Acute lung transplant rejection

Acute lung transplant rejection is one of the early post lung transplant complications.

Epidemiology

It can occur as several episodes and the first episode may occur early as 5 days after transplantation. The incidence is thought to peak at approximately 2 months post-transplantation (with several episodes occurring) . After 6 months, acute rejection is an uncommon event.

Pathology

Histologically, it is defined as perivascular or peribronchiolar mononuclear inflammation and may affect up to 55% of lung transplant recipients within the first year after a transplant .

Radiographic features

CT

While no single individual CT finding can be specific to the diagnosis , CT may show:

• ground-glass opacities: considered the most frequent finding  and, when absent, it almost excludes acute rejection
• consolidation
• interlobular septal thickening
• pleural effusion
• nodular opacities
• mild volume loss in the graft

Radiographic features may show a dramatic response to steroid therapy .

Treatment and prognosis

Complications

Acute lung rejection can be further complicated by the subsequent development of bronchiolitis obliterans syndrome (BOS) which is a condition of progressive airflow obstruction that limits survival to only 50% at 5 years post-transplantation .

Differential diagnosis

Radiographic appearances can mimic :

• reimplantation response: pulmonary edema following lung transplantation 
• pulmonary infection
  • especially when consolidative changes are present