Background: We studied the effect of antirejection therapy on intragraft cytokine mRNA expression.
Methods: Therapy consisted of three doses of 1 gm of intravenous methylprednisolone. We determined its effect on intragraft mRNA expression of immunoregulatory (interleukin-2, interleukin-4) and inflammatory cytokines (interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha), and the high-affinity interleukin-2 receptor (p55 chain) in endomyocardial biopsy specimens from cardiac allograft recipients.
Results: By reverse-transcriptase polymerase chain reaction methods, we detected mRNA transcription for interleukin-2 in 56% of the pretreatment endomyocardial biopsy specimens (n = 16), for interleukin-4 in 31%, and for interleukin-6 in 56% of the specimens, and interleukin-2 receptor, interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha were constitutively expressed. Individual cytokine mRNA profiles were not helpful in differentiating between rejections that proved to be methylprednisolone resistant (n = 9) or methylprednisolone sensitive (n = 7). After successful antirejection therapy, the overall intragraft mRNA expression was downregulated. None of the posttreatment endomyocardial biopsy specimens taken from six patients with methylprednisolone-sensitive rejections expressed the interleukin-2 gene, in contrast to 88% of the endomyocardial biopsy specimens obtained from eight patients with methylprednisolone-resistant rejections (p = 0.005). Moreover, intragraft interleukin-4 and interleukin-6 mRNA transcripts were hardly detectable (both 17%) in methylprednisolone-reversible rejections, but in ongoing rejections interleukin-4 mRNA expression was found in 62% (p = 0.14), and interleukin-6 was found in 88% of the endomyocardial biopsy specimens (p = 0.03). Semiquantitative analysis showed that the intragraft interleukin-2 receptor, interleukin-1 beta, and tumor necrosis factor-alpha mRNA levels were lower in posttreatment endomyocardial biopsy specimens from methylprednisolone-reversible rejections than in endomyocardial biopsy specimens from methylprednisolone-irreversible rejections (p = 0.03).
Conclusions: Our data suggest that the efficacy of antirejection therapy with methylprednisolone is reflected in intragraft cytokine mRNA profiles.