The RNA content of alveolar macrophages in canine lung allografts

To evaluate the utility of RNA synthesis by alveolar macrophages (AM) in lung allografts as a marker of acute rejection, we performed canine left lung allotransplantation and measured the AM RNA content during immunosuppressive therapy with azathioprine (AZ), cyclosporine A (CsA), or CsA combined with AZ and prednisolone (Pr). We determined the RNA content by determining the RNA index (RI) (peak channel number of AM/peak RNA channel number of peripheral blood lymphocytes) by flow cytometry. The dogs were classified into one of five treatment groups: Group 1 (n = 18), control (no surgery) dogs; Group 2 (n = 11), allotransplanted dogs without pre- or postoperative immunosuppressive therapy; Group 3 (n = 14), received AZ at dose of 5 mg/kg/day orally; Group 4 (n = 17), received CsA at dose of 20 mg/kg/day orally; Group 5 (n = 15), CsA combined with AZ (5 mg/kg/day) and Pr (0.5 mg/kg/day). The RI of normal lungs was 2.14 +/- 0.20 (mean +/- SD) (n = 18). The RI of rejected lungs was significantly higher than the RI of normal lungs in Group 2 (2.51 +/- 0.21, n = 8, P < 0.05) or Group 3 (2.76 +/- 0.36, n = 7, P < 0.05), but did not differ significantly from that in Group 4 (2.19 +/- 0.20, n = 7) or Group 5 (2.05 +/- 0.45, n = 8). The RI of rejected lungs was higher than the RI of nonrejected lungs in Group 2 (vs 2.18 +/- 0.12, n = 3, P < 0.05) or in Group 3 (vs 2.18 +/- 0.22, n = 7, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)