708 Even Shaw, after falling and breaking his leg in 1950 while picking apples in his garden-an action directed towards a definite goal and which entailed a modicum of effort-would have been surprised to find a psychologist advising him. At present, patients have a vested interest in doctors.

ALLERGY AND BRONCHIAL HYPERREACTIVITY IN CYSTIC FIBROSIS A LITTLE-KNOWN feature of cystic fibrosis is the frequent occurrence of positive skin-prick tests to environmental allergens. Over half the patients show positive tests to such allergens as the house-dust mite, pollens,

and, particularly, Aspergillus fumigatus,I.2

as

against

about a third of normal children.3 The excess in cystic fibrosis is probably real, and points to a causal relationship : it is found only in patients themselves and not in close relatives.4Positive tests to A. fumigatus are readily explained because the fungus often becomes a more-orless harmless saprophyte in damaged and infected bronchi. Increased sensitisation to other environmental allergens may indicate defects in handling of antigens at mucosal surfaces, allowing increased access to immunologically reactive sites. Here mechanisms might include poor clearance, increased absorption, and local immuno-

with post-exercise constriction. It is noteworthy that several children with cystic fibrosis actually had better peak-flow rates soon after exercise, probably because sputum had been mobilised from obstructed bronchi under the stimulus of increased ventilation. An upward trend in pulmonary function after exercise has also been found by British workers,8 although the same group has reported, in different patients, some instances of bronchoconstriction in response to exercise.4 Thus, although bronchial hyperreactivity is not universally present in cystic fibrosis, it may exist and be important in some patients. That it should arise is hardly surprising, since even a transient viral infection of the bronchi can lead to long-lasting hyperreactivity.9 In cystic fibrosis, continuous inflammation and infection of the bronchial tree might cause hyperreactivity by lowering the response threshold of irritant receptors. In practical terms, the Canadian work confirms previous clinical impressions of the rarity of frank asthma in cystic fibrosis; the often positive skin tests, although of considerable immunological interest, do not necessarily imply additional clinical disease. Naturally, any clinician dealing with cystic fibrosis will be especially alert to the possibility of asthma and will treat it accordingly; but not every patient will benefit from anti-asthmatic remedies. The clinical picture continues to be dominated by airway obstruction and infection due to difficulty in mobilising viscid sputum, for which we still desperately need an effective mucolytic agent.

deficiency. In the normal population only about half those with positive prick tests actually have clinical allergic disease; so, are the positive skin-tests of cystic fibrosis clinically important? In particular, do they mean a high prevalence of asthma, overt or hidden, amongst these patients ? A general clinical impression is that asthma is no more frequent amongst cystic fibrotics than in the normal population, and some pxdiatricians will maintain that wheeziness is positively unusual in a child with cys-

tic fibrosis. Workers in Toronto have

now looked into this matter by doing provocation tests. In one study5 no less than 113 cystic fibrotics of varying ages were subjected to bronchial provocation with methacholine, one of the most potent irritant stimuli. Using a standardised proceduresthey detected bronchial hyperreactivity in 51% of cystic fibrotics, against 98% of frankly asthmatic children. However, using histamine as the provoking agent, they found hyperreactivity in only 20% of cystic fibrotic children, against 100% of asthmatics. Therefore bronchial hyperreactivity is not an invariable feature of cystic fibrosis-a conclusion supporting earlier work from the same group in which exercise was used to provoke bronchoconstriction.’ In the exercise study the cystic fibrotics had no statistically significant constriction, whereas the asthmatics showed typical bronchial lability

1. Warner, J. O., Taylor, B. W., Norman, A. P., Soothill, J. F. Archs Dis. Childh. 1976, 51, 507. McCarthy, D. S., Pepys, J., Batten, J. Proceedings of the 5th International Cystic Fibrosis Conference, Cambridge (edited by D. Lawson); p. 194. Cystic Fibrosis Research Trust, London, 1969. 3. Godfrey, R. C., Griffiths, M. Clin. Allergy, 1976, 6, 79. 4. Counahan, R., Mearns, M. B. Archs Dis. Childh. 1975, 50, 477. 5. Mitchell, I., Corey, M., Woenne, R., Krastins, I R. B., Levison, H. J. Pediat.

DOES UNEMPLOYMENT KILL? IN the mid-1960s the unemployment-rate in Britain around 1%;in the 1970s it has been rising and now stands at well over 5%. Over this period standardised mortality has shown some considerably less spectacular changes. In the United States too there have been peaks and troughs in mortality which could be linked with indices of the national economy; however, the peaks that followed the great pre-war depressions (there were two) seem unspectacular when set beside the massive upsurge in unemployment to a point when a quarter of the male work-force of the country were out of a job. For some years Dr Harvey Brenner,who works, from a background in sociology, at the Johns Hopkins School of Hygiene and Public Health, has been arguing that unemployment contributes directly to mortality and morbidity,’ and interest in his work has lately spread to the U.K. and other European countries. If his theory is correct then the rising unemployment-rate in Britain ought by now to have been associated with mortality considerable enough to put the nation’s economy firmly in the domain of community health. For a hundred years troughs in a generally downward-running U.S. mortality curve have coincided with was

2.

1978, 93, 744. 6 Chai, H., Farr, R. S., Froehlich, L. A. J. Allergy clin. Immun. 1975, 56, 323. 7. Skoreckis, K., Levison, H., Crozier, D. N. Acta pædiat. scand. 1976, 65, 39.

8. Day, G., Mearns, M. B. Archs Dis Childh. 1973, 48, 355. 9. Empey, D. W., Leitinen, L. A., Jacobs, L., Gold, W. M., Rev. resp. Dis. 1976, 113, 131.

Nadel, J. A.

Am

1. Brenner, M. H. Report to U.S. Congress Joint Economic Committee on Estimating the Social Costs of National Economic Policy. U.S Government Printing Office, 1976; see also Brenner, M H Int. J Hlth Serv 1977,7, 581.

Allergy and bronchial hyperreactivity in cystic fibrosis.

708 Even Shaw, after falling and breaking his leg in 1950 while picking apples in his garden-an action directed towards a definite goal and which enta...
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