Objecfive To detect the specific autoantibodies against platelet in idiopathic thrombocytopenic purpura (ITP) and to study the relationship between these autoantibodies and the severity of ITP as well as therapeutic effect.Methods Autoantibodies (GPⅡbⅢa and GPIb) against platelet glycoprotein was measured by a monoclonal antibody immobilization of platelet antigen assay (MAIPA) in 40 ITP patients.Results 10 patients had mono-specific antibodies to GP Ⅱ bⅢa and 6 patients had mono-specific antibodies to GPIbα.Another 20 patients had antibodies to both antigens and 4 patients had no detectable antibody to either platelet antigen.There Was negative correlation between the antibody against GPⅡbⅢa(b=-0.071,P<0.01),CPIbα(b=0.092,P<0.01) and platelet counts.The ratio of refractory cases in patients with antibodies to both antigens(8/20) was significantly higher than that in patients with mono-specific antibodies(1/16)(χ2=6.09,P<0.05).Conclusion The specific autoantibadies against platelet might be valuable for discrininafion of idiopathic thrombocytopenic purpura and non immune thrombocytopenia.The types of antibodies are related with severity of ITP and therapeutic effect.

OBJECTIVETo assess the platelet and plasma concentrations of fibronectin (Fn) and fibrinogen (Fg) in congenital fibrinogenopenic (FgP) patients and explore their role in inducing platelet adhesion and aggregation.

METHODSA FgP family was selected as study group and the platelets isolated and purified to assess concentrations of Fn and Fg in platelets, alpha-granules and plasma with Western blotting, immuofluoresence staining and flow cytometry (FACS), respectively, the expression of platelets GP II b/III a by FACS.

RESULTSThe concentration of platelets Fn in FgP patients is higher than that in controls, and is higher in homozygote than in heterozygote. In contrast, plasma Fn levels were identical in all samples. The amount of platelet Fg from FgP patients is lower than that from the controls and positively correlated with the concentration of their plasma Fg. No difference in the expression of platelet GP II b/III a had been found.

CONCLUSIONIt suggested that increased platelet Fn could partially compensate the lack of Fg and lead the platelet adhesion and aggregation.

Afibrinogenemia ; congenital ; metabolism ; pathology ; Blood Platelets ; metabolism ; pathology ; Cell Adhesion ; physiology ; Female ; Fibrinogen ; genetics ; metabolism ; Fibronectins ; blood ; genetics ; metabolism ; Heterozygote ; Homozygote ; Humans ; Male ; Pedigree ; Platelet Aggregation ; physiology ; Platelet Membrane Glycoproteins ; metabolism

OBJECTIVETo investigate the different outcomes by dexamethasone in adults immune thrombocytopenia purpura (ITP) with different types of platelet specific-autoantibodies.

METHODSA total of 185 ITP were enrolled, 61 males and 124 females, with a median age of 42 (18-83) years, including 117 newly diagnosed, 35 persistent, and 33 chronic cases. All the patients received the dexamethasone at an initial dose of 40 mg per day for 4 days and a low dose of 5-10 mg for 3-4 weeks. The platelet specific-autoantibodies were identified by the modified monoclonal antibody-specific immobilization of platelet antigen (MAIPA) assay.

RESULTSAmong the IgG positive patients, the response rates in anti-GPIIb/IIIa antibody, anti-GPIbα antibody, both antibody positive, and both antibody negative were 87.5%, 50.0%, 68.0%, and 72.3% (χ²=11.489, P<0.05), respectively. Among the IgM positive patients, the response rates in the four groups were 82.1%, 71.4%, 61.9%, and 68.9% (χ²=2.719, P=0.437), respectively. Among the GPIbα antibody positive patients, the response rates in IgG alone, IgM alone, both positive, and both negative were 52.4%, 59.1%, 76.1%, and 77.9% (χ²=10.811, P<0.05), respectively. Among the GPIIb/IIIa antibody positive patients, the response rates in the four groups were 73.3%, 71.0%, 78.6%, and 66.3% (χ²=1.374, P=0.719), respectively.

CONCLUSIONITP patients with GPIbα-IgG antibody have worse response to dexamethasone treatment.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antibodies, Monoclonal ; Autoantibodies ; Blood Platelets ; Dexamethasone ; Female ; Humans ; Male ; Middle Aged ; Platelet Glycoprotein GPIIb-IIIa Complex ; Purpura, Thrombocytopenic, Idiopathic ; Young Adult