Prostaglandin D2 and histamine release in cold urticaria

Area of Science:

• Immunology
• Dermatology
• Pharmacology

Background:

• Cold urticaria is a physical urticaria triggered by cold exposure.
• Mast cell mediators, such as histamine, are implicated in its pathogenesis.
• The role of prostaglandin D2 (PGD2) in cold urticaria is not fully understood.

Purpose of the Study:

• To measure concentrations of prostaglandin (PG) D2 and histamine in blood from cold-challenged forearm skin in patients with cold urticaria.
• To investigate the relationship between mediator release and clinical response in cold urticaria.

Main Methods:

• Blood samples were collected from the forearm venous drainage of patients with cold urticaria following cold challenge.
• Concentrations of histamine and PGD2 were measured using validated assays.
• Clinical whealing response was assessed and timed relative to mediator release.

Main Results:

• Both histamine and PGD2 concentrations significantly increased in the blood of patients who developed a whealing response to cold challenge.
• Peak plasma histamine levels rose from a mean resting value of 0.24 ng/ml to 16.9-96.6 ng/ml.
• Peak plasma PGD2 levels ranged from 166 to 279 pg/ml, with similar time courses to histamine release.
• PGD2 production was associated with mast cell degranulation, but the amount relative to histamine was low.

Conclusions:

• Prostaglandin D2 is produced during mast cell degranulation in cold urticaria patients.
• Despite its inflammatory potential, PGD2 likely has a minor direct role in the pathophysiology of cold urticaria.
• PGD2 may potentiate the effects of other mediators in cold urticaria.