Subsequent studies (2-DE, Western blot, immunohistochemistry, morphometry) on COPD, a disease with a different type of parenchymal lung damage, detected no or very minimal changes in the expression of Hbα and Hbβ compared to control with both Hb forms being localized mainly in the alveolar epithelium of COPD lungs. The gene discussed is GSTM1; the disease is chronic obstructive pulmonary disease.