Histological evaluation of the lungs of Ifnγ−/− mice, at distress, revealed a similar pneumonitis to that in C57BL/6J mice (p = 0.6; Fig. 6C) but that the Ifnγ−/− mice developed more fibrosis than levels detected in C57BL/6J mice, at distress, by both histological examination (Fig. 6D,E; p = 0.0045) and by expression of collagen 3α1 (p = 0.02), as shown in Fig. 6F. The gene discussed is IFNG; the disease is pneumonitis.