Flow cytometry detection of platelets autoantibodies in children with idiopathic thrombocytopenic purpura

Abstract

Immune thrombocytopenic purpura is an acquired disorder, in which accelerated platelet consumption is due to platelet autoantibodies. The aim of this study was to investigate the clinical value of platelet autoantibodies assay in children with ITP and to evaluate fl ow cytometry in the detection of platelet autoantibodies in comparison with monoclonal antibody specifi c immobilization of platelet antigen (MAIPA) assay. We measured platelet autoantibodies by fl ow cytometry and MAIPA in 18 children with ITP (6 acute, 7 chronic and 5 in remission), in addition to 5 healthy children with matched age and sex as a control group. Signifi cant elevation of platelet-associated immunoglobulin G (PAIgG), PAIgM and PAIgA was demonstrated in children with acute ITP compared to controls and children with chronic ITP (P < 0.05). There was signifi cant elevation of PAIgG and PAIgM in children with acute ITP compared to children with ITP in remission (P < 0.05). There was signifi cant negative correlation between platelet count and PAIgG levels in ITP children (r = -0.717; P = 0.001). Flow cytometry found PAIgG in 94.4% of ITP children. MAIPA has detected platelet specifi c IgG autoantibodies in 83.3% of ITP children. ROC analysis revealed sensitivity of 94%, specifi city of 57% with overall accuracy of 83% for detection of PAIgG by fl ow cytometry compared to MAIPA.Conclusions Platelet autoantibodies testing in ITP can discriminate acute from chronic forms of the disease and is helpful in follow up of patients. Determination of PAIgM in combination of PAIgG could be of interest in the investigation of ITP. Flow cytometry is a sensitive method of detection of platelet autoantibodies that could be used in screening of suspected ITP and should be followed by MAIPA assay in positive cases to establish the diagnosis.

Flow cytometric measurement of platelet‐associated immunoglobulin in children with newly diagnosed Immune Thrombocytopenia

“…Aref et al . in a study of 18 children found higher levels in acute than in chronic or remitted ITP and noted a negative correlation between PAIgG and platelet count; in a ROC analysis, the test was 83% accurate in predicting the result of MAIPA. Badrawy et al .…”

“…A version permitting quantitation of PAIG using calibration with fluorescent immunobeads has been developed . Most clinical studies have investigated adults with ITP, but a few concerning children have been reported . FCM may also simplify measurement of platelet‐specific autoantibodies, as shown in a recently described immunobead assay .…”

Thrombopoietin and its receptor expression in pediatric patients with chronic immune thrombocytopenia

“…In our previous study, we found that the levels of plateletspecific auto-antibodies and platelet-associated antibodies declined during prolonged ITP. The expression of platelet antibodies was different between cITP and acute immune thrombocytopenia (aITP) patients, but no significant difference between cITP patients and the healthy control group was reported [10], suggesting that antibody-mediated destruction of platelets may not be the primary cause of childhood cITP.…”