Excessive inflammation occurs during infection and autoimmunity in mice lacking the alpha-subunit of the interleukin 27 (IL-27) receptor. The molecular mechanisms underlying this increased inflammation are incompletely understood. Here we report that IL-27 upregulated IL-10 in effector T cells that produced interferon-gamma and expressed the transcription factor T-bet but did not express the transcription factor Foxp3. These IFN-gamma+T-bet+Foxp3- cells resembled effector T cells that have been identified as the main source of host-protective IL-10 during inflammation. IL-27-induced production of IL-10 was associated with less secretion of IL-17, and exogenous IL-27 reduced the severity of adoptively transferred experimental autoimmune encephalomyelitis by a mechanism dependent on IL-10. Our data show that IL-27-induced production of IL-10 by effector T cells contributes to the immunomodulatory function of IL-27.

PurposeNext-generation sequencing (NGS) based methods are being adopted broadly for genetic diagnostic testing, but the performance characteristics of these techniques have not been fully defined with regard to test accuracy and reproducibility.MethodsWe developed a targeted enrichment and NGS approach for genetic diagnostic testing of patients with inherited eye disorders, including inherited retinal degenerations, optic atrophy and glaucoma. In preparation for providing this Genetic Eye Disease (GEDi) test on a CLIA-certified basis, we performed experiments to measure the sensitivity, specificity, reproducibility as well as the clinical sensitivity of the test.ResultsThe GEDi test is highly reproducible and accurate, with sensitivity and specificity for single nucleotide variant detection of 97.9% and 100%, respectively. The sensitivity for variant detection was notably better than the 88.3% achieved by whole exome sequencing (WES) using the same metrics, due to better coverage of targeted genes in the GEDi test compared to commercially available exome capture sets. Prospective testing of 192 patients with IRDs indicated that the clinical sensitivity of the GEDi test is high, with a diagnostic rate of 51%.ConclusionThe data suggest that based on quantified performance metrics, selective targeted enrichment is preferable to WES for genetic diagnostic testing.

Leber congenital amaurosis (LCA) is an infantile-onset form of inherited retinal degeneration characterized by severe vision loss1, 2. Two-thirds of LCA cases are caused by mutations in 17 known disease genes3 (RetNet Retinal Information Network). Using exome sequencing, we identified a homozygous missense mutation (c.25G>A, p.Val9Met) in NMNAT1 as likely disease-causing in two siblings of a consanguineous Pakistani kindred affected by LCA. This mutation segregated with disease in their kindred, including in three other children with LCA. NMNAT1 resides in the previously identified LCA9 locus and encodes the nuclear isoform of nicotinamide mononucleotide adenylyltransferase, a rate-limiting enzyme in nicotinamide adenine dinucleotide (NAD+) biosynthesis4, 5. Functional studies showed the p.Val9Met mutation decreased NMNAT1 enzyme activity. Sequencing NMNAT1 in 284 unrelated LCA families identified 14 rare mutations in 13 additional affected individuals. These results are the first to link an NMNAT isoform to disease and indicate that NMNAT1 mutations cause LCA.