A 25-year-old female received a double lung transplant for cystic fibrosis 2 years ago and has done reasonably well. She works full time and is now married. She has had four acute rejection episodes...

A 25-year-old female received a double lung transplant for cystic fibrosis 2 years ago and has done reasonably well. She works full time and is now married. She has had four acute rejection episodes over the past 2 years and is on maintenance immunosuppression with tacrolimus 6 mg twice daily, prednisone 20 mg daily, and mycophenolate mofetil 1.5 g twice daily. She is admitted to the hospital with increased shortness of breath, low-grade fever, and overall malaise. She describes a recent decrease in her ability to walk up and down stairs without becoming dyspneic. What form of rejection may she be experiencing?