1492-P: IL-8/CXCL8 May Identify a New Type 1 Diabetes Endotype

Recent research focused on identifying mechanisms explaining the observed heterogeneity of type 1 diabetes (T1D) in age at onset, residual β-cell function and rate of disease progression. Mechanisms include changes in both the immune system and β-cells, leading to the loss of tissue-specific immune tolerance and disease onset. Interleukin-8 (IL-8; CXCL8) is a pro-inflammatory chemokine released by macrophages, endothelial, epithelial and airway smooth muscle cells playing a major role in the innate immune response. Macrophages release IL-8 at the site of an injury where they recruit and activate neutrophils by interacting with the IL-8 receptors CXCR1 and CXCR2. An increase in circulating IL-8 has been shown in several autoimmune disorders. IL-8 levels, but not IL-6 or TNF-α, are elevated in adolescents with T1D, and also associated with insulin resistance, suggesting a role for IL-8 beyond acute inflammation in this setting. In vitro experiments revealed that IL-8 transcription is induced by hyperglycaemia. In the present study newly diagnosed T1D patients within the first year of disease onset (mean age 16.2 ± 7.6 yrs and % HbA1c of 10.7 ± 2.7) (N=42) were studied. Clinical and laboratory features included age, gender, body mass index (BMI), disease duration, HbA1c, and C-peptide. Serum IL-8 and myeloperoxidase (MPO) were measured with commercial enzyme-linked Immunosorbent assays. When compared to normal subjects, T1D patients showed a significantly higher IL-8 values (median [IQR] 112.0 [64.74-311.8] vs 43.05 [30.94-49.70], p-value= 0.002, respectively). Furthermore, T1D patients showed a significantly higher MPO levels than controls (median [IQR], 95327 [55718 - 168974] vs 42729 [24147 - 95327], p-value= 0.0349, respectively). This study shows for the first time that IL-8 and MPO are elevated in patients with recent onset T1D compared to normal subjects. There is also a trend for a positive correlation between IL-8 and HbA1c levels suggesting that elevated IL-8 values are associated with poor metabolic control.