Review Question - QID 213891

A 3-year-old boy is brought to the emergency department after having 4 days of a runny nose, low-grade fever, and general malaise. This morning, he started to experience shortness of breath with coughing and purulent sputum. The mother states that she is particularly concerned since the patient has already had 3 episodes of bacterial pneumonia during his lifetime, along with 2 episodes of viral gastroenteritis requiring hospitalization and intravenous fluids. On exam, the patient’s temperature is 101.0°F (38.3°C), blood pressure is 88/58 mmHg, pulse is 100/min, and respirations are 18/min. The patient is actively coughing, with crackles heard in the right lower chest. There are no palpable lymph nodes, but the exam is also notable for an absence of tonsils. After the patient is stabilized, blood testing and flow cytometry demonstrate the following:

IgA: Undetectable
IgE: Low
IgG: Low
IgM: Low
CD3 positive cells: Normal
CD19 positive cells: Low

Which of the following characterizes this child’s condition?