Depressed spontaneous cell-mediated cytotoxicity in Crohn's disease.

Cytotoxicity of peripheral blood mononuclear cells of 30 patients with Crohn's disease (CD) and 30 matched controls was assayed by measuring isotope release from 75Se-L-methionine labelled RPMI 4788 human colon cancer cells. Effector populations were studied with and without monocyte depletion after 4 and 24 hr incubations in 10% fetal calf serum or autologous serum or plasma. Cytotoxicity was negligible at 4 hr. Twenty-four hour cytotoxicity was consistently lower in CD patients than in healthy controls, mean values ranging from 13.6 +/- 2.7% (s.e.m.) to 19.5 +/- 3.7% in patients and from 27.2 +/- 4.1% to 33.6 +/- 5.3% in controls. Cytotoxicity of disease controls was not significantly different from that of healthy subjects. Cytotoxicity was reduced by monocyte depletion, was weakly and inversely related to disease activity, was relatively stable for up to 24 months and was not HLA restricted. Cell lysis was attributable to spontaneous cell-mediated cytotoxicity. Antibody-dependent cellular cytotoxicity and antibody-complement-dependent cytotoxicity were not detected.

Respiratory symptoms and lung function in a sample of Vermont dairymen and industrial workers.

This study reviews the respiratory status of a sample of Vermont male dairy farmers, and a comparison group from industry, matched for age, sex and smoking. Survey instruments included a standardized questionnaire and simple pulmonary function tests. In general, past and present smokers had more respiratory symptoms than never-smokers; and farmers, in all smoking categories, reported symptoms with greater frequency than did their counterparts from industry. Forced vital capacity (FVC) tended to be lower among men with a history of smoking but, within each smoking category, dairymen and factory workers had very similar FVCs. Farmers who had never smoked or who were current cigarette users had lower FEV1/FVC (forced expiratory volume at one second/forced vital capacity) ratios than their controls from industry. Sixteen diarymen demonstrated precipitins to either Micropolyspora faeni (13) or Thermoactinomyces vulgaris, (3), but only one reported a constellation of symptoms compatible with farmer's lung disease. The estimated prevalence of antibodies to thermophilic actinomyces in this farm population was approximately 10 per cent. Although sample sizes were limited, dairymen from small farms tended to be older, have more respiratory symptoms, less satisfactory pulmonary function, and more serologic evidence of exposure to farmer's lung antigens than their counterparts from large farms.

Farmer's lung disease in Vermont.

Several Vermont population groups were surveyed for the occurrence of antibodies to thermophilic actinomycetes. Antibodies to M. faeni and T. vulgaris were measured by the precipitin method in all subjects and, in 124 subjects, M. faeni antibodies were also measured by the indirect fluorescent antibody (IFA) technique. There was relatively good correlation between the two techniques (r 0.48, p less than 0.01). Hospital employees, blood donors and patients with chronic bronchitis were generally negative for precipitins to thermophilic actinomycetes. Of the 258 Vermont dairy farmers surveyed, 14 (5.4%) had precipitins to M. faeni, 3 (1.2%) had precipitins to T. vulgaris but only 1 farmer with antibodies to M. faeni had symptoms of possible farmer's lung disease (FLD). On the other hand, 10 (4.1%) precipitin-negative farmers had symptoms possibly consistent with FLD. The IFA test did not correlate any better with symptoms. 7 (5.6%) patients with pulmonary fibrosis had precipitins to M. faeni 5 of these were diagnosed as having FLD. 18 (14.4%) had precipitins to T. vulgaris and only 3 of these patients were felt to have hypersensitivity pneumonitis. Patients with pulmonary fibrosis and FLD hat IFA titers of greater than or equal to 1/128, but so did asymptomatic farmers.

Sources of variance in the measurement of intrapulmonary killing of bacteria.

Sources of variability are described for a method used for the quantitative measurement of pulmonary resistance to inhaled bacteria in individual animals. Factors contributing significantly to variability include aerosol exposure chamber design, bacterial species used for aerosol challenge, location of animals in the chamber, and individual intrapulmonary bacterial killing rates. Laboratory error accounted for a small portion of the variance. The data demonstrate that with appropriate modifications in protocol, statistical design and analysis experiments can be performed with increased accuracy, thereby reducing the number of animals needed for each experiment.

Amino acid residues of serum and CSF protein in multiple sclerosis. Clinical application of statistical discriminant analysis.

Statistical discriminant analysis of the amino acid compostion of serum and cerebrospinal fluid (CSF) proteins provides an objective method for distinguishing between normal controls and patients with multiple sclerosis (MS). This method also results in a high degree of specificity in separating MS patients from those with other diseases of the nervous system. The CSF protein serine residue is highly correlated with the CSF IgG and holds promise for a more sensitive diagnostic test for MS than the currently used CSF IgG. Finally, the serum/CSF protein serine ratio seems to correlate best with clinically determined degree of activity for the disease, the most active cases having the lowest ratio. These results suggest that investigation of the amino acid composition of serum and CSF protein in multiple sclerosis and, possibly, in other diseases might lead to the development of clinically useful tests of diagnosis and degree of activity of MS.