1/31. Further evidence that exacerbation of ulcerative colitis causes the onset of immune thrombocytopenia: a clinical case.Ulcerative colitis associated with immune-mediated thrombocytopenia is rare. It has been suggested that antigenic mimicry between platelet surface antigen and bacterial glycoprotein plays a role in this association. We present a case in which exacerbation of UC sequentially induced development of ITP associated with elevation of PAIgG. In the case, two episodes of ITP occurred, with each preceded by exacerbation of UC. After remission of UC, ITP remitted and PAIgG simultaneously decreased. In the first episode, the onset of ITP was about 1 month after the exacerbation of UC. However, in the second episode, the onset of ITP was much faster, 11 days after that of UC, and the magnitude of elevation of PAIgG was much higher in the second episode. This may provide further evidence that ITP is causally associated with UC, and is the result of immunostimulation from luminal antigens and altered immunoregulation.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/31. Refractoriness to platelet transfusion following double valve replacement in an ITP patient who had undergone splenectomy.Reports of patients with idiopathic thrombocytopenic purpura (ITP) undergoing cardiac surgery are rare, and almost all of the reported cases required platelet transfusion. ITP patients, especially those having a history of splenectomy or a history of heavy bleeding, may have to undergo multiple platelet transfusions. Such transfusions may induce alloimmunization against the human leukocyte antigen (HLA) and result in refractoriness to subsequent platelet transfusions. We report a case of a 63-year-old female with ITP, with a history of splenectomy and multiple platelet transfusions, who underwent aortic and mitral valve replacement. Although corticosteroid administration, high-dose immunoglobulin therapy, and repeated platelet transfusion led to a temporary increase in platelet count and successful hemostasis, refractoriness to platelet transfusion occurred postoperatively because of the presence of the anti-HLA antibody. In addition, the patient showed complications of pyothorax. Corticosteroids might have exerted an inhibitory influence on the occurrence of pyothorax.- - - - - - - - - - ranking = 0.33333333333333keywords = antigen (Clic here for more details about this article) |
3/31. Glycoprotein V-specific platelet-associated antibodies in thrombocytopenic patients.In autoimmune thrombocytopenia, platelet-associated IgG (PA-IgG) frequently displays specificity against glycoprotein (GP) IIbIIIa and/or GP IbIX. Because in a high proportion of patients positive PA-IgG may not be explained by these GP specificities, studies on other target proteins are needed. We studied the presence of GP V-specific PA-IgG by direct monoclonal antibody-specific immobilization of platelet antigens (MAIPA) with the monoclonal antibody SW16. We focused on 69 consecutive random patients with histories of thrombocytopenia who were strongly positive for PA-IgG detected by the direct platelet immunofluorescence test (PIFT). PA-IgG against GP V (ratio > or = 1.5) was noted in 15 (22%) patients. The degree of PA-IgG measured by PIFT, and of GP IIbIIIa-and/or GP IbIX-specific PA-IgG measured by direct MAIPA, correlated directly with the GP V-specific PA-IgG (P < 0.001). In one patient, GP V-specific antibodies were associated with quinidine-induced thrombocytopenia. Although this patient had strongly positive GP V-specific PA-IgG, she remained negative in GP IIbIIIa- and GP IbIX-specific direct MAIPA. Two patients studied because of thrombocytopenia associated with gold therapy had strongly positive GP V-specific PA-IgG. In one patient with rheumatoid arthritis and severe gold-induced thrombocytopenia, the amount of GP V-specific PA-IgG decreased during the recovery phase. Thus, GP V may represent an important target antigen in autoimmune-mediated thrombocytopenia, especially in drug-induced thrombocytopenia.- - - - - - - - - - ranking = 0.66666666666667keywords = antigen (Clic here for more details about this article) |
4/31. Fatal acute myocardial infarction during severe thrombocytopenia in a patient with idiopathic thrombocytopenic purpura.Because platelets play a major role in most thrombotic events, it is not surprising that all cases of myocardial infarctions in patients with idiopathic thrombocytopenic purpura (ITP) have been reported to occur only when platelets counts begin to rise. We report on a 69-year-old man with ITP who had acute myocardial infarction while he was severely thrombocytopenic (2000/microL). We hypothesize that the pathogenesis of myocardial infarction in thrombocytopenic patients with ITP may result from endothelial damage induced by autoantibodies directed against antigens present on both platelets and coronary endothelial cells.- - - - - - - - - - ranking = 0.33333333333333keywords = antigen (Clic here for more details about this article) |
5/31. Refractory Evans' syndrome treated with allogeneic SCT followed by DLI. Demonstration of a graft-versus-autoimmunity effect.Evans' syndrome, a combination of autoimmune haemolytic anaemia and autoimmune (idiopathic) thrombocytopenic purpura, is generally harder to treat and more refractory than the single entities. In a male patient with refractory disease, predominantly thrombocytopenic, an allogeneic reduced intensity BMT from his human leukocyte antigen (HLA)-identical sister was followed by a dramatic platelet peak while he was still experiencing initial engraftment (presumably of autologous origin), but subsequently by progressive relapse associated with mixed chimerism. Five gradually incremental DLI achieved complete donor chimerism, which was associated not only with grade II graft-versus-host disease (GVHD), but also with complete clinical and biological remission for 2 years post-transplant. Long-term FU is necessary before claiming that allogeneic stem cell transplantation (SCT) is capable of curing an autoimmune blood disease. However, there is evidence for a graft-versus-autoimmunity effect in this case.- - - - - - - - - - ranking = 0.33333333333333keywords = antigen (Clic here for more details about this article) |
