Relations between serum IgA level and cartilage erosion in 436 cases of rheumatoid arthritis

The objective of this work was to explore the correlation between the cartilage erosion tested with X-ray image and the serum immune globulin level in rheumatoid arthritis (RA). Four hundred and thirty-six patients with active RA in preliminary diagnosis were selected for the study. The cartilage erosion was measured by X ray in both hands as a grade index, and IgG, IgM as well as IgA in serum were determined with immunoturbidimetry. The correlation between the X-ray grading and serum immune globulin outcomes was analyzed by SPSS13.0 statistic package.

More patients with X-ray grading as cartilage erosion (slight, medium or severe) showed abnormal IgA comparing to those in X-ray grading as normal (p<0.05-0.01) both in preliminary investigation and after 6 months' follow-up. The serum IgA level in RA with X-ray grading as slight, medium or severe cartilage erosion was elevated remarkably comparing with in grading as normal (p<0.05-0.01). The Spearman Analysis showed that the level of serum IgA presents positive correlation with X-ray grading both in preliminary investigation (p=0.003, rIgA=0.143) and after 6 months follow-up (p=0.001, rIgA=0.173). IgG and IgM, however, have no correlation with X-ray image outcomes. The increase of serum IgA shows positive correlation with the grade of cartilage damage in active RA. IgA seems to be involved in the mechanism of joint cartilage erosion in active RA.