In an experimental toluene diisocyanate (TDI)-induced animal model of severe asthma, MSC transfer significantly reduced the TDI-induced increase in the inflammatory index as well as numbers of eosinophils and neutrophils in BALF; the MSC transfer also significantly reduced the number of goblet cells, collagen deposition and immune staining for smooth muscle actin and proliferating cell nuclear antigen with concomitant normalization of the airway response to MCh. The gene discussed is PCNA; the disease is asthma.