Q. A 1.5-year-old male child is brought to the emergency department because of a productive cough. The patient's medical history is significant for 4 attacks of pneumonia in the past 6 months, 2 requiring intensive care admission. His family history is noncontributory. Chest x-ray confirms left upper lobar pneumonia, and the patient was admitted for further investigations. Flow cytometric analysis reveals an absence of the CD40 ligand on the surface of circulating lymphocytes. Which of the following immunoglobulins profile is expected in the above patient?