CD30 expression and its potential significance for heart transplantation

The human CD30 gene (TNFRSF8) codifies for a transmembrane glycosylated protein, which intracellular part can be proteolytically cleaved producing a soluble form of CD30 (sCD30). In cadaveric kidney transplantation (KT), sCD30 before transplantation is an excellent predictor of kidney graft outcome. Moreover, a microsatellite - in the promoter region - of (CAAT)n type is able alone to repress transcription: shortened versions of this microsatellite determine lower levels of repression in vitro. To investigate whether CD30 might be a good pre-transplant indicator for graft rejection risk also in heart transplantation (HT), we analysed 83 HT recipients (R) and 79 HT donors (D). We studied: i) pre-transplant sCD30 levels by ELISA assays from Bender (Austria); ii) the number (CAAT)2-12 repeats by PCR. Preliminary results showed: a) a slight (but not significant) increase of sCD30 levels in heart R (mean: 28,07 U/ mu l plus or minus SD: 17,83) in respect to D (21,24 plus or minus 22,18); b) no differences between D and R for CD30 microsatellite allele frequencies; c) a negative correlation between the number of CAAT repeats and sCD30 levels, at least in D (R2 = 0,0338); d) no differences in patient survivals, subdividing R according to high (>26 U/ mu l, n: 43) or low (26 U/ mu l, n: 40) pre-transplant sCD30 levels (at 5 years: 69% and 73%, respectively). In conclusion we were unable to confirm in heart transplantation the same results as for kidney transplantation.