Monocytes of Patients with Type 1 Diabetes Harbour Enterovirus RNA

BackgroundIntracellular 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 (PBMCs) of patients, and the invitro infection of these cells with an EV, was investigated. Materials and methodsBlood was collected from 42 patients with T1D, PBMCs were isolated and monocytes were purified. Interferon alpha (IFN) mRNA and EV RNA were investigated using RT-PCR. Levels of IFN in plasma were measured using an immunoassay. Cells were inoculated with Coxsackievirus B4 (CBV4) invitro, and infection was assessed by indirect immunofluorescence (IFI). ResultsInterferon alpha mRNA was detected in blood and in monocytes of 12 of 42 patients with T1D, but not in monocyte-depleted PBMCs of the same individuals. Significant plasma levels of IFN (5IU/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 and/or EV RNA in their blood were inoculated with CVB4, the proportion of cells stained by an anti-VP1 antibody was881%, whereas no VP1 was detected in the monocytes of IFN, EV RNA negative patients. Nevertheless, when CBV4 was mixed with plasma, VP1 was detected in monocytes of all patients with T1D (staining ranging from 12 to 36%). ConclusionsOur data indicate that monocytes of patients with T1D can harbor EV RNA and IFN mRNA and can be infected with an EV invitro.