Factors relating to circulating immune complexes in rheumatoid arthirits

Area of Science:

• Immunology
• Rheumatology

Background:

• Circulating immune complexes are frequently observed in rheumatoid arthritis (RA) patients.
• These complexes, specifically IgG-containing, are small and distinct from those in healthy individuals.

Purpose of the Study:

• To investigate the characteristics and clinical relevance of circulating immune complexes in rheumatoid arthritis.
• To explore the correlation between these complexes and immune cell function, including K cell activity and polymorphonuclear leucocyte chemotaxis.

Main Methods:

• Gel filtration chromatography (Sepharose 6B) was used to analyze serum samples.
• Quantification of complexed IgG was estimated using a derived ratio from the IgG profile.
• In vitro assays measured the inhibition of K cell-mediated cytolysis and polymorphonuclear leucocyte chemotaxis.

Main Results:

• Small IgG-containing immune complexes were detected in over half of RA patient sera, absent in healthy controls.
• The quantity of these complexes correlated with the inhibition of K cell-mediated cytolysis.
• A significant inverse correlation was found between complex quantity and polymorphonuclear leucocyte chemotactic index.

Conclusions:

• Circulating immune complexes in RA patients may impair immune cell functions.
• These complexes are implicated in the reduced chemotaxis observed in rheumatoid arthritis.
• No correlation was found between complex levels and standard clinical, haematological, or biochemical markers.