Positive Impact of Chronic Graft-Versus Host Disease on Survival in 928 Allogeneic Hematopoietic Stem Cell Transplant Recipients

Introduction:

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is a standard curative treatment option in hematological diseases. The anti-leukemic activity relies not only the effects of conditioning regimen but also the immune mediated graft-versus leukemia (GVL) effect. Donor T cells are responsible for the GVL and causes complications namely acute and chronic graft versus host disease (GVHD). Herein, we aim to present the relation of graft versus host disease with survival and relapse.

Patients and Methods:

We retrospectively evaluated 928 Allo-HSCT between 1989 and 2015 followed in our institution.  Chi-square test and student's t test were used in comparison. P <0.05 was considered statistically significant.

Results:

 551 patients were male (59%) and 377 patients (41%) were female. The median age of the group was 34 (range 15 -71).  Patients received stem cell from related donors  more frequently (85%) with HLA full match (66%). Peripheral blood was the source of stem cells in 645 recipient (70%) followed by bone marrow (28%).  75 patients were diagnosed as benign hematological disorders. The most common malign hematological diagnosis was acute myeloid leukemia in 366 patients  (39%).  Patients received 80% of myeloablative conditioning regimen prior to transplantation. 43% of the patients diagnosed as acute GVHD and 45% had chronic GVHD.  798 achieved engraftment (86%) neutrophil  engraftment median of 16 days, platelet engraftment median of 14 days.  Relapse was detected in 6% of patients. The overall survival (OS) was 59 months and progression free survival (PFS) was 33 months. Acute GVHD had no impact on OS, PFS, relapse rate.  The OS in patients with chronic GVHD was significantly higher than in GVHD negative patients (68.8 vs 56.9, P=0.009). Although chronic GVHD patients had lower risk of relapse and higher PFS, the results were not statistically significant.

Conclusion:

 GVHD is a serious complication and important cause of post transplant morbidity. Chronic GVHD is associated with lower risk of relapse in previous studies. In this study, we have concluded the improved OS in patients with chronic GVHD. The immune mediated GVL effect may be the reason for anti-leukemia effect and improved survival.