Interaction between viruses and platelets: requirement of haemolytic activity for platelet aggregation induced by paramyxoviruses

Predictors for Early Identification of Hepatitis C Virus Infection

Hepatitis C virus (HCV) infection can cause permanent liver damage and hepatocellular carcinoma, and deaths related to HCV deaths have recently increased. Chronic HCV infection is often undiagnosed such that the virus remains infective and transmissible. Identifying HCV infection early is essential for limiting its spread, but distinguishing individuals who require further HCV tests is very challenging. Besides identifying high-risk populations, an optimal subset of indices for routine examination is needed to identify HCV screening candidates. Therefore, this study analyzed data from 312 randomly chosen blood donors, including 144 anti-HCV-positive donors and 168 anti-HCV-negative donors. The HCV viral load in each sample was measured by real-time polymerase chain reaction method. Receiver operating characteristic curves were used to find the optimal cell blood counts and thrombopoietin measurements for screening purposes. Correlations with values for key indices and viral load were also determined. Strong predictors of HCV infection were found by using receiver operating characteristics curves to analyze the optimal subsets among red blood cells, monocytes, platelet counts, platelet large cell ratios, and mean corpuscular hemoglobin concentrations. Sensitivity, specificity, and area under the receiver operator characteristic curve (P < 0.0001) were 75.6%, 78.5%, and 0.859, respectively.

Platelets from thrombocytopenic ponies acutely infected with equine infectious anemia virus are activated in vivo and hypofunctional

Thrombocytopenia is a consistent finding and one of the earliest hematological abnormalities in horses acutely infected with equine infectious anemia virus (EIAV), a lentivirus closely related to human immunodeficiency virus. Multifactorial mechanisms, including immune-mediated platelet destruction and impaired platelet production, are implicated in the pathogenesis of EIAV-associated thrombocytopenia. This study was undertaken to investigate whether regenerative thrombopoiesis and platelet destruction occurred in ponies acutely infected with EIAV. Circulating large, immature platelets were increased in ponies acutely infected with EIAV late in the infection when platelet count was at a nadir. Morphometric analysis of bone marrow from acutely infected ponies revealed significant increased in megakaryocyte area and megakaryocyte nuclear area. A trend toward increased numbers of megakaryocytes was also observed. Platelets from acutely infected ponies had increased surface-bound fibrinogen and ultrastructural changes consistent with in vivo platelet activation. Platelets also had hypofunctional aggregation responses to three agonists in vitro. We conclude that thrombocytopenia in ponies acutely infected with EIAV is regenerative and suggest that bone marrow platelet production is not severely compromised in these ponies. Our findings reveal that in vivo platelet activation occurs in ponies acutely infected with EIAV, and as a result platelets are hypofunctional in vitro. Activation of platelets in vivo may cause platelet degranulation or formation of platelet aggregates, which would result in removal of these damages platelets from circulation. This may represent a form of nonimmune-mediated platelet destruction in ponies acutely infected with EIAV.

Association of herpes simplex virus with platelets of experimentally infected mice

In mice infected with herpes simplex virus (HSV) type 1 by the intracerebral route or with HSV type 2 by the vaginal route, virus was shown to be present in greater quantities in purified platelets than in leucocytes or other blood components. Results of the studies described suggest that platelets may play a major role in the hematogenous dissemination of HSV infection.