Aquagenic pruritus (AP) is a symptom typical for polycythemia vera, but very little is known about its exact frequency, characteristics, influence on quality of life, and proper treatment. Therefore, we investigated these aspects in a large cohort of German patients with polycythemia vera using a patient directed questionnaire. Our analysis revealed that 301 of 441 analyzed patients suffered from AP. In 64.8%, AP occurred on average 2.9 years prior to diagnosis of polycythemia vera. Only in 15.4% did this lead to a hematological investigation. AP occurs primarily on the trunk and proximal parts of the extremities. Most patients complain about itching (71.8%), the remainder about tickling, stinging, or burning sensations. Forty‐four patients (14.6%) classified the pruritus as “unbearable.” Patients with AP reported reduced global health status and higher fatigue, pain, and dyspnea. Only 24% of patients received pruritus specific treatment for pruritus consisting mostly of histamine antagonists, which ameliorated symptoms in about half of the patients. In 5.6% of patients, polycythemia vera directed therapy (phlebotomy/cytoreduction) resolved the symptoms. In summary, AP is a serious symptom in patients with polycythemia vera, which until recently was difficult to treat. The advent of the novel JAK2 inhibitors, however, may open new ways for therapy. Am. J. Hematol. 88:665–669, 2013. © 2013 Wiley Periodicals, Inc.

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4218 Primary thrombocythemia (PT) is a myeloproliferative disease with a high incidence of thrombotic complications. First-line therapy is the inhibition of platelet aggregation with aspirin (via COX-1 inhibition) for the prevention of thromboembolic complications. However, this does not account for the potential for COX-2 expression in newly synthesized platelets. The purpose of the present study was 1) to determine whether aspirin reduces the thrombotic potential of PT patients who did not undergo cytoreductive therapy to the levels of those achieved in healthy volunteers (HV), and 2) to determine whether the presence of the JAK2V617F mutation is responsible for the elevated thrombotic potential in PT patients. We determined the thrombotic potential of a cohort of 16 PT patients and compared these values to those of 10 healthy volunteers all treated with 100mg aspirin QD. Thrombotic potential was determined using a custom built Real Time Thrombosis Profiler (RTTP). Whole blood anticoagulated with a Factor Xa inhibitor (to preserve physiological Ca++ concentration) with Rhodamine 6G-labeled platelets was perfused over a fibrillar collagen surface at shear rates approximating those in veins (100s-1), arteries (600 s-1) and moderately stenosed arteries (1600s-1). The deposition of fluorescently labeled platelets on the collagen surface was monitored in real time by fluorescence microscopy in the RTTP. Endpoint thrombosis (size of thrombi at t=300sec expressed as Mean Fluorescent Intensity/Area of coverage) and rate of thrombus growth (initial rate of platelet deposition) were recorded for each individual as measures of thrombotic potential and data are expressed as mean ± SEM (statistics performed using GraphPad Prism v4.03 using unpaired, 2-tailed Students t-test). Despite aspirin therapy, PT patients were characterized by significant increases in thrombotic potential at venous and arterial shear rates (Table 1) with a greater than 2-fold increase in the rate of platelet deposition. Interestingly only the size of thrombi formed but not the rate of formation was elevated in PT patients at moderately stenosed shear, likely a reflection of the increasing contribution of shear and decreasing dependence on absolute platelet count and other individual cellular factors in whole blood. The Disclosures: No relevant conflicts of interest to declare.

. (2010) V gamma 9V delta 2 T lymphocytes efficiently recognize and kill zoledronate-sensitized, imatinib-sensitive, and imatinib-resistant chronic myelogenous leukemia cells.