For both COPD groups and controls, a significantly lower percentage of CD28nullCD8+ T and NKT-like cells expressing Hsp90 was found, compared with CD28+ T and NKT-like cells (data for T cell and NKT-like cell subsets from COPD group shown in Fig. 1) (data for controls not shown). The gene discussed is CD28; the disease is chronic obstructive pulmonary disease.