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.

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.

Marked increase of interferon-β 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)-β, while the other had no effusion, with serum IFN-β 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-β levels observed in the case with pleural effusion may reflect an excessive response from the innate immune system to mRNA vaccines.