PubMed Health⌕ Search

Biomedical subjects

P Fromont

Publications and source records attributed to P Fromont.

At least 19 recordsLinked to original sources
PubMed1999

CD36 deficiency is frequent and can cause platelet immunization in Africans.

BACKGROUND: CD36 is expressed on several cell lineages. About 5 to 10 percent of Asians lack platelet membrane CD36 (pCD36), but the frequency of pCD36 deficiency in other ethnic groups is not known. Persons who are pCD36-negative are apparently healthy but can develop CD36 isoimmunization. STUDY DESIGN AND METHODS: The pCD36 phenotype was studied in 1885 subjects belonging either to a group of 1127 healthy French blood donors (almost all of whom were white Europeans) or to a group of 758 patients of known ethnic origin. RESULTS: No pCD36-negative persons were found among the blood donors. Only 1 of the 301 white European patients was pCD36-negative. In contrast, 16 of the 206 sub-Saharan Africans was pCD36-negative, a proportion higher than that among that black Caribbeans (1/148, p<0.01). The frequency of pCD36-negative patients was similar in blacks with and without sickle cell disease. Monocyte CD36 (mCD36) expression was studied in 15 of 22 pCD36-negative individuals: it was <10 percent in 7 subjects (type I deficiency) and between 12 and 100 percent in 8 others (type II deficiency). Thirteen pCD36-negative individuals had risk factors for immunization, and 4 had anti-CD36. Some had a history resembling posttransfusion purpura (n = 2), platelet transfusion refractoriness (n = 1), and recurrent miscarriage (n = 1). No correlation was found between immunization and the amount of mCD36. Anti-CD36 from an immunized type II-deficient woman reacted with monocytes from normal controls but not with monocytes from type I- or type II-deficient individuals, and thus it is postulated that mCD36 could be structurally different in normal and type II CD36-deficient individuals. CONCLUSION: CD36 deficiency is frequent in sub-Saharan Africans; development of anti-CD36 can lead to serious complications in multiply transfused patients, such as those with sicke cell disease.

Adult↗
PubMed1998

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↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1996

Altered trabecular architecture induced by corticosteroids: a bone histomorphometric study.

Prolonged corticosteroid (CS) therapy induces osteoporosis and fractures. Osteoporosis is characterized at the histomorphometric level by reduced bone volume (BV/TV) and disruption of the three-dimensional (3D) trabecular architecture. Several stereological methods have been proposed to characterize these alterations: measurements of trabecular thickness and trabecular number, star volumes, interconnectivity index (ICI) of the bone marrow spaces, and trabecular bone pattern factor (TBP(f)). These methods were computerized with a single program running on an image analyzer to evaluate the bone changes in a series of iliac biopsies performed on 31 male patients. All of them were asthmatic and had received CS for a long period of time. BV/TV was reduced when compared with age-matched controls. In the CS-treated population, exponential relationships were obtained between bone volume and the different connectivity parameters. The various methods used to measure connectivity were well correlated. When the population was divided into two groups (BV/TV greater or less than an 11% threshold), the architectural disturbances were found to imply two mechanisms. A progressive decline in trabecular thickness was noted in both groups versus controls. Trabecular perforations were not established in the group with BV/TV> 11% with the star volume or ICI, although some alterations were detected by trabecular bone pattern factor measurement. However, perforations were revealed in the group with BV/TV < 11% by all the different methods. Perforations seemed to occur when the trabecular thickness was below 70 mu m. This strongly suggests that bone histomorphometry should take into consideration bone volume in combination with detailed 3D descriptors of the trabecular architecture. Several histological methods need to be used in combination to appreciate the 3D architecture of trabecular bone.

Adrenal Cortex Hormones↗
PubMed1996

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↗
PubMed1996

Bacterial endocarditis revealed by infectious discitis.

A study of 30 patients admitted for infectious discitis identified four cases with concomitant bacterial endocarditis. All four patients were male and had concomitant streptococcal septicemia. Two patients had known aortic valve disease. The vertebral infection was located to the thoracic or lumbar spine. Ultrasonography disclosed aortic lesions in all four patients and mitral lesions in two. Management consisted of intravenous antimicrobial therapy for four weeks followed by a three-month course of oral antimicrobial therapy. The outcome of the discitis was favorable within the usual period of time. However, the endocardial lesions continued to progress, and three patients rapidly required valve replacement. Analysis of available data in the 30 patients with discitis showed that half the patients with streptococcal discitis also had bacterial endocarditis and that the latter condition developed in all the patients with streptococcal discitis and a history of valve disease. A number of risk factors were identified. An echocardiogram should be done routinely in patients with infectious discitis and risk factors for bacterial endocarditis.

