[Antiplatelet antibodies].
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Antibodies, Monoclonal↗
Biomedical subjects
P Bierling
Publications and source records attributed to P Bierling.
Irinotecan-induced immune thrombocytopenia.
BACKGROUND: Irinotecan is currently used as second-line chemotherapy for advanced colorectal cancer. We report a case of severe thrombocytopenia after Irinotecan, suggesting an immune mechanism, in a 53-year-old patient. PATIENTS AND METHODS: The patient's sera were screened for platelet antibodies with an indirect platelet immunofluorescence test (PIIFT). The monoclonal antibody immobilization of platelet antigen assay (MAIPA) was used to characterize the antibody target. RESULTS: We detected an IgG platelet antibody in the patient's serum in the presence of Irinotecan by means of PIIFT, and not in the presence of SN-38, its active metabolite. The specificity of the binding was asserted after CD32 MoAb blockade. The platelet binding site could not be strictly identified with MAIPA and immunoblotting but GpIIb/IIIa can be excluded after experiments with Glanzmann platelets. CONCLUSION: This case can be considered the first documented Irinotecan-induced immune thrombocytopenia.
Adenocarcinoma↗
Apparent reactivation of a red cell alloantibody in a healthy individual after G-CSF administration.
Granulocyte-colony stimulating factor (G-CSF) has been successfully administered to healthy subjects to mobilize peripheral blood stem cells (PBSC) for allogeneic transplantation. Adverse events are moderate. We report the first case of apparent reactivation of an alloantibody to a blood cell antigen (Jk(a)) after G-CSF administration to a healthy subject and its transmission to the PBSC transplant recipient; no concomitant reactivation of other alloantibodies was detected. This case raises questions on the effect of G-CSF on the immune system and its safety in healthy individuals.
Adjuvants, Immunologic↗
Identification of a novel HLA-B*51 variant: HLA-B*5112.
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Amino Acid Sequence↗
Predictive value of host-specific donor helper T-cell precursor frequency for acute graft-versus-host disease and relapse in HLA-identical siblings receiving allogeneic bone marrow transplantation for hematological malignancies.
BACKGROUND: Acute graft-versus-host disease (aGVHD) is still one of the main causes of morbidity and mortality after allogeneic bone marrow transplantation. Attempts to avoid GVHD are associated with an increased risk of relapse, probably because the graft-versus-leukemia effect is also abrogated. It was recently suggested that a high frequency of host-specific donor helper T cell precursors (HTLp) might be predictive of significant aGVHD (grade > or = II). METHODS: We retrospectively studied the frequency of HTLp by means of simplified limiting-dilution analysis to determine its predictive value for aGVHD and relapse. Pre-bone marrow transplantation, host-specific donor HLTp frequencies were analyzed in 32 patients who had received marrow from HLA-identical siblings for hematological malignancies, in terms of aGVHD and relapse. RESULTS: HTLp frequencies were significantly higher in patients who had aGVHD > or = grade II (n=14) than in those without aGVHD (n=18) (P=0.007). Patients who relapsed (n=13) had significantly lower HTLp frequencies than those who did not relapse (n=19) (P<0.0001). The probabilities of relapse (Kaplan-Meier method) when the HTLp frequency was higher and lower than 1/200,000 were 0% and 88%, respectively (P<0.0001). CONCLUSIONS: The definition of HTLp cut-off values predictive of aGVHD and relapse should contribute to donor selection and could open the way to protocols adapting immunomodulation to the likely risk of aGVHD and relapse.
Adolescent↗
[Thrombocytopenia. Diagnostic orientation].
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Female↗
[Autoimmune thrombopenic purpura. Clinical practices during diagnosis. A French survey and recommendations. French College of Hemotologists Evaluation Commission].
THE SURVEY: To better ascertain diagnostic and treatment strategies used by physicians for idiopathic thrombocytopenic purpura, a questionnaire was addressed to 298 French hematologists and pediatricians. One hundred and ten responses were analyzed. DIAGNOSTIC APPROACH: Thrombocytopenia was determined on capillary blood samples by 50% of the physicians and platelet-associated antibody by 44%. Bone marrow aspirates were obtained more frequently in adults (85%) than in children (47%) and immune disorders were more often investigated in 95% of adults and in 68% of children. THERAPEUTICS: Treatment threshold was lower in children (20.10(9)/l) than in adults (50.10(9)/l). Corticoidsteroids was the treatment of choice in adults (98%) and children received either IV immunoglobulins (61%) and/or corticosteroids (63%); higher doses were used in children (> or = 2 mg/kg versus 1 mg/kg) for shorter periods (> or = 2 weeks versus > 3 weeks). Treatment failure was evaluated earlier in children (< 10 days) than in adults (> 20 days). RECOMMENDATIONS: 1. Diagnosis. Based on repeatedly low platelet counts and verification that only platelets are involved. Clinical examination is normal excepting rare cases of severe hemorrhage. Search for antiplatelet antibodies is non-contributive 2. Treatment Short-term corticosteroids, both in children and adults. Intravenous gammaglobulins should be limited to cases with signs of severe hemorrhage. 3. Consult the complete guidelines for each individual clinical situation.
