Objective: We aimed to assess humoral immunity markers that provide prognostic value for the development of infections in heart transplant recipients.
Patients and methods: Forty-one heart transplant recipients underwent humoral immunity studies, including Immunoglobulin (IgG, IgA, IgM) and IgG subclasses determined by nephelometry on serum samples obtained before transplantation and 1 month after transplantation. Potential clinical risk factors were evaluated: waiting time for transplantation, pretransplant cytomegalovirus (CMV) serologic status of donor and recipient; recipient age; gender; cardiac disease severity before transplantation; type of immunosuppression; and occurrence of rejection.
Outcome measures: We measured infections requiring intravenous (IV) drug therapy during the first year. The association between variables and outcome was assessed using Cox proportional hazards modelling. Immunoglobulin levels were split into two groups using the median value observed as the cut-off.
Results: Of 41 patients studied, 19 (46%) had at least one episode of infection, 16 of which were CMV infections treated with IV gancyclovir, 1 CMV disease + aspergillosis and 2 bacterial pneumonia. Pretransplant IgG (<1055 mg/dL; RR 5.32; 95% confidence interval [CI] 1.73 to 16.29; P = .0034); pretransplant IgG1 (<695 mg/dL; RR 4.80; CI 1.57 to 14.68; P = .006), and posttransplant IgG levels (<589 mg/dL; RR 3.38; CI 1.21 to 9.44, P = .019) were associated with an increased risk of developing infections. Both waiting time for transplantation (RR 0.95; CI 0.91 to 0.98, P = .007) and pretransplant cardiac disease severity (RR 1.94; CI 1.17 to 3.21, P = .009) were significant risk factors for infection. After adjustment for clinical predictive variables, decreased values of posttransplant IgG remained significant predictors.
Conclusions: The existence of decreased levels of IgG in the setting of heart transplantation was associated with an higher risk for infection. Monitoring of immunoglobulin levels, a rapid and well-standardized nephelometric determination, in heart transplantation, may identify a subset of patients at risk for development of infections.