Using quantitative RT-PCR, we next detected a significant increase in the expression of furin in whole lung tissue of PR8-infected C57BL/6 mice, but not in whole lung tissue of C57BL/6 mice administered phosphate-buffered saline (PBS), on day 6 after infection [P = 0.0034, Fig. 1A (relative data), SI Appendix, Fig. S1 (absolute data)], indicating that inflammation indeed induces furin expression. The gene discussed is FURIN; the disease is infection.