Specific binding of paraprotein to platelet receptors as a cause of platelet dysfunction in monoclonal gammopathies.

The study included 48 untreated patients with monoclonal gammopathies (MG). Paraprotein was isolated from the serum of 10 patients with decreased platelet aggregation. Platelet aggregation was measured before and after the addition of the isolated paraprotein to platelet-rich plasma (PRP) from 10 healthy donors, in vitro. Expression of platelet von Willebrand factor (vWF) receptor glycoprotein (GP)Ib and platelet collagen receptor GPVI was determined by flow cytometry in the PRP of healthy donors before and after the addition of isolated paraprotein using the monoclonal antibodies, CD42b (for GPIb) and CD36 (for GPVI). Flowcytometry showed that expression of CD42b and CD36 positive cells was reduced after the addition of isolated paraprotein to PRP from healthy donors (p < 0.001). These investigations demonstrated that paraprotein causes platelet dysfunction in patients with MG due to specific binding to the platelet vWF receptor GPIb and platelet collagen receptor GPVI.

Pretreatment prognostic factors for overall survival in primary resistant acute myeloid leukemia.

AIM: Primary resistant acute myeloid leukemia has a very poor prognosis. We assessed pretreatment parameters for their significance as prognostic factors in the overall survival (OS) of 53 acute myeloid leukemia (AML) patients who had failed to achieve complete remission (CR) after first-line standard-dose remission-induction therapy. RESULTS: During the period January 2005-December 2009, 53 with acute myeloid leukemia received two cycles of the 3+7 protocol as a first-line standard-dose remission-induction therapy (ARA-C, days 1-7 and daunorubicin, days 1-3). The HiDAC (5 patients), MiDAC (7 patients), and FLAG-IDA protocols (3 patients) were given as salvage therapy. None of these patients achieved CR. There were 27 (51%) males and 26 (49%) females (median age, 55 years, range 28-76). The median white blood cell count was 53 (range 0.9 -350)×10(9)/L, platelets 44 (range 3-856×10(9)/l) and bone marrow blasts 67%. HCT-IC comorbidity scores were 3 in two (3.8%) patients, 2 in 11 (20.8%), 1 in 12 (22.6%) and 0 in 16 (30.2%) patients. Median OS was 3.9 months (range 1 -20 months). The hepatomegaly, white blood cell count, ECOG PS, serum level of lactate dehydrogenase, dysplastic changes, coexpression of CD64, CD15, CD11b, comorbidities and disease cytogenetics influenced survival. CONCLUSION: This single-center study evaluated the significance of pretreatment factors, and found that patient age, comorbidities, ECOG performance status, leukocytosis, hepatomegaly, LDH, and the disease cytogenetics were factors which influenced the outcomes of primary resistant patients with acute myeloid leukemia. An understanding of these factors may help to predict OS in cases where CR has not been achieved and may help when making further treatment decisions.