C4 Component of the complement system (Complement Component C4)

The complement system (from Latin. complement-tum is a term introduced in 1899 by P. Ehrlich and J. Morgenroth. C4 is a glycoprotein with a molecular weight of 205,000 Da. It is synthesized in the lungs and bones. It participates only in the classical way of activating the complement system. C4 supports phagocytosis, increases the permeability of the vascular wall, and participates in the neutralization of viruses. Its decrease in blood is observed with active consumption associated with the classical pathway of activation of the complement system.

Blood collection is preferably carried out in the morning on an empty stomach, after 8-14 hours of the night fasting period (you can drink water), it is permissible in the afternoon 4 hours after a light meal. On the eve of the study, it is necessary to exclude increased psychoemotional and physical activity (sports training), alcohol intake, and smoking an hour before the study.

Suspected genetic complement deficiency. Dynamic monitoring of patients with systemic autoimmune diseases. In the diagnosis of diseases: systemic lupus erythematosus (SLE), rheumatoid vasculitis, subacute bacterial endocarditis, shunt nephritis, post-streptococcal glomerulonephritis, mesangiocapillary glomerulonephritis, rheumatic polymyalgia, mixed cryoglobulinemia, gram-negative bacteremic shock (early diagnosis), gram-positive bacteremia, disseminated cytomegalovirus infection.

The interpretation of the research results contains information for the attending physician and is not a diagnosis. The information in this section cannot be used for self-diagnosis and self-medication. An accurate diagnosis is made by a doctor using both the results of this examination and the necessary information from other sources: anamnesis, results of other examinations, etc. Units of measurement in the INVITRO laboratory: g/l. Reference values: Women 1 – 14 years old 0.13 – 0.46 g/l 14 – 80 years old 0.15 – 0.57 g/L Men 1 – 14 years old 0.14 – 0.44 g/l 14 – 80 years old 0.15 – 0.53 g/L Increasing C4 values: Congenital conditions the presence of more than four C4 alleles; deficiency of components C1q, C1r, C1s. Acquired conditions rheumatoid arthritis; bacterial infection, bacterial endocarditis; glomerulonephritis; systemic lupus erythematosus; malaria; cryoglobulinemia; sepsis; inflammatory reaction of the acute phase; the use of drugs cimetidine (in patients with AIDS), cyclophosphamide (in patients with SLE), danazol. Lowering C4 values: Congenital deficiency C4 shortage of newborns; hereditary angioedema; Acquired deficit rheumatoid arthritis; hereditary and acquired angioedema; complement activation caused by diseases of immune complexes; glomerulonephritis; systemic lupus erythematosus; rheumatoid arthritis; respiratory distress syndrome; autoimmune hemolytic anemia; fasting; sepsis; autoimmune thyroiditis; cryoglobulinemia; kidney transplantation; systemic vasculitis; liver damage.