VPB1140 - Role of activated platelets in compensation of bleeding severity in Hemophilia A

Tuesday, July 12, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: Virtual

Presenting Author(s)

Chitrali Laha Roy, MSc

PhD Student
Blood and Vascular Biology Research Lab, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu
Thiruvarur, Tamil Nadu, India

Co-Author(s)

SM

Samarjit Maharana

PhD Student
Blood and Vascular Biology Research Lab, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu
Thiruvarur, Tamil Nadu, India
Kamal Kishor, PhD

Post Doctorate fellow
All India Institute of Medical Sciences
New Delhi, Delhi, India
RR

Ravi Ranjan

Scientist
ALL INDIA INSTITUT OF MEDICAL SCIENCES, NEW DELHI
New Delhi, Delhi, India
MM

Manoranjan Mahapatra

Professor Of Hematology
AIIMS NEW DELHI
DELHI, Delhi, India
RS

Renu Saxena

Professor
Medanta - The Medicity Hospital, Gurgaon, India
Gurgaon, Haryana, India
MK

Meganathan Kannan

Assistant Professor
Blood and Vascular Biology Research Lab, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu
Thiruvarur, Tamil Nadu, India

Background: Hemophilia A (HA) is an X linked bleeding disorder which is due to the deficiency of factor VIII (FVIII). Severity of the disease is categorized based on the FVIII level and the HA patients with factor level < 1% are characterized ad severe. Majority of these patients tend to have major hemorrhages. However, in general, 10% of severe patients compensate major bleeding. We hypothesize that activated platelets may have a role in compensation of bleeding severity in these patients.

Aims: To investigate the role of activated platelets in severe HA with mild hemorrhages.

Methods: Twelve severe HA patients and equal number of age matched normal were included after obtaining informed consent. Clinical details such as bleeding type, frequency and number of transfusions were recorded. 10 ml whole blood was collected and subjected for flow cytometry analyses to study the activated platelets. For this purpose, platelets were incubated with CD62P, PAC-1 and Annexin V and a minimum of 10,000 events were recorded for the analysis.

Results: All HA patients had < 1% FVIII and their age ranged between 7 and 39 years. Two of these patients never had muscle bleed and FVIII was infused to them only on demand. In addition to this, one of these two patients never developed any joint bleed. Based on bleeding and FVIII infusion, these patients were categorized as mild bleeders. When examined their platelets using flow cytometry, the PAC-1 binding were higher in both the patients (3.64% and 2.91% respectively) compared to that of normal (0.95%). However, the CD62P and AV binding in these patients were within the normal.

Conclusion(s): Patients with mild bleeding had higher expression of integrin receptor complex αIIbβ3 which indicates the activated status of platelets in them. Thus, it is possible that activated platelets may contribute to mild hemorrhage in these patients.