Summary. Background: Glycoprotein (GP)VI deficiency is a rare platelet disorder with a mild bleeding tendency. However, its pathophysiology remains unclear. Objectives: We characterized a novel GPVI-deficient patient with immune thrombocytopenic purpura and searched for the presence of anti-GPVI autoantibodies in this and another patient with GPVI deficiency. Methods and results: A 12-year-old Japanese girl (case 1) with moderate thrombocytopenia and mild bleeding showed selectively impaired collagen-induced platelet aggregation. Flow cytometric analysis indicated that the patient had a defect in the expression of GPVI-FcRc. An eluate of her platelet-associated IgG contained anti-a IIb b 3 autoantibodies. Moreover, using GPVI-FcRc-transfected cells, we unexpectedly identified anti-GPVI antibodies against the soluble ectodomain of GPVI in the eluate, despite the patientÕs GPVI deficiency. In contrast, anti-GPVI antibodies were not detectable in her plasma. In another case of GPVI deficiency (case 2) without detectable plasma anti-GPVI antibodies, we again detected platelet-associated anti-GPVI antibodies. In a 2-year followup of case 1, the platelet count increased to within the normal range and the bleeding tendency improved. Interestingly, GPVI was again expressed on her platelets, in association with a decrease in the relative amount of anti-GPVI antibodies. Conclusions: This is the first demonstration of platelet-associated anti-GPVI antibodies in GPVI-deficient subjects, in one case with spontaneous restoration of GPVI expression. These results strongly suggest an autoimmune mechanism in GPVI deficiency.
A 20-year-old female developed a relapse of B-precursor acute lymphoblastic leukemia (ALL) as a mass in her left breast after 6 years of maintained continuous complete remission. No leukemic lesions were identified in other sites such as the bone marrow or cerebrospinal fluid. The relapsed leukemic cells in the breast revealed the same immunophenotypes (CD10(+), CD19(+), CD20(+), HLA-DR(+), CD34(+)) as those of the onset ALL cells in the bone marrow. A literature survey found 10 other cases of ALL relapse in the breast without bone marrow involvement, mostly consisting of adolescent girls. Including the present report, a total of 11 cases were analyzed; the onset ages of ALL were a median of 16.5 (range 5-50) years old and the ages of relapse in the breast a median of 20 (range 12-51) years old. Data suggest that, although rare, the breast could become one of the extramedullary relapse sites of ALL developed in adolescent girls.
Acquired haemophilia A (AHA) is a life-threatening haemorrhagic disorder that occurs with various underlying conditions such as autoimmune disease, drug reactions, lymphoproliferative diseases, solid tumours and pregnancy/postpartum status. However, in half of all reported cases, the underlying disease is unknown. Most AHA cases develop in adults; paediatric/adolescent cases are extremely rare. The main clinical symptom is bleeding into the skin, muscles, soft tissues and/or mucous membranes. Here, we report the case of an otherwise healthy 12-year-old girl who presented with prolonged bleeding postexodontia. After being diagnosed with AHA, she was successfully treated with recombinant activated factor VII infusion and oral prednisolone. To avoid such unanticipated bleeding when performing dental extraction, preoperative haemostatic screening tests are recommended.
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