Case Report: Patient with Hepatitis C, p-ANCA, and Cryoglobulin Antibodies Presenting with Necrotizing Crescentic p-ANCA Glomerulonephritis

Renal Manifestations of Chronic Hepatitis C: A Review

Hepatitis C virus (HCV) has emerged as a major global health concern and, if left untreated, can lead to significant liver damage, including cirrhosis, decompensated liver disease, and hepatocellular carcinoma (HCC). Approximately 40% of patients with HCV infection experience extrahepatic manifestations, including renal involvement. HCV-related renal disease is of significant importance among patients with chronic kidney disease (CKD), leading to higher morbidity and mortality. The renal damage due to HCV infection primarily results from cryoglobulinemia and glomerulonephritis, with conditions such as membranoproliferative glomerulonephritis (MPGN) and membranous nephropathy (MN) being most prevalent. Despite advancements in treatment, including the use of directly acting antiviral agents (DAAs), renal complications remain a significant burden in untreated patients. HCV-positive patients on hemodialysis (HD) or those who have undergone kidney transplantation face increased mortality rates compared to their HCV-negative counterparts. Managing HCV infection before kidney transplantation is crucial to mitigate the risk of HCV-related renal complications. Conversely, kidney transplantation from HCV-infected donors is well established, as post-transplant treatment for HCV is safe and effective, potentially reducing mortality and morbidity for patients on transplant waiting lists. This review aims to provide a comprehensive analysis of the renal manifestations of HCV, emphasizing the importance of early diagnosis and treatment to improve patient outcomes.

Viral Glomerulopathy

Background

The association between viral infections and glomerular diseases, commonly known as "viral glomerulopathies," has been described in various clinical scenarios for decades. Despite advancements in diagnostic tools, it remains challenging to establish a causative link fully.

Summary

Data from mouse models have substantiated clinical observations and implicate direct viral infection in the pathogenesis of viral glomerulopathy, particularly in human immunodeficiency virus-associated nephropathy. In addition to the traditional concept of direct viral effects on kidneys, other factors such as APOL1 risk alleles can further modify the clinical outcomes or presentations of different viral glomerulopathies. Newly developed antiviral drugs are now applicable to a wider range of patients with lower kidney function and fewer side effects.

Key Message

Efforts focusing on vaccines and antiviral treatments have significantly reduced the incidence of viral glomerulopathies. However, the most recent pandemic caused by severe acute respiratory syndrome coronavirus 2 infection complicated by COVID-associated nephropathy illustrates our susceptibility to novel viruses. Ongoing research is pivotal to deciphering the mechanisms behind viral glomerulopathies and discovering therapeutics in a collaborative approach.

Antineutrophil cytoplasmic antibody-associated vasculitis, update on molecular pathogenesis, diagnosis, and treatment

Circulating antineutrophil cytoplasmic antibodies (ANCAs) are the central pathogenic mechanism for a group of systemic and renal syndromes called the ANCA-associated vasculitis (AAV). The nomenclature has changed from eponymous labeling to granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, and microscopic polyangiitis. These syndromes predominantly affect the pulmonary and renal systems. We also review the molecular pathology behind ANCAs and associated antigens and infections. Various clinical presentations, the multiple target organs affected, and diagnostic challenges involved in identifying these diseases are discussed. Treatment updates are also provided with regard to new studies and the now standard use of anti-CD-20 monoclonal antibodies as first-line therapy in all but the most aggressive presentations of this disease. Maintenance regimens and monitoring strategies for relapse of vasculitis and associated systemic complications are discussed.