| Background Immune thrombocytopenia is a common autoimmune disease characterized by autoantibody-induced platelet destruction and resulting in bleeding disorders. The major targeted platelet autoantigens are GPIIb IIIa and GPIb complexes. a lot of researches have demonstrated that anti-GPIba-mediated-ITP by different approach. We tested platelet specific autoantibodies here,if steroid therapy has equal efficacy in ITP patients.Methods a total of 320 ITP patients(215 females and 105 males,the median age 43(13-91)) were recruited for the present study and were treated with dexamethasone(40mg*4d,reduce the dose gradually after effeciency with 5-10mg/d,drug withdrawal between three and four weeks).Detecting the kinds of platelet specific autoantibodies in 140 ITP(99 females and 41 males)patients,their plasma was anticoagulated by two different anticoagulants EDTA-k2 and heparin. Detecting the types of platelet specific autoantibodies in 185 ITP(124 females and 61 males)patients with plasma anticoagulated by EDTA-k2.Then compareing the treatment results between the two different platelet specific autoantibodies.Results From the 320 ITP patients research, 19.4%(62/320) had antibodies against GPIIb IIIa, 18.4%(59/176) had antibodies against GPIba, 26.3%(84/176) had antibodies against both GPIIb IIIa and GPIba(double positive), and 35.9%(115/176) had no detectable antibody to either of these two antigens(double negative)。There was statistically significant difference between GPIIb IIIa group and GPIba group(χ2=26.833,P<0.01). and there was statistically significant difference between GPIIb IIIa group and double positive group( χ2=14.227,P<0.05). There was no statistically significant difference between GPIba group and double positive group(χ2=3.664,P >0.05). There was no statistically significant difference between GPIIb IIIa group and double negative group(χ2=0.296,P >0.05). There was statistically significant difference between GPIba group and double negative group(χ2=42.818,P <0.05). Detecting the platelet- specific autoantibodies( GPIIb/IIIa and GPIba) in 140 ITP samples by modified MAIPA, 55 cases were anti-GPII b/III antibody-positive in EDTA-k2 group,while 76 cases in heparin group were anti- GPⅡb/Ⅲ-positive.The detection results of 42 cases in the both groups were repeatable,13 cases were positive in EDTA-k2 group, and negative in heparin group. On the contrary, 34 cases were positive in heparin group and negative in EDTA group,the difference was statistically significant( χ2=9.38,P<0.05). 62 out of 140 patients in EDTA-k2 group were the GPIbaantibody-positive, and 51 cases in heparin group were the GPIbaantibody-positive,42 cases were double-positive in both groups,and 20 cases were positive in EDTA-k2 and negative in heparin,and 9 cases were negative in EDTA-k2 and positive in heparin,the difference between them was not statistically significant(χ2=3.44, P > 0.05). Detecting the types of platelet specific autoantibodies( Ig G and Ig M) in 185 ITP samples by modified MAIPA,53 cases was only Ig G antibody-positive,56.7%(30/53) to be efficient with glucocorticoid treatment. 22 cases was only Ig G antibody-positive, 59.1%( 13/22) to be efficient with glucocorticoid treatment. 41 cases was both Ig G +Ig M antibody-positive,80.5%(33/41)to be efficient with glucocorticoid treatment. 69 cases was both Ig G +Ig M antibody-negative,76.8%(53/69)to be efficient with glucocorticoid treatment. There was no statistically significant difference between only Ig G antibody-positive group and only Ig M antibody-positive group( χ2=0.039, P=0.843 > 0.05).There was statistically significant difference between only Ig G antibody-positive group and bothIg G+ Ig M antibody-positive group(χ2=5.966,P=0.015<0.05).There was statistically significant difference between only Ig G antibody-positive group and both Ig G+ Ig M antibody-negative group( χ2=5.628, P=0.018 < 0.05).There was no statistically significant difference between only Ig M antibody-positive group and both Ig G+ Ig M antibody-positive group( χ2=3.327, P=0.068 > 0.05).There was no statistically significant difference between only Ig M antibody-positive group and both Ig G+ Ig M antibody-negative group(χ2=2.629, P=0.105 > 0.05).There was no statistically significant difference between both Ig G+ Ig M antibody-positive group and both Ig G+ Ig M antibody-negative group(χ2=0.204,P=0.652>0.05).Conclusions GPIba antibody positive may be lead to dexamethasone treatment insensitive in adults ITP patients. EDTA-k2 anticoagulant(a divalent cation chelator) has a significant effect on detection of ITP platelet-specific autoantibodies( GPIIb/IIIa) by modified MAIPA method. |
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