With development of newer immunosuppressing agents and using them in various combinations (poly pharmacy therapy) the rate of acute rejection currently is very low after liver transplantation. We have reported a rate of acute rejection of< 5% with use of intravenous Mycophenolate Mofetil, steroid and tacrolimus without any need of antibody preparation. Currently, the only monitoring performed is the measurement of the concentration of calcineurin inhibitor or Rapamycin when used. Monitoring of MPA levels have not found to be useful for LTx recipients. Monitoring the concentration of one medication does not reflect the overall cumulative effect on individual patient after LTx. Further more it is well known that every patient needs different amounts of immunosuppression (IS), yet we practically provide the same amount of immunosuppression to all patients. Fortunately, the rate of infection is not alarming either. However, metabolic morbidity in terms of hypertension, diabetes mellitus and impaired lipid profile and weight gains posses an additional challenge after successful LTx. Currently there is no biological monitoring with proven benefit. ImmuKnow (Cylex) assay, which measures the ATP generated by CD4 proliferation in vitro, although FDA approved, has not been useful in LTx patients.
Aim of the study is to develop biomarker that can quantify the overall IS in LTx recipient.
We developed ex-vivo stimulation of peripheral blood lymphocyte with CD3 and CD28 mono clonal antibodies and observed the generations of division over 7 days (figure on the left). We simultaneously compared the soluble CD30 (sCD30) and ImmuKnow values. The study was conducted just before LTx and on post-op day 2, 4, 6, 14, 21, 28, 42, 60 and 90 days. We also measured the peripheral leucocyte counts and ratio of CD4 and CD 8 counts.
Results: Preliminary results in 5 patients with 2 months of follow-up shows a diminution of division of recipient lymphocytes using CFSE stain and flowcytometry. In the figure on the right (pre LTx, one and two weeks post LTx) we see that lymphocyte proliferation slows down with duration after transplant, and more lymphocytes remain in earlier generations of division. Correlation with sCD30 and ImmuKnow are awaited.
Conclusion: Preliminary observations suggest that the test may have utility in evaluating overall immunosuppression if the generation of proliferation can be quantified. More than one modality of monitoring may be necessary to have clinical utility.
Future: In the future we are planning to measure immunologically relevant Cytokines and tissue array to identify the cytokine phenotypic and genomic differences between individuals of allo reactivity. This could improve our understanding of allogeneic response of the host to the graft with overall biological measurement of immunosuppression requirement after successful LTx.
Volume : 11
Issue : 6
Pages : 11
Professor of Surgery
Director of Liver Transplantation
Temple University Hospital
Philadelphia, PA, USA