes (IC)
e prote?nas envolvidas na via cl?ssica de ativa??o do sistema complemento. No
estudo 1, observou-se um aumento na quantidade de anticorpos espec?ficos ao longo
do espectro cl?nico da doen?a e este foi correlacionado com o ?ndice bacilosc?pico.
Al?m disso, foi verificado que mais de 82% dos comunicantes haviam sido expostos
? infec??o pelo M. leprae. Esse achado mostra que a quantifica??o de anticorpos
espec?ficos pode ser utilizada para estimar o risco para o desenvolvimento de
hansen?ase. No estudo 2, observou-se que a exacerbada resposta imune humoral de
e pessoas com MB est? associada a altera??es num?ricas e funcionais em c?lulas B,
com aumento na frequ?ncia de plasmoblastos e reduzida express?o de CD32 nestes.
Pessoas com hansen?ase MB apresentaram maior concentra??o de IgG1 e
imunocomplexos (IC) no sangue perif?rico quando comparados a PB. Pessoas com
hansen?ase MB que desenvolveram ENH (durante ou ap?s a poliquimioterapia) j?
apresentavam, ao diagn?stico n?veis mais elevados de IgM, IgG1, anticorpos
espec?ficos e IC quando comparados ?queles que n?o desenvolveram rea??o.
Durante o ENH h? uma expans?o na popula??o de plasmoblastos, contudo h?
diminui??o na concentra??o destas imunoglobulinas no sangue. Indiv?duos com
n?veis elevados de anticorpo anti-LID-NDO, ao diagn?stico, apresentaram um risco
at? 20 vezes maior de desenvolverem rea??o. Nossos resultados mostram que o uso
de ant?genos recombinantes em testes sorol?gicos pode contribuir para um
diagn?stico mais r?pido da doen?a, levando a diminui??o da transmiss?o de M.
leprae. Al?m disso, verificamos que a exacerbada resposta imune humoral de
pacientes MB pode ser, em parte, explicada por altera??es em c?lulas B. A
quantifica??o de anticorpos anti-M. leprae e das subclasses IgM e IgG1 ao diagn?stico
da hansen?ase pode contribuir para identifcar indiv?duos em risco de desenvolverem
rea??o. Do ponto de vista cl?nico, esse ? um dado importante pois pode direcionar
interven??es terap?uticas futuras. / Leprosy is a spectral disease caused by Mycobacterium leprae infection. Subjects can
present single lesions with a reduced number of bacilli (paucibacillary - PB), but also
disseminated lesions and a high bacterial load (multibacillary - MB). The former present
a strong cellular immune response and the latter have a predominantly humoral
response. Brazil is the second country in number of cases, with hyperendemic areas
in several states, including Rio Grande do Norte. Disease?s high morbidity is directly
associated with the occurrence of leprosy reactions: reversal reaction (RR) and
erythema nodosum leprosum (ENL). These reactions occur predominantly in MB
patients. Our aim was to determine the role of B cells and antibodies in the
pathogenesis of leprosy and its immune reactions. For this, the work was subdivided
in two studies: 1. Determination of the profile of specific antibodies to the recombinant
antigens LID-1 and LID-NDO according to the clinical spectrum of the disease and in
household contacts. 2. Analysis of changes involved in the regulation of antibody
production in B cells of patients with different clinical forms of leprosy. For this latter,
the frequency of different B cell subpopulations, the expression of CD32 and CD21 in
these cells, subclasses of immunoglobulins present in the blood, immune complexes
(IC) and proteins involved in the classical pathway of complement activation were
evaluated. In the study 1, it was observed a gradual increase in the level of specific
antibodies along with the clinical spectrum of the disease, and this increase was
correlated with the bacterial index. More than 82% of the household contacts recruited
in the study had been previously exposed to M. leprae infection, with a potential risk of
developing leprosy. This finding shows that the quantification of specific antibodies in
the blood can be used to define groups at risk for leprosy development. MB subjects
presented an exacerbated humoral immune response that was associated with
numerical and functional alterations in B cells, with increased frequency of plasmoblast
and reduced expression of CD32 in these cells. MB patients presented higher
concentrations of IgG1 and IC in the blood when compared to PB. MB patients that
developed ENL (during or after multidrug therapy) presented increased levels of IgM,
IgG1, specific antibodies, and IC in the blood, when compared to those that did not
develop reactions. During ENL, there is an expansion in the plasmoblast population,
however a decrease in the concentration of these immunoglobulins in the blood.
Patients with elevated levels of anti-LID-NDO antibody at diagnosis presented a 20-
fold increased risk of developing reactions. Our results show that the use of
recombinant antigens in serological tests can contribute to an early diagnosis,
decreasing the risk of M. leprae transmission. The exacerbated humoral immune
response of MB patients may be explained, at least in part, by changes in B cells. The
quantification of anti-M. leprae antibodies and IgM and IgG1 subclasses at leprosy
diagnosis may contribute to identify individuals at risk of developing reaction. Clinically,
this is an important data since it can direct future therapeutic interventions.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/23515 |
| Date | 28 April 2017 |
| Creators | Amorim, Francianne Medeiros |
| Contributors | 15603016434, http://lattes.cnpq.br/7120263570947836, Uchoa, Adriana Ferreira, 58024867320, http://lattes.cnpq.br/6644671747055211, Sarno, Euzenir Nunes, 10507833791, http://lattes.cnpq.br/3330957069068672, Donelson, John, 00000000000, http://lattes.cnpq.br/0960973398320605, Costa, Marcos Romualdo, 05278916737, http://lattes.cnpq.br/6118493598074445, Jer?nimo, Selma Maria Bezerra |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM BIOQU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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