Evidence for circulating complexes containing IgE in patients with atopic dermatitis.

18 out of 34 patients with atopic dermatitis were shown to have 5-32% of their serum IgE present in a high molecular weight (HMW) form (470,000 daltons). There was no simple correlation between the amount of HMW and the total serum IgE. The HMW peak was not affected by freezing and thawing the serum, but the complexes could be split by lowering the pH of serum fractionation. Some patients were tested sequentially on different occasions and although their clinical status may have altered during this time, there was no marked alteration of the HMW fraction. Results are compared with patients with raised IgE due to parasitic infections. Anti-IgE antibodies have been demonstrated in the HMW fraction.