Adult↗
PubMed1995

Hepatitis C virus infection and autoimmune thrombocytopenic purpura.

BACKGROUND/AIMS: Chronic hepatitis C virus infections are often associated with extra-hepatic immunological manifestations, including various autoimmune disorders. The aims of this study were: (i) to determine the prevalence of hepatitis C virus markers in patients with autoimmune thrombocytopenic purpura, and (ii) to determine whether a relationship could exist between autoimmune thrombocytopenic purpura and hepatitis C virus infections. METHODS: One hundred and thirty-nine patients with autoimmune thrombocytopenic purpura (45 men, 94 women, mean age 42 years, range 16-90) were studied. RESULTS: Anti-HCV antibodies were sought in their first and last available cryopreserved sera. In case of seropositivity, all their available cryopreserved sera were tested for anti-HCV antibodies and for HCV-RNA. Anti-HCV antibodies were detected in 14 of the 139 patients (10%). Four patients had transient anti-HCV seropositivity due to passive transfer of anti-HCV antibodies secondary to the infusion of intravenous immunoglobulin concentrates. Three patients seroconverted during follow up, due to intravenous drug use in one case, transfusion of non-HCV-screened blood units in one case, and infusion of intravenous immunoglobulins in one case. Seven patients had chronic hepatitis C discovered at the same time as autoimmune thrombocytopenic purpura. In two of them, hepatitis C virus transmission was the consequence of autoimmune thrombocytopenic purpura treatment but, in five cases, hepatitis C virus infection predated autoimmune thrombocytopenic purpura, so that the role of hepatitis C virus in autoimmune thrombocytopenic purpura could be suggested. CONCLUSIONS: Whereas hepatitis C virus does not appear to be the main etiological agent of autoimmune thrombocytopenic purpura can be envisaged. On the other hand, treatment of autoimmune thrombocytopenic purpura or autoimmune thrombocytopenic purpura-related symptoms by blood product infusion can be complicated by hepatitis C virus transmission.

Adolescent↗
PubMed1995

Posttransfusion purpura-like syndrome associated with CD36 (Naka) isoimmunization.

BACKGROUND: CD36 deficiency, which could lead to CD36 isoimmunization, has been reported in the Japanese population. CD36 isoantibody has been involved in platelet transfusion refractoriness. CASE REPORT: A 50-year-old woman originally from Corsica developed severe acute thrombocytopenia after massive transfusion. She was found to be CD36 deficient, and platelet immunoassays revealed a CD36 (Naka) platelet isoantibody. Although the involvement of another mechanism could not be entirely ruled out, the thrombocytopenia was attributed to posttransfusion purpura-like syndrome. The antibody was also involved in platelet transfusion refractoriness. CD36 deficiency was present in two members of the patient's family as well. Flow cytometry studies demonstrated the absence of CD36 expression on the surface of blood monocytes and cultured erythroblasts and megakaryocytes from one of the two CD36-deficient family members studied, but, in the absence of previous immunization, these CD36-deficient patients were not isoimmunized. In contrast, CD36 deficiency was not found in a population of 808 healthy blood donors in the Paris, France, area. CONCLUSION: CD36 isoantibody might be involved in some cases of posttransfusion purpura and platelet transfusion refractoriness. These findings also confirm the extremely low frequency of CD36 deficiency among whites.

Blood Platelets↗
PubMed1994

Thrombocytopenia after bone marrow transplantation caused by a recipient origin Br(a) allo-antibody: presence of mixed chimerism 3 years after the graft without hematologic relapse.

We report a case of mild, clinically asymptomatic, immune thrombocytopenia after allogenic bone marrow transplantation (BMT) for chronic myeloid leukemia (CML) caused by the presence of a recipient-origin Br(a) antibody that recognized the donor platelets. Although the antibody titer decreased, it remained detectable more than 3 years after BMT. Chimerism studies were performed combining cytogenetics, blood cell phenotype studies, and genomic amplification of hypervariable sequences. Cytogenetic studies and molecular analysis of peripheral blood cells, purified B- and T-lymphocyte subpopulations, and bone marrow colonies showed the hematopoiesis to be of donor origin, but absorption-elution experiments with peripheral RBCs showed a small amount of recipient RBCs. The CML chimeric transcript was also detected by means of polymerase chain reaction on samples collected until day +867 post-BMT. This case shows that recipient-origin platelet alloantibodies can cause thrombocytopenia after BMT and that the persistence of small numbers of recipient cells (even leukemic) is not necessarily associated with hematologic relapse.

