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Exacerbations or de novo autoimmune/autoinflammatory disease have been reported after COVID-19 vaccination. A young male presented with cutaneous IgA vasculitis with glomerular hematuria, diarrhea and pericarditis following his second COVID-19 mRNA vaccination. He also showed positivity for proteinase 3 anti-neutrophil cytoplasmic antibody (PR3-ANCA) and anti-cardiolipin antibody. Skin biopsy was compatible to IgA vasculitis. His purpura subsided and hematuria spontaneously disappeared. Treatment with anti-inflammatory medications and prednisolone resolved the pericarditis. He had a history of persistent diarrhea, and colonic biopsies showed possible ulcerative colitis without vasculitis. Kidney biopsy after prednisolone therapy revealed minor glomerular abnormalities without any immune reactants and did not show vasculitis. After prednisolone treatment, PR3-ANCA decreased in a medium degree despite of improvement of symptoms and inflammatory data, suggesting that his PR3-ANCA may be associated with ulcerative colitis. The cause of the transient glomerular hematuria was unclear, however, it might be caused by focal glomerular active lesions (glomerular vasculitis) due to vaccine-induced IgA vasculitis with nephritis. This case highlights that COVID-19 mRNA vaccination can activate multiple autoimmune/autoinflammatory systems. The conditions might help us better understand the mutual mechanisms of the relevant disorders., (© 2022. The Author(s) under exclusive licence to The Japan Society of Nephrology.)

Patients with monoclonal gammopathy of uncertain significance (MGUS) is sometimes associated with renal diseases, usually due to the deposition of secreted monoclonal immunoglobulin or a fragment thereof, a condition which is defined as monoclonal gammopathy of renal significance. Patients with MGUS appear to be at increased risk for various autoimmune conditions. We report the case of a 68-year-old man developed nephritic syndrome and mild renal insufficiency during the course of IgG λ MGUS. Laboratory findings showed hypocomplementemia, cryoglobulinemia, proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) positivity and monoclonal proteins (λ light chain and λ-Bence-Jones protein) in the urine. A kidney biopsy revealed crescentic glomerulonephritis with mesangial immune deposits without paraproteins. Treatment with prednisolone for ANCA-associated glomerulonephritis, normalized urinalysis and decreased PR3-ANCA but MGUS persisted. This is a rare case of PR3-ANCA-associated glomerulonephritis with comorbid IgG λ MGUS with various pathological paraproteins. We highlight it as a clinical example with diagnostic and therapeutic implications., (© 2022. The Author(s) under exclusive licence to The Japan Society of Nephrology.)

Preeclampsia and superimposed preeclampsia usually develop after 20 weeks of gestation. We report a case of a 35-year-old Japanese woman who developed hypertensive disorders of pregnancy (HDP) before 20 weeks of gestation. She presented with hypertension and proteinuria at 9 and 11 weeks of gestation, respectively, and developed nephrotic syndrome at 17 weeks of gestation. She did not have definite hypertension or urinary abnormalities before pregnancy. The patient was serologically positive for the antinuclear antibody. However, the complement levels were normal and anti-phospholipid antibody was not detected. A renal biopsy performed at 18 weeks of gestation showed diffuse endotheliosis and tip lesions of secondary focal segmental glomerulosclerosis but no hypertensive changes of the arterioles. Although electron microscopic examination showed electron-dense deposits in the subendothelial lesions, they were considered nonspecific plasma exudation by mass spectrometry. An abortion was performed at 20 weeks gestation because the patient's congestive symptoms due to nephrotic syndrome had worsened and marked fetal growth restriction was observed. After delivery, the patient's symptoms resolved immediately without any additional treatment; however, continuous antihypertensive medication was required. Finally, the patient was diagnosed with HDP based on the renal biopsy findings and her clinical course after delivery. Compared to previous reports, this case describes the earliest onset of HDP. Thus, HDP should be considered as a differential diagnosis in pregnant women with hypertension or proteinuria presenting with symptoms before 20 weeks of gestation., (© 2021. Japanese Society of Nephrology.)

