Restoration of humoral immunity after intravenous immunoglobulin replacement therapy in heart recipients with post-transplant antibody deficiency and severe infections.

IgG hypogammaglobulinemia is a risk factor for infection in heart recipients. We assessed reconstitution of humoral immunity after non-specific intravenous immunoglobulin (IVIg) replacement therapy administered to treat secondary IgG hypogammaglobulinemia in heart recipients with severe infections. The study population comprised 55 heart recipients who were administered IVIg (IVIg group) and 55 heart recipients with no severe infectious complications (control group). An event was defined as a severe infection requiring intravenous drug therapy during the first year after transplantation. The IVIg protocol comprised non-specific 5% pasteurized IVIg at a dose of 300-400 mg/kg/months. IgG titers were lower in the IVIg group than in controls at seven d (577 vs. 778 mg/dL, p < 0.001) and at one month (553 vs. 684, p = 0.003). After IVIg therapy, IgG concentrations were similar in both groups at three months (681 vs. 737, p = 0.25) and at six months (736 vs. 769, p = 0.46). At three months, the IVIg group had higher levels of antitetanus toxoid and anti-HBs (ELISA, 2.07 ± 2.11 vs. 0.60 ± 1.24 mg/dL [p = 0.003] and 42 ± 40 vs. 11 ± 31 IU/mL [p = 0.005], respectively) than controls. The mean number of infectious complications was significantly lower after IVIG therapy in the IVIG group. IVIg was associated with restoration of humoral immunity in heart recipients with post-transplant IgG hypogammaglobulinemia and severe infections.