A simplified human whole blood assay for measurement of dust mite-specific gamma interferon production in vitro

A simplified microassay for the measurement of spontaneous and dust mite antigen-induced gamma interferon (IFN) production in vitro using unseparated human blood has been developed. Gamma IFN in 72-hour culture supernatants was measured using a solid phase radioimmunoassay. Maximum production in allergic patients occurred between 25 and 50 micrograms/mL of mite antigen. Both spontaneous and antigen-stimulated levels were highest in the group of mite-allergic patients compared with nonallergic patients or normal controls. Gamma IFN production was lower in a group of mite-allergic patients on immunotherapy compared with the nonimmunotherapy group. Treatment with even small doses of oral corticosteroids completely obliterated both spontaneous and stimulated gamma IFN production. These results indicate that this whole blood assay coupled with a lymphokine radioimmunoassay is a convenient, rapid, and sensitive method for measuring cell-mediated immunity to allergens and responses to IT or drug treatment that can be easily adapted to testing large number of patients.