Outcomes in Sensitized Pregnant Kidney Transplant Recipients

GettyImages_178054713Philadelphia—An increased risk of antibody mediated rejection (AMR), graft loss, and adverse pregnancy outcomes was seen in sensitized kidney transplant recipients in a single-center retrospective cohort study. The study was conducted by Maria Ajaimy, MD, and colleagues and reported during a poster session at Kidney Week 2014. The poster was titled Increased Risk of Antibody Mediated Rejection and Graft Loss in Sensitized Pregnant Kidney Transplant Recipients.

According to the researchers, pregnancy and allograft outcomes in sensitized renal transplant recipients are not well documented. This study was designed to examine the clinical outcomes of these immunologically high-risk pregnancies.

The study cohort included adult kidney transplant recipients who became pregnant between June 1, 2009, through December 31, 2012. Donor specific anti-HLA antibodies (DSA) and panel reactive antibody (PRA) levels were studied by Luminex single antigen beads.

Among those in the cohort, nine became pregnant at a median of 3.1 years (range, 1.1-7.2years) following transplantation. Median age was 36 years (range, 22-38 years) and 33% were African American. Patients’ median serum creatinine levels and spot urine protein/creatinine ratio were 1.1 mg/dL (range, 1.1-2.1 mg/dL) and 0.55 g/day (range, 0-1.2 g/day), respectively.

Of the total cohort, six patients were sensitized (PRA >0%) and three had PRA of 0%. Of those sensitized patients, median PRA level was 46% (range, 25%-98%) for class I and 0% (range, 9%-86%) for class II. Two had DSA.

Prior to pregnancy, all patients were on triple drug immunosuppression with tacrolimus, mycophenolate mofetil, and prednisone; mycophenolate mofetil was switched to azathioprine.

There was a higher incidence of adverse pregnancy outcomes in the sensitized group, including one stillbirth and one miscarriage in the second trimester. The remaining four high PRA patients and three 0% PRA patients delivered babies at a median of 34.5 weeks (range, 34-36.5 weeks).

During follow-up (median of 2.3 years after delivery), three high PRA patients (50%) developed AMR within 1 year after delivery that led to graft loss. In the low PRA group, there were no rejection episodes and all patients maintained stable graft function (median creatinine level of 1.1 mg/dL and median proteinuria of 0.4 g/day) without the development of new DSAs.

In summary, the researchers said, “Our observational cohort suggests that there is an increased risk of AMR, graft loss, and adverse pregnancy outcomes in sensitized kidney transplant recipients. These results should be assessed in a larger cohort for a better counseling of high immunologic risk patients who wish to become pregnant.”

Source: Ajaimy M, Lubetzky ML, Kamal L, et al. Increased risk of antibody rejection and graft loss in sensitized pregnant kidney transplant recipients. Abstract of poster presented at Kidney Week 2014, Philadelphia, Pennsylvania, November 14, 2014.