Immunological features of asthma (Part II). A report to the Research Committee of the British Thoracic and Tuberculosis Association.

Abstract

A serological comparison was made of two groups of 120 matched asthmatic and healthy subjects, between the ages of 20 and 49 years and matched for age and sex, in terms of serum total levels of IgG, IgM, IgA, IgD and IgE and of specific antibody levels in each immunoglobulin class to five common UK allergens. The relationship of clinical features to the serological tests was also examined in the asthmatic subjects. The following statistically significant findings were shown. The patients had higher levels than the controls of total globulins and of IgG, IgA and IgD but not IgM. In both patients and controls the females had higher IgM levels than the males. The total IgE levels were higher in patients than in the controls and the male patients had higher levels than the female patients. Total IgE levels were also related, to the numbers of first degree relatives with asthma, hay fever and eczema, to the severity of hay fever and to the amount of time off work in the male patients. In those male patients with exercise induced asthma the total IgE levels were lower than in those not showing this reaction. As for the other immunoglobulins, the only significant differences were a higher IgG level in patients with FEV1 or PFR greater than 50% predicted and a higher IgD level in patients with hay fever. Radio-immunodiffusion tests for specific precipitins were positive for Dermatophagoides pteronyssinus in comparable numbers of asthmatics (25.8%) and controls (21.7%). Positive precipitin tests were uncommon in tests with extracts of grass pollen, Aspergillus fumigatus, cat and dog hair in the patients and even less so in the controls. Positive RAST tests for specific IgE antibodies were obtained in patients and controls respectively, against D. pteronyssinus 59% and 11%, grass pollen 37.0 and 12%, and A. fumigatus 6% and 4%. The male patients showed the closest significant relationship of specific IgE to D. pteronyssinus and the history of house dust allergy, positive skin test and nasal test. In the females only the skin and specific IgE tests were related. Both sexes showed a significant association between specific IgE to grass pollen and positive skin tests and nasal tests, but only the males showed an association with the history. The sizes of skin test weal to D. pteronyssinus were related to the levels of specific IgE antibody. No differences were found between the four skin test groups and between the asthmatics and the control subjects in the incidence of bacterial precipitins and auto-antibodies.