Isolation of peripheral blood mononuclear cells (PBMCs)
Heparinized peripheral blood (approximately 3 mL) was obtained from
patients and healthy children. Sample blood was diluted with an equal
volume of phosphate-buffered saline (PBS). Mononuclear cells were
separated by centrifugation using Lymphprep®, aliquoted in Cellbanker®,
and subsequently stored in a −80°C refrigerator until analysis. All
patients and control subjects were free from any infectious episodes at
the time of venipuncture.