Pathogen-specific IgG antibody levels in immunodeficient patients receiving immunoglobulin replacement do not provide additional benefit to therapeutic management over total serum IgG.

摘要

The conventional way of monitoring immunoglobulin replacement in antibody-deficient patients is by measuring the total IgG in serum by nephelometry. Despite adequate levels of total IgG, some patients continue to have upper respiratory tract infections, especially with Streptococcus pneumoniae (pneumococcus) and Haemophilus influenzae. Lucas et al1 reported recently that the optimal dosage of immunoglobulin replacement to prevent infection is not necessarily based on trough IgG levels. One possible explanation for this finding is that pathogen-specific antibody levels do not correlate with total IgG in these patients. We therefore explored the clinical utility of measuring pathogen-specific antibodies with commercially available assays for pneumococcus and Haemophilus influenzae in antibody-deficient patients receiving immunoglobulin replacement.