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Biomedical subjects

P Fromont

Publications and source records attributed to P Fromont.

26 records · Page 2Linked to original sources
PubMed1990

Pregnancy in women with immune thrombocytopenic purpura.

Thirty-six women with immune thrombocytopenic purpura were studied during 37 pregnancies, and maternal characteristics with predictive value for the fetal platelet count were determined. Nine neonates were thrombocytopenic, with a platelet count of less than 50 x 10(9)/L in eight. Four of these nine neonates delivered to a subgroup of 31 mothers were studied prospectively; the frequency of thrombocytopenia in neonates of women with immune thrombocytopenic purpura was thus 13%. Only two of these nine neonates presented with hemorrhagic syndromes (two, petechial purpura; one, intracranial bleeding). The frequency of neonatal thrombocytopenia was higher in mothers with deep thrombocytopenia and in those who had not responded to corticosteroid treatment following diagnosis. No prognostic value could be assigned to the other maternal characteristics studied, such as a history of splenectomy, maternal treatment at the time of delivery, or the presence of platelet autoantibodies evaluated either with the platelet immunofluorescence test or the platelet Western blot immunoassay.

Autoantibodies↗
PubMed1989

Immunochemical analysis of platelet autoantibodies in HIV-related thrombocytopenic purpura: a study of 68 patients.

Serum antiplatelet IgG and platelet-associated IgG (PAIgG) were studied in 68 AIDS-free human immunodeficiency virus (HIV)-infected patients with severe immunologic thrombocytopenic purpura (ITP), for the presence of platelet autoantibodies. Serum IgG with antiplatelet activity was found in 72% of the sera. However, the presence of autoantibodies against platelet surface glycoproteins was not found in these sera by means of Western blot and immunoprecipitation procedures. Nevertheless, an immunoblot immunoassay and an indirect immunofluorescence test against semi-permeabilized platelets demonstrated the presence of antibodies in the patient sera, that reacted with intracytoplasmic platelet components, and which might participate in the elimination of platelet fragments. Direct immunofluorescence tests demonstrated an increased amount of PAIgG in 75% of the patients; the bound antibodies could be eluted with ether in 44% of the cases. These eluates were found to bind to normal platelets but not to Glanzmann type I platelets. Finally, immunoprecipitation procedures demonstrated the presence of platelet autoantibodies in six of the 35 eluates studied. These antibodies recognized GPIIb in two cases, GPIIIa in one case, and an unidentified platelet protein of 150 kDa in the three other cases. The discrepancy between sera and platelet eluates was interpreted as being due to the low titre of the antibodies and to their dilution in polyclonal hypergammaglobulinaemia. The present study provides direct evidence that isolated ITP in some HIV-positive patients is due to the presence of platelet autoantibodies. These results, however, do not exclude either direct or indirect involvement of HIV in the platelet destruction.

Autoantibodies↗
PubMed1988

Early immunization against platelet glycoprotein IIIa in a newborn Glanzmann type I patient.

Alloimmunization against platelet glycoprotein IIb and/or IIIa is a complication rarely observed during the evolution of type I Glanzmann's thrombasthenic patients. The occurrence of such alloantibodies is usually due to repeated blood transfusion and greatly complicates the treatment of these patients since they prevent effective platelet transfusion and might, theoretically, cause posttransfusion purpura. We describe the case of a newborn thrombasthenic patient who developed an IgG platelet allo-antibody 1 month after birth. The diagnosis of Glanzmann's thrombasthenia was complicated by the rare platelet phenotype (PLA1-negative PLA2-positive) of the healthy mother, which was probably heterozygous for the abnormal thrombasthenic gene. Immunofluorescence and immunoblotting techniques demonstrated that the patient antibody was principally directed against the platelet glycoprotein IIIa. Surprisingly, this patient had only received four blood transfusions (fresh frozen plasma on days 1 and 2, and standard red blood cell concentrates on days 5 and 6) before the discovery of the antibody, suggesting prior in utero sensitization. This study emphasizes the need for early diagnosis of the disease. Thrombasthenic patients should be transfused with deleukocyted platelet-free blood products.

Blood Platelet Disorders↗
PubMed1985

Acquired autoimmune thrombocytopenia after allogeneic bone marrow transplantation.

A 29-year-old man in remission from acute myeloblastic leukaemia was treated by chemoradiotherapy and transplantation of bone marrow (BMT) collected from his HLA identical brother. Engraftment was documented on D12. Transient acute GVHD (grade II) appeared from D34. No infection complicated the BMT. Nevertheless severe thrombocytopenia persisted and was unresponsive to marrow donor platelet transfusion. The platelet immunofluorescence test demonstrated the autoimmune basis of the thrombocytopenia. This study suggests that the transient immune imbalance observed in the early post graft period could facilitate the appearance of autoimmune cytopenias.

Adult↗
PubMed1984

[Autoimmune thrombopenic purpura and pregnancy. Absence of thrombopenia in the newborn infant despite the presence of circulating IgG auto-antibody in the mother].

Many pregnant women with AITP bear children with transient thrombocytopenia which is a potentially life threatening complication. Previous reports have demonstrated that monitoring of IgG circulating platelet antibodies may help with the management of these women. We report the case of a pregnant woman with AITP whose sera contained an IgG auto antiplatelet demonstrated by the fluorescein labelled antiglobulin techniques. Steroids had a beneficial effect with a return to a normal of the mother's platelet count but with no disappearance of the circulating antibody. Surprisingly the neonatal platelet count was normal and studies in the baby showed that the antibody had not crossed the placenta in detectable amounts. This case demonstrates our current inability to predict fetal thrombocytopenia and plan the mode of delivery.

Autoimmune Diseases↗