Abstract: Methods and materials for identifying and/or treating mammals (e.g., humans) as having vaccine-induced immune thrombotic thrombocytopenia (VITT) are provided herein. In some cases, the methods and materials provided herein can be used to differentiate between VITT and spontaneous heparin-induced thrombocytopenia (s-HIT). Specifically, the method comprising contacting the sample from a mammal that (i) has thrombocytopenia, and/or thrombosis, and (ii) does not have heparin-induced thrombocytopenia (HIT) with an uncomplexed platelet factor 4 (PF4) polypeptide for detection.

Abstract: This document relates to methods and materials for assessing and/or treating mammals (e.g., humans) having a monoclonal or oligoclonal gammopathy of thrombotic/thrombocytopenia significance (MGTS). For example, the presence of a population of monoclonal antibodies having binding specificity for a platelet factor 4 (PF4) polypeptide in a sample obtained from a mammal (e.g., a human) can be used to identify the mammal as having MGTS. In some cases, materials and methods for treating a mammal (e.g., a human) identified as having MGTS are provided.

Abstract: The compositions and methods described herein provide stabilized platelets by a controlled freezing process coupled to methods for recovery upon thawing. The stabilized platelets maintain the ability to be activated after freezing and thawing.

Abstract: Described is a method for identifying pathogenic platelet-activating antibodies in a subject's blood and particularly antibodies implicated in heparin-induced thrombocytopenia (HIT) which comprises the preparation of a platelet releasate from a normal subject's platelets, the combination of the platelet release with a normal subject's platelets, a test subject's blood sample, and analyzing the sample for platelet activation.

Abstract: The present invention provides a method of detecting platelet activation in a patient, the method comprising the steps of a) obtaining a blood sample from a patient suspected of having heparin-induced thrombocytopenia (HIT); b) incubating an effective amount of platelet factor 4 (PF4) with a sample of platelets to yield a sample of PF4-treated platelets; c) contacting the patient blood sample with the PF4-treated platelets; and d) measuring the extent of platelet activation, wherein an increase in platelet activation compared with results obtained using a normal blood sample is indicative of the patient having HIT.

Abstract: The present invention provides a method of detecting platelet activation in a patient, the method comprising the steps of a) obtaining a blood sample from a patient suspected of having heparin-induced thrombocytopenia (HIT); b) incubating an effective amount of platelet factor 4 (PF4) with a sample of platelets to yield a sample of PF4-treated platelets; c) contacting the patient blood sample with the PF4-treated platelets; and d) measuring the extent of platelet activation, wherein an increase in platelet activation compared with results obtained using a normal blood sample is indicative of the patient having HIT.

Abstract: The present invention provides a method of detecting platelet activation in a patient, the method comprising the steps of a) obtaining a blood sample from a patient suspected of having heparin-induced thrombocytopenia (HIT); b) incubating an effective amount of platelet factor 4 (PF4) with a sample of platelets to yield a sample of PF4-treated platelets; c) contacting the patient blood sample with the PF4-treated platelets; and d) measuring the extent of platelet activation, wherein an increase in platelet activation compared with results obtained using a normal blood sample is indicative of the patient having HIT.

Abstract: The present invention provides a method of detecting platelet activation in a patient, the method comprising the steps of a) obtaining a blood sample from a patient suspected of having heparin-induced thrombo-cytopenia (HIT); b) incubating an effective amount of platelet factor 4 (PF4) with a sample of platelets to yield a sample of PF4-treated platelets; c) contacting the patient blood sample with the PF4-treated platelets; and d) measuring the extent of platelet activation, wherein an increase in platelet activation compared with results obtained using a normal blood sample is indicative of the patient having HIT.