Abstract
In 139 workers exposed diatomaceous earth and 100 normal subjects we examined the levels of serum inter-α-trypsin inhibitor (IαI) by single radial immunodiffusion methods.
1) In 100 normal controls the levels of serum IαI seemed to increase by age in both sexes and was a little higher in the female group than in the male.
2) In 139 diatomaceous exposed workers, the more extended the exposure time, the lower the mean levels of serum IαI. Such a trend was much more obvious in the pneumoconiosis group diagnosed by chest x-ray film. Some workers, however, showed a higher level of serum IαI than normal controls.
3) The values of EEV10%, V50/Ht and V25/Ht decreased and correlated well with times of exposure to diatomaceous earth (p<0.01) and that of FEV also decreased and correlated well with the pack years smoked in diatomaceous exposed subjects (p<0.01). There was, however, no definite correlation between the above lung function parameters and the levels of serum IαI.
From our data and allied literature we discussed the possibility of significant biological function of serum IαI as a possible protector of broncho-alveolar tissue from proteolysis by excess amounts of endogenous and exogenous proteases.
