OBJECTIVETo investigate the relationship between coxsackievirus infection and type 1 diabetes mellitus (T1DM), and observe the changes of T lymphocyte subsets in the development of T1DM.

METHODSWe detected Coxsackievirus RNA by reverse transcription PCR, and measured the change in T-lymphocyte subsets by flow cytometry in 22 cases of newly diagnosed T1DM (group I), 30 patients with diabetes for some time (group II), and 30 healthy subjects (group III).

RESULTSThe positivity rate of coxsackie virus RNA in groups I, II, and III was 55.55%, 23.33%, and 6.67%, respectively, showing a significant difference among the 3 groups (P<0.01). Patients with upper respiratory tract infection had a higher positivity rate for coxsackie virus RNA than those without upper respiratory tract infection in group I (P<0.05). Compared with the control group, the percentage of CD3, CD4 and CD4/CD8 ratio decreased significantly in groups I and II (P<0.01 or P<0.05). CD3, CD4 and CD4/CD8 tended to increase in group II in comparison with group I, and there was an significant difference in CD3 and CD4 between the two groups (P<0.01 or P<0.05). Compared with the control group and CVBRNA-negative group, CVBRNA-positive group showed significantly lowered CD3, CD4, CD8 and CD4/CD8 (P<0.01 or P<0.05).

CONCLUSIONThe occurrence and development of type 1 diabetes is closely related to coxsackie virus infection, and the changes in T lymphocyte subsets serves as a probable mechanism of its pathogenicity.