HLA among Brazilian patients with spontaneous chronic urticaria and positive autologous serum skin test.
BACKGROUND
An association between class I and II alleles of the major histocompatibility complex and idiopathic chronic urticaria has previously been observed in different populations, but there are still no studies on Brazilian populations in this regard.


OBJECTIVE
The involvement of the major histocompatibility complex classes I and II (loci A, B and DR) in Brazilian patients with idiopathic chronic urticaria and a positive autologous serum skin test was investigated and compared with a healthy population group.


METHODS
DNA was extracted from the blood of 42 patients with idiopathic chronic urticaria and major histocompatibility complex classes I and II alleles were determined using the polymerase chain reaction and a laboratory test for oligonucleotide hybridization using a single-filament probe. The frequencies of these alleles in patients with chronic urticaria were compared with the frequencies in 1000 genetically unrelated voluntary blood donors from the same region of Brazil. The diagnosis of idiopathic chronic urticaria was based on the patients' clinical history and routine laboratory tests. Only the patients with positive autologous serum skin test were selected. The allele distribution resulted from the patient and control groups were analyzed using odds ratios and 95% confidence intervals.


RESULTS
No statistically significant differences were found between the positive autologous serum skin test patients with chronic urticaria and the control group.


CONCLUSIONS
We found that in this population group, there was no specific association between the HLA alleles studied and chronic urticaria. We believe that further population studies are needed in order to investigate the possible existence of this association.
Faculdade Estadual de Medicina de Marília, SP, Brazil. calamita@unimedmarilia.com.br
Zamir
Z
Calamita
Andrea Bronhara
AB
Pelá
Márcia
M
Gamberini
Wilson
W
Baleotti Júnior
Odilon Marques de
OM
Almeida Filho
Marcelo O
MO
Ruiz
Dione G
DG
Arevalo
Antônio
A
Fabron Júnior
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D020022:Genetic Predisposition to Disease; D015395:Histocompatibility Antigens Class I / Q000032:analysis* / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000032:analysis* / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012882:Skin Tests; D014581:Urticaria / Q000235:genetics* / Q000276:immunology; D055815:Young Adult
D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II