Does increasing immunoglobulin levels impact survival in solid organ transplant recipients with hypogammaglobulinemia?

Background: Severe hypogammaglobulinemia (IgG < 400 mg/dL) has adverse impact on mortality during the first year post-transplantation. The aim of the study was to determine whether increasing IgG levels to ≥400 mg/dL improved outcomes.

Methods: Kaplan-Meier analyses were performed to estimate survival, log-rank test to compare survival distributions between groups, and Fisher's exact test to determine the association between hypogammaglobulinemia and rejection or graft loss.

Results: Thirty-seven solid organ transplant (SOT) recipients were included. Hypogammaglobulinemia was diagnosed at median of 5.6 months (range: 0-291.8 months) post-transplantation. Types of transplants: liver-small bowel (17); liver-small bowel-kidney (2); liver (5); small bowel (4); liver-kidney (1); kidney/kidney-pancreas (3); heart (3); heart-kidney (1); and heart-lung (1). The three-yr survival after the diagnosis of hypogammaglobulinemia was 49.5% (95% CI: 32.2-64.6%). Patients were dichotomized based upon IgG level at last follow-up: IgG ≥ 400 mg/dL (23 patients) and IgG < 400 mg/dL (14 patients). There was no evidence of a difference in survival (p = 0.44), rejection rate (p = 0.44), and graft loss censored for death (p = 0.99) at one yr between these two groups. There was no difference in survival between patients receiving or not immunoglobulin (p = 0.99) or cytomegalovirus hyperimmunoglobulin (p = 0.14).

Conclusion: Severe hypogammaglobulinemia after SOT is associated with high mortality rates, but increasing IgG levels to ≥400 mg/dL did not seem to translate in better patient or graft survival in this cohort.