Interaction of human IgG preparations with polymorphonuclear leukocytes in vitro

Area of Science:

• Immunology
• Biochemistry

Background:

• Intravenous immunoglobulin G (IVIG) is used therapeutically.
• The in vitro effects of purified IVIG on immune cells are not fully understood.
• Potential mechanisms for IVIG-related side effects require investigation.

Purpose of the Study:

• To investigate the in vitro effects of purified human immunoglobulin G (IgG) on polymorphonuclear leukocytes (PMN).
• To explore the potential role of IgG-induced PMN activation in adverse reactions to intravenous IgG therapy.

Main Methods:

• Purified human IgG was prepared using polyethylene glycol precipitation and ion exchange chromatography.
• The oxidative metabolism of PMN was assessed by measuring superoxide anion release and chemiluminescence.
• The effect of maltose on IgG-induced PMN stimulation was evaluated.

Main Results:

• Purified IgG demonstrated a dose-dependent stimulation of PMN oxidative metabolism.
• Superoxide anion release and chemiluminescence increased with IgG concentration, with effects detected at 0.001 mg/ml.
• Commercially available IgG preparations showed similar stimulatory effects.
• Addition of 10% maltose significantly reduced IgG-induced PMN stimulation.

Conclusions:

• Purified IgG can activate host phagocytic cells (PMN) in vitro without complement involvement.
• This IgG-mediated PMN activation may contribute to unexplained side effects observed during intravenous IgG infusions.
• Further research is warranted to elucidate the clinical implications of these findings.