Patients with kidney failure have to face a double dilemma - they often have to wait for years before they find a matching donor, sometimes succumbing to the illness even before they find one. Secondly, despite finding a matching donor, they still run at a risk of rejection - their body may treat the donor kidney as foreign and refuse to accept it. The body produces antibodies against the donor kidney; this ultimately leads to rejection of the transplant and brings the patient back to square one. This could also increase the chances of death in the patient.
Cross reaction between the donor kidney and the recipient is avoided by matching of the HLA or Human Leucocyte Antigen. Subjecting the recipient to treatment with certain medications prior to transplantation has made it possible to transplant kidneys even if the HLA types do not match. However, the duration of survival of these patients is less that of those receiving HLA-matched kidney.
AdvertisementThe Johns Hopkins Medical Institutions developed and tested one such pretreatment to permit transplantation in patients having anti-HLA antibodies against the donor, and thus at a high risk for rejection. In this procedure, kidney failure patients initially underwent plasmapheresis i.e. a process through which antibodies that could react against the transplanted kidney were removed from the blood. After each session, patients were injected with intravenous immune globulin. The number of treatments depended upon the baseline level of donor-specific anti-HLA antibodies. This process conditioned the patient's body to accept the transplantation. Out of the 215 patients who underwent this process, 211 proceeded to transplantation. The patients received at least two plasmapheresis sessions after the transplantation as well. As with normal transplantation procedures, drugs that suppress immunity were administered in addition before, during and after transplantation.
The researchers found that with this approach, the survival rates in the kidney transplant patients were 90.6% at 1 year, 85.7% at 3 years, 80.6% at 5 years and 79.7% at 8 years. The survival rate at 3, 5 and 8 years was much better than patients who continued on dialysis (dialysis-only group) or those receiving dialysis, some of whom underwent transplantation with an HLA-compatible kidney during the study (dialysis-or-transplantation group).
In the study, the plasmapheresis procedure was associated with minor adverse effects. Anaphylaxis or a severe allergic reaction occurred in 3 patients. Some patients suffered from excessive bleeding, which could have been associated with plasmapheresis.
The researchers thus claim that pretreatment of renal transplant patients with plasmapheresis and low dose immune globulin permits transplantation in patients with anti-HLA antibodies against the donor kidney. These patients in addition show better survival as compared to patients continuing on dialysis while waiting for a matched transplantation.
This research thus provides good news for patients who have a willing but non-matching donor. The desensitization procedure will permit such transplantations and hopefully reduce the waiting list of people in need of a matched kidney transplant.
However, since the study was conducted on a small number of kidney failure patients and within a single center, the findings of the study should be confirmed through a larger study.
Montgomery RA, Lonze BE, King KE, Kraus ES, Kucirka LM, Locke JE, et al. Desensitization in HLA-Incompatible Kidney Recipients and Survival. N Engl J Med 2011; 365:318-326.
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