Discussion
Bleeding is the only clinical manifestation of ITP and varies from mild skin mucosal hemorrhage to severe intracranial hemorrhage. Severe bleeding not only affects the quality of life but also threatens life in children with ITP. Therefore, it is important to explore the influencing factors of bleeding in ITP. GPIIb/IIIa and GPIb/IX mediate platelet aggregation and adhesion and play an important role in hemostasis. The antibodies could theoretically aggravate bleeding symptoms in ITP patients. However, previous studies that elucidated the relationship between the platelet-specific antibodies and bleeding severities, reached different conclusions. Nomura et al.9 reported that patients with anti-GPIb/IX antibodies had more severe bleeding manifestations than patients without anti-GPIb/IX antibodies. Mehta et al.10found that patients with both anti-GPIIb/IIIa and anti-GPIb/IX antibodies were more prone to develop moderate or severe bleeding symptoms than patients with only one antibody or without antibodies. Al-Samkari et al.11found a statistically significant predictive relationship between the increasing number of positive autoantibodies and disease severity. Fu et al.8 from our research group found no significant difference in the degree of bleeding between different types of platelet-specific antibodies. However, that study focused on the relationship between platelet-specific antibodies and glucocorticoid response, but less on bleeding, and did not exclude the influence of platelet count and chronic ITP on bleeding. Therefore, whether platelet-specific antibodies result in severe bleeding manifestation requires more evidence.
Our study was a prospective and observational cohort study. The enrolled cases were all diagnosed according to the international consensus guidelines and did not have a history of taking special platelet elevation drugs before the detection of platelet-specific antibodies. The baseline platelet counts in all cases were less than 10×109/L to eliminate the influence of platelet count on bleeding. We detected platelet-specific antibodies in both plasma and eluent and analyzed antibodies’ levels qualitatively and quantitatively to ensure a more accurate and credible conclusion of the relationship between platelet-specific antibodies and bleeding severities.
Our data demonstrated that there was no significant difference in the distribution of platelet-specific antibodies between the two bleeding severity groups, and also displayed no difference in antibody titer ratios between the two bleeding severity groups in both plasma and eluent. Finally, we concluded that platelet-specific antibodies (anti-GPIIb/IIIa and anti-GPIb/IX antibodies) were not related to the bleeding severities in children with newly diagnosed ITP with serious decline of platelet count.
Authorship Contributions: All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Shuyue Dong, Linging Fu, Xingjuan Xie and Hao Gu; Hao Gu and Xingjuan Xie did the sample collection and antibody test;Lingling Fu, JingyaoMa and Jie Ma recruited all the subjects and collected the written informed consents;The first draft of the manuscript was written by Shuyue Dong and all authors commented on previous versions of the manuscript. Runhui Wu and Zhenping Chen read and approved the final manuscript.
Acknowledgements: None.