RESUMO
AIM: To explore whether predisposition to autoimmune gastritis (AIG) is found in human leukocyte antigen (HLA), cytokine or killer cell immunoglobulin-like receptor (KIR) gene variations. METHODS: Twelve Finnish patients with autoimmune-type severe atrophy of the gastric corpus were included. The patients' serum was analyzed for pepsinogen I and Helicobacter pylori (H. pylori) antibodies. DNA was separated and the patients were genotyped for HLA-A, B, Cw, DRB1 and DQB1 antigens, and studied for single nucleotide polymorphisms for the following cytokines: interleukin (IL)-1 gene cluster, IL-2, IL-4, IL-6, IL-10, IL-12, interferon gamma, transforming growth factor beta, and tumor necrosis factor alpha. Variation in KIR genes was also explored. The results were compared with prevalence of the polymorphisms in Finnish or European populations. RESULTS: All patients had pepsinogen I levels below normal (mean: 11 microg/L, range: < 5 to 25 microg/L). Three patients had elevated H. pylori IgG antibodies, while H. pylori serology was negative in the rest of the patients. AIG patients carried significantly more often HLA-DRB1*04 (58%) and DQB1*03 (83%) than the general Finnish population did (28% and 51%, respectively; P = 0.045 and 0.034 by the Fisher's exact test). No patient was positive for HLA-B8-DRB1*03, a well-established autoimmune marker. Neither cytokine polymorphisms nor KIR gene variation showed association with AIG. CONCLUSION: As explored with modern DNA-based methods, HLA-DRB1*04 and DQB1*03 alleles, but not HLA-B8-DRB1*03, may predispose to AIG.
Assuntos
Doenças Autoimunes/genética , Gastrite/genética , Predisposição Genética para Doença/genética , Antígenos HLA-DQ/genética , Antígenos HLA-DR/genética , Glicoproteínas de Membrana/genética , Adulto , Doenças Autoimunes/etnologia , Estudos de Casos e Controles , Citocinas/genética , República Tcheca , Feminino , Finlândia , Gastrite/etnologia , Genótipo , Cadeias beta de HLA-DQ , Cadeias HLA-DRB1 , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Canais de Potássio Corretores do Fluxo de Internalização/genéticaRESUMO
AIM: To study the association between Helicobacter pylori (H. pylori) infection and autoimmune type atrophic gastritis. METHODS: Twenty-three patients with different grades of atrophic gastritis were analysed using enzyme immunoassay-based serology, immunoblot-based serology, and histology to reveal a past or a present H. pylori infection. In addition, serum markers for gastric atrophy (pepsinogen I, pepsinogen I/II and gastrin) and autoimmunity [parietal cell antibodies (PCA), and intrinsic factor (IF), antibodies] were determined. RESULTS: Of the 14 patients with severe gastric atrophy, as demonstrated by histology and serum markers, and no evidence for an ongoing H. pylori infection, eight showed H. pylori antibodies by immunoblotting. All eight had elevated PCA and 4/8 also had IF antibodies. Of the six immunoblot-negative patients with severe corpus atrophy, PCA and IF antibodies were detected in four. Among the patients with low to moderate grade atrophic gastritis (all except one with an ongoing H. pylori infection), serum markers for gastric atrophy and autoimmunity were seldom detected. However, one H. pylori negative patient with mild atrophic gastritis had PCA and IF antibodies suggestive of a pre-atrophic autoimmune gastritis. CONCLUSION: Signs of H. pylori infection in autoimmune gastritis, and positive autoimmune serum markers in H. pylori gastritis suggest an etiological role for H. pylori in autoimmune gastritis.