[A comparative study of serum complement (C3 and C4) in inflammatory joint diseases]

Area of Science:

• Immunology
• Rheumatology
• Clinical Chemistry

Background:

• Inflammatory joint diseases involve complex immune responses.
• Acute phase reactants are crucial biomarkers for inflammation.
• The role of complement fractions in various arthritic conditions requires further elucidation.

Purpose of the Study:

• To investigate the levels of complement fractions (C3 and C4) and other acute phase reactants in patients with diverse inflammatory joint diseases.
• To assess the correlation between complement fractions and established acute phase indices.
• To determine the potential utility of C3 and C4 as acute phase reactants in rheumatology.

Main Methods:

• Quantitative analysis of complement fractions (C3, C4), haptoglobin, fibrinogen, alpha 1-glycoprotein, alpha 2-macroglobulin, and transferrin.
• Study population included 692 patients with various inflammatory joint diseases and 60 healthy controls.
• Comparison of marker levels in active and non-active disease phases.

Main Results:

• Elevated levels of complement fractions C3 and C4 were observed across most patient groups and disease phases.
• Significant positive correlations were found between C3, C4, and other acute phase indices.
• A clear hierarchy of acute phase reactivity was established, with fibrinogen and haptoglobin being the most reactive, followed by alpha 1-glycoprotein, C3, C4, alpha 2-macroglobulin, and transferrin.

Conclusions:

• Complement fractions C3 and C4 demonstrate significant elevations in inflammatory joint diseases.
• C3 and C4 exhibit strong correlations with other established acute phase reactants.
• C3 and C4 can be considered valuable additions to the panel of acute phase reacting indices for assessing inflammatory arthritis.