Clinical importance of cytokine (IL-6, IL-8, and IL-10) and vitamin D levels among patients with Type-1 diabetes

Abstract

Type-1 diabetes (T1D) is an autoimmune disorder characterized by impaired insulin release by islet β cells. It has been shown that proinflammatory cytokines released during the disease can exacerbate the condition, while anti-inflammatory cytokines offer protection. This study analyzed the clinical role of interleukin (IL)-6, -8, -10, and vitamin D levels in T1D patients compared to healthy controls. The levels of IL-6, IL-8, IL-10, and vitamin D in the participants' serum samples were analyzed using ELISA. The findings showed that T1D patients had significantly increased levels (p < 0.0001) of fasting blood glucose, HbA1c, systolic blood pressure, low-density lipoprotein, triglycerides, cholesterol, and very low-density lipoprotein and decreased levels of high-density lipoprotein and vitamin D (p < 0.0001) compared to healthy controls. Moreover, the levels of IL-6, IL-8, and IL-10 were also significantly greater (p < 0.0001) in T1D patients. The study also determined the significance of these cytokines among T1D patients and healthy controls using ROC curves. Furthermore, we found that smokers had significantly higher levels of IL-6 (p = 0.01) and IL-8 (p = 0.003) than non-smokers. These results showed that elevated levels of IL-6, IL-8, and IL-10, decreased vitamin D levels, and smoking among T1D participants could contribute to the worsening of T1D disease and could serve as predictive indicators.

Keywords: Anti-inflammatory; Cytokines; Proinflammatory; T1D prognosis; Type-1 diabetes; Vitamin D.

Fig. 1

Serum levels of inflammatory cytokines, IL-6 (a), IL-8 (b), and IL-10 (c) in individuals with T1D (n = 100) compared to healthy controls (n = 100). The error bars represent the standard deviations. A p value of ˂ 0.01 was considered significant.

Fig. 2

Correlations between serum vitamin D levels and the levels of the inflammatory cytokines IL-6 (a), IL-8 (b), and IL-10 (c) in individuals with T1D. Each point represents an individual with T1D.

Fig. 3

Receiver operating characteristic (ROC) curves illustrating the prognostic significance of (a) IL-6, (b) IL-8, and (c) IL-10 cytokine levels in T1D patients compared to healthy controls.

Fig. 4

Comparison of interleukin (IL) (a) IL-6, (b) IL-8, and (c) IL-10 levels between nonsmokers (n = 72) and smokers (n = 28). Data are presented as box plots showing the median, interquartile range, and minimum/maximum values. The mean ± standard deviation values are displayed above each box. The p values indicate the statistical significance of differences between nonsmokers and smokers for each interleukin.

Fig. 5

Comparison of interleukin (IL) (a) IL-6, (b) IL-8, and (c) IL-10 levels between nonhypertensive and hypertensive T1D patients. Data are presented as box plots showing the median, interquartile range, and minimum/maximum values. The mean ± standard deviation values are displayed above each box.