Th1/Th2 cytokine expression in diabetic retinopathy

Abstract

ABSTRACT. Diabetic retinopathy (DR), an important complication of diabetes mellitus (DM), is not well understood. T helper cell balance (Th1/Th2) is involved in various autoimmune diseases; however, its role in DR is not understood. This study explores changes in Th1 and Th2 cytokine expression during DR. Blood samples were collected from 25 healthy volunteers (normal control group), 35 patients with type 2 DM (T2DM group) without DR, and 30 cases of T2DM patients with DR (DR group). Real-time PCR was used to measure mRNA expression of IL-2 and TNF-α, secreted from Th1 cells, and of IL-4 and IL-10, secreted from Th2 cells. We used ELISA to detect cytokine expression in serum to analyze the correlation between Th1 and Th2 cytokines. IL-2 and TNF-α mRNA and protein expression levels in the T2DM and DR groups were significantly higher than in the normal control group (P < 0.05). Compared with the T2DM group, the DR group had higher IL-2 and TNF-α levels (P < 0.05). IL-4 and IL-10 levels were lower in the DR group compared with the normal and T2DM groups (P < 0.05), while T2DM showed no difference compared with the normal control (P > 0.05). IL-2 and TNF-α were negatively correlated with IL-4 and IL-10 in the DR group, respectively. We found that Th1 cytokine secretion was higher and Th2 cytokines secretion was lower during DR, leading to a Th1/ Th2 imbalance, suggesting that Th1/Th2 imbalance is a side effect for DR occurrence and development.

Role of Adaptive and Innate Immunity in Type 2 Diabetes Mellitus

“…Previous studies have reported that the frequency of cytokines can be influenced by other types of lymphocytes. B cells support Th17 inflammation in T2DM patients but not in the normal people, whereas monocytes support Th17 inflammation regardless of whether an individual is suffering from T2DM [ 27 ]. In addition, the cytokines produced by Th1, IL-2, and TNF- β ; the cytokines produced by Th17, IL-17F, and IL-17A; and the cytokines produced by both Th1 and Th17 cells are important for explaining the HbA1c variance [ 28 ].…”

“…As we had discussed before, B cells could affect the proliferation of Th17 and the production of proinflammatory cytokines in T2DM patients. It was found that on depletion of CD19+ cells, Th17 proliferation was decreased in T2DM patients but not in individuals without T2DM [ 27 ]. Not only obese T2DM patients but also nonobese T2DM patients exhibited significantly high levels of fecal IgG, which is produced by B cells, compared to control individuals with similar BMI [ 70 , 72 ].…”

Rola autoimmunizacji w rozwoju powikłań cukrzycowych – przegląd badań

“…TNF-alfa i IL-2wydzielanych przez limfocyty Th1, a niższe stężenia cytokin działających przeciwzapalnie, tj. IL-4 i -10 -wydzielanych przez limfocyty Th2 [49]. Coraz więcej wyników badań sugeruje udział układu odpornościowego w patogenezie cukrzycy typu 2 oraz jej powikłań, wskazując na możliwość zastosowania nowych immunoterapii ukierunkowanych na redukcję stanu zapalnego [50].…”

Group 2 Innate Lymphoid Cells Participate in Renal Fibrosis in Diabetic Kidney Disease Partly via TGF-β1 Signal Pathway

“…They are also the first class of cells to activate type 2 immunity and play an important role in Th1/Th2 balance [12]. Th1/Th2 imbalance would induce disease; researchers have found that patients with diabetic retinopathy and DKD have Th1/Th2 imbalance [13, 14]. ILC2s not only provide protective immunity toward helminth infection but also are responsible for allergic inflammation, tissue repair, and metabolic homeostasis and mediate multiple types of tissue fibrosis such as intestinal fibrosis, hepatic fibrosis, and pulmonary fibrosis [15–17].…”