IgG2 deficiency in methicillin-resistant Staphylococcus aureus infections after esophageal surgery.

We previously reported the selective development of methicillin-resistant Staphylococcus aureus (MRSA) infections following esophageal surgery in patients with a reduced ability to produce anti-pneumococcal polysaccharide (PPS) IgG. Since the response to the PPS vaccine is correlated to the serum IgG2 levels, we measured IgG2 in the same series of esophageal cancer patients. IgG subclasses were determined in 21 patients, 8 of whom developed MRSA infections. IgG2 was thus found to be significantly lower (P < 0.01) in patients with MRSA infections (453 mg/dl) than in those without such infections (666 mg/dl). There was also a significantly positive correlation (r = 0.61) between anti-PPS IgG and serum IgG2. Therefore, the preoperative measurement of serum IgG2 is considered to be useful in detecting patients who are at risk for developing an MRSA infection after esophageal surgery.