Background: Although a solitary prominent perivascular mononuclear infiltrate is diagnostic of mild acute rejection (A2) in lung allograft recipients, its significance is still poorly defined. We evaluated the significance of a solitary perivascular mononuclear infiltrate and its correlation with clinical outcome in lung allograft recipients.
Methods: Thirteen patients had mild acute rejection as diagnosed by the presence of a solitary perivascular mononuclear infiltrate. The patients were divided into 2 groups based on subsequent treatment: treated (Group 1) and non-treated (Group 2) patients. We analyzed the difference between the 2 groups according to clinical presentation, histologic parameters and outcome.
Results: Nine patients were women (69%), 4 were men (31%); 12 were white and 1 was African American. Ages at the time of biopsy ranged from 20 to 68 years, with a mean of 47.2 years and a median of 52 years. Eight had a history of single-lung transplant and 5 had a history of double-lung transplant. The most common reasons for transplantation were emphysema (n = 6) and cystic fibrosis (n = 3). Nine patients (65.4%) showed decreased rejection grade or no evidence of acute rejection (Group 1) after treatment. Four patients who were untreated had persistent multifocal mild or worsening moderate rejection on subsequent biopsy (Group 2).
Conclusions: Treated and untreated patients with mild rejection based on a solitary perivascular infiltrate have similar clinical presentations and histologic characteristics. Solitary mononuclear infiltrates showed persistence or progression without therapy and therefore need to be treated as, not segregated from, the "usual" forms of mild acute allograft rejection.