Factors Associated with Successful Downregulation of Anti-HLA Antibodies in Heart Transplant Candidates

Introduction: The presence of HLA antibodies in highly sensitized heart transplant candidates is a barrier preventing individuals from receiving a lifesaving transplant.  In efforts to downregulate their HLA antibodies, many candidates are treated with intravenous immunoglobulin (IVIG; 1-2 mg/kg). While this therapeutic approach is successful in some subjects, others show no response.

Objectives: Identify factors associated with the successful downregulation of HLA antibodies in highly sensitized candidates eligible for heart transplant.

Study Design: Retrospective chart review of highly sensitized heart transplant candidates.

Methods: This retrospective study evaluated data including gender, age, race, ventricular assist device (VAD) type, desensitization regimen, panel reactive antibody (PRA) levels, antibodies present before/after IVIG, as well as history of blood transfusions, pregnancies, and previous transplants in efforts to see trends in desensitization. Patients were considered responders to IVIG therapy if their PRA decreased by ≥ 50%, and non-responders if the decrease was < 50%, which was chosen based on potential for significant clinical implications.

Results: Patients (n=15; ages 18-89) all received monthly IVIG (number doses ranging from 2-25) and had a VAD with a mean PRA of 83.8 prior to IVIG treatment. Efficacy was observed by lower PRAs post IVIG (p<0.001) in the responder group. Compared with the non-responder group, trends towards response was seen with white race (p=0.12), no previous pregnancy and male gender (both p=0.08). A total of 9 patients were subsequently transplanted. 

Conclusions: IVIG is an appropriate treatment in highly sensitized patients eligible for heart transplant. Male gender, white race and no previous pregnancy may make patients more responsive to therapy.