High level of serum soluble interleukin-2 receptor at transplantation predicts poor outcome of allogeneic stem cell transplantation for adult T cell leukemia

Abstract

The prognosis for adult T cell leukemia/lymphoma (ATL) is very poor, and only allogeneic hematopoietic stem cell transplantation (allo-SCT) has been considered to be a curative treatment for ATL. In this study, we retrospectively analyzed data for patients who had received allo-SCT for ATL in Hokkaido, the northernmost island of Japan, to determine prognostic factors. Fifty-six patients with a median age of 57 years received allo-SCT. Twenty-eight (50.0%) patients had acute type and 22 (46.4%) had lymphoma type. Twenty-three (41.1%) patients received allo-SCT in complete remission (CR), whereas the others were in non-CR. Seventeen (30.4%) patients received myeloablative conditioning and the others received reduced-intensity conditioning. With a median follow-up period of 48 months (range, 17 to 134 months), 1-year overall survival (OS) and 5-year OS rates were 55.4% and 46.1%, respectively. The survival curve reached a plateau at 22 months after stem cell transplantation (SCT). Male sex, high level of serum soluble interleukin-2 receptor (sIL-2R) at SCT, and non-CR at SCT were determined to be significant risk factors for OS. A high level of sIL-2R at SCT was a risk factor for poor OS in patients with non-CR at SCT by univariate analysis (P = .02), and it remained significant after adjustment by sex (hazard ratio, 2.73 [95% confidence interval, 1.07 to 7.90]). A high level of sIL-2R at SCT was also determined to be a risk factor for disease progression (P = .02). This region-wide study showed encouraging results for survival after allo-SCT for ATL and demonstrated for the first time that a high level of sIL-2R at SCT predicts worse SCT outcome.

Keywords: Adult T cell leukemia; Allogeneic stem cell transplantation; Prognostic factor; Region-wide study; Soluble interleukin-2 receptor.