LADA患者外周血单个核细胞对胰岛素和谷氨酸脱羧酶的增殖反应

目的探讨成人隐匿性自身免疫糖尿病(LADA)患者外周血单个核细胞(PBMC)对胰岛素和谷氨酸脱羧酶(GAD)的增殖反应。方法密度梯度离心法分离21例LADA、25例2型糖尿病(DM)及20名正常对照PBMC,3HTdR掺入法检测其对胰岛素和GAD及其分别联合白细胞介素2(IL2)刺激的增殖反应,以刺激指数(SI)反映增殖反应强度。结果(1)PBMC对PHA、胰岛素或GAD刺激的增殖反应在LADA、2型DM和正常对照组间差异无统计学意义。(2)对于胰岛素或GAD联合IL2(胰岛素 IL2,GAD IL2)刺激,LADA组SI高于2型DM组(5.1vs0.8;;7.0vs0.8,均P<0.05);;胰岛素 IL2刺激较胰岛素或IL2单独刺激的倍增值,GAD IL2刺激较GAD或IL2单独刺激的倍增值LADA组高于2型DM组(4.0vs1.0;;3.4vs0.3;;6.3vs1.2;;4.6vs0.3,均P<0.05)。(3)LADA患者胰岛素刺激的SI胰岛素与GAD抗体指数呈负相关。结论LADA患者体内存在已致敏的T细胞,其活化效应在特异性抗原(GAD或胰岛素)和IL2共刺激时方可被发现。

Proliferative response of peripheral blood mononuclear cells to insulin and glutamic acid decarboxylase in LADA patients

Objective To investigate the proliferative responses of peripheral blood mononuclear cells (PBMCs) to insulin and glutamic acid decarboxylase (GAD) in patients with latent autoimmune diabetes of adults(LADA). Methods PBMCs were separated by density gradient centrifugation from 21 patients with LADA, 25 patients with type 2 diabetes mellitus (DM) and 20 healthy subjects, and incubated in triple or quadruple wells in the presence of either recombinant human insulin, GAD, interleukin 2 (IL-2) alone or insulin/GAD combined with IL-2 (Insulin IL-2 or GAD IL-2) respectively. ~3H-thymidine incorporation was applied to measure PBMC proliferation which was expressed as stimulation index (SI). Results (1) No statistical difference of the proliferative response of PBMC to PHA, insulin or GAD were found among LADA, type 2 DM and control groups. (2) Insulin IL-2 or GAD IL-2 stimulation showed significant differences between LADA and type 2 DM groups with higher SI in LADA patients (5.1 vs 0.8;7.0 vs 0.8, both P<0.05). The ratio of SI of insulin IL-2 to insulin or IL-2 alone was higher in LADA than in type 2 DM group. Tthe same trend between the two groups was also found during GAD IL-2 stimulation (4.0 vs 1.0;3.4 vs 0.3;6.3 vs 1.2;4.6 vs 0.3, both P<0.05). (3) SI of insulin was negatively correlated to GAD antibody index. Conclusion The GAD- or insulin- reactive T cells exist in LADA patients, which can be revealed by costimulation of specific antigen (GAD or insulin) combined with non-specific stimulator (IL-2).