While depletion of CD4+CD25+ T cells with an anti-CD25 antibody during an early stage of BLM-induced lung disease reduced the levels of inflammatory cells, collagen deposition, TGF-β, and lung fibrosis in mice, Treg depletion during later stages in this model led to a more pronounced infiltration of inflammatory cells and increased fibrosis scores (196). Here, CD4 is linked to pulmonary fibrosis.