T cell reconstitution in allogeneic haematopoietic stem cell transplantation: prognostic significance of plasma interleukin-7.

Infections and acute graft-versus-host disease (aGVHD) are major causes of treatment-related mortality and morbidity following allogeneic haematopoietic stem cell transplantation (HSCT). Both complications depend on reconstitution of the T-lymphocyte population based on donor T cells. Although it is well established that Interleukin-7 (IL-7) is a cytokine essential for de novo T cell development in the thymus and homoeostatic peripheral expansion of T cells, associations between circulating levels of IL-7 and T cell reconstitution following HSCT have not been investigated previously. We prospectively measured IL-7 levels in 81 patients undergoing myeloablative HSCT with either sibling donor or an unrelated donor. Plasma IL-7 levels peaked at day +7 post-transplant (1.3-82.4 pg/ml), at the time of maximal lymphopaenia. In multivariate analysis, peak levels of IL-7 were significantly higher in patients treated with anti-thymocyte globulin (ATG) compared with those not treated with ATG (P = 0.0079). IL-7 levels at day +7 were negatively associated with T cell counts at day +30 to +60 (at day +60: CD3(+) : ß = -10.6 × 10(6) cells/l, P = 0.0030; CD8(+) : ß = -8.4 × 10(6) cells/l, P = 0.061; CD4(+) : ß = -2.1 × 10(6) cells/l, P = 0.062) in multivariate analyses. In adults, high IL-7 levels were associated with increased risk of grade II-IV aGVHD (OR = 5.4, P = 0.036) and reduced overall survival (P = 0.046). The present data indicate that high plasma levels of IL-7 in the early post-transplant period are predictive for slow T cell reconstitution, increased risk of aGVHD and increased mortality following HSCT.

Pretransplant C-reactive protein as A prognostic marker in allogeneic stem cell transplantation.

We evaluated the prognostic role of baseline levels of C-reactive protein (CRP) as well as CRP levels during conditioning in patients undergoing myeloablative allogeneic stem cell transplantation (SCT). Furthermore, we studied the impact of baseline clinical factors and conditioning regimens on CRP levels in the same period. We conducted a population-based retrospective study of 349 patients undergoing SCT at the National Danish SCT centre between January 2000 and January 2009. CRP levels increased significantly during the conditioning and peaked at day -3 before infusion of the graft. Elevated CRP was associated with older age, non-malignant disease, reduced pretransplant Karnofsky score and high-risk leukaemia. By univariate and multivariate analyses, increased CRP levels (>10 mg/l) before the start of treatment (day -7) and at the day of graft infusion (day 0) were associated with decreased overall survival [HR 1.35 (95%CL) (1.18-1.54); P < 0.0001] and increased treatment-related mortality [1.5 (1.24-1.82); P < 0.0001]. Similar findings were seen for mean CRP levels during the conditioning. CRP was not associated with risk of relapse or aGvHD in multivariate analysis. This study suggests that increased CRP levels before and during the conditioning are associated with baseline clinical factors and that elevated pretransplant CRP levels predict a poorer survival in SCT.