THE VARIANT I1 OF VACA GENE OF HELICOBACTER PYLORI (HP) IS ASSOCIATED WITH DUODENAL ULCER (DU) AND GASTRIC CARCINOMA (GC)

Gifone Aguiar Rocha (F. Medicina/UFMG); Fabrício Freire de Melo (ICB/UFMG); Luciana Ramos de Almeida (ICB/UFMG); Andreia Maria Camargos Rocha (F. Medicina/UFMG); Juliana Becattini Guerra (F. Medicina/UFMG); Dulciene Maria de Magalhães Queiroz (F. Medicina/UFMG)

The gene vacA of HP is polymorphic with different types encoding different levels of vacuolating A cytotoxin. The major variation occurs in the vacA signal region (s1 or s2) and the mid region (m1 or m2) and more recently, an intermediate region (i1 and i2) has been described. The variant i1 was associated with GC in an Iranian population. Variant the variant i1 of vacA as well as of s1 and m1 variant s and HP-associated diseases in a Brazilian population. We studied 415 patients (210 with chronic gastritis - CG, 125 DU and 80 GC). s and m allele status was investigated by PCR. s1 was observed in 69.4% (141/203), 91.1% (112/123) and 95.0% (76/80) of HP isolates from CG, DU and GC patients, respectively being associated with DU (p<10^-3; OR=4.48; 95%CI=2.16–9.48) and GC (p<10^-3; OR=8.35, 95%CI=8.35-28.13. The variant m1 was identified in 46.4% (97/209), 64.8% (83/128) and 80.2% (65/81) of the HP isolates from patients with CG, DU and GC, respectively being associated with DU (p=0.001; OR=2.13; 95%CI=1.32–3.44) and GC (p=0.03; OR=4.69; 95%CI=2.47–9.24). The variant m1 was also more often found in GC patients than in DU ones (p=0.03; OR=2.20; 95%CI=1.09–4.48). The genotypes s1m1, s1m2 and s2m2 were isolated from 49.0% (98/200), 21.0% (42/200) and 30.0% (60/200) of patients with CG, respectively. In the group of patients with DU 67.5% (81/120), 23.3% (28/120) and 9.7% (11/120) of the HP strains were s1m1, s1m2 and s2m2, respectively whereas in the patients with GC 83.3% (65/78), 11.5% (9/78) and 5.1% (4/78) were infected with s1m1, s1m2 and s2m2 strains respectively. Concerning the i region of the vacA, we evaluated HP strains from 63, 53 and 31 patients with CG, DU and GC, respectively. The vacA i region polymorphisms were assayed by PCR. The variant i1 associated with DU (p<10^-3, OR=10.26, 95%CI=2.66–46.34) and GC (p<10^-3, OR=18.46, 95%CI=2.41–386.95). In contrast, no difference was observed between the patients with GC and DU (p = 1). The variant i1 associated with the allele s1 (p < 10^-3) and with m1 (p < 10^-3). In conclusion, the allele i1 of vacA gene was associated with DU and GC in Brazilian population. Grants: FAPEMIG, CNPq and CAPES, Brazil.