RESUMO Introdução: Aproximadamente 2/3 dos pacientes com a Síndrome de Guillain-Barré (SGB) apresentam alguma doença infecciosa precedente. Recentemente, uma epidemia de infecção por o vírus Zika resultou em surto de SGB na América Latina, principalmente no Brasil, concomitante à circulação contínua de sorotipos do vírus da Dengue. No entanto, não há estudo sobre a infecção por citomegalovírus (CMV) como fator de risco para SGB no Brasil. Objetivos: Neste estudo, relatamos uma série de casos de SGB com o intuito de determinar a prevalência de CMV e as características associadas à infecção. Métodos: Foi estudada uma coorte de 111 casos de SGB diagnosticados entre 2011 e 2017 na cidade de Natal, capital do estudo do Rio Grande do Norte, nordeste do Brasil. A presença de anticorpos IgM CMV foi determinada por eletroquimiluminescência. A análise foi realizada considerando o status de infecção por CMV e os achados clínicos. Resultados: Foi observada uma soroprevalência de 15,3% (n = 17) para o CMV. Os casos de CMV eram mais jovens (26 vs. 40, p = 0,016), sem história de infecção gastrointestinal (p = 0,762) ou respiratória superior (0,779) ou perda sensorial (p = 0,03). Apresentaram-se mais frequentemente como uma variante sensitiva-motora clássica da SGB (p = 0,02) e subtipo desmielinizante nos estudos eletrofisiológicos (p <0,001). Conclusão: No Brasil, o perfil clínico-epidemiológico do SGB associado à infecção por CMV é semelhante ao descrito em outros países. O melhor entendimento das relações entre processos infecciosos e SGB é um componente-chave de uma agenda de pesquisa e estratégia de assistência para iniciativas globais de saúde em neuropatia periférica.

ABSTRACT Background: Guillain-Barré syndrome (GBS) is currently the most common cause of acute flaccid paralysis worldwide. Risk factors for GBS include previous viral or bacterial infections or vaccination. Recently, an outbreak of Zika virus led to an outbreak of GBS in Latin America, mostly in Brazil, concomitant to continuous circulation of dengue virus serotypes. However, there is no study about cytomegalovirus (CMV) infection as a risk for GBS in Brazil. Objectives: In this study, we report a series of cases of GBS with the aim of determining the prevalence of CMV and the characteristics associated with the infection. Methods: A cohort of 111 GBS cases diagnosed between 2011 and 2017 in Natal, northeastern Brazil, was studied. Presence of CMV IgM antibodies was determined by means of electrochemiluminescence. The analysis was performed considering CMV infection status and the clinical outcome. Results: We found seroprevalence of 15.3% (n = 17) for CMV. CMV patients were younger (26 vs. 40; p = 0.016), with no apparent gastrointestinal (p = 0.762) or upper respiratory infections (p = 0.779) or sensory loss (p = 0.03). They presented more often with a classic GBS sensorimotor variant (p = 0.02) and with a demyelinating pattern in electrophysiological studies (p < 0.001). Conclusion: In Brazil, the clinical-epidemiological profile of GBS associated with CMV infection is similar to that described in other countries. Better understanding of the relationship between infectious processes and GBS is a key component of the research agenda and assistance strategy for global health initiatives relating to peripheral neuropathic conditions.

Leprosy remains prevalent in Brazil. ErbB2 is a receptor for leprosy bacilli entering Schwann cells, which mediates Mycobacterium leprae-induced demyelination and the ERBB2 gene lies within a leprosy susceptibility locus on chromosome 17q11-q21. To determine whether polymorphisms at the ERBB2 locus contribute to this linkage peak, three haplotype tagging single nucleotide polymorphisms (tag-SNPs) (rs2517956, rs2952156, rs1058808) were genotyped in 72 families (208 cases; 372 individuals) from the state of Pará (PA). All three tag-SNPs were associated with leprosy per se [best SNP rs2517959 odds ratio (OR) = 2.22; 95% confidence interval (CI) 1.37-3.59; p = 0.001]. Lepromatous (LL) (OR = 3.25; 95% CI 1.37-7.70; p = 0.007) and tuberculoid (TT) (OR = 1.79; 95% CI 1.04-3.05; p = 0.034) leprosy both contributed to the association, which is consistent with the previous linkage to chromosome 17q11-q21 in the population from PA and supports the functional role of ErbB2 in disease pathogenesis. To attempt to replicate these findings, six SNPs (rs2517955, rs2517956, rs1810132, rs2952156, rs1801200, rs1058808) were genotyped in a population-based sample of 570 leprosy cases and 370 controls from the state of Rio Grande do Norte (RN) and the results were analysed using logistic regression analysis. However, none of the associations were replicated in the RN sample, whether analysed for leprosy per se, LL leprosy, TT leprosy, erythema nodosum leprosum or reversal reaction conditions. The role of polymorphisms at ERBB2 in controlling susceptibility to leprosy in Brazil therefore remains unclear.