Humans↗
Characterization of a new alloantigen (SH) on the human neutrophil Fc gamma receptor IIIb.
Polymorphic structures of the neutrophil Fc gamma receptor IIIb (Fc gamma RIIIb) result in alloantibody formation that causes alloimmune neonatal neutropenia and transfusion reactions. Alloantigens located on Fc gamma RIIIb include the antigens NA1 and NA2. In four cases of alloimmune neonatal neutropenia, granulocyte-specific alloantibodies directed against a thus far unknown antigen were detected by granulocyte agglutination and immunofluorescence tests in the maternal sera. By the use of the monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA) assay, the new antigen, termed SH, was located on the Fc gamma RIIIb. Nucleotide sequence analysis of the Fc gamma RIIIb coding region from a SH(+) individual showed a single-base C-->A mutation at position 266, which results in an Ala78Asp amino acid substitution. A family study confirmed that this nucleotide difference is inherited, and corresponds to the SH phenotype. Serologic typing of 309 randomly selected individuals showed an antigen frequency of 5% in the white population. The same frequency was found by genotyping, for which a technique based on polymerase chain reaction (PCR) using sequence-specific primers (PCR-SSP) was developed. Typing of all SH(+) individuals for NA1 and NA2, and PCR-restriction fragment length polymorphism analysis of the NA-specific PCR products from five SH(+) individuals using the SH-specific endonuclease SfaN 1 showed that SH antigen is very probably the result of an additional mutational event in the NA2 form of the Fc gamma RIIIB gene. Immunochemical studies also demonstrated that the SH determinants reside on the 65- to 80-kD NA2 isoform of the Fc gamma RIIIb. Our findings show the existence of an additional polymorphism of the Fc gamma RIIIb, which can result in alloantibody formation causing alloimmune neonatal neutropenia.
Adult↗
Specific antiplatelet glycoprotein autoantibodies are associated with the thrombocytopenia of primary antiphospholipid syndrome.
Thrombocytopenia is a frequent complication of primary antiphospholipid syndrome (PAPL) and has been attributed to antibodies directed against platelet glycoproteins (Gp) and also to antiphospholipid antibodies. We tested patients with PAPL with and without thrombocytopenia for specific antiplatelet autoantibodies. Platelet autoantibodies were detected by means of platelet immunoassays which included MAIPA with a panel of monoclonal antibodies directed against all the platelet Gps known to be possible targets for platelet autoantibodies. A high prevalence of serum platelet antibodies was found in patients with thrombocytopenia (73%, 11/15 patients) whereas antiplatelet antibody was detected in only one of the 10 control patients (P < 0.01). The antibodies mainly recognized GpIIbIIIa (n = 7), but also CD9 (n = 5), GpIaIIa (n = 4). GpIbIX (n = 3) and GpIV (n = 3). Platelet-Gp antibodies eluted from the platelet surface had the same reactivity as those found in the original sera from three of the four patients tested, whereas no anticardiolipin activity was found in the platelet eluates, suggesting the absence of cross-reactivity between anticardiolipin and antiplatelet antibodies. The MAIPA assay was also performed with F(ab')2 fragments obtained by pepsin digestion of serum IgG from four patients. The same results were obtained with F(ab')2 fragments and the original serum, demonstrating that platelet antibodies specifically bind in vivo to platelet Gps via their F(ab')2 fragments. Our results suggest a link between specific platelet antibodies and the thrombocytopenia of PAPL.
Adult↗
Dapsone for chronic autoimmune thrombocytopenic purpura: a report of 66 cases.
Sixty-six adults with chronic autoimmune thrombocytopenic purpura AITP and platelet count <50 x 10(9)/l were treated with dapsone (75-100 mg orally). A response was observed in 33 patients. The median duration of treatment required to obtain a response was 21 d (range 8-90). The median maximal platelet count on treatment was 130 x 10(9)/l (range 71-355). Dapsone was continued in 20/33 responders for a median of 12.5 months (range 1-48) and the response persisted in 19. Treatment was intentionally withdrawn in the other 13 responders and thrombocytopenia immediately recurred in 12. Reversible side-effects required cessation of treatment in seven patients. These results demonstrate that dapsone is an effective, inexpensive, and well-tolerated treatment for chronic AITP.
