Differential scanning calorimetry (DSC) has been applied for studies of blood serum from patients sick with chronic obstructive
pulmonary disease (COPD). The denaturation of serum proceeds as endothermic process over the temperature range 45–85 °C. Distinct
changes in the shape of DSC curves have been observed for serum from patients with severe stage of COPD (treated with inhaled
corticosteroids) relative to serum from healthy individuals. The first moment of the thermal transition with respect to the
temperature axis shifts from the normal value of 63.9 ± 0.3 to 65.3 ± 0.7 °C and to 67.6 ± 1.6 °C for early and advanced stages
of disease, respectively. The results of our studies suggest age dependence of blood serum denaturation transition.