Adult↗
PubMed1994

Anti-GMP140 (CD62) autoantibody in a patient with autoimmune thrombocytopenic purpura.

The presence of platelet GMP140 (CD62) antibodies was analysed by the MAIPA test in 57 sera from patients with AITP and on platelets from 54 patients with thrombocytopenia of suspected immune origin. A CD62 antibody was found in only one serum. Its specificity was confirmed by an ELISA and a radioimmunoprecipitation procedure using total intact platelets and immuno-purified GMP140. An increased amount of platelet-associated (PA) IgG, due to in vivo fixation of GMP140 and GpIIb/IIIa antibodies, was also found on the patient platelet membrane. suggesting that GMP140 autoantibody may contribute to immune platelet destruction. No increase in PAGMP140 antibody was found on the other 54 platelet suspensions.

Aged↗
PubMed1992

Presence of cross-reactive antibody between human immunodeficiency virus (HIV) and platelet glycoproteins in HIV-related immune thrombocytopenic purpura.

We previously reported the presence in platelet eluates of autoantibodies directed against epitopes of the platelet glycoprotein (GP)IIb/IIIa complex in acquired immunodeficiency syndrome (AIDS)-free human immunodeficiency virus (HIV)-infected patients with immunologic thrombocytopenic purpura (ITP). We investigated whether HIV antibodies recognized platelet membrane antigens to determine whether the virus might be directly or indirectly responsible for the thrombocytopenia in this context. Direct eluates of platelets from 25 patients with HIV-related ITP contained IgG reacting with HIV-GP160/120 and also, in 45% of patients, detectable antiplatelet antibodies, immunochemically characterized as anti-GPIIb and/or anti-GPIIIa in 5 patients. Furthermore, serum HIV-GP160/120 antibodies could be absorbed on and eluted from platelets from normal non-HIV-infected healthy blood donors (indirect eluates). In contrast, GP160/120 antibodies present in the serum of nonthrombocytopenic HIV-infected patients were not absorbable on normal platelets in most patients, suggesting a pathogenic role in HIV-related ITP. We performed detailed studies of a patient with the highest titer of both HIV-GP160/120 and GPIIb/IIIa antibodies in direct and indirect platelet eluates. No antibody binding to GPIIb/IIIa-deficient Glanzmann thrombasthenic platelets was detected. Furthermore, binding/elution experiments conducted with insoluble recombinant GP160 (expressed in baculovirus) and purified platelet GPIIb/IIIa demonstrated that the patient's IgG bound specifically, through the F(ab')2 portion, to a common epitope of HIV-GP160/120 and platelet GPIIb/IIIa. This common epitope was present on a recombinant GP160 expressed in baculovirus but absent from another recombinant GP160 expressed in vaccinia virus, suggesting that the cross-reactivity is dependent on the glycosylation or conformational structure of the GP. We conclude that molecular mimicry between HIV-GP160/120 and platelet GPIIb/IIIa may explain at least some cases of ITP in AIDS-free HIV-infected patients.

Autoantibodies↗
PubMed1992

Frequency of the polymorphonuclear neutrophil Fc gamma receptor III deficiency in the French population and its involvement in the development of neonatal alloimmune neutropenia.

We report the case of a healthy woman (K.M.) who, after multiple pregnancies, developed an antibody directed against a nonpolymorphic region of the polymorphonuclear neutrophil (PMN) Fc gamma receptor III (FcRIII-CD16), which caused transient neonatal alloimmune neutropenia (NAIN). The antigenic target of the antibody was determined by an immunoprecipitation procedure and by phenotyping the mother's PMN. These latter did not react with monoclonal CD16 or polyclonal and monoclonal NA1 and NA2 antibodies, demonstrating the absence of PMN-FcRIII and, consequently, the NA-null phenotype. We also determined the frequency of the NA-null phenotype in a healthy, white population. Among 3,377 random blood donors, only four (in addition to K.M.) were PMN-FcRIII-deficient. These five individuals were healthy and only one (K.M.) presented an allo-CD16 antibody. The gene frequency of the NA-null phenotype was calculated as 0.0274 +/- 0.0059. We conclude that PMN-FcRIII deficiency is a rare phenomenon that can lead to CD16 alloimmunization and thus cause NAIN.

