Review Question - QID 109759

A 5-year-old boy is brought to his pediatrician due to sore throat and fever. He was in his usual state of health until 3 days ago when he began to complain of a sore throat as well as general malaise. The patient's past medical history reveals recurrent upper respiratory infections but no skin or soft tissue infections. The child had cardiac surgery as an infant but has otherwise been healthy. On presentation, his temperature is 100°F (37.8 °C), blood pressure is 115/72 mmHg, pulse is 65/min, and respirations are 22/min. Physical exam shows white plaques on the tongue and mouth. A scraping of this material reveals a characteristic morphology after being treated with KOH. Serum protein electrophoresis shows a normal distribution of bands from this patient. Which of the following findings would most likely be found in this patient?