Single-cell multi-omics analysis identifies two distinct phenotypes of newly-onset microscopic polyangiitis.

The immunological basis of the clinical heterogeneity in autoimmune vasculitis remains poorly understood. In this study, we conduct single-cell transcriptome analyses on peripheral blood mononuclear cells (PBMCs) from newly-onset patients with microscopic polyangiitis (MPA). Increased proportions of activated CD14+ monocytes and CD14+ monocytes expressing interferon signature genes (ISGs) are distinctive features of MPA. Patient-specific analysis further classifies MPA into two groups. The MPA-MONO group is characterized by a high proportion of activated CD14+ monocytes, which persist before and after immunosuppressive therapy. These patients are clinically defined by increased monocyte ratio in the total PBMC count and have a high relapse rate. The MPA-IFN group is characterized by a high proportion of ISG+ CD14+ monocytes. These patients are clinically defined by high serum interferon-alpha concentrations and show good response to immunosuppressive therapy. Our findings identify the immunological phenotypes of MPA and provide clinical insights for personalized treatment and accurate prognostic prediction.

The Onset of IgG4-related Retroperitoneal Fibrosis under Administration of a TNF Inhibitor in a Rheumatoid Arthritis Patient.

An 80-year-old woman with rheumatoid arthritis during treatment with etanercept, a tumor necrosis factor (TNF) inhibitor, showed swelling of the salivary glands and retroperitoneal fibrosis, which was diagnosed as IgG4-related disease. Although some reports have shown the efficacy of TNF inhibitors for IgG4-related disease or retroperitoneal fibrosis, TNF inhibitors sometimes cause paradoxical reactions like psoriasis, and the mechanisms are considered to involve the upregulation of plasmacytoid dendritic cells and IFN-α, which is also common in patients with IgG4-related disease. This is a case report of IgG4-related retroperitoneal fibrosis with the possibility of a rare paradoxical reaction by a TNF inhibitor.

Marked increase of interferon-ß after BNT162b2 mRNA vaccination: a case of polyarthritis with pleurisy.

Exacerbation of rheumatic disease after vaccination against SARS-CoV-2 is being reported. However, there are only a few cases of new-onset rheumatic diseases. We present two cases of new-onset persistent polyarthritis that developed in patients after receiving the mRNA vaccine against SARS-CoV-2. One patient had bilateral pleural effusions with markedly elevated serum interferon (IFN)-ß, while the other had no effusion, with serum IFN-ß comparable with that in healthy subjects. Other cytokines were unaltered in association with effusion. Both patients responded well to treatment with 20 mg prednisolone. Although more investigations are needed, the marked increase in serum IFN-ß levels observed in the case with pleural effusion may reflect an excessive response from the innate immune system to mRNA vaccines.

Partial suppression of M1 microglia by Janus kinase 2 inhibitor does not protect against neurodegeneration in animal models of amyotrophic lateral sclerosis.

BACKGROUND: Accumulating evidence has shown that the inflammatory process participates in the pathogenesis of amyotrophic lateral sclerosis (ALS), suggesting a therapeutic potential of anti-inflammatory agents. Janus kinase 2 (JAK2), one of the key molecules in inflammation, transduces signals downstream of various inflammatory cytokines, and some Janus kinase inhibitors have already been clinically applied to the treatment of inflammatory diseases. However, the efficacy of JAK2 inhibitors in treatment of ALS remains to be demonstrated. In this study, we examined the role of JAK2 in ALS by administering a selective JAK2 inhibitor, R723, to an animal model of ALS (mSOD1G93A mice). FINDINGS: Orally administered R723 had sufficient access to spinal cord tissue of mSOD1G93A mice and significantly reduced the number of Ly6c positive blood monocytes, as well as the expression levels of IFN-γ and nitric oxide synthase 2, inducible (iNOS) in the spinal cord tissue. R723 treatment did not alter the expression levels of Il-1ß, Il-6, TNF, and NADPH oxidase 2 (NOX2), and suppressed the expression of Retnla, which is one of the markers of neuroprotective M2 microglia. As a result, R723 did not alter disease progression or survival of mSOD1G93A mice. CONCLUSIONS: JAK2 inhibitor was not effective against ALS symptoms in mSOD1G93A mice, irrespective of suppression in several inflammatory molecules. Simultaneous suppression of anti-inflammatory microglia with a failure to inhibit critical other inflammatory molecules might explain this result.

Mild caloric restriction up-regulates the expression of prohibitin: a proteome study.

Caloric restriction (CR) is well known to expand lifespan in a variety of species and to retard many age-related diseases. The effects of relatively mild CR on the proteome profile in relation to lifespan have not yet been reported, despite the more extensive studies of the stricter CR conditions. Thus, the present study was conducted to elucidate the protein profiles in rat livers after mild CR for a relatively short time. Young growing rats were fed CR diets (10% and 30% CR) for 1month. We performed the differential proteomic analysis of the rat livers using two-dimensional electrophoresis combined with MALDI-TOF mass spectrometry. The most remarkable protein among the differentially expressed proteins was found to be prohibitin, the abundance of which was increased by 30% CR. Prohibitin is a ubiquitously expressed protein shown to suppress cell proliferation and to be related to longevity. The increase in prohibitin was observed both in 10% and 30% CR by Western blot analysis. Furthermore, induction of AMP-activated kinase (AMPK) protein, related to the actions of prohibitin in promoting longevity, was observed. The increased prohibitin level in response to subtle CR suggests that this increase may be one of the early events leading to the expansion of lifespan in response to CR.