Beta adrenergic receptor binding on polymorphonuclear leukocytes in atopic dermatitis.

Area of Science:

• Immunology
• Dermatology
• Pharmacology

Background:

• Atopic dermatitis is associated with potential beta-adrenergic receptor dysfunction.
• Diminished cyclic AMP generation in atopic dermatitis patients suggests a generalized defect.
• Previous studies indicated impaired responses to isoproterenol and PGE1.

Purpose of the Study:

• To directly measure beta-adrenergic receptor binding in atopic dermatitis patients.
• To investigate the nature of the abnormality in beta-adrenergic receptor function.
• To determine if receptor number or affinity is altered in atopic dermatitis.

Main Methods:

• Beta-adrenergic receptor binding was assessed on polymorphonuclear leukocyte membranes.
• The radiolabeled antagonist (-) [3H]dihydroalprenolol (DHA) was used.
• Binding assays were performed on 6 mild and 9 moderate-to-severe atopic dermatitis patients and 8 controls.

Main Results:

• No significant differences in the total number of beta-adrenergic receptors per polymorphonuclear leukocyte (PMN) were observed between controls, mild, and severe atopic dermatitis groups.
• No significant differences in receptor affinity were found among the study groups.
• DHA binding assays revealed normal receptor characteristics in atopic dermatitis.

Conclusions:

• Beta-adrenergic receptor binding is normal in patients with atopic dermatitis.
• The observed reduction in cyclic AMP generation is likely caused by a defect distal to the beta-adrenergic receptor.
• This suggests the abnormality lies in the signaling pathway beyond the receptor itself.