1| INTRODUCTION
Bronchiolitis is the most common lower respiratory tract infection in
children younger than 1 year1. Viruses are the most
common cause of acute bronchiolitis, especially respiratory syncytial
virus. Bronchiolitis is characterized by airway obstruction and edema,
increased mucus production, and the loss of airway epithelial cells. The
clinical severity of bronchiolitis ranges from mild cases that can be
treated on an outpatient basis to severe cases that require mechanical
ventilation or extracorporeal membrane oxygenation in intensive care
units2. The lack of any single biomarker for acute
bronchiolitis that may be applied across all clinical scenarios is a
recurring problem and has led many clinicians and researchers to pursue
alternative diagnostic strategies.
Platelets play an important role
in hemostasis, inflammation, allergic reactions, and angiogenesis, as
well as the repair and renewal of tissues. They also secrete mediators
such as chemokines, cytokines, and coagulation factors, which provoke a
strong inflammatory response and tissue regeneration. Platelet
production in bone marrow increases and platelets are redistributed
during the inflammatory response3. In addition to
platelet count (PLT), platelet indexes include plateletcrit, mean
platelet volume (MPV), platelet distribution width (PDW), and a new
parameter called the immature
platelet fraction (IPF). The IPF is the percentage of reticulated
platelets that can be measured in the blood, and it may be used to
quantify the production of bone marrow platelets. The IPF correlates
directly with the thrombopoietic
rate, increasing when platelet production rises and decreasing when
production falls. Inflammation causes changes in the bone marrow,
leading to increases in platelet production and the circulation of
immature
platelets4,5.
Here, we evaluate the relationship between changes in platelet
parameters such as IPF and the clinical severity of acute bronchiolitis.