Hypogammaglobulinemia following cardiac transplantation: A link between rejection and infection

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 sev ere HGG to infection and acute cellular rejection following heart transplan tation. Methods: Between February 1997 and January 1999, we retrospectively analyze d the clinical outcome of 111 consecutive heart transplant recipients who h ad immunoglobulin G (IE;G) level monitoring at 3 and 6 months post-transpla nt and when clinically indicated. Results: Eighty-one percent of patients were males, mean age 54 +/-: 13 yea rs, and the mean follow-up period was 13.8 +/- 5.7 months. Patients had nor mal 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-transpla nt. The average time to the lowest IgG level was 196 <plus/minus> 125 days. Patients with severe HGG were at increased risk of opportunistic infection s 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, pa tients who experienced three or more episodes of rejection had lower mean I gG (580 <plus/minus> 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 sev ere 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 wa s 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 cons equence of intensification of immunosuppressive therapy for rejection and h ence, confers an increased risk of opportunistic infections. IgG level may be a useful marker for identifying patients at high risk.