Is delayed pressure urticaria associated with increased systemic release of sCD40L?

Elevated levels of soluble CD40 Ligand (sCD40L) were found in serum but not in plasma of patients with chronic spontaneous urticaria (CU). What is important is that sCD40L has proinflammatory properties, and its elevated plasma level may indicate increased risk of cardiovascular events. These observations should stimulate further evaluation of sCD40L in different forms of urticaria. In the present study, sCD40L plasma level was investigated in delayed pressure urticaria (DPU). As platelets are predominant and variable sources of sCD40L, we investigated sCD40L concentration in platelet-poor plasma (PPP), which seems the best way to minimize the potential contribution of these cells to the ligand level. Plasma sCD40L concentration was significantly increased in the DPU group compared to the healthy controls. It seems that DPU is associated with increased systemic release of sCD40L, which is believed to derive predominantly from activated platelets. The present study as well as the earlier contributions suggest that distinct cells activity, including platelets, may be identified in different types of urticaria.