Role of Phosphorylcholine-Specific Immunoglobulin M in Acute Upper Respiratory Tract Infections

Objectives: The aim of this study was to clarify the role of serum phosphorylcholine (PC)–specific immunoglobulin M (IgM) as a natural antibody against infectious diseases. Methods: The relationship between serum PC-specific IgM level and C-reactive protein level or white blood cell counts was examined in patients with severe upper respiratory tract infections (ie, acute epiglottitis and peritonsillar abscess). Results: PC-specific IgM level was significantly negatively correlated with C-reactive protein level and white blood cell count. In addition, C-reactive protein level and white blood cell count was significantly lower in women than in men, whereas PC-specific IgM level was significantly higher in women. Conclusions: PC-specific IgM is suggested to have protective and suppressive effects against the progression of infectious and inflammatory reactions. Higher levels of PC-specific IgM in women might be one of the reasons why the incidence and severity of acute epiglottitis and peritonsillar abscess are lower in women.