Apoptosis of Peripheral Blood Lymphocytes in Severe Steroid−Dependent Bronchial Asthma

Background. The pathomechanism of resistance to corticosteroids is complex. Great significance is attributed in its etiology to the increased activity of cells involved in the late phase of the asthmatic reaction producing proinflammatory mediators such as cytokines and transcription factors. Apoptosis plays an important role in bronchial asthma as it affects the survival of the cells participating in the allergic inflammation of the airways. Objectives. The aim was to evaluate the apoptosis of peripheral blood mononuclear cells (lymphocytes) in corticosteroid-resistant (CR) and corticosteroid-sensitive (CS) asthmatics and in healthy persons. Material and Methods. Forty-four subjects were studied: 14 CR asthmatics, 14 CS asthmatics, and 16 healthy volunteers. The diagnosis of CR asthma was based on the oral prednisolone test according to Carmichael and the cutaneous vasoconstrictor response test according to McKeinzie and Staughton. Apoptosis was evaluated using a Becton Dickinson FACScan flow cytometer. Peripheral blood lymphocytes were isolated using Gradisol L. The remaining research procedures regarding the evaluation of necrosis, apoptosis, and late apoptosis were conducted according to the instructions of the producer (Becton Dickinson). Results. No statistically significant differences were detected in the percentages of lymphocytes in the apoptotic and late apoptotic stages in the group of CR and CS patients compared with the control group or between the groups of patients (p > 0.05). Similarly, no statistically significant differences were found in lymphocytes demonstrating symptoms of necrosis. Conclusions. This study found no inhibition of apoptosis of peripheral blood lymphocytes in corticosteroid-dependent asthmatics (both CR and CS) compared with healthy subjects. This demonstrates the complicated character of the pathomechanism of CR asthma, where lymphocytic apoptosis may be only one of the factors affecting the dynamics of the disease. These results indicate the need to extend research on apoptosis in these groups of asthmatics to include subpopulations of Th-2 and Th-1 lymphocytes with evaluation of the concentrations of transcription factors.