 The effects of infliximab on the Be-stimulated immune response will be assessed by comparing the following markers before and after infliximab therapy: 1. BeLPT from blood and lavage cells BAL; 2. Be-stimulated cytokine production from BAL cells including TNF-a, IFN-γ, and IL-2; 3. Cell-specific apoptosis. The assay will include an unstimulated control, 100 mM BeSO4, 100 mM Al2SO43 metal-salt control, PHA - lymphocyte proliferation control, infliximab control, infliximab BeSO4, infliximab Al2SO43. At days 4, 5, and 6 after Be exposure, the wells are pulsed with the DNA-specific precursor, 3H-TdR, incubated for four hours, harvested on glass fiber filters, and liquid scintillation methods are used for counting. Results are reported as a stimulation index, which is a ratio of the counts per minute of the treatment group to the counts per minute of the unstimulated group. To determine the effect of infliximab on cytokine production, CBD BAL and CBD PBMC will be stimulated with Be for 24 hours. ELISA will be used to determine TNF-α, IFN-γ, and IL-2 supernatant levels. After 24 hours of beryllium exposure, we will harvest supernatants and perform ELISA testing for TNF-α, IFN-γ, and IL-2. In order to determine if infliximab causes an increase in lymphocyte or macrophage apoptosis, CBD BAL cells will be cultured for 24 hours with Be. Cells will be double stained for CD4 Th1 and CD71 macrophages versus intracellular activated caspase-3, caspase-8 and caspase-9. These in vitro studies will be used to assess the potential biologic function of infliximab on immune mediated diseases using a disease model with known antigen, CBD. 