Theophylline alters neutrophil function in preterm infants

Area of Science:

• Immunology
• Neonatal Medicine
• Pharmacology

Background:

• Theophylline (1,3-dimethylxanthine) is used to treat apnea in premature infants.
• It affects cyclic AMP metabolism, influencing neutrophil functions like respiratory burst, chemotaxis, and motility.
• The impact of theophylline on neonatal neutrophil function requires further investigation.

Purpose of the Study:

• To determine the in vitro effects of theophylline on neutrophil function in preterm infants, term infants, and adults.
• To assess the in vivo effects of theophylline on neutrophils from premature infants undergoing treatment.
• To investigate the dose-dependent effects of theophylline on neutrophil chemiluminescence, chemotaxis, and random motility.

Main Methods:

• Neutrophils were isolated from 20 preterm infants, 16 term infants, and 14 adults.
• In vitro studies exposed neutrophils to theophylline (0-84 micromol/l).
• Neutrophil functions (chemiluminescence, chemotaxis, motility) were measured; in vivo correlation with serum theophylline levels was performed in 13 preterm infants.

Main Results:

• High theophylline concentrations (84 micromol/l) reduced neutrophil chemiluminescence, chemotaxis, and motility in all groups, with greatest reduction in preterm infants.
• Reduced neutrophil activity in preterm infants correlated with serum theophylline levels >46 micromol/l.
• Low theophylline concentrations (28 micromol/l) increased neutrophil activities in vitro and in vivo.

Conclusions:

• High-dose theophylline impairs neonatal neutrophil functions, with preterm infants being more susceptible.
• Low-dose theophylline may enhance neutrophil activity.
• Altered neutrophil function due to theophylline may influence neonatal susceptibility to infection and inflammatory conditions.