A Case of Severe Pneumococcal Pneumonia Requiring Ventilator-Support in a Hypogammaglobulinemia Patient on IVIG Infusion Therapy Despite Adequate IgG Troughs

Rationale: In primary immunodeficiency disease, encapsulated organisms play a large role in infection -- one of the main culprits being Streptococcus pneumoniae. It is assumed that IVIG is relatively uniform and contains adequate titers given that it is purified human sera of thousands of donors, however products are neither standardized nor quantified for all pathogen-specific titers. Here we present one of our hypogammaglobulinemia patients who developed sputum positive pneumococcal pneumonia requiring ventilator-support despite adequate IgG troughs; however, discovered to have inadequate pneumococcal titers.

Methods: IgG troughs routinely obtained and pneumococcal titers obtained after pneumococcal infection.

Results: This 67 year old female patient presented to the ED in respiratory distress and admitted for respiratory failure secondary to pneumonia. CXR revealed RLL consolidation and sputum culture positive for Streptococcus pneumoniae. IgG trough on admission was 1470 mg/dL. Pneumococcal IgG Antibody panel to 23 serotypes were non-protective. Patient was treated with IV antibiotics, eventually weaned off the ventilator, and sent home on Bactrim prophylaxis and continued IVIG infusions.

Conclusions:   We believe it would be beneficial to routinely monitor and quantify antibody titers against encapsulated organisms in patients on IVIG replacement therapy in addition to obtaining IgG trough levels, given these organisms play a big role in infection in our PID patients and to help determine if patients need to be on dual therapy with antibiotic prophylaxis.