Male (XY) + Encapsulated organisms = X linked (Bruton) agammaglobulinemia

• First: S pneumoniae
• Then: H influenza type B
• And now... S pneumoniae again!

Remember: S pneumoniae is a gram positive lancet-shaped diplococcus and is the #1 cause of MOPS (meningitis, otitis media, pneumonia, sinusitis)

N meningitidis is a gram negative diploccocus

• Young boy who has been infected with Strep pneumo, H. influenzae, and now is infected N. meningitidis, all of which are the classic encapsulated bacteria, most consistent with X-linked Bruton’s agammaglobulinemia
• Key idea: Encapsulated bacteria (SHiN: Strep pneumo, H. Influenzae and Neisseria) are harder for our bodies to destroy and are therefore more dependent upon opsonization, which requires IgG (which will be absent in patients with defects in B lymphocytes because they can’t produce plasma cells and therefore can’t produce immunoglobulins)

https://step-prep.org/tutoring/

Nobody has mentioned this but I think another thing that helps with this answer is that the boy was infected with all these that he was immunized for. A 12 month old should've had immunizations for H. flu, and Strep pneumo, yet he was still getting sick. This makes me think he isnt making proper antibodies --> therefore a B cell issue