Histamine release from basophils in cystic fibrosis

We determined the histamine release from basophils in patients suffering from cystic fibrosis (CF) (median 17.2 years of age) and compared the data with an age-matched group of healthy donors. No significant differences in the basophil counts were determined between the CF and control groups. However, the absolute histamine content per basophil was elevated in the CF group (2.6 +/- 0.4 pg/basophil versus 1.4 +/- 0.2, mean +/- s.e.m., n = 15/10, P less than 0.004). Stimulation of basophils with the Ca ionophore (7.5 microM) and anti-IgE (10(-2) of a stock preparation) leads to a significantly higher release of histamine per basophil in CF patients as compared to healthy donors (Ca ionophore: 1.6 +/- 0.2 versus 0.9 +/- 0.2, mean +/- s.e.m., P less than 0.008; anti-IgE: 0.45 +/- 0.007 versus 0.28 +/- 0.04, P less than 0.02). These data indicate that basophils in CF may have a greater potential to release mediators although their releasability, expressed as the percentage of histamine release of the total histamine content, does not differ significantly compared to the healthy donors (62.1 +/- 8.3% versus 60.2 +/- 13%, mean +/- s.e.m.). Within the 14-day period of intravenous antibiotic treatment of the pulmonary infection (in 14 out of 15 cases P. aeruginosa was isolated from sputa samples) histamine release per basophil and total histamine content decreased to normal levels (day 1 2.6 +/- 0.3 versus 1.8 +/- 0.3, P less than 0.05). This decline was accompanied by an improvement of the clinical condition of the patient and reduction of P. aeruginosa isolates in sputa (n = 8). In contrast, in three patients with sustained P. aeruginosa colonization of the upper airways and impaired lung function histamine levels remained elevated. Our data demonstrate that the histamine content of basophils, as well as the release of histamine, is increased in patients with cystic fibrosis and correlates with the clinical signs of the chronic infection.