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The subclass distribution of human IgG rheumatoid factor
Journal of Immunology (Baltimore, Md. : 1950)
|September 1, 1987
Summary
Rheumatoid factor (RF) subclass distribution in rheumatoid arthritis revealed IgG1 and IgG4 as key players. IgG4 RF specifically targets the Fc region of IgG, with unique Fab region activity in rheumatoid arthritis patients.
Area of Science:
- Immunology
- Rheumatology
Background:
- Rheumatoid factor (RF) is a hallmark of rheumatoid arthritis (RA).
- The subclass distribution of IgG RF is crucial for understanding its pathogenic role.
Purpose of the Study:
- To determine the subclass distribution of IgG rheumatoid factor (RF) in rheumatoid arthritis (RA) patients.
- To investigate the specificity and characteristics of IgG4 RF.
Main Methods:
- Sensitive ELISA assay to quantify IgG RF subclasses in patient and control sera.
- Analysis of RF activity in pepsin-digested sera and comparison with myeloma proteins.
Main Results:
- IgG1 and IgG4 were the predominant IgG RF subclasses in both RA patients and normal controls.
- IgG4 RF recognized the Fc region of human and rabbit IgG, with additional specificity in RA sera.
- Persistent RF activity in digested RA sera indicated a Fab region component of IgG4 RF.
Conclusions:
- IgG4 plays a significant role as a rheumatoid factor in RA.
- The unique characteristics of IgG4 RF, including its Fab region involvement, warrant further investigation.
- Understanding IgG4 RF is important given its potential roles in complement fixation, Fc receptor binding, and vascular permeability.