Platelet-associated IgM elevated in patients with chronic hepatitis C contains no anti-platelet autoantibodies

Abstract: We investigated whether thrombocytopenia in patients with chronic hepatitis C is due to anti-platelet autoantibodies. Platelet-associated IgG (PAIgG) and platelet-associated IgM (PAIgM) were measured by direct immunofluorescent flow cytometric analysis. Elevation of PAIgM level was detected in 70% of chronic hepatitis C patients, while only a mild elevation of PAIgG level was detected in 32% of the cases. The elevation of PAIgM values in these patients was comparable to that in patients with chronic immune thrombocytopenic purpura (ITP). However, elevated PAIgM was also found in both patients with and without thrombocytopenia, and no correlation was found between PAIgM and platelet count. Eluted PAIgM did not react with normal platelets in all cases with a positive PAIgM value, indicating that eluted PAIgM contained no detectable anti-platelet antibodies. During alpha-interferon therapy, the level of PAIgM increased in association with the decrease in platelet counts in 75% of the cases; however, eluted PAIgM at any day point never reacted with platelets from normal donors. PAIgM was elevated in patients with chronic hepatitis C, but contained no detectable anti-platelet autoantibodies. Thrombocytopenia in these patients is not due to anti-platelet autoantibodies.     

Malignant histiocytosis associated with autoimmune thrombocytopenia

We describe a patient with malignant histlocytosis whose serum contained an autoantlbody against platelet protein. The patient was admitted because of nasal bleeding and high-grade fever. The clinical course was fulminantly progressive and terminated with cerebral hemorrhage. Bone marrow aspirate showed the proliferation of large atypical cells, some of which exhibited phagocytic activity. At postmortem examination, there was diffuse infiltration of these atypical cells In the liver, spleen, kidney, and bone marrow. Morphological, cytochemlcal, immunohistochemlcal, and genotypic characteristics suggested that the proliferating cells were derived from the monocyte-rnacrophage system. Western blot analysis revealed the presence of autoantibody against an ～88 kd molecule of platelet proteins. Although the relationship of cause and effect remains to be clarified, this autoantibody appeared to have stimulated thrombophagocytosls of the neoplastic cells. © 1994 Wiley-Liss, Inc.     

Cardiobacterium hominis endocarditis associated with very severe thrombocytopenia and platelet autoantibodies

Severe thrombocytopenia is a life-threatening condition. It is often associated with immune-mediated platelet destruction or myeloablative chemotherapy. Infective endocarditis has been associated with thrombocytopenia, which, as in sepsis, tends to be mild and is often the result of several pathological mechanisms. We report a case of Cardiobacterium hominis endocarditis associated with very severe thrombocytopenia and bleeding in a patient who refused platelet transfusion. Platelet autoantibodies directed against glycoprotein (Gp) IIb/IIIa and Gp Ib/IX were detected during active infection using a glycoprotein-specific assay. Successful treatment of C. hominis endocarditis was associated with loss of platelet autoantibodies and recovery of the platelet count. This report illustrates that the development of platelet autoantibodies can contribute to very severe thrombocytopenia in occasional patients with infective endocarditis.     

Cyclic thrombocytopenia in a patient treated with cyclosporine for refractory idiopathic thrombocytopenic purpura

Cyclic thrombocytopenia (CT) is a rare disorder with cyclic changes of the platelet counts. Though the pathogenesis of this disorder has not been clarified, recent reports suggest that periodic destruction and/or ineffective production of platelets may be important causes of the disease. We report a case of a patient with refractory idiopathic thrombocytopenic purpura (ITP) in whom CT developed after cyclosporine A (CyA) therapy. There was an inverse relation between platelet counts and the serum levels of platelet-associated immunoglobulin G (PAIgG). The ploidy of bone marrow megakaryocytes also had an inverse relation with platelet counts. When the platelet count was low, the ploidy of megakaryocytes increased (P < 0.01). The number and area of bone marrow megakaryocytes were unrelated to platelet counts. These results indicate the possibility of platelet destruction caused by immunological mechanisms in CT. Cyclosporine A could have certain but fluctuating regulatory effects against antibody production for circulating platelets, which could lead to cyclic changes of the platelet counts. This case also suggests that CyA can be effective in severe refractory ITP. Regulatory mechanisms of platelet production and destruction and appropriate doses of CyA should be further studied in autoimmune-mediated thrombocytopenias. Am. J. Hematol. 56:272–276, 1997. © 1997 Wiley-Liss, Inc.     

