Management of immune‐mediated thrombocytopenia

Low circulating platelet numbers can be caused by platelet underproduction, sequestration, hemodilution, consumption, or destruction. This chapter explores the problem of immune‐mediated thrombocytopenia, including autoimmune conditions, secondary immune conditions, and alloimmune conditions. Platelets are usually quantitated during a complete blood cell count with a particle counter. Various monoclonal antibody‐based assays can be used to detect plate let antibodies. The principal mechanism for immune‐mediated thrombocytopenia is antibody‐mediated destruction of platelets. Drugs can produce several immune‐mediated thrombocytopenic disorders. Heparin‐induced thrombocytopenia is a clinicopathologic syndrome, that is, the diagnosis is made most reliably on both clinical and serologic grounds. Alloantigens are genetically determined molecular variations of proteins or carbohydrates that can be recognized immunologically by some healthy persons. Platelet transfusion refractoriness, which is failure to achieve the expected platelet increment after two consecutive platelet transfusion episodes, has several explanations.