The Importance of Pseudo Thrombocytopenia Due to Platelet Cold Agglutination before Surgery, What Should We Do? A Case Report.

Platelet cold agglutination (PCA) is a rare in-vitro phenomenon caused by Immunoglobulin M (IgM) autoantibodies, which results in Ethylenediaminetetraacetic Acid (EDTA) independent pseudo thrombocytopenia (PTCP). Its diagnosis is made based on the peripheral blood smear (PBS) examination and pre-test warming blood sample. Here, a case of PTCP secondary to PCA is presented. He was first admitted for pre-surgical tests but his platelet count was low. His blood was taken with EDTA and sodium citrate anticoagulant to rule pre-analytical error out. Then his sample warmed up and the test was run again with Mindray BC-6000 automated cell counter. Moreover, the rheumatologic tests were done for him. His platelet count was 23×109/L at first, and PBS showed many platelet aggregates. The low platelet count was not correct with Sodium Citrate or re-sampling with EDTA so platelet satellitism and improper sampling were ruled out. By warming the sample up to 37⸰C, the Platelet count rose to 216×109 / L. The rheumatologic tests were negative except for HLA-B27 which was positive. Finally, he was diagnosed with PCA which is due to a cold antibody (clinically insignificant). This diagnosis is important for the prevention of recurrent tests, unnecessary platelet transfusion, and other problems. Here these conditions will be discussed.

Reporting two hemoglobin J Iran cases, molecular follow-up, or is it insignificant?

Background: Hemoglobin J is one of the fast hemoglobin that has a more negative charge due to ß77His→Asp substitution. Acquisition of this hemoglobin is not associated with any specific clinical sign, but the combination of this hemoglobinopathy with beta-thalassemia and other hemoglobinopathies can cause challenges. Case Presentation: In this article, two cases with hemoglobin J are introduced; the first patient for premarital testing and the other for his fatigue. The hemoglobin electrophoresis was done by Sebia capillary zone electrophoresis and Hb J as heterozygote and homozygote were determined. Conclusion: It must be noted that although this hemoglobinopathy is not related to any problem alone but could be confusing in combination with other hemoglobinopathies or thalassemia. In this paper, these two cases are introduced and an attempt was made to investigate the importance of molecular follow-up.

Agitation-dependent biomechanical forces modulate GPVI receptor expression and platelet adhesion capacity during storage.

BACKGROUND: Continuous agitation during storage slows down the platelet storage lesions. However, in special circumstances, manual-mixing can be alternatively used to store products for short time periods without compromising platelet quality. Based on this finding, and given the role of shear stress in modulating receptor expression, we were interested in comparing the levels of platelet adhesion receptor, GPVI and platelet adhesion capacity under each storage condition. METHODS: Platelet concentrates (PCs) were divided into three groups: continuously-agitated PCs (CAG-PCs) with or without PP2 (Src kinase inhibitor) and manually-mixed PCs (MM-PCs). Platelet count/MPV, swirling, GPVI and P-selectin expression, GPVI shedding, platelet adhesion/spreading to collagen were examined during 5 days of storage. RESULTS: While MM- and CAG-PCs showed similar levels of P-selectin expression, GPVI expression was significantly elevated in MM-PCs with lower GPVI shedding/expression ratios, enhanced platelet adhesion/spreading and swirling in manually-mixed PCs. Of note, CAG-PCs treated with PP2 also demonstrated lower P-selectin expression and GPVI shedding, higher GPVI expression and attenuated swirling and spreading capability. CONCLUSION: Given the comparable platelet activation state in MM and CAG-PCs as indicated by P-selectin expression, enhanced platelet adhesion/spreading in MM-PCs, along with relatively higher GPVI expression here, supports previous studies demonstrating a role for biomechanical forces in modulating GPVI-dependent function. Thus, lower GPVI expression in CAG-PCs may be due to shear forces induced by agitation, which keeps this receptor down-regulated while also attenuating platelet adhesion/spreading capacities during storage. Low platelet function in PP2-CAG-PCs also highlights the importance of Src-kinases threshold activity in maintaining platelets quality.

Reducing state attenuates ectodomain shedding of GPVI while restoring adhesion capacities of stored platelets: evidence addressing the controversy around the effects of redox condition on thrombosis.

Thrombosis involves different stages including platelet adhesion to the site of injury, aggregatory events governed by integrin activation, pro-inflammatory responses recruiting leukocytes and finally, pro-coagulant activity which results in fibrin generation and clot formation. As important signaling agents, reactive oxygen species (ROS) reduce thrombus volume and growth, however given such a multistage mechanism, it is not well-elucidated how ROS inhibition modulates thrombosis. PRP-platelet concentrates (PCs) were either treated with ROS-reducing agents (1 mM NAC or 30 µM NOX inhibitor, VAS2870) or kept untreated during storage. Shedding and expression of platelet adhesion receptors in presence of inhibitors, agonists and CCCP (as controls) were analyzed by flow cytometery and western blot respectively. Besides above parameters, platelet adhesion to collagen in stored platelets was examined in presence of ROS inhibitors using fluorescence-microscopy. Highest levels of adhesion receptors shedding were achieved by ionophore and CCCP while collagen induces much more GPVI shedding than that of GPIbα. ROS inhibition reduced receptors shedding from day 3 of storage while enhanced their expressions. ROS inhibition not only did not reduce platelet adhesion capacity but it also enhanced platelets adhesion (in presence of NAC) or spreading (in presence of VAS2870) in 5 days-stored PCs. While reducing state significantly inhibits platelet aggregation and thrombus growth, our results indicated that as a first stage of thrombosis, platelet adhesion is resistance to such inhibitory effects. These findings highlight the fact that integrin-dependent platelet activation is much more vulnerable to the inhibition of ROS generation than GPVI-dependent platelet adhesion. Presumably, inhibition of platelet activating signals by ROS inhibitors preserves platelet adhesiveness to collagen due to lessening GPVI shedding.