1.6
#35
RELATIONSHIP OF THE RENAL ALLOGRAFT BIOPSY WITH THE CYLEX ™ IMMUNE CELL FUNCTION ASSAY.
B. S. Fyfe, MD , A. M. Kumar, MD , R. F. McAlack, PhD , E. Tecza BS , S. G. Xiao, MD , M. Heifets MD and M. Moritz MD . Philadelphia PA, Drexel University College of Medicine, 19102, Department of Pathology and Laboratory Medicine ; Surgery/Division of Transplantation and Medicine and Philadelphia PA, Drexel University College of Medicine, 19102, Division of Nephrology .
Background: The Cylex ™ (Cylex, Inc.) immune cell response (ICR) assay assesses cell mediated immunity by measuring ATP concentration in stimulated CD4 cells. Here we compare renal biopsy and ICR data from patients with protocol or clinically directed renal biopsies.
Methods: Biopsy and ICR assays were determined on 21 patients. C4d staining was used to assess any humoral component. Eighteen biopsies were done per protocol and three were performed for clinically suspected rejection. Biopsies were assessed for rejection utilizing the Banff ’97 schema. The patients were classified as either no rejection (NR – no biopsy or clinical rejection, N=11); subclinical rejection (SCR–histologic but no clinical rejection, N=7); clinical rejection (CR–clinical and histologic rejection, N=2); and clinical, not biopsy proven rejection (CNBPR, N=1). Within each group, patients were categorized as having strong;moderate; or low ICR.
Results: Strong ICR was noted in 27% of NR, 1% of SCR and 0% of CR and CNBPR. Moderate ICR was noted in 46% of NR, 11% of SCR, and 100% of CNBPR. Low ICR was noted in 27% of NR, 58% of SCR, and 100% of CR.
Conclusions: Most subclinical or clinical biopsy-proven rejections occur in the setting of low to moderate ICRs. A strong ICR is not predictive of the presence of histologic rejection. This suggests that many histologic rejections occur in the setting of adequate immunosuppression. When a humoral component is found the ICR is usually low as was noted when a viral component was observed. More data is warranted in order to correlate between ICR and clinical/subclinical histologic rejection in renal allografts but it is clear that biopsy results are an important element when assessing the ICR results..