Cyclic change of cytokines in a patient with cyclic thrombocytopenia

The serial change of various cytokines in the serum from a patient with cyclic thrombocytopenia is described. Interleukin 7, stem cell factor, and transforming growth factor β1 synchronized with the platelet count, and there was a significant positive correlation between the three cytokines and the platelet count. Levels of macrophage colony-stimulating factor, thrombopoietin, platelet-associated IgG and erythropoietin changed reciprocally with the platelet count, and there was a significant negative correlation between the platelet count and these cytokines except erythropoietin. No cyclic change was observed in IL-3, IL-6, IL-11, granulocyte-macrophage colony-stimulating factor, or leukaemia inhibitory factor. These observations suggest that this disease involves two cyclic changes: megakaryocytopoiesis and platelet destruction, in both of which the cytokines play an important role.     

Cyclic immune thrombocytopenia responsive to thrombopoietic growth factor therapy.

We report a patient with cyclic thrombocytopenia and antiplatelet antibodies, a variant of chronic immune thrombocytopenic purpura (ITP), with a several year history of periodic fluctuation of the platelet count, megakaryocytic hyperplasia and high-titer anti-GPIb-specific antiplatelet antibodies. The patient was resistant to multiple forms of therapy but has responded to the thrombopoietic growth factor, pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF). This case suggests that some patients with classic ITP may respond to thrombopoietic growth factors.     

Determination of platelet-bound glycoprotein-specific autoantibodies by flow cytometric immunobead assay in primary immune thrombocytopenia

Objectives: Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by premature platelet destruction induced by autoantibodies directed against platelet glycoproteins (GPs). Despite being a clinically important disorder, ITP lacks a feasible diagnostic assay for routine clinical use. This study was meant to evaluate a newly developed flow cytometric immunobead assay for determination of platelet‐bound GP‐specific autoantibodies in comparison with indirect monoclonal antibody‐specific immobilization of platelet antigen (MAIPA) in the diagnosis of ITP. Methods: Platelet‐bound and plasma GPIIb/IIIa and GPIb/IX autoantibodies were determined by flow cytometric immunobead assay and indirect modified MAIPA, respectively. The average fluorescence level for platelet‐bound, GP‐specific autoantibodies was given as a ratio to three normal controls tested simultaneously. Results: The median value of platelet‐bound GPIIb/IIIa and GPIb/IX autoantibodies in ITP group were 3.09 (range 0.78, 30.2) and 3.09 (range 0.72, 19.2), respectively, which were significantly higher than non‐ITP group [1.01 (0.67, 5.59) and 1.01 (0.79, 5.56), respectively, P < 0.001] and normal controls [1.02 (0.72, 1.76) and 1.03 (0.79, 1.73), respectively, P < 0.001]. The receiver‐operating characteristics curve analysis showed an area under the curve of 0.895 for GPIIb/IIIa autoantibody and 0.859 for GPIb/IX autoantibody, respectively. Combined detection of GPIIb/IIIa or GPIb/IX autoantibodies by flow cytometric immunobead assay showed a sensitivity of 82.11% for ITP diagnosis. Conclusion: This study demonstrated that determination of platelet‐bound, GP‐specific autoantibodies by flow cytometric immunobead assay was a convenient, sensitive, and specific test for the differential diagnosis of thrombocytopenic patients.     

Megakaryopoiesis in patients with cyclic thrombocytopenia

Summary Megakaryopoiesis was examined in 10 patients (eight females and two males) with cyclic thrombocytopenia (CT) to investigate the underlying pathogenesis. Numbers of CFU-Meg and megakaryocytes and the mean cytoplasmic area (mean area) of megakaryocytes at the peak, nadir, ascent mid phase, and descent mid phase of the platelet cycle were determined. The patients were classified as female cases group I (cases 1–4; previously diagnosed as ITP and CT occurred during remission), female cases group II (cases 5–8; persistent CT from initial diagnosis), and male CT (cases 9 and 10). In three of the four female cases in group I, numbers of CFU-Meg and megakaryocytes were normal or increased persistently during the platelet cycle, whereas the mean area fluctuated in synchrony with the platelet cycle, suggesting failure of cyclic production rather than platelet destruction. In the female cases in group II and one female case in group I, numbers of CFU-Meg and megakaryocytes were also normal or increased at four phases of the cycle, but the mean area did not fluctuate, remaining large during the cycle, suggesting cyclic destruction or platelet clearance. In contrast, in the male patients values for numbers of CFU-Meg, megakaryocytes and mean cytoplasmic area fluctuated during the platelet cycle, indicating that cyclic changes in megakaryopoiesis generated the platelet cycle. These findings indicate that the measurement of cytoplasmic area is useful for distinguishing cyclic platelet production from cyclic destruction or clearance in CT.     

