Early vitamin D supplementation may have dual effects, protecting against type 1 diabetes and inducing allergy. Is that possible? Yes, individual genes variants may determine the outcome.

In addition to HLA the most prominent type 1 diabetes genes are INS – CTLA4 – PTPN22 – CD25 – IF1H1, the most prominent asthma/allergy genes ADAM33 – DPP10 – IL12 – IL4 – GPR154 – FLG. I can´t see any joint master regulator, however, we know that

• CD25 is the IL2R
• and just learned from an excellent new mouse study that IL2 gene variation impairs regulatory T cell function
• while IL2 variants are associated with allergy
• IL2 is suppressed by vitamin D – known since 1985

Could that be a model to explain the dual involvement of vitamin D in both diseases?