Eosinophilia predicts better overall survival after acute graft-versus-host-disease.

The prognostic significance of eosinophilia after allogeneic hematopoietic SCT (HSCT) and the relationship between eosinophilia and acute GVHD are not well studied. We retrospectively analyzed 201 adult patients who underwent their first allogeneic HSCT. Seventy-three (36%) patients developed eosinophilia within the first 100 days after HSCT. Eosinophilia was observed more frequently among those patients with acute GVHD than those without it (48 vs 25%, P=0.009). However, it was associated with milder acute GVHD and lower incidence of gut and liver acute GVHD. Among patients with acute GVHD, the 3-year OS for patients with and without eosinophilia was 63.4 and 47.2% (P=0.02), respectively, and 3-year nonrelapse mortality (NRM) was 20.2 and 37.5% (P=0.01), respectively. Multivariate analysis confirmed that eosinophilia was associated with a better OS (P=0.03) and lower NRM (P=0.046) in patients with acute GVHD, whereas it was not associated with a higher relapse rate (P=0.45). In contrast, eosinophilia was not associated with outcomes in those patients without acute GVHD. In conclusion, eosinophilia was associated with milder acute GVHD and better prognosis among patients with acute GVHD. The pathophysiology behind eosinophilia after allogeneic HSCT remains to be investigated.