Are children with type 1 diabetes immunocompromised?

In their clinical report of a 4-year-old child with leukemia and an enlarging arm lesion that proved to have been caused by an opportunistic fungus, Ahmed Mater and associates1 state that “[these i]nfections generally occur in immunocompromised patients with conditions such as neutropenia, diabetes or hematologic malignant disease.”1 This statement implies that all patients with type 1 or type 2 diabetes mellitus are immunocompromised. Our interest is children (up to 18 years of age) with type 1 diabetes, and we challenge the accuracy of the statement in this context.

Mater and associates1 cite 2 papers2^,3 that listed “diabetes,” specifically diabetes complicated by ketoacidosis, as a risk factor for opportunistic infections. However, those articles did not provide evidence to support this claim in children with type 1 diabetes. Is there any evidence to show increased rates of infection or prolonged recovery from infection in children with type 1 diabetes? In-vitro data have demonstrated impaired immune function due to hyperglycemia and/or hypoinsulinemia in association with type 1 diabetes.4^,5 However, those studies did not show that the differences in cell-mediated and humoral immune function translate into significant morbidity or mortality in the clinical setting. In fact, the humoral response to influenza vaccine in patients with type 1 diabetes is no different from that of controls with respect to protection rates.6 The incidence of candidal infection is greater among patients with type 1 diabetes, but the reason for this is unclear.7^,8 It may be due to a genetic polymorphism in the gene encoding β-defensin 1.8 However, there is no evidence that this genetic difference leads to an immunocompromised state allowing invasive fungal disease to occur. There have been case reports of patients with type 1 diabetes and diabetic ketoacidosis in whom severe opportunistic infections have developed.9 The increased susceptibility may be attributed to the short-term acidic environment of diabetic ketoacidosis, which is ideal for certain opportunistic pathogens.

In summary, there is insufficient evidence to conclude that children with type 1 diabetes mellitus are immunocompromised. The evidence indicates that an immunocompromised state occurs only in the context of poor glycemic control with severe complications such as diabetic ketoacidosis or in adults with vasculopathy and peripheral neuropathy. Fortunately, with modern standards of care and education of families to manage intercurrent illness in their children with type 1 diabetes mellitus, hospital admission for diabetic ketoacidosis is now rare.