Prognostic impact of pretransplant iron overload measured with magnetic resonance imaging on severe infections in allogeneic stem cell transplantation.

Objective: Infections and graft-versus-host disease (GVHD) are the main causes of transplant-related mortality (TRM) of patients undergoing allo-SCT. The role of iron overload (IO) has been debated in this context. Studies, performed with non-specific surrogate markers of iron, suggest that IO predicts poor outcome after allo-SCT.

Methods: In this prospective study, we quantified pretransplant IO with MRI-based hepatic iron concentration (HIC) measurement; the degree of IO was used to predict infections, GVHD, and mortality after allo-SCT. Logistic univariate, multivariate, and Cox's regression analyses were performed.

Results: Iron overload was present in 78% of the patients (HIC>36 μmol/g). The median HIC was 98 μmol/g (range 5-348). There were no cases of cardiac iron excess. IO was significantly associated with severe infections during the early post-transplant period (for every 10 μmol/g increase OR: 1.15, 95% CI 1.05-1.26, P = 0.003). The odds for severe infections increased 6.5- (>125 μmol/g OR: 6.5, P = 0.013) to 14-fold (>269 μmol/g OR: 14.1, P = 0.040) with increasing HIC. IO was found to be associated with reduced risk of acute and chronic GVHD. Although TRM was due to infection-related deaths, IO was not associated with TRM or OS.

Conclusion: Pretransplant IO, measured with a direct MRI-based measurement, predicts severe infections in the early post-transplant period.