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Seasonal variations in cyclic AMP production by peripheral blood mononuclear cells in allergic asthmatics
Author(s) -
Y Hoekstra,
Ejm Weersink,
Dirkje S. Postma,
Hf Kauffman
Publication year - 1998
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1046/j.1365-2222.1998.00208.x
Subject(s) - adenylyl cyclase , medicine , peripheral blood mononuclear cell , asthma , endocrinology , immunology , cytokine , bronchial hyperresponsiveness , receptor , respiratory disease , biology , lung , in vitro , biochemistry
Background Dysfunction of the β‐adrenoceptor (βAR)/adenylyl cyclase (AC) system can impair the response of different cell types, including lymphocytes. In asthma, impairment of this system as well as changes in cytokine production by lymphocytes have been described. Because the severity of asthma can change over the year, a circannual pattern of the βAR/AC system activity may also exist. Objectives We set out to examine the activity of this βAR/AC signal transduction system in peripheral blood mononuclear cells (PBMCs) of allergic asthmatics to asses whether differences existed between seasons. We investigated whether changes were associated with asthma severity and circannual changes in serum cortisol levels. Methods During 19 months, 41 allergic asthmatics (mean age 28 years) with nocturnal airway obstruction were enrolled in the study. AC activity was measured by cyclic AMP production. Resting, stimulated and potentiated AC activities and their relationships with clinical parameters, seasonal influences and serum cortisol levels were assessed. Results The AC activity in resting, stimulated and potentiated cells varied during the year. AC activity was relatively low in the periods June–August and September–November, and higher in December–February and March–May. Receptor‐mediated and potentiated responses expressed as percentage of the resting response were equivalent throughout the year. Serum cortisol levels were positively related to AC activity. No relationships were found between clinical parameters and AC activity or serum cortisol levels. Conclusions These results indicate that AC activity in PBMCs of allergic asthmatics shows a seasonal variation. However, seasonal differences in AC activity seems to be unrelated with clinical parameters. Other factors such as serum cortisol levels may have a modulating influence on AC activity. Future studies of AC systems in blood cells of asthmatic patients need to take into account these seasonal influences.