Intact splenic function in cystic fibrosis.

Patients with cystic fibrosis (CF) suffer from severe chronic pulmonary infections but rarely develop bacteremia/septicemia suggestive of an intact splenic mononuclear phagocyte function. The splenic function of 25 patients diagnosed with CF, aged 2 to 37 years, was evaluated using erythrocyte pit count by direct interference contrast microscopy. Results were compared with patients with sickle cell disease and normal individuals. All CF patients displayed normal splenic function by pit count. The mean percentage of pitted erythrocytes was 0.20 +/- 0.28 (range: 0.0% to 1.0%) versus 0.19 +/- 0.33 (range: 0.0% to 1.4%) in normal eusplenic controls. There were no episodes of bacteremia or septicemia despite recurrent acute exacerbations of chronic bacterial bronchitis and the use of central lines. We conclude that splenic function in CF is unabridged and may account for the rarity of bacteremia/septicemia in patients with CF despite the high prevalence of chronic bronchial infection in this population.