BACKGROUND: Hepatitis B virus (HBV) vaccine reduced the incidence of Hepatitis B worldwide. Genetic variability, by the presence of specific haplotypes of HLA system (HLA-DR3, HLA-DR4), influences the response to the vaccination. Subjects affected by type 1 diabetes (T1D), contrary to non-diabetics, have a high prevalence of Hepatitis B.METHODS: The objective of the study was to evaluate anti-HBs antigen (anti-HBsAg) antibody (Ab) in a group of 201 children (age range: 2-18 years), regularly vaccinated against HBV according to the national vaccination schedule. Patients with anti-HBs Ab >= 10 mIU/mL have been defined "responders" and those with anti-HBs Ab<10mIU/mL have been defined "non-responders." The possible association between the T1D and a low immune response to the vaccine has been subsequently valued. Besides the presence of T1D, other possible influential variables have been studied: sex, age, presence of celiac disease and Hashimoto's thyroiditis, intervening years from the diagnosis of diabetes and presence/ absence of diabetic ketoacidosis at time of diagnosis.RESULTS: Among the 201 subjects with T1D, 90 (44.8%) were responders, while 111 (55.2%) were non-responders; among the 145 subjects without T1D, 86 (59.3%) were responders and 59 (40.7%) non-responders. We invited "Subjects with T1D non-responders" to undergo a booster dose of the same vaccine. Of these, 21 refused the booster, reducing the sample to 90 patients. After 4 weeks from the booster dose 81 patients showed seroconversion ("false non-responders"), and 9 did not ("true non-responders").CONCLUSIONS: After the booster dose, immune response in our cross-section has been similar to general population. Given the high frequency of "false non-responders" anti-HBsAg Ab should be tested in T1D patients and a booster dose should be administrated in non-responders.
