HLA genotyping in children with celiac disease allows to establish the risk of developing type 1 diabetes.

BACKGROUND AND AIMS: Celiac Disease (CD) and Type 1 Diabetes (T1D) often co-occur and share genetic components in the HLA class II region. We aimed to study the usefulness of HLA genotyping in predicting the risk of developing T1D in patients with CD and the temporal relationship between these diseases. METHODS: A cohort of 1,886 Sardinian patients, including 822 with CD, 1,064 with T1D, and 627 controls, underwent HLA class II typing. Seventy-six out of 822 CD patients were also affected by T1D (CD-T1D), and their HLA genotypes were analyzed for specific HLA associations with CD, T1D and controls. RESULTS: High-risk HLA-DQ genotypes, including HLA-DQ2.5/DQ8, -DQ2.5/DQ2.5, and -DQ2.5/DQ2.3, were strongly associated with CD-T1D with frequencies of 34.5%, 15.9%, and 18.8%, respectively. Conversely, certain HLA genotypes associated with CD appeared to confer protection against T1D development. Therefore, HLA genotyping allows the identification of those CD patients that might develop T1D. The frequency of patients with CD preceding T1D is higher in younger children than older ones, with implications for the early childhood approach to diabetes prevention. CONCLUSIONS: CD is a condition for future T1D development, and specific HLA genotypes can predict this risk. Early screening for celiac autoimmunity and subsequent HLA typing in CD children could help identify those at high risk for T1D, allowing for proactive interventions and immunotherapies to preserve beta-cell function. These findings may support the re-evaluation of HLA typing in children with CD.

Peripheral blood mononuclear cells reactivity in recent-onset type I diabetes patients is directed against the leader peptide of preproinsulin, GAD65271-285 and GAD65431-450.

Introduction: T cell reactivity against pancreatic autoantigens is considered one of the main contributors to the destruction of insulin-producing cells in type 1 diabetes (T1D). Over the years, peptide epitopes derived from these autoantigens have been described in NOD mice and in both HLA class II transgenic mice and humans. However, which ones are involved in the early onset or in the progressive phases of the disease is still unclear. Methods: In this work we have investigated, in early-onset T1D pediatric patients and HLA-matched controls from Sardinia, the potential of preproinsulin (PPI) and glutamate decarboxylase 65 (GAD65)-derived peptides to induce spontaneous T cell proliferation responses of peripheral blood mononuclear cells (PBMCs). Results: Significant T cell responses against PPI1-18, PPI7-19 and PPI31-49, the first two belonging to the leader sequence of PPI, and GAD65271-285 and GAD65431-450, were found in HLA-DR4, -DQ8 and -DR3, -DQ2 T1D children. Conclusions: These data show that cryptic epitopes from the leader sequence of the PPI and GAD65271-285 and GAD65431-450 peptides might be among the critical antigenic epitopes eliciting the primary autoreactive responses in the early phases of the disease. These results may have implications in the design of immunogenic PPI and GAD65 peptides for peptide-based immunotherapy.