Open Access Articles- Top Results for Complement component 4

Complement component 4

complement component 4A (Rodgers blood group)
Symbol C4A
Entrez 720
HUGO 1323
OMIM 120810
RefSeq NM_007293
UniProt P0C0L4
Other data
Locus Chr. 6 p21.3
complement component 4B (Chido blood group)
Symbol C4B
Entrez 721
HUGO 1324
OMIM 120820
RefSeq NM_000592
UniProt P0C0L5
Other data
Locus Chr. 6 p21.3

Complement component 4 is a protein involved in the complement system.

It is cleaved into proteins 4a and 4b; 4b can be further cleaved into 4c and 4d.[1]

File:Droga klasyczna.png
Classical pathway. (Some labels are in Polish.)

Clinical significance

It is responsible for the Chido Rodgers blood group system.[2]

C4d has been identified as a biomarker for systemic lupus erythematosus.[3]


  2. Chido Rodgers blood group system at BGMUT Blood Group Antigen Gene Mutation Database at NCBI, NIH
  3. Liu CC, Manzi S, Kao AH, Navratil JS, Ruffing MJ, Ahearn JM (2005). "Reticulocytes bearing C4d as biomarkers of disease activity for systemic lupus erythematosus". Arthritis Rheum. 52 (10): 3087–99. PMID 16200588. doi:10.1002/art.21305.