The patient was a boy who needed to have his infection diagnosed and treated so he could donate bone marrow to his leukemia-stricken brother. While this analysis covers only one brother, in the final tally it counts as two patients.

Initial Symptoms: Boy with a sneeze + fever + enlarged spleen
Diagnosis: Histoplasmosis (Wilson+Foreman)

Contributions by Team
House (2): Idea to make patient sicker to diagnose him, idea to stop medication to figure out if it's infection that is suppressing bone marrow production
Chase (1): Sees elevated enzymes, leading to discovery of a fibrous growth in mitral valve
Cameron (0): None
Foreman (4): Insists on continuing testing for infections, idea to check home for source of infection, diagnosis for histoplasmosis, idea to do bone marrow transplant anyway

Notes: Wilson realized the growth in the patient's mitral valve was fibrous; I'm not sure if this was caused by the fungal infection or not, but it was implied so for this diagnosis I assumed it was.
Wilson pointed out that the patient's family shouldn't have a water pump in their backyard, leading Foreman to test for farm-related diseases. Therefore they shared the histoplasmosis diagnosis.
The 4/6 bone marrow transplant didn't seem to buy the leukemia patient time for a proper diagnosis, but did almost kill him. Foreman received an error as a result.
Foreman's idea to perform the bone marrow transplant after the diagnosis, while horrible in its execution, did save the life of the patient's brother after every other doctor had given up on him.

Labels: Season 3