INTERLEUKIN-12 MESSENGER-RNA LEVELS IN RENAL-ALLOGRAFT FINE-NEEDLE ASPIRATES DO NOT CORRELATE WITH ACUTE TRANSPLANT REJECTION

TH1 cytokines, including gamma-interferon (IFN), are critical in the i nitiation and progression of allograft rejection. As interleukin (IL)- 12 up-regulates gamma-IFN, we assessed the role of IL-12 in human tran splant rejection. Twenty renal allograft fine-needle aspirates from 19 patients were obtained, evaluated in the standard fashion, and assess ed for gamma-IFN and IL-12p40 subunit mRNA levels using nested reverse transcriptase polymerase chain reaction. Ten aspirates demonstrated a cute rejection by clinical criteria, and 9 of the 10 aspirates contain ed gamma-IFN while only 3 demonstrated IL-12; there were no distinguis hing characteristics for these 3 patients with regard to therapy, or t ime of onset and severity of rejection. Seven patients without clinica l or morphologic rejection failed to demonstrate gamma-IFN or IL-12, T hree patients had discrepant findings; there was no morphologic reject ion, yet all 3 patients contained gamma-IFN and 1 patient demonstrated rejection on subsequent biopsy. However, only 1 aspirate exhibited IL -12 and this patient had no documented subsequent rejection. This stud y confirms the association of gamma-IFN mRNA with acute rejection. In contrast, IL-12 mRNA does not appear to play a key role early in the r ejection process.