Aged ; Cross Reactions ; Female ; Heparin ; adverse effects ; immunology ; Heparin, Low-Molecular-Weight ; adverse effects ; immunology ; Humans ; Male ; Middle Aged ; Platelet Factor 4 ; immunology ; Thrombocytopenia ; blood ; chemically induced ; immunology

Heparin-induced thrombocytopenia (HIT) is an antibody-mediated complication of heparin treatment that can lead to thrombosis and thromboembolism. HIT is mainly caused by immunoglobulin G (IgG) class among anti-heparin/platelet factor 4 antibodies that bind to epitopes on platelet factor 4 (PF4) released from activated platelets that developed when it forms complexes with heparin. Platelet aggregation and hypercoagulation status result from this process. Besides, the reactions between antibodies and vascular endothelial cells and monocytes are involved in HIT. Laboratory detection of anti-heparin/platelet factor 4 antibodies after heparin administration may help diagnose HIT early. Tests for detecting antibodies to the heparin/PF4 complex can be classified into functional platelet assays (which rely on the demonstration of platelet activation) and immunoassays (which detect the presence of an antibody without regard for its functional ability). But there is no simple and effective test available currently. In this article the anti-heparin/platelet factor 4 antibodies, pathogenesis of HIT, clinical laboratory assays and immunoassays are reviewed.
Antigen-Antibody Complex ; immunology ; Heparin ; adverse effects ; immunology ; Humans ; Immunoglobulin G ; immunology ; Platelet Aggregation ; Platelet Factor 4 ; immunology ; Thrombocytopenia ; chemically induced ; immunology

In autoimmune thrombocytopenic purpura (AITP) specific autoantibodies bind platelet GP via their Fab fragments. Both splenic CD5+ B and CD5- B cells produce platelet glycoprotein-specific antibodies. There is limited number of antigenic determinants, and the GP-specific autoantibodies are derived from a restricted number of B-cell clones in chronic AITP. Blocking co-stimulatory signals could induce platelet-specific T cell anergy. MMF could be used as a second line agent for the treatment of steroid-resistant AITP. Detection of plasma thrombopoietin levels play an important role in the differentiation of thrombocytopenic states caused by platelet destruction or due to bone marrow hypoplasia. Endogenous TPO level is also important on the differential diagnosis of ET and RT. Quinine- or heparin-dependent antibodies could induce thrombocytopenia. PCR-SSP is useful for the genotyping of the platelet-specific alloantigen HPA. Biotinylated platelets have an impaired response to agonists as evidenced by in vitro platelet aggregation tests.
Antigens, Human Platelet ; immunology ; Blood Platelets ; immunology ; Heparin ; adverse effects ; Humans ; Platelet Membrane Glycoproteins ; immunology ; Purpura, Thrombocytopenic, Idiopathic ; etiology ; immunology ; Thrombopoietin ; blood

Adolescent ; Adult ; Cells, Cultured ; Dendritic Cells ; immunology ; Female ; Heparin ; pharmacology ; Hepatitis B, Chronic ; immunology ; Humans ; Interleukin-12 ; biosynthesis ; Interleukin-6 ; biosynthesis ; Male ; Middle Aged ; Phenotype

BACKGROUNDThe management of patients with recurrent miscarriage (RM) and antiphospholipid antibody syndrome (APS) includes prolonged treatment with heparin and aspirin, starting from the confirmation of pregnancy and continuing until 6 weeks after birth. This study was conducted to determine the relationship between changes in antiphospholipid antibody titers and clinical outcomes. The effect of a shortened treatment regimen was also evaluated.

METHODSA prospective study of 123 patients with RM and APS between March 2012 and May 2014 was conducted. Patients were pretreated with a low dose of prednisone plus aspirin before pregnancy, and heparin was added after conception. The levels of antiphospholipid antibodies and pregnancy outcomes were evaluated.

