Attenuation of immune complex–mediated injury by PPT-A gene deletion and capsaicin-selective sensory denervation. (a) Bronchoalveolar lavage fluid obtained after intravenous injection of chicken ovalbumin and intratracheal instillation of a polyclonal antibody against ovalbumin shows alveolar hemorrhage in WT mice, but not in mice with targeted deletion of the PPT-A gene (PPT-A^–/–). (b) Casein zymogram demonstrates increased bronchoalveolar lavage fluid protease activity in WT compared with PPT-A^–/– and capsaicin-denervated mice. The proteolytic bands visible in the illustration have the electrophoretic mobility profiles of matrilysin and macrophage metalloelastase. Black arrowheads indicate molecular weight markers. (c) Erythrocyte and neutrophil counts in the bronchoalveolar lavage fluid, Evans blue lavage/serum concentration ratios, and TNF-α levels in the bronchoalveolar lavage fluid demonstrate protection against immune complex injury by PPT-A gene deletion and capsaicin denervation (P < 0.0001, except for TNF-α levels where P = 0.01). Cell counts and Evans blue ratios (black bars; n = 18 WT, 11 PPT-A^–/–, and 19 capsaicin) are compared with those of control mice injected intravenously with ovalbumin and intratracheally with normal saline (white bars; n = 8 WT, 2 PPT-A^–/–, and 12 capsaicin). TNF-α levels were measured in fewer mice (n = 10 WT, 7 PPT-A^–/–, and 11 capsaicin). Values are shown as mean ± SE, except for TNF-α levels, which are shown as median and 25th to 75th percentile span.