RESUMO
BACKGROUND: Young age and thiopurine therapy are risk factors for lymphoproliferative disease among patients with inflammatory bowel disease (IBD). AIMS: The aims of this study were to evaluate the prevalence of seropositivity for the Epstein-Barr virus (EBV) and human cytomegalovirus (CMV) among children and adolescents with IBD, to assess the viral load of EBV, CMV, and BK and JC polyomaviruses (BKV, JCV) in these patients, and to assess the influence of different therapeutic regimens on seroprevalence and viral load. METHODS: Children who had been followed in our center were tested for EBV, CMV, BKV, and JCV in a cross-sectional study. One hundred and six children were included who had Crohn's disease (68%), ulcerative colitis (29%), and unclassified IBD (3%). RESULTS: We found that 64% of patients were EBV seropositive. The proportion of EBV seropositive patients increased during childhood. Azathioprine therapy (p = 0.003) was associated with EBV seropositivity in a multiple logistic regression model, after adjusting for gender, age, and disease activity at determination. We found a significant association between the number of polymerase chain reaction copies and infliximab dose (p = 0.023). We did not find any significant association between CMV serology and CMV, BKV, or JCV viral load, or any other therapeutic regimen or clinical characteristics. CONCLUSIONS: Treatment with azathioprine appears to be a risk factor for early EBV seropositivity in children with IBD, and the infliximab dose was associated with a higher EBV viral load.