A 16 year old female comes to your clinic with a 1 week history of pleuritic chest pain, cough, fever, and purulent sputum. Her history is remarkable for recurrent upper respiratory infections with Streptococcus pneumoniae and Hemophilus influenza five to six times per year since she was 9 months old. Which of the following is most likely the source of her inadequate immune system?
A - Macrophages
B - B lymphocytes
C - T lymphocytes
D - IgE
E - Natural Killer cells
A - Macrophages
B - B lymphocytes
C - T lymphocytes
D - IgE
E - Natural Killer cells