Serositis and lymphopenia are common features of systemic lupus erythematosus following SARS-CoV-2 infection: A case report and literature review.

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can affect a number of human systems, including the respiratory, cardiovascular, neurological, gastrointestinal, and musculoskeletal systems. These symptoms persist long after the acute infection has healed and is called "long COVID". Interestingly, there have been a series of reports that SARS-CoV-2 infections trigger the development of various autoimmune diseases such as systemic lupus erythematosus (SLE), inflammatory arthritis, myositis, vasculitis.

Superior mesenteric vein thrombosis and osteoporotic vertebral fractures.

Superior mesenteric vein (SMV) thrombosis is relatively rare disease with unspecific symptoms. Thrombus formation within the SMV eventually leads to congestive intestinal necrosis. In most cases, the lack of specific symptoms makes early diagnosis difficult.

Cell surface-expressed Ro52/IgG/HLA-DR complex is targeted by autoantibodies in patients with inflammatory myopathies.

Intracellular proteins are often targeted by autoantibodies in autoimmune diseases; however, the mechanism through which intracellular molecules are targeted remains unknown. We previously found that several intracellular misfolded proteins are transported to the cell surface by HLA class II molecules and are recognized by autoantibodies in some autoimmune diseases, such as rheumatoid arthritis, antiphospholipid syndrome, and microscopic polyangiitis. Ro52 is an intracellular Fc receptor that is a target antigen for myositis-associated autoantibodies.

Spontaneous regression of lung metastases after transarterial chemoembolization for hepatocellular carcinoma.

Spontaneous regressions of primary and/or metastatic lesions have been rarely reported in hepatocellular carcinoma (HCC). Herein, we report the case of a 71-year-old man with HCC, focusing on shape changes of lung metastases over time. Lung metastasis of HCC was histologically diagnosed by percutaneous computed tomography (CT)-guided needle biopsy after the treatment of primary HCC lesion.

Transport of cellular misfolded proteins to the cell surface by HLA-B27 free heavy chain.

HLA class I molecules play a central role in the immune system by presenting peptide antigens to cytotoxic T cells. Although most HLA class I molecules are associated with β2-microglobulin, HLA class I heavy chain that is not associated with β2-microglobulin is also expressed on certain cells. We recently found that cellular misfolded proteins are transported to the cell surface by HLA class II molecules via association with their peptide-binding grooves.

FcγRIIIA-mediated activation of NK cells by IgG heavy chain complexed with MHC class II molecules.

Natural killer (NK) cells are a major FcγRIIIA-expressing lymphocyte population that mediate antibody-dependent cellular cytotoxicity. Although NK cells are critical for immunity against viruses and tumors, they are also activated in the joints of patients with rheumatoid arthritis (RA) and may be involved in disease progression. We previously found that human leukocyte antigen (HLA) class II molecules transport misfolded cellular proteins, such as IgG heavy chain (IgGH), to the cell surface via association with their peptide-binding grooves.

Utility of fluorodeoxyglucose positron emission tomography/computed tomography for early diagnosis and evaluation of disease activity of relapsing polychondritis: a case series and literature review.

Objective: Relapsing polychondritis (RPC) is relatively rare and early diagnosis is difficult. We investigated the utility of fluorodeoxyglucose (FDG)-PET/CT for the diagnosis of RPC and evaluation of disease activity.

Methods: Five RPC patients undergoing FDG-PET/CT in our hospital between 2006 and 2012 were studied.

Cytomegalovirus disease of the upper gastrointestinal tract in patients with rheumatic diseases: a case series and literature review.

Cytomegalovirus disease of the upper gastrointestinal tract (CMV-UGT) is a rare but significant complication in patients with rheumatic diseases. We reviewed records for January 2004 to December 2012 and investigated the occurrence of CMV-UGT in patients with rheumatic diseases to evaluate clinical characteristics, the value of the CMV antigenemia assay, and the association between immunosuppressive therapy and CMV-UGT. Ten CMV-UGT events (six gastric ulcer, two esophagitis, one gastritis, and one duodenal ulcer) in nine patients (three rheumatoid arthritis, three systemic lupus erythematosus, one dermatomyositis, one systemic sclerosis, and one overlap syndrome) were identified based on pathology.