Detection of enterovirus RNA in pancreas and lymphoid tissues of organ donors with type 1 diabetes
Authors: Laiho Jutta E , Oikarinen Sami , Morfopoulou Sofia , Oikarinen Maarit , Renner Ashlie , Depledge Daniel , Ross Matthew C , Gerling Ivan C , Breuer Judith , Petrosino Joseph F , Plagnol Vincent , Pugliese Alberto , Toniolo Antonio , Lloyd Richard E , Hyöty Heikki ,   JDRF nPOD-Virus Group
Published: September 2024

Aims/hypothesis

The nPOD-Virus group collaboratively applied innovative technologies to detect and sequence viral RNA in pancreas and other tissues from organ donors with type 1 diabetes. These analyses involved the largest number of pancreas samples collected to date.

Methods

We analysed pancreas, spleen, pancreatic lymph nodes, and duodenum samples from the following donor groups: a) donors with type 1 diabetes (n=71), with (n=35) or without (n=36) insulin-containing islets, (b) donors with single or double islet autoantibody positivity without diabetes (n=22) and c) autoantibody-negative donors without diabetes (control donors) (n=74). Five research laboratories participated in this collaborative effort using approaches for unbiased discovery of RNA viruses (two RNA-Seq platforms), targeted detection ofEnterovirus A-Dspecies using RT-PCR, and tests for virus growth in cell-culture.

Results

Direct RNA-Seq did not detect virus signal in pancreas samples, whereas RT-PCR detected enterovirus RNA confirmed by sequencing in low amounts in pancreas samples in three of the five donor groups, namely donors with type 1 diabetes with insulin-containing islets, 16% (5/32) donors being positive, donors with single islet autoantibody positivity with 53% (8/15) donors being positive, and non-diabetic donors with 8% (4/49) being enterovirus RNA positive. Detection of enterovirus RNA was significantly more frequent in single islet autoantibody-positive donors compared to donors with type 1 diabetes with insulin-deficient islets (p-value <0.001) and control donors (p-value 0.004). In some donors, pancreatic lymph nodes were also positive. RT-PCR detected enterovirus RNA also in spleen of a small number of donors and virus enrichment in susceptible cell lines before RT-PCR resulted in much higher rate in spleen positivity, particularly in donors with type 1 diabetes. Interestingly, the enterovirus strains detected did not cause a typical lytic infection, possibly reflecting their persistence-prone nature.

Conclusions/interpretation

This was the largest coordinated effort to examine the presence of enterovirus RNA in pancreas of organ donors with type 1 diabetes, using a multitude of assays. These findings are consistent with the notion that both the subjects with type 1 diabetes and those with islet autoantibodies may carry a low-grade enterovirus infection in the pancreas and lymphoid tissues.

Research in context

What is already known about this subject?

Enterovirus infections are among the prime candidates for environmental triggers of type 1 diabetes.

Pancreas (and other tissue) samples of subjects with type 1 diabetes have not been extensively studied for the presence of enterovirus RNA.

What is the key question?

Can enterovirus RNA be detected in the pancreas and lymphoid tissues of individuals with and without type 1 diabetes?

What are the new findings?

Enterovirus RNA can be detected in low amounts in the pancreas and lymphoid tissues using selected enterovirus-specific methods.

Detection of enterovirus RNA in the pancreas was most frequent in prediabetic subjects.

Enterovirus RNA was found also in pancreatic lymph nodes and in spleen where it was more frequently detected in donors with type 1 diabetes compared to non-diabetic donors, with properties previously observed in persistent infections.

How might this impact on clinical practice in the foreseeable future?

The findings support the enterovirus - type 1 diabetes association and may have an effect on the primary and secondary prevention strategies towards the disease.