Monocytes of Patients with Type 1 Diabetes Harbour Enterovirus RNA

Background Intracellular enterovirus ( EV ) RNA was detected in blood of patients with type 1 diabetes (T1D). The presence of EV RNA in subsets of peripheral blood mononuclear cells ( PBMC s) of patients, and the in vitro infection of these cells with an EV, was investigated. Materials and methods Blood was collected from 42 patients with T1D, PBMC s were isolated and monocytes were purified. Interferon alpha ( IFN α) mRNA and EV RNA were investigated using RT ‐ PCR . Levels of IFN α in plasma were measured using an immunoassay. Cells were inoculated with Coxsackievirus B4 ( CBV 4) in vitro , and infection was assessed by indirect immunofluorescence ( IFI ). Results Interferon alpha mRNA was detected in blood and in monocytes of 12 of 42 patients with T1D, but not in monocyte‐depleted PBMC s of the same individuals. Significant plasma levels of IFN α (≥ 5 IU/mL) were found in six patients. EV RNA was detected in whole blood and in monocytes of seven patients and negative‐strand EV RNA was found in monocytes of 6 of them. When monocytes of patients with IFN α and/or EV RNA in their blood were inoculated with CVB 4, the proportion of cells stained by an anti‐ VP 1 antibody was 8·8 ± 1%, whereas no VP 1 was detected in the monocytes of IFN α, EV RNA negative patients. Nevertheless, when CBV 4 was mixed with plasma, VP 1 was detected in monocytes of all patients with T1D (staining ranging from 12 to 36%). Conclusions Our data indicate that monocytes of patients with T1D can harbor EV RNA and IFN α mRNA and can be infected with an EV in vitro .