[Acquired platelet storage pool deficiency in rheumatoid arthritis]

A 64-year-old woman with a 15-years-history of rheumatoid arthritis developed generalized hemorrhagic diathesis. Routine coagulation tests revealed a slightly diminished platelet count only. Platelet aggregation in vitro induced by ADP, collagen, thrombin, arachidonic acid and ristocetin were reduced. The patient's plasma aggregating activity was significantly diminished which was due to a decrease of the intraplatelet nucleotide pool. The number of mepacrine labelled bodies as well as dense bodies in electron microscopy was below the normal values as well. Moreover, the intraplatelet concentration of cyclooxygenase--malonylodialdehyde (MDA) and lipoxygenase pathway products were lowered. Total platelet immunoglobulin G and M contents were significantly increased. The platelet survival time (in vitro aspirin method) was slightly shortened. Finally the diagnosis of delta-acquired platelet storage pool deficiency (delta-SPD) was established and possibilities of treatment were discussed.