Immune (or idiopathic) thrombocytopenic purpura (ITP) is commonly encountered by the practicing hematologist. Clinical management decisions have traditionally been guided by individual training and past experience. Input from the literature has been more from observational reports of case series than from scientific results of hypothesis-driven research. Practice guidelines and several surveys of clinical hematology practice have highlighted important questions in the field, and in the past 5 to 10 years both clinical and laboratory investigations have produced valuable new information, especially about options in refractory disease. Unfortunately, the last comprehensive guideline have been published a decade ago.
Generally, the standard of practice for patients who cannot maintain an adequate platelet count on tapering steroids is to undergo splenectomy. In 60% to 70% of patients this restores a normal platelet count for at least 5 to 10 years. It allows those patients who respond to this procedure to avoid both the risks of low platelet counts and the toxicity of daily steroids. However, although both the site of platelet destruction and the response to intravenous immunoglobulin (IVIG) have been suggested to predict response to splenectomy, there is no universally acknowledged way to predict which patients will respond. SOme patients do not respond and otehrs relapse, sometimes due to a regrowth of accessory spleen tissue. WHen clearly identifeid, an accessory spleen should be removed, if spenectomy reviously resulted in a remission. However, the decision to repeat what is now an open splenectomy is fraught with uncertainty. Patients are often reluctant to be exposed to the inherent risks of surgery and the small but significant risk of overwhelming sepsis after splenectomy without a guarantee of success. It is acceptable to proceed with other therapies at that point. Anti-RhD is one such option.
IV anti-D is a safe and effective treatment in approximately two thirds of Rh+, nonsplenectomized adults with ITP and can be used as a steroid-sparing agent. There is no reason to believe that anti-D is curative or that it affected the natural history of the ITP in these adults. Rather, it appeared to give patients time to improve on their own.
George JN, Woolf SH, Raskob GE, et al. Idiopathic Thrombocytopenic Purpura: a practice guideline developed by explicit methods for the American Society of Hematology. Blood. 1996;88:3–40.
Cines DB, Bussel JB. How I treat idiopathic thrombocytopenic purpura (ITP). Blood. 2004;106:2244–2251.
Cines DB, Blanchette VS. Immune thrombocytopenic purpura. N Engl J Med. 2002;346:995–1008
Cooper N, Woloski BMR, Fodero EM, Novoa M, Leber M, Bussel JB. Does treatment with intermittent infusions of IV anti-D allow a proportion of adults with recently diagnosed immune thrombocytopenic purpura (ITP) to avoid splenectomy? Blood. 2002;99: 1922