Multidrug resistance in lung allograft recipients: possible correlation with the development of acute and chronic rejection.

The expression of drug resistance antigens in mononuclear inflammatory cells was studied in transbronchial lung biopsy specimens of lung allograft recipients who experienced steroid-sensitive and steroid-resistant bouts of acute rejection and bronchiolitis obliterans. Immunostains for C494 and C219 epitopes of p-glycoprotein and human metallothionein revealed that (1) mononuclear cells expressing these antigens are present in the lung allograft during rejection, (2) that steroid-resistant acute rejection is associated with increased percentages of C494 and metallothionein-positive cells as compared to steroid-sensitive cases, (3) that bronchiolitis obliterans was associated with a higher percentage of cells with drug-resistant antigen expression, and (4) that steroid-resistant bronchiolitis obliterans is associated with the highest percentage of C494 and metallothionein-positive cells in the five clinical situations studied. P-glycoprotein and metallothionein expression may be a marker of aggressive or persistent cases of acute rejection and bronchiolitis obliterans.