Adult↗
Hepatitis B vaccination in diabetic patients. Randomized trial comparing recombinant vaccines containing and not containing pre-S2 antigen.
OBJECTIVE: To investigate the immunogenicity of two recombinant hepatitis B vaccines containing S antigen alone (Engerix B) or both S and pre-S2 antigens (GenHevac B) in diabetic patients. RESEARCH DESIGN AND METHODS: Of the adult diabetic patients, 71 (26 IDDM, 45 NIDDM) were randomized to receive Engerix B or GenHevac B at 0, 1, 2, and 12 months in a single-blind clinical trial; if the antibody to hepatitis B surface antigen (anti-HBs) titers were < 10 i.u./l at month 4, a fourth injection of vaccine was given. A positive response was defined by anti-HBs titer > or = 10 IU/l at month 13. RESULTS: The anti-HBs response rate and the titers of anti-HBs did not differ significantly between the two types of vaccine. Overall, > 90% of the patients responded at month 13. In patients vaccinated with GenHevac B, anti-pre-S2 antibodies appeared earlier than anti-HBs. The anti-HBs response tended to decrease with age (P = 0.07) and tended to be higher in IDDM patients than in NIDDM patients (P = 0.06). Metabolic control, as assessed by HbA1c level, did not influence the response rate. The presence of the HLA DQ2 allele was associated with a low response. CONCLUSIONS: A large majority of diabetic patients can be efficiently vaccinated against the hepatitis B virus using a booster dose at month 4. The choice of the vaccine (with or without pre-S2 antigen) appears to have little influence, if any, on the response rate.
Adult↗
High-dose dexamethasone therapy for resistant autoimmune thrombocytopenic purpura.
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Adult↗
[Treatment of autoimmune thrombopenic purpura in adults].
Autoimmune thrombocytopenic purpura (AITP) is a common hematological problem. Steroids are the usual first-line treatment but give long-term remission in less than 20% of adults. High doses of human intravenous immunoglobulin G (IVIg) can increase the platelet count in 70 to 80% of patients, but the treatment is expensive and the platelet response usually only transient. Seventy to 80% of the adults have the chronic form of AITP (ie, disease duration of more than 6 months) that only improves on specific treatment. Splenoctomy is the treatment of choice when thrombocytopenia is severe and/or associated with life threatening bleeding, as it cures 60-80% of patients. The best treatment for patients with severe chronic AITP in whom splenectomy is ineffective or contra-indicated is a difficult challenge. In this situation, spontaneous remission is rare and 5% of patients will die from hemmorrhage. However, the treatments so far proposed in refractory chronic AITP (danazol, vinca alcaloids, azathioprine, cyclophosphamide, dapsone, etc) are inconsistently and transiently effective. The aim of the treatments in AITP are thus different in the acute and chronic forms of the disease. In the acute phase, the treatment should quickly increase the platelet count, even if the effect in transient, and aggressive treatments (ie, splenectomy, immunosuppressive drugs) must be avoided since spontaneous remission is possible. On the contrary, splenectomy is the treatment of choice for chronic AITP since it obtains complete persistent recovery in nearly 80% of patients. In the case of unsuccessfullness, treatments should then be administered with the aim to maintain a "safe" platelet count (> 20 to 30 x 10(9)/L).
Acute Disease↗
Fusidic acid induced acute immunologic thrombocytopenia.
Fusidic acid is used in hospitals as second-line therapy for multidrug-resistant staphylococcal infections. We report the first fully documented case of fusidic acid induced thrombocytopenia, in a 48-year-old patient. The thrombocytopenia was abrupt and severe but resolved spontaneously 7 d after drug withdrawal. The thrombocytopenia transiently relapsed 6 d later, when fusidic acid was reintroduced. Haemorrhagic signs were observed, but no severe bleeding occurred. Platelet transfusions failed to increase the platelet count. We detected an IgG platelet antibody in the patient's serum, that specifically recognized platelet glycoprotein IIb/IIIa only in the presence of fusidic acid. Fusidic acid induced thrombocytopenia should be considered as a possible cause for the thrombocytopenia frequently seen in the intensive care setting.
Acute Disease↗
Cross-reactive antibodies between HIV-gp120 and platelet gpIIIa (CD61) in HIV-related immune thrombocytopenic purpura.
