Background: Hypogammaglobulinemia (HGG) has been reported after solid organ transplantation and is noted to confer an increased risk of opportunistic infections.
Objectives: In this study, we sought to assess the relationship between severe HGG to infection and acute cellular rejection following heart transplantation.
Methods: Between February 1997 and January 1999, we retrospectively analyzed the clinical outcome of 111 consecutive heart transplant recipients who had immunoglobulin G (IgG) level monitoring at 3 and 6 months post-transplant and when clinically indicated.
Results: Eighty-one percent of patients were males, mean age 54 +/- 13 years, and the mean follow-up period was 13.8 +/- 5.7 months. Patients had normal IgG levels prior to transplant (mean 1137 +/- 353 mg/dl). Ten percent (11 of 111) of patients developed severe HGG (IgG < 350 mg/dl) post-transplant. The average time to the lowest IgG level was 196 +/- 125 days. Patients with severe HGG were at increased risk of opportunistic infections compared to patients with IgG > 350 mg/dl (55% [6 of 11] vs. 5% [5 of 100], odds ratio = 22.8, p < 0.001). Compared to patients with no rejection, patients who experienced three or more episodes of rejection had lower mean IgG (580 +/- 309 vs. 751 +/- 325, p = 0.05), and increased incidence of severe HGG (33% [7 of 21] vs. 2.8% [1 of 35], p = 0.001). The incidence of rejection episodes per patient at 1 year was higher in patients with severe HGG compared to patients with IgG >350 (2.82 +/- 1.66 vs. 1.36 +/- 1.45 episodes/patient, p = 0.02). The use of parenteral steroid pulse therapy was associated with an increased risk of severe HGG (odds ratio = 15.28, p < 0.001).
Conclusions: Severe HGG after cardiac transplantation may develop as a consequence of intensification of immunosuppressive therapy for rejection and hence, confers an increased risk of opportunistic infections. IgG level may be a useful marker for identifying patients at high risk.