A case report of 
A 57-year-old man with longstanding CD was hospitalized with a four-day history of fever (38.5 °C), dyspnea, left pleuritic pain, and weight loss (more than 6 kg) about six weeks after beginning treatment with ustekinumab, a human monoclonal antibody approved in the United States for two indications (plaque psoriasis and psoriatic arthritis) and currently under investigation as a potential treatment for CD and other inflammatory disorders. During the preceding 25 years, the man had been treated for severe CD with a number of agents (e.g., infliximab, adalimumab, certolizumab); ultimately, off-label ustekinumab therapy (90 mg subcutaneously weekly) was initiated due to persistent severe CD symptoms. Chest x-ray studies at the time of admission demonstrated left upper lobar consolidation, and a urine antigen test was positive for 
Pneumonia caused by 