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

Background: 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. Objective: To test whether ASST+ CU patients can benefit from repeated low-dose intramuscular injections of AWB. Methods: We characterized CU severity and duration, anti-Fc(epsilon)RI and anti-IgE expression, use of antihistamines, and quality of life in 56 CU patients (ASST+: 35, ASST-: 21) and assessed the therapeutic effects of 8 weekly AWB injections in a randomized, placebo-controlled, single-blind, parallel-group trial. Results: Numbers, size, intensity, and/or duration of CU symptoms, quality of life, as well as expression of anti-Fc(epsilon)RI or anti-IgE were similar inASST+ and ASST-CU patients. However, CU in ASST+ patients was of longer duration and required markedly more antihistaminic medication. Interestingly, ASST+ patients, but not ASST- patients, showed significantly (1) reduced CU activity, (2) decreased use of antihistamines, and (3) improved quality of life after AWB treatment. Placebo treatment was ineffective in both groups, but differences of AWB and placebo treatment responses did not achieve statistical significance in either group, most likely due to the limited number of patients treated. Conclusion: Our findings suggest that ASST+ CU is clinically different from other CU subforms and that ASST+ CU patients can benefit from AWB therapy.