Platelet function and its clinical significance in the myelodysplastic syndromes

Abstract

The current study was aimed at investigating platelet function in MDS and its clinical significance. There were 23 patients with untreated MDS at presentation, including refractory anemia (RA), RA with ringed sideroblasts, RA and excess blasts and chronic myelomonocytic leukemia RAEBt. The mean platelet count was 167.9 x 109/L. Patients with a platelet count less than 70 x 109/l were excluded. The mean bleeding time (BT) was 2.7 min. Only four MDS patients had BT longer than the normal 1-4 min range. Platelet aggregation (PA) was studied with epinephrine (Epi), ADP, arachidonic acid (AA), ristocetin and collagen. Overall, 16 (70%) patients had PA abnormality, 65% had impaired Epi-induced PA, 57% demonstrated reduced ADP-induced PA. AA, ristocetin and collagen was decreased PA in 48, 22 and 17%, respectively. Five patients (22%) demonstrated spontaneous PA. Only seven patients (30%) were found to have normal PA with all five inducers. Six (26%) patients had spontaneous mild bleeding and all six bleeding MDS patients demonstrated at least one abnormal platelet function. The only bleeding patient with all five PA tests normal demonstrated prolonged BT. In the present study of 23 newly diagnosed MDS patients, PA abnormalities were relatively common, the BTs were usually normal, and bleedings were relatively uncommon and mild at platelet count between 70 and 397 x 109/l.

Platelet Proteome Analysis Reveals Integrin-dependent Aggregation Defects in Patients with Myelodysplastic Syndromes

“…Recently, a detailed study of the clinical features of 2900 patients with MDS reported that even among patients with platelet counts of Ͼ50,000/l, 19% had signs of bleeding at the time of diagnosis (4). Taken together, these data suggest a platelet count-independent functional platelet defect in MDS, which is supported by sporadic reports indicating insufficient platelet aggregation (3,(5)(6)(7)(8). The existence of such a functional platelet defect may very well contribute to the high rate of hemorrhagic complications observed in patients with MDS.…”

Serum proteome profiling detects myelodysplastic syndromes and identifies CXC chemokine ligands 4 and 7 as markers for advanced disease

“…Disturbed maturation of megakaryocytes and ␣-granule defects in platelets are frequent features of MDS (38)(39)(40) and might be reflected by either low CXCL4 expression or a release deficiency in MDS platelets. Our Western blot analyses of platelet lysates showed CXCL4 protein expression in platelet lysates from 9 of 10 non-MDS cytopenia patients but a lack in 7 of 10 MDS platelet lysates.…”

Defective Platelet Aggregation in Myelodysplastic Syndromes

“…In 2004, Zeidman et al [14] investigated the clinical impact of platelet function in MDS. The study enrolled 23 MDS patients.…”

“…No major hemorrhage was observed. However, minor bleeding events occurred in 6 patients; all of them had defective platelet function as tested by aggregation in response to 1 or more agonists [14]. …”