Complement cascade activation results in the formation of complement split products C 3 a, C 4 a, and C 5 a. 4 These proteins, referred to as anaphylatoxins, facilitate the phagocytosis of immune complexes, viral particles, toxic cell debris and apoptotic corpses.

2021年7月6日 · WHAT DOES IT MEAN IF YOUR COMPLEMENT C4A RESULT IS TOO LOW? Lower-than-normal complement C4 values could indicate: – bacterial infections. – hepatitis. – malnutrition. – rejection of a kidney transplant. – systemic lupus erythematosus, which is an autoimmune disease affecting the skin, joints, kidneys, and other organs.

2024年8月1日 · Complement C4 protein is expressed as two isotypes, C4A and C4B, which are encoded by the C4 genes (C4A or C4B gene), and share >99% sequence identities. The difference lies in four isotype-specific amino acid substitutions at amino acid positions 1120–1025 (C4A: 1120 PCPVLD 1125; C4B: 1120 LSPVIH 1125).

2025年3月28日 · C4A (Complement C4A (Chido/Rodgers Blood Group)) is a Protein Coding gene. Diseases associated with C4A include Complement Component 4A Deficiency and Blood Group, Chido/Rodgers System.

The testing for C4a can help determine if a deficiency or abnormality is a contributing factor to increased infections or increased autoimmune activity. The measurement can also be used to monitor autoimmune disorders. C4a, in conjunction with C3a, may be useful markers in acute and chronic Lyme disease. Reference Ranges for Complement C4a:

2022年11月3日 · We show that the CSF elevation of C4A in FEP-SCZ exceeds what can be expected from genetic risk variance in the C4 locus, and in patient-derived cellular models we identify a mechanism dependent...

2021年9月22日 · Our findings are consistent with a specific role for C4A protein in schizophrenia and raise the possibility that its activation product, C4-ana, increases BBB permeability.

2022年10月5日 · Complement component 4 (C4), encoded by two closely linked, highly polymorphic genes C4A and C4B within the major histocompatibility complex (MHC) class III region on chromosome...

We elucidated the gene copy number (GCN) variations of total C4, C4A and C4B, long and short genes in 1644 Caucasian patients with IIM, plus 3526 matched healthy controls using real-time PCR or Southern blot analyses. Plasma complement levels were determined by single radial immunodiffusion.

2019年8月6日 · Complement component 4 (C4) gene copy number (GCN) affects the susceptibility to systemic lupus erythematosus (SLE) in different populations, however the possible phenotype significance remains to be determined. This study aimed to associate C4A, C4B and total C4 GCN and SLE, focusing on the clinical phenotype and disease progression.