Gene expression using microarrays in transplant recipients at risk of EBV lymphoproliferation after organ transplantation: preliminary proof-of-concept.

We hypothesized that aspects of the virus-host interaction could be measured to help predict progression to EBV-PTLD. We examined the spectrum of host genes differentially expressed and any relevant clustering in children at risk of EBV lymphoproliferation after organ transplantation. We compared the genes expressed among patients with different levels of viral loads. Gene expression was measured by microarray analysis of RNA from CD19+ B lymphocytes using the Human Genome U133 Plus 2.0 GeneChip. Among 27 samples from 26 transplant recipients, the viral load categories were: low or undetectable loads (LU), n = 14; high or intermediate loads (HI), n = 13. There were seven healthy EBV-seropositive (P) and -seronegative controls (N). Median time of post-transplantation was 0.5 yr (range 0.1-3.8). We identified 24-54 differentially expressed genes in each of four comparisons of HI vs. P, LU vs. P, HI vs. LU, and P vs. N. We identified patterns of 563 gene expressions, creating five clusters aligned with levels of viral load. PTLD occurred in four of five clusters. In summary, we demonstrated varying degrees of alignment between levels of VL and gene clusters. Analyses for differential expression of genes showed genes that could be implicated in the pathogenesis of EBV-PTLD.