Alloimmune neonatal thrombocytopenia associated with incidental maternal thrombocytopenia

In this report, we describe a mother with mild incidental thrombocytopenia who delivered a severely thrombocytopenic infant having alloimmune thrombocytopenia. This coincidental association should be considered because the recognition and proper diagnosis of alloimmune neonatal thrombocytopenia is important, not only in the current pregnancy, but also in future pregnancies.     

Splenic hamartoma associated with thrombocytopenia

A case of splenic hamartoma associated with thrombocytopenia is reported. A 70-year-old man was referred to our hospital because of carcinoma of the body of the pancreas. Hematological examination disclosed thrombocytopenia and elevated serum CA19-9 and Span-1 levels. In addition to typical findings of pancreatic carcinoma, a solid mass was observed in the spleen by imaging procedures. On ultrasonography, the splenic mass was well demarcated and slightly hypoechoic. Computed tomography demonstrated a homogeneous low-density mass 5 cm in diameter. On T1- and T2-weighted magnetic resonance images, the splenic mass was demonstrated as low intensity and high intensity, respectively. On selective angiography, the tumor was hypervascular. Distal pancreatectomy plus splenectomy was performed. Microscopically, the splenic tumor consisted of red pulp tissue and was diagnosed as splenic hamartoma.     

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 antiplatlet 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.     

Complement-fixing platelet autoantibodies in autoimmune thrombocytopenia

A 16-year-old male patient is described with chronic autoimmune thrombo-cytopenic purpura and, after two years, “warm” autoimmune hemolytic anemia (Evans syndrome) who transiently developed complement-fixing platelet autoantibodies. The autoreactivity of these antibodies was established by quantitative complement fixation as well as by absorption and elution studies using autologous platelets. We believe this to be the first documented case with this very rare and peculiar type of platelet autoantibody.     

Platelet autoantibodies and lupus-associated thrombocytopenia

To characterize the antigenic targets of anti-platelet antibodies (APA) found in systemic lupus erythematosus (SLE)-associated thrombocytopenia, 48 patients with immune thrombocytopenia and SLE were compared with 20 patients with SLE who had never been thrombocytopenic. Both cases and controls were tested for circulating APA by an indirect platelet suspension immunofluorescence assay (PSIIFT) and by indirect monoclonal antibody specific immobilization of platelet antigens (MAIPA). A direct platelet suspension immunofluorescence assay (PSIFT) was also used for antibodies bound to platelets in vivo in thrombocytopenic patients; 13 of them with high titres of platelets-bound APA were investigated by direct and indirect MAIPA and platelet eluate analysis. Circulating APA were detected by PSIIFT in 88% of cases and 55% of controls (P = 0.0066) and platelet-bound antibodies were detected by PSIFT in 90% of cases. Indirect MAIPA detected specific APA (mainly directed against GpIIbIIIa) in 36% of cases and only 5% of the controls (P = 0.0076). Nine out of the 13 fully investigated thrombocytopenic patients (69%) had a positive direct MAIPA and/or APA detected in platelet eluates. In conclusion, the production of specific anti-platelet autoantibodies, mainly directed against GpIIb/IIIa, and their binding to platelet membrane plays an important role in the pathogenesis of SLE-associated thrombocytopenia.     

Relationships between severe neonatal thrombocytopenia and maternal characteristics in pregnancies associated with autoimmune thrombocytopenia

In pregnant women with antecedents of autoimmune thrombocytopenia (AITP), no predictive factor for severe fetal thrombocytopenia has been identified. We evaluated the relationships between the course of the maternal disease before and during pregnancy and the risk of severe fetal thrombocytopenia, in 64 pregnant women with known chronic AITP antecedents, over a 12-year period. 28 pregnant women had undergone splenectomy before pregnancy and 17 experienced severe thrombocytopenia (< 50 × 10⁹/l) during pregnancy (monthly determination). Eight infants presented with severe thrombocytopenia at birth (12.5%), and four in the following days (6.25%). No severe haemorrhage was observed. Severe thrombocytopenia at birth was present in 57% (CI 95% 18–90%) of the infants born to mothers with severe pregnancy-associated thrombocytopenia and splenectomy antecedents, and in 0% (CI 95% 0–15%) of the infants born to mothers who presented none of these antecedents ( P  = 0.001). In thrombocytopenic mothers the infant platelet counts at birth were positively correlated to the nadir maternal platelet count during the index pregnancy ( r  = 0.42, P  = 0.0075).
These results suggest that severe autoimmune disease is a risk factor for severe fetal thrombocytopenia, and that pregnant women with no antecedent of splenectomy nor severe thrombocytopenia during pregnancy have a very low risk of severe fetal thrombocytopenia.     

