Autologous whole blood injections to patients with chronic urticaria and a positive autologous serum skin test: a placebo-controlled trial.

<i>Background:</i> Patients with chronic urticaria (CU) frequently exhibit positive skin test reactions to autologous serum (ASST). Therapies aimed at inducing tolerance to circulating histamine-releasing factors in ASST+ CU patients, e.g. by treatment with autologous whole blood (AWB), have not yet been tested. <i>Objective:</i> To test whether ASST+ CU patients can benefit from repeated low-dose intramuscular injections of AWB. <i>Methods:</i> We characterized CU severity and duration, anti-Fc<sub>Ε</sub>RI and anti-IgE expression, use of antihistamines, and quality of life in 56 CU patients (ASST+: 35, ASST–: 21) and assessed the t…