To investigate this hypothesis, we determined whether peripheral blood CD28null T cells (particularly CD8+) and NKT-like cells from COPD patients express reduced levels of HDAC2 and/or increased HAT and whether loss of HDAC2 (and/or increased HAT) is associated with increased expression of cytotoxic mediators or pro-inflammatory cytokines. The gene discussed is TMPRSS11D; the disease is chronic obstructive pulmonary disease.