The presence of hypodense eosinophils and diminished chemiluminescence response in asthma.

Although peripheral blood eosinophilia is a prominent feature of asthma, the contribution of eosinophils to asthma has yet to be fully comprehended. Furthermore, study of isolated eosinophil function in asthma has been complicated by difficult purification methods and, now, the presence of hypodense eosinophils. In our study, eosinophils were isolated from normal subjects and patients with asthma. Two principal evaluations were performed: (1) a comparison of the density-gradient profiles on peripheral blood leukocytes from normal subjects and patients with asthma and (2) a comparison of the chemiluminescence (CL) response with normal dense eosinophils from these two study groups. Granulocyte preparations were initially isolated from Ficoll-Hypaque gradients and were then applied to a continuous Percoll density gradient. In asthma, 40.8 +/- 5.8% of the peripheral blood eosinophils were hypodense (defined as a density less than 1.081 gm/ml), whereas normal subjects had only 9.1 +/- 1.9% of this subpopulation (p less than 0.01). Functional assessment of purified (greater than 90%) normal dense eosinophils was made by measurement of CL to opsonized zymosan particles and the soluble stimulus phorbol myristate acetate. In asthma, eosinophil CL to zymosan, but not phorbol myristate acetate, was significantly less. Differences in eosinophil CL between normal subjects and subjects with asthma did not correlate with the severity of airway obstruction or the peripheral blood eosinophil count. The reasons for the appearance of hypodense eosinophils and diminished metabolic activity in asthma are not established but raise the possibility that their presence represents previous eosinophil activation.

Interleukin-1 alpha and beta genes: linkage on chromosome 2 in the mouse.

Two interleukin-1 polypeptides, alpha and beta, are known, and cDNAs corresponding to each have been described. Genomic cloning and Southern blotting experiments suggest that in the mouse each is encoded by a gene present in one copy per haploid genome. Analysis of a panel of somatic cell hybrids carrying various mouse chromosomes on a constant Chinese hamster background indicates that both genes map to mouse chromosome 2. Further, analysis of the inheritance of DNA restriction fragment length polymorphisms associated with each gene in recombinant inbred strains of mice shows the two loci to be tightly linked to one another, and to lie approximately 4.7 centimorgans distal to B2m (beta-2 microglobulin). We have named the locus encoding IL-1 alpha Il-1 alpha and the locus encoding IL-1 beta Il-1b.