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

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.