Serum IgA and gold toxicity in rheumatoid arthritis: lack of predicting value

The previously reported predictive value of serum IgA for gold toxicity was investigated by measuring such immunoglobulins in 114 patients affected with rheumatoid arthritis and treated with gold salts over a period of 36 months. Side effects were observed in 41 cases (35.9%) (toxic group), mostly within the first year of treatment. Basal levels of IgA were normal in all but 2 patients who maintained low levels throughout the follow-up but did not show any toxic effects. Before therapy and during gold salt administration no difference in serum IgA was noted between the toxic and the non-toxic group. After 6 months of therapy a significant decrease (p less than 0.05) in serum IgA (although never below normal limits) was detected in the toxic group as compared to both the basal values of the same group and the values of the non-toxic group at the same control. Moreover, we did not find any difference in serum IgA between toxic patients with and without mucocutaneous reactions. In our experience the monitoring of serum IgA is not useful in predicting gold toxicity.