Evidence of an immediate hypersensitivity mechanism in systemic lupus erythematosus

SummARY In 30 patients with systemic lupus erythematosus the number of circulating basophils was counted in different stages of activity. An inverse correlation was found between the absolute basophil count and anti-DNA antibodies and presumptive circulating immune complexes (as judged by polyethylene glycol precipitation of serum). A positive correlation was found between the absolute basophil count and C3 or C4 levels. IgE on the basophil surface was determined by radioimmunoassay in 7 patients. All of them showed a significantly high surface IgE number. When the count of circulating basophils was roughly normal, 5 out of the 6 patients showed a positive basophil degranulation test with native DNA. These results suggest the existence of an anti-DNA specific IgE in lupus patients. Depression of the circulating basophil count may be a useful index of lupus activity. In the acute serum sickness of rabbits the deposition of immune complexes in the blood-vessel walls involves an increase in vascular permeability induced by the release ofvasoactive amines from the platelets.' In these animals the occurrence of the glomerula