Nutrition and immunity in cystic fibrosis

Of all man's miseries the bitterest is this, to know so much and to have control over nothing'. HERODOTUS.The precise defect in cystic fibrosis is still unknown despite vast amounts of basic research over the past twenty years (Beam, 1973~).It is common in white European and North American populations with a birth incidence of around I in 2000 (Beam, 1973b), and where intensive birth screening has been undertaken, the incidence may be as high as I in 1200 (Stephan, 1973).It is a multisystem disorder with its main impact on the respiratory tract, leading to repeated chest infections, and on the gut where the main problem is exocrine pancreatic insufficiency.In the neonate this latter defect leads to acute intestinal obstruction due to meconium ileus, a complication which was encountered in 5% of a large series of cystic fibrosis (CF) patients studied in France (Chazalette, Dutau, Chevalier, Filliat & Galabert, 1977).Other clinical problems in the disease include rectal prolapse and ileal atresia, and in older patients nasal polyposis, diabetes and hepatic cirrhosis.Abnormalities in vitro are also diverse and include abnormal serum factor(@ as well as histochemical changes in cultured fibroblasts and various leucocytes (see Raeburn, 1975~).Amidst so many definable abnormalities both clinical and in the laboratory the problem is to distinguish primary from secondary defects.In most CF patients the hallmark of the disease is the chronic cough and other respiratory symptoms associated with repeated infections.At first sight the cause of such infection seems obvious for the sputum is excessively viscid (Sturgess & Reid, 1969) and the pathological changes, including emphysema and bronchiectasis, would lead to inadequate bronchial clearance.However, none of these findings is specific for cystic fibrosis (Reid & Ryland, 1973); in addition, the glycoprotein constituents of bronchial mucus from CF patients are qualitatively (but not quantitatively) similar to those of other patients with chronic lung disease.Nevertheless, since severe respiratory infection and respiratory failure are the major causes of death the main focus in management has been upon attempts to minimize respiratory damage.This has led to a variety of studies of antibiotic therapy (e.g.