RESULTSAll patients were positive for anti-β2-glycoprotein 1 (anti-β2-GP1) IgM. After prepregnancy treatment with low-dose prednisone plus aspirin, 99 of 123 patients became pregnant, and 87 of those pregnancies resulted in successful live births, while 12 resulted in miscarriage, showing a success rate of 87.9%. In the live birth group, levels of anti-β2-GP1 were 56.8 ± 49.0 RU/ml before the pretreatment regimen, 32.1 ± 26.0 RU/ml after 2 months of pretreatment, and 24.1 ± 23.1 RU/ml during early pregnancy (P < 0.05). In the miscarriage group, antiphospholipid antibody titers were 52.8 ± 30.7 RU/ml before pretreatment, 38.5 ± 34.2 RU/ml after pretreatment, and 33.9 ± 24.7 RU/ml during early pregnancy; the decrease in antiphospholipid antibodies was lower in the miscarriage group than in the live birth group (P < 0.05). Of the 24 infertile patients, the average antibody titer did not decline after pretreatment (P = 0.802).

CONCLUSIONSAnti-β2-GP1 IgM was the predominant form of antibody in patients with RM and APS. The decreases in antiphospholipid antibody titers correlated with better pregnancy outcomes. The shorter treatment regimen was effective and economical.

Abortion, Habitual ; immunology ; prevention & control ; Adult ; Antibodies, Antiphospholipid ; immunology ; Anticoagulants ; therapeutic use ; Antiphospholipid Syndrome ; drug therapy ; immunology ; Aspirin ; therapeutic use ; Female ; Heparin ; therapeutic use ; Humans ; Live Birth ; Prednisone ; therapeutic use ; Pregnancy ; Pregnancy Complications ; prevention & control ; Pregnancy Outcome ; Prospective Studies

Since heparin is an anticoagulant commonly used in hemodialysis and the patients on hemodialysis are repeatedly exposed to heparin, heparin may be the cause of the development of heparin-dependent antibodies and thrombotic complications in patients on hemodialysis. The purpose of this study was to determine the prevalence and the clinical significance of the antibodies against heparin-platelet factor 4 complexes as determined by enzyme immunoassay in patients on maintenance hemodialysis. The prevalence of anti-heparin-platelet factor 4 antibodies was higher in hemodialysis patients than in normal subjects (8.8 vs 0.0%, p<0.05). The number of past episodes of vascular access obstruction per year was significantly higher in the anti-heparin-platelet factor 4 antibody positive group than antibody negative group. Anti-heparin-platelet factor 4 antibody positive patients experienced more frequent vascular access obstructions than control subjects. In conclusion, anti-heparin-platelet factor 4 antibody might be a risk factor for vascular access obstructions in patients with end-stage renal disease on maintenance hemodialysis.
Adult ; Autoantibodies/immunology* ; Autoimmune Diseases/immunology* ; Catheters, Indwelling* ; Enzyme-Linked Immunosorbent Assay ; Female ; Heparin/immunology* ; Human ; Kidney Failure, Chronic/blood ; Kidney Failure, Chronic/immunology ; Kidney Failure, Chronic/therapy* ; Male ; Middle Aged ; Platelet Factor 4/immunology* ; Recurrence ; Renal Dialysis* ; Risk Factors ; Thrombophilia/immunology* ; Thrombosis/epidemiology* ; Thrombosis/immunology ; Thrombosis/prevention & control

OBJECTIVETo study the plasma HCII activity and antigen level variations and their relationship with arterial and deep venous thrombotic diseases.

METHODSSeventy-five patients with brain infarction (BI), 50 myocardial infarction (MI), 36 deep venous thromboembolic disease (DVT) and 50 healthy controls were entered in this study. Plasma HCII activity was measured with chromogenic substrate method and the HCII antigen level by Western blotting assay. Plasma antithrombin (AT) activity was detected for the HCII deficiency individuals with DVT using chromogenic substrate method.

