Etiology and incidence of thrombotic and hemorrhagic disorders in Thai patients with extreme thrombocytosis.

A retrospective study of 126 patients with extreme thrombocytosis (defined as a platelet count > or = 1,000 x 10(9)/L) was performed during a five-year period (June 1994-June 1999). The aim of this study was to determine the etiology and to evaluate the clinical consequences of extreme thrombocytosis. Seventy patients (55.5%) had reactive thrombocytosis (RT) with an age range of 43 +/- 2.2 years, 56 (44.5%) had chronic myeloproliferative disorders (MPD) with an age range of 53 +/- 2.4 years. Underlying causes of RT were malignancy (25/70 or 35.7%), infection (16/70 or 22.9%), postsplenectomized beta-thalassemia/Hb E (11/70 or 15.7%), inflammation (12/70 or 17.1%), iron deficiency anemia (6/70 or 8.6%). Duration post splenectomy in our beta-thalassemia/Hb E patients ranged from 4 months to 21 years, with a median of 10 years. Subtypes of our MPD cases were chronic myeloid leukemia (30/56 or 53.6%), essential thrombocytosis (18/56 or 32.1%), polycythemia vera (4/56 or 7.1%), agnogenic myeloid metaplasia (3/56 or 5.4%) and unclassified MPD (1/56 or 1.8%). Bleeding and thrombotic tendency were respectively noted in 7 (12.5%) and 2 (3.6%) of MPD patients. Two patients of the MPD group (3.6%) experienced both bleeding and thrombotic episodes. One patient (1.4%) of the RT group developed vasculitis-associated thrombosis. However, none of the patients in the RT group had bleeding complications. Extreme thrombocytosis was not a rare condition in a university hospital population, and bleeding and/or thrombotic complication was more common in the MPD group.

Experience with factor VIII: C inhibitors and acquired von Willebrand's disease in an adult at Ramathibodi Hospital.

Eleven cases of acquired inhibitors against factor VIII: C and von Willebrand's factor (vWF) seen at the Department of Medicine, Ramathibodi Hospital from 1979 to 1991 were reviewed. Factor VIII: C inhibitor was found in 6 of 36 patients (17%) with hemophilia A (median age 18 years). Three patients each were weak (titer < 10 Bethesda units/ml), and strong antibody producers. Two cases of weak antibody producers had spontaneous disappearance of inhibitor, while all 3 strong antibody producers required specific treatment (corticosteroids, immunosuppressive drugs, and plasmapheresis). The inhibitor level temporarily declined in 2 patients, and disappeared in one. Spontaneous acquired inhibitor to factor VIII: C was seen in 3 patients. One each respectively had pemphigus vulgaris and bullous pemphigoid, autoimmune disease, and NIDDM. They were characterized by older age (median age 54 years), frequent skin and soft-tissue hematoma, but less hemarthroses. Inhibitor titer ranged from 15-280 Bethesda units/ml. Disappearance of the inhibitor after treatment with corticosteroids and immunosuppressive drugs were observed in all patients. Acquired von Willebrand's disease developed in 2 previously healthy patients. One patient was in the postpartum period, while the other had simultaneous acute viral hepatitis A infection. Both presented with the recent onset of spontaneous severe gingival bleeding, and demonstrated a prolonged bleeding time, reduced vWF:Ag (F VIIIR:Ag), and ristocetin cofactor (F VIIIR:vWF). Treatment with cryoprecipitate and corticosteroid resulted in remission of bleeding symptoms. Despite the rarity of these disorders, the recognition and proper management are of importance.

Clinical features of acute lymphoblastic leukemia subclasses in 28 Thai children--a preliminary study.

Twenty-eight Thai children with newly diagnosed acute lymphoblastic leukemia were evaluated for pretreatment characteristic, including immunophenotype of lymphoblast, outcome of treatment, and the correlation among them. By APAAP technique using a panel of eight monoclonal antibodies (HLA-DR, CD 19, CALLA (CD 10), IgM, CD 7, CD 3, CD 4, and CD 8), five subclasses were identified: 67.9, 17.9, 7.1, 3.6, and 3.6 per cent were respectively shown to be common-, null-, mature thymocyte T-, pre B-, and B-ALLs. Clinical features in each subclass conformed to previous reports. All of the 27 evaluable patients attained initial complete remission, but subsequent relapses were noted in 7 patients (25.9%). Three of the 19 cases in the common ALL group relapsed at 6-12 months, whereas, 4 of the 8 cases in the non-common ALL group relapsed at 2-15 months. Probability of relapse at 12 months in the common and non-common ALL groups were 19 and 49 per cent respectively. Disease-free survival from time of remission was shorter in the non-common ALL group. Multivariate analysis of the 6 factors predicting disease-free survival showed that the only strong factor was the immunophenotype of lymphoblast.