As shown in Fig. 6a, a large number of macrophages infiltrated and colocalized with GPNMB in the lungs of mice 7 days and 56 days after silica instillation, and macrophage depletion decreased the GPNMB level, thus suggesting that macrophages increased in quantity and synthesized and secreted GPNMB during the progression of PF. The gene discussed is GPNMB; the disease is pemphigus foliaceus.