Mannan binding protein in sera positive for rheumatoid factor

Area of Science:

• Immunology
• Rheumatology
• Biochemistry

Background:

• Mannan binding protein (MBP) deficiency may offer protection against rheumatoid arthritis (RA).
• A proposed mechanism involves agalactosyl IgG and complement activation in RA pathogenesis.
• Understanding MBP's role in RA is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the association between mannan binding protein (MBP) levels and rheumatoid arthritis (RA).
• To evaluate the hypothesis that low MBP levels protect against RA.
• To assess MBP concentrations in RA patients compared to healthy controls.

Main Methods:

• Serum samples from 99 rheumatoid factor-positive individuals (including 41 RA patients) and 352 controls were analyzed.
• Mannan binding protein (MBP) concentrations were quantified using immunoassays.
• Statistical comparisons were made between patient and control groups.

Main Results:

• Undetectable MBP levels were found in similar proportions of RA patients (4.0%) and controls (4.3%).
• Low MBP values were generally similarly distributed between the two groups.
• Overall MBP levels were higher in RA patients, suggesting an acute-phase response.

Conclusions:

• The study found no evidence to support the hypothesis that low MBP levels protect against rheumatoid arthritis.
• Observed higher MBP levels in RA patients indicate an acute-phase reaction, not a protective deficiency.
• The findings do not support a role for MBP-agalactosyl IgG-mediated complement activation in RA pathogenesis.