HLA class II alleles as markers of tuberculosis susceptibility and resistance.
BACKGROUND
Not every individual exposed to Mycobacterium tuberculosis becomes infected. One host genetic factor, involved in modulating the immune response that has been studied in many ethnic groups is the association of human leukocyte antigens (HLA) with susceptibility to tuberculosis (TB).


OBJECTIVE
To investigate the association between TB, HLA-DRB1 and HLA-DQB1 alleles in a Portuguese population.


METHODS
HLA-DRB1 and HLA-DQB1 gene polymorphisms were analyzed by PCR-SSP in 92 TB patients, and 82 healthcare professionals without TB but exposed on a daily basis to infectious patients for more than two years (healthy exposed - HE). Tuberculin skin test reaction (TST), was positive in 69 individuals (all over 15 mm) in the HE group (HE+) and negative in thirteen (HE-).


RESULTS
HLA-DRB1*14 frequency is higher in the TB patients group (7 % vs. 0; p = 0.038) than in HE+.


CONCLUSIONS
No genetic marker clearly indicative of disease susceptibility or resistance was identified in this study. However, HLA-DRB1*14 was more frequent in TB patients suggesting that it may be involved in the evolution infection towards active TB in our population.
Centro de Diagnóstico Pneumológico (CDP) de Vila Nova de Gaia, Vila Nova de Gaia, Portugal. rdmelo@med.up.pt
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Duarte
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Carvalho
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Pereira
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Bettencourt
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A
Carvalho
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M
Villar
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A
Domingos
H
H
Barros
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Marques
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Pinho Costa
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Mendonça
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Martins
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease; D006683:HLA-DQ Antigens / Q000235:genetics*; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D014397:Tuberculosis, Pulmonary / Q000235:genetics* / Q000276:immunology*; D055815:Young Adult
D005819:Genetic Markers; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains