Related Experiment Video
Updated: May 10, 2026
12:23
Granulocyte-dependent Autoantibody-induced Skin Blistering
Published on: October 12, 2012
Cutaneous vasculitis and glomerulonephritis associated with C4 deficiency
1Department of Dermatology, Nippon Medical School, Tokyo, Japan. p-chan@nms.ac.jp
Clinical and Experimental Dermatology
|June 20, 2013
Summary
A rare undetectable complement component 4 (C4) level was observed in a patient with vasculitis and glomerulonephritis. Genetic analysis did not confirm C4 deficiency, suggesting a complex immune disorder.
Area of Science:
- Immunology
- Nephrology
- Dermatology
Background:
- Complete deficiency of the fourth component of complement (C4) is rare.
- Partial C4 deficiency is linked to immune diseases.
Observation:
- A 44-year-old woman presented with edema and purpura after a cold.
- She had persistent microscopic hematuria, proteinuria, and undetectable C4 levels.
- Skin biopsy revealed leucocytoclastic vasculitis with immune deposits.
- Renal biopsy showed mesangial proliferative glomerulonephritis with immune deposits.
Findings:
- The patient exhibited clinical signs of vasculitis and glomerulonephritis.
- Despite undetectable C4 levels, genetic testing did not confirm C4 deficiency.
- Immune deposits (IgG, IgM, C3, C1q, C4) were found in skin and renal biopsies.
Implications:
- This case highlights a potential disconnect between undetectable C4 levels and genetic C4 deficiency.
- It suggests complex immune dysregulation in patients with vasculitis and glomerulonephritis.
- Further research is needed to understand the mechanisms of C4 dysfunction in such cases.
More Related Videos
06:35An Immunohistopathologic Study to Profile the Folate Receptor Beta Macrophage and Vascular Immune Microenvironment in Giant Cell Arteritis
Published on: February 8, 2019
07:50A Metadata Extraction Approach for Clinical Case Reports to Enable Advanced Understanding of Biomedical Concepts
Published on: September 20, 2018
Related Concept Videos
01:19Hypersensitivity Reactions: Immune-Complex Reactions
Type III hypersensitivity reactions occur when antigen–antibody complexes form and activate the complement system. Normally, these complexes help the clearance of antigens by phagocytes and red blood cells. However, when large numbers of immune complexes are present, they can deposit in tissues—particularly in the walls of blood vessels—leading to inflammation and tissue injury. These deposits trigger complement activation and neutrophil recruitment, resulting in serum sickness, a systemic...
01:25Endocarditis II: Clinical Features of Infective Endocarditis
Endocarditis can present various clinical features depending on the causative organism and the patient's underlying health conditions. Initially, the clinical features of infective endocarditis develop gradually, presenting with nonspecific symptoms that can be easily mistaken for other illnesses.General SymptomsEarly symptoms of infective endocarditis are fever, chills, weakness, malaise, fatigue, and weight loss. These symptoms reflect the systemic nature of the infection and the body's...
01:24Nephrotic Syndrome I : Introduction
Nephrotic Syndrome is a chronic kidney disorder defined by clinical findings such as severe proteinuria, hypoalbuminemia, hyperlipidemia, and edema. These symptoms result from damage to the glomeruli, the kidney’s filtering units, increasing their permeability to proteins.Definition and Meaning:Proteinuria, defined as the loss of more than 3.5 grams of protein per day in adults, is a crucial feature of nephrotic syndrome. This condition is often accompanied by edema, the accumulation of fluid...
01:24Chronic Kidney Disease II: Clinical Manifestations
Chronic Kidney Disease (CKD) progressively impairs multiple body systems due to the accumulation of uremic toxins, which disrupt cellular functions across various organs.Neurologic symptomsNeurologic symptoms often arise early in CKD, as uremic toxin buildup drives changes in cognitive and motor functions. Patients frequently experience fatigue, headache, confusion, difficulty concentrating, and, in severe cases, seizures. Peripheral neuropathy commonly manifests as burning sensations in the...
01:20Renal Corpuscle
The glomerulus and Bowman's capsule are two essential components of the nephron, which is the functional unit of the kidney. These microscopic structures play a critical role in the process of blood filtration to produce urine.
Glomerulus: Structure and Function
The glomerulus is a tiny, intricate network of capillaries located at the beginning of the nephron. It's enveloped by the Bowman's capsule and receives its blood supply from an afferent arteriole, which divides into numerous capillaries...
Glomerulus: Structure and Function
The glomerulus is a tiny, intricate network of capillaries located at the beginning of the nephron. It's enveloped by the Bowman's capsule and receives its blood supply from an afferent arteriole, which divides into numerous capillaries...
01:01Hypersensitivity Reactions: Cytolytic Reactions
Type II hypersensitivity involves IgG and IgM antibodies targeting cell surface antigens, leading to cell destruction. This can occur through complement activation, antibody-dependent cell-mediated cytotoxicity (ADCC), or acting as opsonins for phagocytosis. When excessive, these reactions cause significant tissue damage.Drug-induced hemolytic anemia is a common example, where drugs like penicillin or cephalosporins bind to red blood cells, forming drug-protein complexes. These complexes...