RESULTSThere was no significant difference in the mean plasma HCII activity and antigen levels between BI group [(99.97 +/- 21.14)% and 0.96 +/- 0.24], MI group [(98.18 +/- 29.35)% and 0.95 +/- 0.20] and healthy controls [(96.80 +/- 20.11)% and 0.93 +/- 0.19]. The plasma HCII activity and antigen concentrations in patients with DVT [(89.57 +/- 17.12)% and 0.87 +/- 10.18] tended to be decreased as compared with healthy controls, but they were not significant. No significant difference was found for the prevalence of HCII deficiency between patient groups and control group. The HCII deficiency individuals with DVT had normal AT activity and fibrinogen concentration.

CONCLUSIONSPlasma HCII deficiency may not be the risk factor for arterial thrombosis in the Han population of Hunan Chinese. It is needed to further confirm if decreased plasma HCII is correlated with venous thrombosis.

Adult ; Aged ; Blotting, Western ; Cerebral Infarction ; blood ; etiology ; Female ; Heparin Cofactor II ; analysis ; deficiency ; immunology ; Humans ; Male ; Middle Aged ; Myocardial Infarction ; blood ; etiology ; Venous Thrombosis ; blood ; etiology

This study was aimed to prepare the polypeptide of N-terminal heparin-binding domain of fibronectin(rhFNHN-29 polypeptide) with pichia expression system, to detect biological activity of recombinant polypeptide and investigate its effect on disseminated intravascular coagulation (DIC) in rats. The sequence of N-terminal heparin-binding domain of fibronectin was amplified from FNcDNA by PCR. The aim gene was cloned into T vector for selection. Then it was cloned into pAo815SM and pPIC9K vectors.Lined pPIC9K vectors were transformed into GS115 Pichia cells so as to express the aim polypeptide in Pichia expression system. The fermentation liquid were precipitated by 80% ammonium sulfate, and the further dissolved sediment were purified using S-100 column and SP column. Its activity of binding with heparin were detected by Western-blot. The established DIC rats (40 rats) were randomly divided into two groups. One group was treated with rhFNHN-29 polypeptide, and the other was treated with normal saline. The rats in the former group were injected with rhFNHN-29 polypeptide (10 mg/kg) through tail vein at 0.5 hour before, 2 hours and 4 hours after injection of LPS respectively. The rats in latter group were injected with equal volume saline. In addition, 20 normal rats injected with normal saline were as normal controls. 500 microl blood was taken from the rat vein, at 6 hours after the injection of LPS. White blood cell (WBC), hemoglobin (Hb) and platelets were tested from 50 microl blood. The rest 450 microl blood was used to isolate plasma for detecting TNFa level and coagulogram. The rats were killed at 24 hours after injection with LPS. Their livers, lungs, hearts, kidneys, and brain tissues were taken for histopathologic examination. The results showed that the aim polypeptide was successfully expressed in Pichia expression system. The expression level reached approximately 30 mg/L. The polypeptide had activity of binding with heparin antibody. In the experiment study of polypeptide effect on DIC in rats, the plasma TNFa level in polypeptide-treated group was lower than that in saline control group, the hemogram, coagulogram and histopathology were more obviously improved in polypeptide-treated group as compared with saline control group. It is concluded that the rhFNHN-29 polypeptide is successfully prepared, this polypeptide can antagonize DIC induced by endotoxin in rats.
Animals ; Disseminated Intravascular Coagulation ; therapy ; Endotoxins ; Female ; Fibronectins ; genetics ; immunology ; therapeutic use ; Heparin ; metabolism ; Male ; Peptides ; genetics ; therapeutic use ; Pichia ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the influence of divalent cation chelator EDTA and heparin sodium on the detection of ITP platelet-specific autoantibodies by the modified monoclonal antibody immobilization of platelet antigen assay (MAIPA) and to explore the relationship between types of platelet specific autoantibodies and glucocorticoid efficacy.

METHODSThe samples were obtained from EDTA- and heparin- anticoagulant ITP patients, respectively, so as to detect the platelet-specific autoantibodies (GPIIb/IIIa and GPIbα) in 140 ITP samples by modified MAIPA, then the differences between these two methods were compared.

