Need for Immunosuppression in Heart Transplant Patients Reduced

Studies related to molecular expression testing were presented at the 27th annual meeting and scientific sessions of the International Society for Heart and Lung Transplantation (ISHLT) in San Francisco (CA, USA) in April 2007.

Researchers presented data demonstrating that molecular testing may be helpful for reducing immunosuppression without the need for invasive biopsies, and, additional data suggesting gene analysis may allow for prediction of future occurrence of cardiac allograft rejection.

These studies suggest that molecular expression testing, currently used to detect the absence of moderate to severe rejection, may also help doctors optimize treatment regimens to meet the specific needs of individual heart transplant patients. Molecular testing works by distinguishing patterns of genes in circulating white blood cells (leukocytes), which are expressed differentially during rejection of foreign tissue compared to states of quiescence (or non-rejection).

These data point to the potential clinical utility of molecular expression testing in monitoring rejection based on gene-expression profiling, said Mario C. Deng, M.D., director of cardiac transplantation research, Columbia University Medical Center/New York Presbyterian Hospital (New York, NY, USA), and co-principal investigator in the Cardiac Allograft Gene Expression Observational (CARGO) study. The fact that we can accomplish this non-invasively, without requiring a routine biopsy, is likely to impact the care and quality of life of many patients who have undergone solid heart transplantation.

Until recently, heart muscle biopsy was the only method available to rule out heart transplant rejection and guide treatment with anti-rejection, or immunosuppressive, therapy. Aside from the invasive and painful nature of the procedure, a biopsy is only able to detect rejection after damage has already occurred to the heart tissue. Doctors initially perform biopsies weekly following heart transplantation, then every one to two months until the end of the first year. Depending on the heart transplant center's protocol, biopsies may be performed every three to six months throughout a patient's lifetime.

Alternatively, non-invasive molecular testing uses a routine blood sample, analyzes gene expression in white blood cells, and provides information on the functional status of the transplanted heart before tissue damage occurs.

Separately, two studies presented at the ISHLT meeting by Daniel Bernstein, M.D., Stanford University School of Medicine, (Palo Alto, CA, USA) and Robert Scott, M.D., Mayo Clinic Hospital (Scottsdale, AZ, USA) demonstrated that the use of non-invasive molecular expression testing may be used to safely reduce the use of immunosuppressants, while decreasing the frequency of invasive biopsy and preventing organ rejection.

The data in these studies show that molecular blood testing may help identify those patients in which it may be appropriate to decrease immunosuppressant therapy, said Howard Eisen, M.D., head of the division of cardiology at the Drexel University College of Medicine and Hahnemann University Hospital (Philadelphia, PA, USA) and a principal investigator. While most heart patients will require a lifelong regimen of immunosuppressants, being able to better identify rejection will allow us to optimize treatment.


Related Links:
New York Presbyterian Hospital
Stanford University School of Medicine
Mayo Clinic Hospital