No abstract

Rituximab is an effective treatment for frequently relapsing/steroid-dependent nephrotic syndrome, but there is concern about infections caused by humoral immunodeficiency. We herein report a case of prolonged (>7 weeks) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A 24-year-old man with minimal-change disease treated with rituximab developed SARS-CoV-2 infection. The clinical response to remdesivir was soon transiently abolished. Treatment with casirivimab and imdevimab (REGEN-COV) monoclonal antibodies in combination with remdesivir resulted in complete clearance of the infection. The REGEN-COV antibody cocktail may improve the outcome of SARS-CoV-2 infection in patients with humoral immunodeficiency.

Background There have been several reports of IgA nephropathy (IgAN) patients with gross hematuria and acute deterioration of urinary findings and kidney function following SARS-CoV-2 mRNA vaccination. Recent case series studies have indicated a possible link between the status of urinary findings at the time of vaccination and the subsequent appearance of gross hematuria. In this study, we aimed to determine whether the status of pre-vaccination urinary findings was associated with post-vaccination gross hematuria in patients already diagnosed with IgAN. Methods Outpatients with IgAN who had been followed up before vaccination were included. We analyzed the association between the remission of pre-vaccination microscopic hematuria (urine sediment <5 red blood cell/high power field) or proteinuria (<0.3 g/gCr) and post-vaccination gross hematuria. Results A total of 417 Japanese patients with IgAN (median age, 51 years; 56% female; estimated glomerular filtration rate (eGFR), 58 mL/min/1.73 m2) were included. The frequency of gross hematuria following vaccination was higher in 20/123 patients (16.3%) with microscopic hematuria than in 5/294 patients (1.7%) without microscopic hematuria prior to vaccination (P <0.001). There was no association between pre-vaccination proteinuria and post-vaccination gross hematuria. After adjusting for potential confounders, such as sex (female), age (<50 years), eGFR (≥60 mL/min/1.73 m2), and histories of tonsillectomy and corticosteroid therapy, pre-vaccination microscopic hematuria was still associated with post-vaccination gross hematuria (OR 8.98, P <0.001). As the severity of pre-vaccination microscopic hematuria increased, the incidence of post-vaccination gross hematuria increased (P <0.001). Conclusions Pre-vaccination microscopic hematuria in patients with IgAN is a major predictor of post-vaccination gross hematuria, regardless of potential confounders including previous treatments for IgAN.

Background: Neural epidermal growth factor-like 1 protein (NELL1) is a target antigen of membranous nephropathy (MN). NELL1-associated MN (NELL1-MN) was originally a primary form but has been associated with other diseases, including malignancies, pre-exposure to certain drugs, hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, and rheumatoid arthritis (RA). Case presentation: A 78-year-old woman with long-standing RA developed persistent proteinuria and was diagnosed with MN. Evaluation of the underlying cause revealed chronic active HCV infection and past HBV infection. The underlying cause was less likely to be drug-related; however, there was no evidence of malignancy. The patient was diagnosed with HCV-associated MN. At 4 years after MN diagnosis, the patient died of breast cancer with multiple metastases. Subsequent immunohistological analysis revealed that she had NELL1-MN and that her breast cancer tissue positively stained for NELL1. Conclusions: Our case illustrates the difficulty in establishing the underlying disease of NELL1-MN, even after diagnosis. However, the incidence of malignancies, particularly breast and prostate cancers, is higher in NELL1-MN than in MN with other target antigens. Therefore, malignancies are considered a priority for investigation because of their frequency and prognosis among patients with NELL1-MN.

Tuberculosis is a common etiology of granulomatous interstitial nephritis (GIN). However, the absence of evidence of lung involvement and lack of mycobacterial isolation in cultures make the etiological diagnosis and treatment decision challenging. We herein report a 46-year-old man with severe renal failure, a persistent fever, and a history of lymphoma. A renal biopsy exhibited GIN. Despite no evidence of tuberculosis except for a positive interferon-gamma release assay (IGRA), the patient was successfully treated with antituberculosis drugs. Our case suggests that anti-tuberculosis therapy should be considered for patients with IGRA-positive GIN after excluding other etiologies.