system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 7-month-old Caucasian male presents with recurrent sinusitis and pharyngitis. The parents say that the child has had these symptoms multiple times in the past couple of months and a throat swab sample reveals the presence of Streptoccocus pneumoniae. Upon workup for immunodeficiency it is noted that serum levels of immunoglobulins are extremely low but T-cell levels are normal. Which of the following molecules is present on the cells that this patient lacks?
assistant
CD19