6/31. Familial association of autoimmune thrombocytopenia and hyperthyroidism.An association between thrombocytopenia and thyrotoxicosis in a single individual is well documented, and the theories for this event include a common immunologic cause or a thyrotoxic-induced decrease in platelet survival. We report the first description of the coexistence of autoimmune thrombocytopenic purpura (AITP) and Graves' disease in several members of the same family, in which four females were thrombocytopenic and two of these were also hyperthyroid. All four patients had high titers of antiplatelet antibodies, and the two hyperthyroid cases were positive for thyroid-stimulating immunoglobulins (TSI). The familial occurrence of two autoimmune disorders is very uncommon, and suggests a genetic etiology. The HLA phenotype was determined and the antigens B8 and DR3, which are reported with high frequency in both diseases, were present in three patients. Although the etiologic cause is still unknown, our findings further support the theory that a genetic predisposition underlies autoimmune disease.- - - - - - - - - - ranking = 0.33333333333333keywords = antigen (Clic here for more details about this article) |
7/31. HLA-DR expression by platelets in acute idiopathic thrombocytopenic purpura.Induction of expression of MHC class II antigens on the surface of cells that do not ordinarily express these proteins has been implicated in the pathogenesis of autoimmunity in diabetes mellitus and autoimmune thyroiditis. Platelets express class I but not class II hla antigens. In this report, we describe a child with acute idiopathic thrombocytopenic purpura who at the time of the thrombocytopenic episode had class II (HLA-DR) antigens on his platelets. Following recovery, the hla-dr antigens were no longer present on the platelets. We postulated that class II had been induced on his megakaryocytes by a cytokine such as interferon gamma, and that the induced expression of class II antigens contributed to the autoimmune disorder. To substantiate this possibility we next studied class I and II antigen expression on an erythroleukaemia cell line (HEL), which has many megakaryocytic features. Following treatment of HEL cells with interferon gamma, class I expression was increased and hla-dr antigens were induced. These observations suggest that cytokine-mediated induced HLA-DR expression may contribute to the pathogenesis of a subset of thrombocytopenias.- - - - - - - - - - ranking = 2.3333333333333keywords = antigen (Clic here for more details about this article) |
8/31. Improving selection of alphaIIbbeta3-binding phage antibodies with increased reactivity derived from immunized donors.Although many studies of the immune response in polytransfused Glanzmann thrombasthenia (GT) patients and in autoimmune thrombocytopenic purpura (AITP) have demonstrated the frequent development of Abs directed against the alphaIIbbeta3 integrin, little is known about the induced anti-alphaIIbbeta3 autoantibodies at the molecular level. Phage display is a powerful technology for selecting and engineering mAbs expressed on the surface of filamentous bacteriophage. Combinatorial libraries of single-chain IgG were constructed from splenocytes from two patients with AITP and one patient with GT. In a previous study, activated platelets or alphaIIbbeta3-expressing cho cells selection was performed to isolate human IgG anti-alphaIIbbeta3 binding fragments using combinatorial libraries created from the B cells of a GT and an AITP patient. However, we have experienced practical problems such as enrichment of truncated antibodies during selection. We decided to test prolonged treatments with elution agents after screening on the purified form of the alphaIIbbeta3 integrin activated with the RGD peptide. We obtained a higher percentage of clones with full-size antibody fragments as well as an enrichment of more specific alphaIIbbeta3-binding phage-Abs. Some of them, recognizing the activated form of the integrin, would be interesting to further study as potential diagnostic or therapeutic agents in acute coronary syndromes. Sequencing of selected phage-Abs revealed that they used different VH and VL genes with, for the majority of them, a high level of extensive hypermutations in the complementarity determining regions, indicating the diversity of the antigen-driven immune response that occurred in GT and AITP patients.- - - - - - - - - - ranking = 0.33333333333333keywords = antigen (Clic here for more details about this article) |
9/31. Immune thrombocytopenic purpura in patients with ulcerative colitis.Extraintestinal manifestations of ulcerative colitis (UC) are well known, but immunologically mediated hematological diseases are relatively rare. We describe two cases of immune thrombocytopenic purpura (ITP) associated with preexisting UC. Our patients had typical symptoms of UC, and endoscopy showed pancolitis. During treatment with 5-aminosalicylic acid and steroids, severe thrombocytopenia was noted. ITP was diagnosed based on a normal to high number of megakaryocytes in the bone marrow, positive autoantibody to platelet membrane antigen, and absence of splenomegaly. Medical treatment, including increased dosage of steroids, failed to control UC and ITP in both patients. In the first patient, the platelet count recovered after colectomy, while the second patient died of a cerebral hemorrhage. We stress that a diagnosis of ITP should be considered for thrombocytopenia in patients with UC, especially those showing extensive and significant colonic inflammation, and that colectomy of UC might resolve resistant ITP.- - - - - - - - - - ranking = 0.33333333333333keywords = antigen (Clic here for more details about this article) |
10/31. Refractory autoimmune thrombocytopenic purpura: responses to treatment with a recombinant antibody to lymphocyte membrane antigen CD20 (rituximab)."Refractory" autoimmune thrombocytopenia represents a life-threatening condition, having failed to respond to a variety of therapeutic measures. We report a series of cases, all failing splenectomy and multiple therapeutic programs, including, in two patients, marrow transplant. Five of the six cases reported responded to a recombinant antibody to the lymphocyte membrane antigen CD20 (rituximab), an agent commonly employed in the treatment of non-Hodgkin's lymphoma. Our experiences over a period of 4 years are documented. The results support the use of this product, rituximab, in the treatment of patients with autoimmune thrombocytopenia who have not attained a hemostatically effective platelet count following splenectomy and require a continuing therapeutic management program.- - - - - - - - - - ranking = 1.6666666666667keywords = antigen (Clic here for more details about this article) |
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