Sequential immunological studies in an asbestos-exposed population. II. Factors affecting lymphocyte function

Our plain-English summary of Sequential immunological studies in an asbestos-exposed population. II. Factors affecting lymphocyte function, by M.J. Campbell, M.M. Wagner, M.P. Scott, et al (Clinical and Experimental Immunology, 1980).

The study

• Authors: M.J. Campbell, M.M. Wagner, M.P. Scott, D.G. Brown
• Journal: Clinical and Experimental Immunology
• Published: 1980;39(1):176-82
• Cited by: 32 articles, as counted by NIH iCite
• Read it: PubMed · Free full text

Abstract

As part of an immunological study being carried out on a population exposed to asbestos the effect of two mitogens, phytohaemagglutinin (PHA) and pokeweed mitogen (PWM) on lymphocyte transformation has been assessed on three separate occasions for each mitogen. Both mitogens were assayed using foetal calf (FCS) or autologous serum (AS). Those men with pulmonary fibrosis (as measured by the presence of small opacities on X-ray) had a decrease (P less than 0.05) using PHA (FCS) when compared with those men with normal chest X-rays. Allowance has had to be made for the significant decline with age for both PHA (FCS and AS) transformation. There is a significant increase in PHA (FCS) and PWM (FCS) in ex-smokers and a further increase in smokers. These trends were consistent (at a lower level of significance) from survey to survey. There was no interaction between X-ray category and smoking. The lymphocyte antibody dependent cytotoxic test was measured on four occasions; the only observable effect was a non-significant increase in relation to smoking.

In plain English

This longitudinal study followed 138 men from an asbestos-exposed working population, seen each May and November; the article reported five successive surveys, though not every man attended all five. The authors measured how strongly the men's blood lymphocytes (white blood cells) responded to two stimulants, PHA and PWM, and ran a cell-killing test (LADC). The PHA response declined with age. Smokers generally had higher responses than non-smokers, with ex-smokers usually in between. This was statistically significant only for PHA and PWM tested in foetal calf serum. After allowing for age, and leaving out ex-smokers and men with pleural changes, men with small opacities on chest X-ray (a sign of lung fibrosis) had a lower PHA response in foetal calf serum than men with normal X-rays (P less than 0.05). The authors reported no interaction between X-ray category and smoking. The cell-killing test gave negative findings. One man who later developed carcinoma of the bronchus had the lowest PHA results about two years before his death. The authors concluded that lymphocytes of men with fibrosis could still respond if the man smoked.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Longitudinal study with repeated laboratory testing of the same men over five surveys
• Who was studied: 138 men, all members of an asbestos-exposed working population, seen in May and November of each year at the same time of day. The article reports five successive surveys, but not every man attended all of them: one man attended only the May and November 1976 surveys. The article says how the men were selected is described in an earlier paper.
• Exposure: Asbestos exposure at work. This article does not give fiber types, products, jobs or doses. Men were grouped by chest X-ray (normal, small opacity, pleural change) and by smoking status.
• Main results:
  • In all men, the maximum PHA response fell with age, by about 850 per year when tested in foetal calf serum (FCS) and about half as fast when tested in the men's own (autologous) serum (AS).
  • Responses were generally higher in smokers than in non-smokers, with ex-smokers usually in between. This reached statistical significance only for PHA and PWM tested in FCS.
  • Men with small opacities on chest X-ray had a lower PHA response in FCS than men with normal chest X-rays (P less than 0.05).
  • The age-adjusted test that found the small opacity effect (and the smoking effect) significant left out the pleural change group and the ex-smokers.
  • The small-opacity group was on average about six years older than the normal and pleural thickening groups, so the X-ray results were adjusted for age.
  • After allowing for age, average PHA FCS uptake among non-smokers was 52.6 (standard error 6.1) thousand d/min for those with small opacities and 69.8 (5.6) for those with normal X-rays.
  • The authors reported no interaction between X-ray category and smoking.
  • Five men with mesothelioma had PHA measured. Their average responses, 37 thousand (FCS) and 47 thousand (AS) d/min, were lower than those of men without mesothelioma. All but one of the five fell within the normal range.
  • For PWM, all men with mesothelioma were within the normal range.
  • One man later developed carcinoma of the bronchus and died. His PHA results were the lowest recorded in both surveys he attended in 1976, two years before his death.
  • In two men with an acute pleural reaction, PHA FCS results were much lower at the second survey.
  • The lymphocyte antibody dependent cytotoxicity test gave negative findings.
• The authors' conclusion: The authors said their results agree with earlier work linking fibrosis to defective T cell function. They added that their work shows lymphocytes can still respond if the man with fibrosis is a smoker.
• Limitations the authors state:
  • The cytotoxicity test and SC50 results were not very repeatable.
  • The stimulant concentrations at which maximum responses occurred were not very repeatable.
  • A different batch of PWM was used for each survey.
  • Because several measurements depend strongly on age, the authors said the X-ray results must be interpreted with care.
  • The negative cytotoxicity findings may reflect techniques that were not sensitive enough.

Topics

Medical terms in this study, explained in our Lexicon: Pulmonary Fibrosis, Chest X-Ray.

Related studies

• Sequential immunological studies on an asbestos-exposed population. I. Factors affecting peripheral blood leucocytes and T lymphocytes — M.M. Wagner, M.J. Campbell, et al. (1979)
• Effects of chrysotile asbestos on mononuclear cells in vitro — S. Kagamimori, M.P. Scott, et al. (1980)
• In vitro depression of human lymphocyte mitogen response (phytohaemagglutinin) by asbestos fibres — R.G. Barbers, W.W. Shih, et al. (1982)
• Aryl hydrocarbon hydroxylase induction in mitogen-stimulated lymphocytes by benzanthracene or cigarette tars adsorbed to asbestos fibers — T.L. McLemore, W.T. Jenkins, et al. (1979)
• Low calretinin expression and high neutrophil-to-lymphocyte ratio are poor prognostic factors in patients with malignant mesothelioma undergoing extrapleural pneumonectomy — S.C. Kao, S. Klebe, et al. (2011)
• Lymphocyte responses to phytohaemagglutinin in patients with asbestosis and pleural mesothelioma — P.L. Haslam, A. Lukoszek, et al. (1978)

Browse more research in Clinical and Experimental Immunology, or return to medical research.