PB0095 - High Prevalence of Anti-PF4 Antibodies Among Hospitalized Pediatric COVID-19 Patients and The Impact on Morbidity and Mortality

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Co-Author(s)

Shiu-Ki R. Hui, MD

Associate Professor
Texas Children's Hospitals / Baylor College of Medicine
Houston, Texas, United States
SS

Sarah Sartain

Assistant Professor, Pediatrics, Section of Hematology/Oncology
Texas Childrens Hospital/Baylor College of Medicine
houston, Texas, United States
KB

Karen Bruzdoski

BS, MT (ASCP)
Department of Pathology & Immunology, Texas Children's Hospital
Houston, Texas, United States
VK

Vadim Kostousov

Professor Instructor
Texas Children's Hospital, Baylor College Of Medicine
Houston, Texas, United States
Amir H. Navaei, MD

Assistant Professor
Texas Children's Hospitals / Baylor College of Medicine
Houston, Texas, United States
LH

Lisa Hensch

Assistant Professor, Department of Pathology and Anesthesia
Texas Children's Hospitals / Baylor College of Medicine
Houston, Texas, United States

Presenting Author(s)

Jun Teruya, MD, DSc

Professor
Department of Pathology & Immunology, Department of Pediatrics, Department of Medicine, Baylor College of Medicine
Houston, Texas, United States

Background: Presence of Anti-PF4 ELISA antibodies (APF4) has been reported among patients with SARS-CoV-2 (COVID) infection and individuals who received COVID vaccines. These data are mostly limited to adults with sparse data among pediatric patients.

Aims: This study aimed to determine the prevalence and demographics of APF4 positivity among hospitalized COVID pediatric patients and its impact on morbidity and mortality including ICU admission, length of stay (LOS), requirement of mechanical ventilation (MV), thrombosis and heparin therapy (HT).

Methods: Seventy-nine plasma samples from COVID positive (via PCR) patients (identified via in-house COVID testing) were tested for APF4 using PF4 Enhanced assay (Immucor GTI Diagnostics, USA). Demographics and clinical data were collected via retrospective review of electronic medical records.

Results: Twenty patients of 79 (25%) COVID positive patients were found to have APF4 compared with 5% among COVID negative age and sex matched controls. There were no differences in age and gender between APF4 positive vs. APF4 negative COVID patients. Proportionally more Hispanic and Asian patients were APF4 positive (60% vs 45% and 10% vs. 5% respectively). Table 1 highlighted the morbidity and mortality data of APF4 positive vs. negative patients. Among patients with thrombotic complications, only 3/8 (37%) patients had APF4. Lastly, there were no significant differences between APF4 positive vs. negative patients on HT in terms of thrombosis, percentage with thrombocytopenia as defined by platelet count < 150,000/uL, ICU admission, LOS and MV.

Conclusion(s): There is a high prevalence of APF4 positivity among pediatric COVID patients. However, the presence of APF4 appears to have no significant impact on morbidity and mortality. In addition, the presence of incidental APF4 should not limit the use of heparin therapy in pediatric COVID patients.