ristocetin and Lupus-Erythematosus--Systemic

Topics: Blood Platelets; Blood Vessels; Epitopes; Factor VIII; Genetic Variation; Humans; Lupus Erythematosus, Systemic; Lymphoproliferative Disorders; Platelet Adhesiveness; Platelet Aggregation; Ristocetin; von Willebrand Diseases; von Willebrand Factor

Topics: Antibody Specificity; Autoantibodies; Diagnosis, Differential; Factor VIII; Female; Humans; Immunosuppressive Agents; Lupus Erythematosus, Systemic; Partial Thromboplastin Time; Platelet Aggregation; Prednisolone; Prothrombin Time; Ristocetin; von Willebrand Diseases; von Willebrand Factor; Young Adult

A 75 year old patient presenting with mucocutaneous bleeding was diagnosed with acquired thrombasthenia. The diagnosis was based on lack of platelet aggregation with adenosine diphosphate (ADP), arachidonic acid and collagen, and normal aggregation induced by ristocetin.. To study the mechanism of platelet function inhibition in a patient with acquired thrombasthenia.. Aggregation assays of platelets from the patient and healthy controls were performed. In addition, anti-glycoprotein (GP) IIbIIIa antibodies bindingto normal in the presence or absence of the patient's serum was by flow cytometry.. Aggregation of normal platelets in the presence of patient's plasma was inhibited four- and 2.5-fold in the presence of ADP and arachidonic acid respectively, while collagen-induced aggregation was completely abolished. Ristocetin-induced aggregation was normal. The patient's serum inhibited binding of commercial anti-glycoprotein IIbIIIa antibodies to normal platelets twofold by flow cytometry. Treatment with anti-CD20 monoclonal antibody (rituximab) normalized the patient's platelet aggregation.. These results suggest that the patient developed inhibitory anti-GPIIbIIIa autoantibodies that caused acquired thrombasthenia.

Topics: Adenosine Diphosphate; Aged; Antibodies, Monoclonal, Murine-Derived; Arachidonic Acid; Autoantibodies; Blood Platelet Disorders; Collagen; Drug Monitoring; Female; Humans; Immunologic Factors; Lupus Erythematosus, Systemic; Platelet Aggregation; Platelet Function Tests; Platelet Glycoprotein GPIIb-IIIa Complex; Remission Induction; Ristocetin; Rituximab; Treatment Outcome

In order to analyse their role as a specific marker of vascular damage and their value in monitoring disease activity the plasma concentrations of von Willebrand factor antigen (vWFAg) and the ristocetin cofactor (RiCoF) activities were determined in 43 children with vasculitis and 20 controls. These patients were sub-divided into three groups according to diagnosis: Henoch-Schönlein purpura (n = 18), polyarteritis nodosa (n = 16), and systemic lupus erythematosus (n = 9). High concentrations of vWFAg and activities of RiCoF were found in all the patient groups. vWFAg and RiCoF returned to normal as the patients became symptom free and remained above normal in those with continuing symptoms. The amount of vWFAg did not correlate with the acute phase reactants. vWFAg acted as a specific marker of vascular damage and was useful for the monitoring of disease activity both in small vessel vasculitis and systemic necrotising arteritis.

Topics: Adolescent; Agglutination Tests; Antigens; Biomarkers; Child; Child, Preschool; Female; Humans; IgA Vasculitis; Lupus Erythematosus, Systemic; Male; Polyarteritis Nodosa; Prospective Studies; Ristocetin; Vasculitis; von Willebrand Factor