We have previously demonstrated that immune platelet destruction observed in an AIDS-free HIV-infected patient was associated with the presence of a cross-reactive antibody recognizing both HIV-glycoprotein (gp)120 and platelet gpIIIa (CD61). We have now investigated the presence of such antibodies in other HIV-infected patients, together with the molecular structure of the cross-reactive epitope. Platelet gpIIb/IIIa antibodies were characterized in sera from HIV-infected patients with immune thrombocytopenic purpura by means of an ELISA and a radio-immunoprecipitation procedure (RIP). The platelet antibodies were purified and tested for their ability to recognize HIV-gp. We also tried to characterize the antibody target epitope on HIV-gp120 using recombinant gp and synthetic peptides. IgG with anti-gpIIb/IIIa activity were detected, by means of an ELISA with purified gpIIb/IIIa, in 101/138 (73%) sera from HIV-infected patients with immune thrombocytopenic purpura. The platelet antibodies were purified from 23 sera by absorption/elution on purified immobilized platelet gpIIb/IIIa, and recognition of gpIIIa was confirmed in eight cases with a RIP. Furthermore, the presence of a cross-reactive antibody between HIV-gp120 and platelet gpIIIa was demonstrated in 18/18 patients (including the eight with a confirmed gpIIIa antibody) by the ability of the serum HIV-gp160/120 antibodies to bind to purified gpIIb/IIIa. The cross-reactive epitope was shown to be independent of the carbohydrate moieties of gp120, since deglycosylation of two recombinant (r)-gp120s did not abolish antibody binding. However, the antibody did not recognize synthetic gp120 peptides spanning 355 of the 516 amino acids of gp120, particularly the four regions exhibiting sequences of four or five consecutive amino acids that are identical between r-gp120 and gpIIIa. Our results thus support the hypothesis that the cross-reactive antibody recognizes the conformational structure of gp120. These results strongly suggest that molecular mimicry between HIV-gp120 and platelet gpIIIa may be important in the pathogenesis of immune thrombocytopenia in AIDS-free HIV-infected patients.
Antigens, CD↗
Treatment of chronic autoimmune thrombocytopenic purpura with monoclonal anti-D.
BACKGROUND: The platelet count increases transiently after treatment with polyclonal anti-D in about 50 percent of D+ patients with autoimmune thrombocytopenic purpura (AITP). The effect is usually attributed to macrophage Fc-receptor blockade by antibody-coated red cells. As polyclonal anti-D is in limited supply, prospective testing was performed on a monoclonal anti-D (MoAb D) in such patients. STUDY DESIGN AND METHODS: Seven D+ patients with chronic AITP received MoAb D intravenously at doses of 47 to 95 microg per kg of body weight. Response was assessed by studying platelet count increment. Hemolysis and red cell-bound MoAb D were measured before and after MoAb D administration. RESULTS: MoAb D red cell binding was demonstrated in all patients at a ratio higher than that observed in AITP patients successfully treated with polyclonal anti-D. However, little or no platelet count increment was observed in six patients, while a transient response was observed in only one (platelet count 97 x 10(9)/L before MoAb D infusion and 163 x 10(9)/L 4 days later). Furthermore, because five patients showed signs of hemolysis and two became anemic, higher doses of MoAb D should be used only with caution in patients with AITP. CONCLUSION: The MoAb D used in this study cannot be proposed as an alternative treatment for patients with AITP.
Antibodies, Monoclonal↗
Prolonged remission of SLE-associated polyradiculoneuropathy after a single course of intravenous immunoglobulin.
Polyradiculoneuropathy is a rare and potentially severe complication of systemic lupus erythematosus (SLE). Treatment is not codified and response to corticosteroid is inconstant. We report the case of a patient with severe SLE-associated polyradiculoneuropathy and autoimmune thrombocytopenia. Dramatic neurologic improvement and correction of thrombocytopenia were observed after a single course of high-dose intravenous immunoglobulin infusions (IVIg, 2g/kg body weight). Our case suggests that IVIg may be effective in the treatment of this unusual condition.
Aged↗
High-dose methylprednisolone is an alternative treatment for adults with autoimmune thrombocytopenic purpura refractory to intravenous immunoglobulins and oral corticosteroids.
Eight patients with severe chronic autoimmune thrombocytopenic purpura (AITP) refractory to high-dose intravenous immunoglobulin (IVIgG) and/or oral prednisone were treated with one to three infusions of high-dose methylprednisolone (HDMP) (15 mg/kg/day). The mean platelet count before treatment was 12 +/- 10 x 10(9)/L. HDMP therapy led to a safe platelet count (> 50 x 10(9)/L) after 2-5 days in five patients, and a minimal platelet increase (34 x 10(9)/L) able to stop bleeding in a sixth patient. The effect of HDMP was, however, transient in four of five responders. No side effects were observed, even in the four patients older than 70 years. HDMP thus appears to be a good alternative in emergency situations or prior to surgery for patients with AITP refractory to conventional therapy.
Administration, Oral↗