Autoimmune diseases are sometimes associated with immune-mediated renal diseases and cryoglobulinemia is one of the causes. Cryoglobulinemia and cryoglobulinemic glomerulonephritis associated with primary Sjögren's syndrome are most frequent condition among non-hepatitis C virus-related condition. Its typical renal manifestation shows high amount of proteinuria with microscopic hematuria and renal insufficiency. We describe a case of 72-year-old woman with Hashimoto disease, autoimmune hepatitis, Sjögren's syndrome, and immune-related pancytopenia complicated by cryoglobulinemic glomerulonephritis. Before kidney biopsy, tubulointerstitial nephritis probably due to Sjögren's syndrome was suspected because of persistent hematuria without significant proteinuria and developing mild renal dysfunction over 6 months. The developing renal dysfunction associated with isolated hematuria is uncommon in glomerular diseases. Kidney biopsy, however, revealed established membranoproliferative glomerulonephritis with subendothelial deposits consisting of tubular structures with IgM, IgG, and C3 staining. Corticosteroids plus mycophenolate mofetil therapy successfully normalized renal function. Physician should not overlook cryoglobulinemic glomerulonephritis, which is potentially poor prognosis, even if urinalysis shows only persistent isolated hematuria in patients with autoimmune diseases.

Cutaneous and systemic plasmacytosis (CSP) is a rare lymphoproliferative disorder that mainly affects middle-aged Asian individuals. Although Castleman disease is often complicated with various renal involvements, glomerulonephritis associated with CSP, which is considered as a variant of Castleman disease, is rare. This report presents the case of a 41-year-old Japanese man with nephrotic syndrome associated with CSP. Renal biopsy findings showed focal segmental glomerulosclerosis (FSGS) and diffusely mild segmental mesangial proliferation. Plasma cell infiltration in the interstitium was not observed. Electron microscopic findings showed diffuse foot process effacement, localized involvement of subendothelial space widening with amorphous materials, and endothelial cell swelling. Lymph node biopsy findings denied Castleman disease. His skin regions and proteinuria were successfully treated with prednisolone and cyclosporine. The causal relationship between CSP and FSGS is unknown. However, increased serum levels of IL-6 and VEGF and decreased VEGF expression in the podocyte may contribute to renal lesions in patients with CSP. To our best knowledge, this is the first case of a patient with FSGS associated with CSP.

A 72-year-old woman exhibited elevated serum myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) levels since 2006. Her serum creatinine (sCr) levels increased from 0.5 to 1.62 mg/dl in a stepwise pattern with proteinuria and hematuria up to January 2011. Renal biopsy indicated global sclerosis (14 %), fibrocellular crescents (28 %), and Swiss cheese-like appearance of the glomerular basement membrane (GBM) on light microscopy. IgG4 staining was negative. Immunofluorescent examination indicated granular staining with IgG and C3 along the GBM. MPO-ANCA-associated glomerulonephritis with membranous nephropathy (MN) was diagnosed. As chronic changes were relatively evident in the renal biopsy specimen without acute augmentation of renal function, immunosuppressive therapy was not administered. Thereafter, rapidly progressive renal dysfunction occurred (sCr, 3.67 mg/dl in May 2011) with proteinuria (~2 g/day), hematuria, and elevated serum MPO-ANCA levels. Therefore, a second renal biopsy was performed in May 2011, indicating global sclerosis (42 %) and cellular crescents (35 %) on light microscopy. Electron microscopy indicated electron-dense deposits in the GBM and mesangial lesions. Steroid therapy was subsequently initiated, and the patient's renal function partially improved. MPO-ANCA levels decreased to within normal limits and hematuria disappeared. MPO-ANCA-associated glomerulonephritis with MN is a rare dual glomerulopathy. However, complication should be considered when urinary protein appears in large amounts. Secondary MN was suspected due to the lack of IgG4 staining and distribution of electron-dense deposits to the mesangial lesion. Renal dysfunction occurring in a stepwise pattern may be attributed to intermittent augmentation in MPO-ANCA-associated glomerulonephritis.