Objective:To investigate the plasma level of interleukin(IL)-37 and assess its regulatory effects on monocyte activity in type 1 diabetes mellitus(T1DM) patients.Methods:This prospective study included 57 T1DM patients and 21 healthy controls who were continuously enrolled from December 2022 to January 2024 at Xinxiang Central Hospital. Plasma and peripheral blood mononuclear cells were isolated. IL-37 and soluble interleukin 1 receptor 8(IL-1R8) levels were measured by enzyme-linked immunosorbent assay(ELISA). Levels of IL-37 receptor subunits in monocytes were analyzed via flow cytometry. Purified monocytes were stimulated with recombinant IL-37 and co-cultured with a human pancreatic β-cell line to assess cytotoxicity, measured by target cell death and cytokine levels. Additionally, monocytes were co-cultured with autologous CD4 + T cells to evaluate antigen presentation by measuring interferon-γ(IFN-γ) and IL-17A secretion. Results:Plasma IL-37 level and IL-37 receptor subunit expression in monocytes were significantly lower in T1DM patients compared to controls(both P<0.001). However, there was no significant difference in soluble IL-1R8 levels between the groups( P=0.457). Monocytes from T1DM patients exhibited increased cytotoxicity, as indicated by higher target cell death and elevated levels of granzyme A, granzyme B, granzyme H, IL-1β, IL-6, and tumor necrosis factor-α( P<0.05). Additionally, monocyte-induced secretion of IFN-γ and IL-17A by CD4 + T cells was elevated in T1DM patients(all P<0.05). Stimulation of T1DM monocytes with recombinant IL-37 reduced target cell death and decreased granzyme B secretion compared to unstimulated monocytes(both P<0.05). However, IL-37 stimulation had no significant effect on other cytokine levels or monocyte-induced IFN-γ and IL-17A secretion( P>0.05). Conclusions:Monocytes exhibit enhanced cytotoxicity and antigen-presenting capacity in T1DM patients. IL-37 reduces monocyte cytotoxicity by inhibiting granzyme B secretion, but does not affect antigen presenting function in T1DM.

Objective:To investigate the plasma level of interleukin(IL)-37 and assess its regulatory effects on monocyte activity in type 1 diabetes mellitus(T1DM) patients.Methods:This prospective study included 57 T1DM patients and 21 healthy controls who were continuously enrolled from December 2022 to January 2024 at Xinxiang Central Hospital. Plasma and peripheral blood mononuclear cells were isolated. IL-37 and soluble interleukin 1 receptor 8(IL-1R8) levels were measured by enzyme-linked immunosorbent assay(ELISA). Levels of IL-37 receptor subunits in monocytes were analyzed via flow cytometry. Purified monocytes were stimulated with recombinant IL-37 and co-cultured with a human pancreatic β-cell line to assess cytotoxicity, measured by target cell death and cytokine levels. Additionally, monocytes were co-cultured with autologous CD4 + T cells to evaluate antigen presentation by measuring interferon-γ(IFN-γ) and IL-17A secretion. Results:Plasma IL-37 level and IL-37 receptor subunit expression in monocytes were significantly lower in T1DM patients compared to controls(both P<0.001). However, there was no significant difference in soluble IL-1R8 levels between the groups( P=0.457). Monocytes from T1DM patients exhibited increased cytotoxicity, as indicated by higher target cell death and elevated levels of granzyme A, granzyme B, granzyme H, IL-1β, IL-6, and tumor necrosis factor-α( P<0.05). Additionally, monocyte-induced secretion of IFN-γ and IL-17A by CD4 + T cells was elevated in T1DM patients(all P<0.05). Stimulation of T1DM monocytes with recombinant IL-37 reduced target cell death and decreased granzyme B secretion compared to unstimulated monocytes(both P<0.05). However, IL-37 stimulation had no significant effect on other cytokine levels or monocyte-induced IFN-γ and IL-17A secretion( P>0.05). Conclusions:Monocytes exhibit enhanced cytotoxicity and antigen-presenting capacity in T1DM patients. IL-37 reduces monocyte cytotoxicity by inhibiting granzyme B secretion, but does not affect antigen presenting function in T1DM.