Antigens, CD↗
PubMed1992

Platelet alloimmunization after multiple transfusions: a prospective study of 50 patients.

Fifty polytransfused patients were prospectively studied to determine the frequency of post-transfusion alloimmunization and its influence on the response to platelet transfusion. Platelet- and HLA-specific antibodies were detected by means of the standard and antiglobulin-augmented lymphocytotoxicity techniques (LCT), the platelet suspension indirect immunofluorescence test (PSIIFT), and monoclonal antibody immobilization of platelet antigens (MAIPA). HLA antibodies were detected in 13 patients (26%) (IgM = 6; IgG = 6; IgM + IgG = 1). The standard LCT was positive in 12 of these 13 patients. Complement-independent HLA antibodies, only detectable in the PSIIFT and the antiglobulin-augmented LCT, were documented in two patients and were associated with poor post-transfusion platelet recovery in the patient who could be evaluated. All the HLA antibodies were detected in the PSIIFT, while only four were detected in the MAIPA. Platelet-specific alloantibodies were found in two patients by means of PSIIFT or MAIPA and may have led to poor post-transfusion platelet recovery in one patient. Platelet autoantibodies were detected in two patients but were not associated with platelet refractoriness. Paraformaldehyde-dependent platelet antibodies were detected in 11 patients but were not associated with platelet refractoriness.

Adolescent↗
PubMed1991

Brb, a platelet alloantigen involved in neonatal alloimmune thrombocytopenia.

Serum from a pregnant woman with the May-Hegglin anomaly contained a platelet-specific antibody. The serum reacted in the platelet indirect immunofluorescence test (PIIFT) with 97.6% of random donor platelets and those of the father but not with the mother's own platelets. This antibody induced a moderate thrombocytopenia in the infant that responded to infusion of intravenous immunoglobulin concentrates. The platelet phenotypes were PLA1+, Baka+, Bra+/Brb- for the mother, PLA1+, Baka+, Bra-/Brb+ for the father, and PLA1+, Bra+/Brb+ for the neonate. Analysis of the maternal serum with an immunoassay based on monoclonal antibody immobilization of platelet antigens (MAIPA) and immunoprecipitation techniques demonstrated the absence of antibodies directed against HLA class I antigens and that the antigen recognized was located on the platelet-GpIa/IIa complex. This antigen was present on 113/115 random donor platelets, in 7 of the 7 unrelated May-Hegglin platelets, and only absent in 3/24 Bra+ individuals, including the mother. No platelet-specific antibody was present in the serum of the 7 unrelated May-Hegglin subjects. The antigen recognized by this platelet-specific antibody thus meets the criteria defining the antithetic allele of Bra, i.e. the Brb alloantigen.

Adult↗
PubMed1990

[Post-transfusion purpura. An unknown cause of acute immune thrombocytopenia. 4 new cases].

Post-transfusion purpura is characterized by the occurrence of acute immune thrombocytopenia 5 to 10 days after transfusion of platelet-containing blood products in subjects who had been alloimmunized to specific platelet antigens. Four cases are reported here. Three of these 4 patients, who had a rare PLA1 platelet phenotype, had developed, during a previous sensitization (pregnancy n = 2, transfusion n = 1), an allo antibody directed against PLA1 antigen. The fourth patient presented a specific anti-PLA2 antibody. Thrombocytopenia (platelet count between 4 and 40 x 10(9)/1) appeared 1 to 12 days after the responsible transfusion and showed as haematomas (n = 3) or haemoptysis (n = 1). One patient was asymptomatic and remained untreated. The remaining 3 patients received corticosteroids orally associated, in one case, with infusions of human immunoglobulin concentrates. Thrombocytopenia was corrected within 5 to 13 days. In such cases, whenever another blood transfusion is necessary, a preventive treatment with perfectly platelet-free blood products is mandatory. Platelet depletion by freezing-thawing of red cell concentrates is probably not always sufficient, since recurrence was observed with such a product in one of our patients. The exact cause of immune destruction of autologous platelet remains a mystery.

Adult↗