Reactivity of autoantibodies from chronic ITP patients with recombinant glycoprotein Ilia peptides

Summary Chronic immune thrombocytopenia is an autoimmune disorder characterized by destructive thrombocytopenia due to the formation of autoantibodies against platelet-associated antigens. Most antiplatelet autoantibodies react with either the platelet glycoprotein IIb/IIIa or Ib/IX complex, whereas some plasma autoantibodies react with glycoprotein IIIa. Previous studies from our laboratory suggested that most platelet-associated autoantibodies to platelet GPIIb/IIIa, which bind to the intact complex, bind much less avidly to the EDTA-dissociated complex, suggesting that the epitopes were complex-dependent. To evaluate this further we have studied the binding of platelet-associated autoantibody and plasma auto- and alloantibody eluates to large recombinant GPIIIa peptides: peptide 1 (GPIIIa Gly¹-Val²⁰⁰); peptide 2 (GPIIIa Arg¹⁵⁰-Glu⁴⁰⁰); peptide 3 (GPIIIa Lys³⁵⁰-Asp⁵⁵⁰); peptide 4 (GPIIIa Asn⁴⁵⁰-Val⁷⁰⁰) and peptide 5 (GPIIIa Trp⁷¹⁵-Thr⁷⁶², cytoplasmic fragment). Of the 33 platelet-associated antibody eluates tested, all bound avidly to the GPIIb/IIIa complex, but only one showed significant binding (>3 SD above control values) to one of the immobilized peptides (peptide 3). Conversely, antibodies known to bind to specific regions of GPIIIa (murine monoclonal antibody, anti-LIBS2; plasma autoantibody against the GPIIIa cytoplasmic fragment and anti-P1^A1 antibody) all bound avidly to the GPIIIa peptide containing the appropriate epitope. Based on these and our previous results, we conclude that platelet-associated antibodies from chronic ITP patients rarely bind to epitopes localized to GPIIIa alone.     

Neuroleptic malignant syndrome associated with severe thrombocytopenia

The case of a 32-year-old woman with neuroleptic malignant syndrome and severe haemorrhagic thrombocytopenia is presented. Detailed investigations were negative, and the thrombocytopenia resolved along with her fever, obtundation, autonomic instability and oculogyric crisis. No prior similar cases have been described in the literature. A discussion of neuroleptic malignant syndrome and neuroleptic-related thrombocytopenia follows, in addition to the possible mechanisms of the thrombocytopenia in this case.     

Bilateral adrenal hemorrhage associated with heparin induced thrombocytopenia

Heparin induced thrombocytopenia (HIT) is associated with serious and sometimes devastating thrombotic events. We report a case of bilateral adrenal hemorrhage (BAH) associated with HIT after prophylactic use of low molecular weight heparin. The vague presenting symptoms of acute adrenal insufficiency offers a diagnostic challenge, which if delayed may be life threatening. A high index of suspicion for adrenal hemorrhage is required in patients receiving any form of heparin therapy presenting with new onset thrombocytopenia, abdominal pain, and fevers.     

Danazol therapy for cyclic thrombocytopenia

Cyclic thrombocytopenia is a rare disease characterized by cyclic oscillations of platelet counts from very low to normal or higher. Severe hemorrhage may occur during the thrombocytopenic phase. To date, treatments for this disorder have been disappointing. Its pathophysiology is unknown. We report a successful outcome using danazol therapy. Prior to danazol treatment, the patient had a 7 year history of cyclic thrombocytopenia, refractory to glucocorticoids, splenectomy, azathioprine, vinca alkaloids, plasma infusions, and hormonal manipulation with Premarin-Provera. Her platelet counts were found to be oscillating in a 21 day cycle between 1 x 10(9)/L and 500 x 10(9)/L. Platelet-associated antibodies were positive and chromium-labeled platelet survival time was shortened. Following 2 months of danazol therapy, her platelet counts at the nadirs were significantly higher than at previous nadirs, and at no time thereafter dropped to the critically low values seen before danazol. Also at 2 months of danazol treatment, the patient reported amelioration of petechiae, and at 9 months it was completely cleared. However, platelet-associated IgG remained positive and platelet counts continued to oscillate, typically between 100 x 10(9)/L and 300 x 10(9)/L in the second year, but stabilized at 3 years, when platelet-associated IgG also disappeared. Danazol was discontinued after 3.5 years. The patient remains in unmaintained remission today, approximately 5 years after discontinuance of danazol. It can be argued that the long-term outcome was due to spontaneous remission. However, significant improvement was noted from the outset of danazol therapy, and further improvement with long-term therapy, as seen in the response of chronic ITP to danazol therapy. Danazol may offer lasting benefit in cyclic thrombocytopenia.