Cytokine genes are associated with tuberculin skin test response in a native Brazilian population.
Tuberculosis was a major cause of population decline among Brazilian indigenous peoples and remains a leading cause of morbidity and mortality among them. Despite high BCG coverage, results of Tuberculin Skin Test (TST) reactivity have shown high rates of anergy in Amazonian Indians. Given the high prevalence of anergy in these populations and the fact that genetic host factors play an important role in susceptibility to Mycobacterium tuberculosis (MTB), the aim of this study was to evaluate the association of nineteen polymorphisms in fifteen genes related to immune response and anergy in the Xavante, an indigenous group from Brazil. A total of 481 individuals were investigated. TST anergy was observed in 69% of them. Polymorphisms in four genes showed absence or very low variability: SP110, PTPN22, IL12RB1 and IL6. IFNG +874 A/T heterozygotes and IL4-590 C/C homozygotes were more frequent in those individuals who presented a positive TST (prevalence ratios of 1.9 and 2.0 respectively). The risk of anergy was 1.5 in IL10-1082 G/G homozygotes when compared to carriers for the A allele. In indigenous groups such as the Xavante exposure to a variety of infections, associated with specific genetic factors, may disturb the T-helper 1 and T-helper 2 balance leading to increased immunological susceptibility.
Zembrzuski
Verônica M
VM
Departamento de Genética, Instituto de Biociências, UFRGS, Universidade Federal do Rio Grande do Sul, Caixa Postal 15053, 91501 970 Porto Alegre, RS, Brazil.
Basta
Paulo C
PC
Callegari-Jacques
Sidia M
SM
Santos
Ricardo V
RV
Coimbra
Carlos E A
CE
Salzano
Francisco M
FM
Hutz
Mara H
MH
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D017635:Clonal Anergy / Q000235:genetics; D016207:Cytokines / Q000235:genetics* / Q000276:immunology; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007199:Indians, South American; D007223:Infant; D007371:Interferon-gamma / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology*; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000453:epidemiology / Q000235:genetics / Q000276:immunology*; D055815:Young Adult
D016207:Cytokines; D007371:Interferon-gamma