How diabetes type 1 affects immune response to hepatitis B virus vaccine in pediatric population? Evaluation of a booster dose in unresponsive subjects with type 1 diabetes

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 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 mlU/mL have been defined "Responders" and those with anti-HBs Ab<10mlU/mL have been defined "Non-Responders".The possible association between the Type 1 Diabetes (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 type 1 diabetes, 90 (44.8%) were Responders, while 111 (55.2%) were non-Responders; among the 145 subjects without type 1 diabetes, 86 (59.3%) were Responders and 59 (40.7%) non-Responders. We invited "Subjects with type 1 diabetes 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.