Association of Interleukin-32α with Interleukin-35 and Transforming Growth Factor-β Produced by the Peripheral Blood Mononuclear Cells from Patients with Type 2 Diabetes Mellitus

Cytokine production was shown to be changed in Type 2 diabetes mellitus (T2DM). Nonetheless, the relationship of pro-inflammatory interleukin (IL)-32α with anti-inflammatory IL-35 and transforming growth factor (TGF)-β is unclear in T2DM. The present study aimed to evaluate the IL-32α, IL-35, and TGF-β levels produced by peripheral blood mononuclear cells (PBMCs) in patients compared to healthy controls (HCs). Correlations between the IL-32α and IL-35 and TGF-β, as well as between those cytokines and paraclinical parameters [(fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c), GFR, albumin, and creatinine)] were assessed.

Blood samples were taken from 38 patients and 38 HCs. The PBMCs from each donor were isolated with the ficoll method and cultured with in vitro stimulator for four days. The production of IL-32α, IL-35, and TGF-β in culture supernatants was determined with ELISA. Paraclinical parameters were evaluated by standard laboratory methods.

High levels of IL-32α and low levels of IL-35 were found in patients compared to in HCs (P=0.006; P<0.001). A negative correlation between IL-32α and IL-35 was detected in patients (P<0.001). IL-32α was positively correlated with FPG and HbA1c (P=0.002, P=0.005), whereas IL-35 was negatively correlated with them in patients (both P<0.001). No correlations were detected between the cytokines and BMI, GFR, albumin, and creatinine, as well as between the TGF-β levels.

Increased IL-32α but diminished IL-35 production are linked with each other and with the glucose metabolism parameters in T2DM. It seems that IL-32α and IL-35 have a potential role in T2DM pathogenesis.