An immunologic and genetic study of asthma in workers in an aluminum smelter.

The cause or causes of asthma among employees in aluminum smelters is unknown. We attempted to ascertain whether such workers who developed asthma differed in respect to indices of immunological function and certain genetic markers. Data were collected from 33 asthmatic and 127 nonasthmatic potroom workers. Asthmatic workers had significantly lower mean serum levels of immunoglobulin (Ig)M; however, mean levels of IgG and IgA, median levels of IgE, the capacity for recall of delayed type hypersensitivity, levels of immune complexes, and frequency of antinuclear or other autoantibodies did not differ from values for nonasthmatic workers. Asthma was found to develop on a background of atopy in 21 workers (64%), whereas there were no features of atopy in 12 workers (36%). Cigarette smoking had independent effects on immunological function. In respect to genetic markers, there was a higher frequency among asthmatic workers of the alpha-1-anti-trypsin deficiency phenotype MS, but the frequency of blood groups, Gm allotypes, or human leucocyte antigen types was similar. The study established that the profile of immune function, or genetic markers tested, did not differ essentially for workers in an aluminum smelter who did or did not develop asthma; however, there was an indication of heterogeneity in causation, as judged by "atopy-related" and "non-atopy-related" groups in the asthma population.

Fatty acid pattern outcomes of a nutritional program for overweight and hyperlipidemic Australian men.

There is growing recognition of the value of changing tissue fatty acid patterns in their own right as coronary risk factors. To examine the effects of a conventional nutritional program on plasma triglyceride (TG), cholesterol ester, and phospholipid fatty acid patterns, a group of 20 hyperlipidemic men and a control group (n = 6) of normolipidemic men were followed for 6 months. As an index of change in energy balance in the hyperlipidemic men, body mass index decreased from 26.5 to 24.4 kg m-2 (an 8% decrease) at 6 months. Saturated fat intake fell from 46.7 to 25.3 g/day (a 46% decrease). Dietary polyunsaturated:saturated fat ratio (P:S) rose from 0.38 and to 0.70 (an 84% increase) at the 6-month review. Ethanol intake fell from 18 to 15 g/day (a 17% decrease). Changes in plasma fatty acid (FA) patterns were found in TG, cholesterol ester, and phospholipid fractions at the 6-week to 3-month period, and these changes were maintained at 6 months. Of the factors possibly contributory to plasma FA pattern change in these men, dietary FA intake underwent the greatest percentage shift and therefore probably makes an important contribution to the change. It was of interest that fatty acid patterns in plasma neutral lipids (triglyceride, cholesterol ester, and phospholipid) significantly predicted body mass index and serum total cholesterol, triglyceride, and high-density-lipoprotein cholesterol.

Assessment of delayed-type hypersensitivity in man: a comparison of the "Multitest" and conventional intradermal injection of six antigens.

Recall of delayed type hypersensitivity (DTH) as a test for cell-mediated immune competence was assessed in 254 subjects using the Multitest device which delivers seven skin-test antigens intradermally; 77 subjects were tested concurrently by Multitest and a conventional panel of six antigens. Similar results were obtained with Multitest and the conventional panel (R = 0.65). Reproducibility of Multitest between three observers, who independently assessed the aggregate size of reactions (the reaction score) in 45 subjects, was high (R = 0.89). Twenty-four subjects were tested twice 3 months apart; the correlation for the reaction score was high (R = 0.88), demonstrating the suitability of Multitest for serial studies of immune function. Anergy was infrequent (1%) among 110 healthy male controls but was more frequent (8%) among a group of 101 healthy male homosexuals (P less than 0.05). The response rate to particular test antigens differed for the three Australian groups tested and a previously studied French group. Hence there is a need to establish normal profiles of DTH responsiveness for different geographic areas, as well as among subjects of known age and sex, when assessing cell-mediated immunity by the level of DTH responsiveness to multiple skin test antigens.