Technical study of the leucocyte migration inhibition test in agarose. Application to PPD and to hepatitis B antigen.

A modification of the leucocyte migration inhibition test, in which cells migrate in an agarose layer, was proposed by Clausen (1971). In the present study, this method was applied to PPD and hepatitis B antigen (HBAg), and its advantages were reassessed. From a technical standpoint, the migration in a monolayer facilitated a study of the morphology of the migrating cells. The proportion of the different kinds of migrating leucocytes was calculated and expressed as a function of the distance of migration. On the whole, 92% of the migrating leucocytes were polymorphonuclears and 8% lymphomonocytes. Three to 10% of the incubated cells were shown to migrate in the agarose layer. The surface area of the controls (migration without inhibition) was sufficiently constant and large (on the average 13 mm) to allow a clear assessment of inhibition when antigen was added. In addition, the small requirement for antigen facilitated the use of this test in experimentation with purified HBAg. Application of the technique to clinical problems revealed that, with PPD as antigen, a highly significant inhibition was obtained in PPD skin test-positive normal individuals (0·0025<<0·005). But this inhibition was not significant (0·05<<0·1) in PPD skin test-positive patients during the course of acute hepatitis B. With HBAg as antigen, a significant inhibition was obtained in individuals having recovered from acute hepatitis B. Such an inhibition was not demonstrable in individuals without a history of hepatitis, nor in patients during the course of the disease. These results demonstrate the suitability of the leucocyte migration inhibition test in agarose for routine detection of cell-mediated immunity in man. They further suggest the development of cell-mediated immunity specific for HBAg after recovery from acute hepatitis B and impairment of this type of immune response to PPD during the acute phase of hepatitis.