RESULTSOut of 140 cases in EDTA group, 55 cases were positive for GPIIb/IIIa, while 76 cases in heparin group were positive for GPIIb/IIIa, 42 cases in both group were repeatable; among them 13 cases were positive in EDTA group and negative in heparin group, while 34 cases were positive in heparin group and negative in EDTA group, there was significant difference between them (x (2) = 9.38, P < 0.05), 62 cases in 140 cases of EDTA group were positive for GPIba, while 51 cases in heparin group were positive for GPIba, 42 cases in both group were repeatabe; among them 20 cases were positive in EDTA group and negative in heparin group, while 9 cases were positive in heparin group and negative in EDTA group, there was no significant difference between them (x (2) = 3.44, P > 0.05). A total of 320 cases received a standard glucocorticoid treatment, out of them 143 cases were positive for GPIbα with effective rate 39.9%, 177 cases were negative for GPIbα with effective rate 79.7%, there was statisticalty significant difference between them (x (2) = 53.115, P < 0.05).

CONCLUSIONEDTA anticoagulant (a divalent cation chelator) has a significant influence on detection of ITP platelet-specific autoantibodies (GPIIb/IIIa) by a modified MAIPA method and the GPIbα antibody positive may be one of the important factors that results in un-sensitivity of ITP patients to glucocorticoid treatment.

Antibodies, Monoclonal ; Anticoagulants ; therapeutic use ; Antigens, Human Platelet ; Autoantibodies ; blood ; Blood Platelets ; immunology ; Fibrinolytic Agents ; Glucocorticoids ; therapeutic use ; Heparin ; Humans ; Platelet Glycoprotein GPIIb-IIIa Complex ; Purpura, Thrombocytopenic, Idiopathic ; blood ; immunology

OBJECTIVETo expand cord blood megakaryocyte progenitor cells in vitro.

METHODSCord blood CD34+ cells were selected by magnetic cell sorting (MACS), and thrombopoietin (TPO), interleukin-11 (IL-11), and heparin were used in the expansion system of megakaryocyte progenitor. The expansion efficiency was measured by fluorescence-activated cell sorting (FACS) using the megakaryocytic specific monoclonal antibodies (CD34+, CD41a+, CD61+, CD34+CD41a+, CD41a+CD61+) and colony-forming units-megakaryocyte (CFU-MK) analysis. The expanded megakaryocyte progenitor were determined by histochemistry staining using CD41a and the observation of the ultrastructure of megakaryocyte (MK) by electron microscopy. The megakaryocyte function were examined by the platelet activation in vitro and nonobese diabetic/severe combined immunodifficiency (NOD/SCID) mice transplantation in vivo.

RESULTSCD34+CD41a+ cells was expanded (4.0 +/- 1.7) folds on day 7 in TPO (50 ng/ml) group and (10.5 +/- 4.8) fold in TPO combined with IL-11 group; after heparin was joined in on day 0, a more significantly elevated expansion was found in the heparin, TPO, and IL-11 group [(29.9 +/- 6.4) folds than the above two groups; P < 0.05]. Meanwhile, the large CFU-MK colony (> 50 cells/colony) was (106.8 +/- 26.9) folds on day 7 (P < 0.05). The megakaryocyte expanding with TPO, IL-11 and heparin for 7 days in vitro transplanted the NOD/SCID mice fasten the recovery of platelet and white blood cell account and improved the survival. Megakaryocyte under culture displayed certain development of territories membrane. Platelet activation test comfirmed that the expanding megakaryocyte progenitor had the normal function.

CONCLUSIONTPO, IL-11, and heparin combination system for ex vivo expansion is an effective expansion system of megakaryocyte progenitor.

Animals ; Antigens, CD34 ; Cell Differentiation ; drug effects ; immunology ; Cell Division ; drug effects ; Cells, Cultured ; Fetal Blood ; cytology ; Hematopoietic Stem Cells ; cytology ; drug effects ; immunology ; Heparin ; pharmacology ; Humans ; Interleukin-11 ; pharmacology ; Male ; Megakaryocytes ; cytology ; immunology ; Mice ; Mice, Inbred NOD ; Mice, SCID ; Thrombopoietin ; pharmacology