Raised levels of Interleukin-8 and myeloperoxidase in patients with recent onset type 1 diabetes.

Aims/hypothesis: Raised levels of circulating interleukin-8 (IL-8) were reported in adults and children with type 1 diabetes (T1D). In this study, we measured IL-8 and IL-8 receptor expression levels in the pancreas, and IL-8 and myeloperoxidase (MPO) in the serum of recent-onset T1D versus controls.

Methods: Pancreatic samples from donors with T1D within 2 years of diagnosis and from non-diabetic controls were obtained from a diabetes biobank. Serum was collected from individuals with newly diagnosed T1D within their first year of disease (n = 42) and healthy controls (n = 11). Serum IL-8 and myeloperoxidase were measured with an ELISA assay.

Results: IL-8 and IL-8 receptor gene expression were significantly increased in the pancreas of individuals with T1D compared to controls. Patients showed significantly increased IL-8 levels compared to controls. MPO levels were higher in T1D versus controls (median (IQR), 95 327 [55718-168 974] vs. 42 729 [24147-95 327] pg/mL, p-value = 0.0349). T1D patients with IL-8 >62 pg/mL showed higher levels of both HbA1c, and blood glucose compared to subjects with IL-8 levels ≤62 pg/mL (HbA1c (mmol/mol); median [IQR], 100 [79.40-122.8] vs. 79.50 [52.25-96.25]; HbA1c (%); median [IQR], 11.30 [9.52-13.38] vs. 9.45 [6.95-10.93], p-value = 0.015) and, blood glucose; median [IQR], 360 [283-488.5] vs. 243.5 [197.5-314.5], p-value = 0.019.

Conclusions/interpretation: Our findings support an elevation of IL-8 in both pancreatic tissue and serum in recent-onset T1D and suggest that higher IL-8 levels may be associated with poorer glycemic control. Further studies are needed to clarify the mechanistic role of IL-8 in T1D pathogenesis.