NOX 5 is expressed in platelets from patients with chronic granulomatous disease

X-CGD is a very rare disease, which is associated with hereditary deficiency of Nox2, the enzyme involved in the cellular formation of reactive oxidant species (ROS) and eventually bacteria killing. In X-CGD patients Nox2 in down-regulated not only in leucocytes but also in platelets but ROS formation is not fully suppressed suggesting the existence of other ROS platelet source. However, the enzymatic pathway responsible for such residual ROS formation has not been clarified. In addition to Nox2, Nox family encompasses other isoforms such as Nox1, Nox3, Nox4 and Nox5, which contribute to ROS formation in different cell lines. There is still uncertainty as to whether platelets express other Nox isoforms and their role on ROS formation. In this study we provide the first evidence that platelets from X-CGD patient express Nox5, which is likely to serve for ROS and isoprostane formation. The expression of Nox5 by platelets from X-CGD suggests Nox5 as reservoir enzyme for ROS formation.