Abstract

Anti-heparin–platelet factor 4 (anti-HPF4) antibodies play a key role in heparin-induced thrombocytopenia (HIT). These antibodies can participate in thrombosis and mortality through platelet activation. HIT is a life-threatening complication. Recently, HIT has been reported as a risk factor of thrombocytopenia exacerbation in COVID-19 patients. In the present study, we assessed the incidence of anti-HPF4 in patients with COVID-19 and the relationship with ICU hospitalization and mortality. This cross-sectional descriptive study was performed on 97 COVID-19 patients in Yasuj City (Southwest zone of Iran). Demographic factors and platelet count, PT, APTT, and D-dimer were recorded and checked at admission and during hospitalization. Anti-HPF4 antibody assay was performed for all eligible patients by ELISA method. Statistical significance was based on two-sided design-based tests evaluated at the 0.05 level of significance. Most of the patients (n = 57, 58.8%) were male. The mean age of the patients was 55.46 ± 15.2 years, and the mean hospitalization was 17.57 ± 7.2 days. The mean length of stay was 209.9 ± 79.8 × 10³/µL. The results of the anti-HPF4 antibody assay showed that 9.3% (n = 9) of the patients were positive for anti-HPF4 antibody. The mortality rate was higher in the HPF4-positive patients. Although the true frequency of HIT in this study was unclear, it can be concluded that anti-HPF4 antibodies are involved in the pathophysiology of HIT which is a life-threatening complication in COVID-19 patients receiving heparin treatment, with a high rate of morbidity and mortality.

中文翻译：

---

COVID-19 患者中抗肝素 PF4（抗 HPF4）抗体的血清阳性率及其与 ICU 住院和死亡率的相关性

摘要

抗肝素血小板因子 4 (抗 HPF4) 抗体在肝素诱导的血小板减少症 (HIT) 中发挥关键作用。这些抗体可以通过血小板活化参与血栓形成和死亡。 HIT 是一种危及生命的并发症。最近，有报道称 HIT 是 COVID-19 患者血小板减少症加重的危险因素。在本研究中，我们评估了 COVID-19 患者中抗 HPF4 的发生率以及与 ICU 住院和死亡率的关系。这项横断面描述性研究是对亚苏季市（伊朗西南地区）的 97 名 COVID-19 患者进行的。在入院和住院期间记录并检查人口统计学因素和血小板计数、PT、APTT 和 D-二聚体。通过ELISA方法对所有符合条件的患者进行抗HPF4抗体测定。统计显着性基于以 0.05 显着性水平评估的双边设计测试。大多数患者（n  = 57，58.8%）为男性。患者的平均年龄为55.46±15.2岁，平均住院时间为17.57±7.2天。平均停留时间为 209.9 ± 79.8 × 10 ³ /μL。抗HPF4抗体检测结果显示，9.3%（n  =9）的患者抗HPF4抗体呈阳性。 HPF4阳性患者的死亡率较高。尽管本研究中 HIT 的真实频率尚不清楚，但可以得出结论，抗 HPF4 抗体参与了 HIT 的病理生理学，HIT 是接受肝素治疗的 COVID-19 患者中危及生命的并发症，发病率很高和死亡率。