Severe Hematopoietic Alterations In Vitro, in Bone Marrow Transplant Recipients Who Develop Graft-Versus-Host Disease

Abstract

Graft-versus-host disease (GVHD) is currently one of the major obstacles for successful allogeneic bone marrow transplantation (BMT). GVHD results from a complex set of interactions between donor T cells and a variety of target tissues from the host. To gain a better understanding of the biology of the human hematopoietic system in GVHD patients, in the present study we have determined the progenitor cell content in bone marrow (BM) samples from BMT recipients, with and without GVHD, and followed their growth kinetics in Dexter-type long-term marrow cultures (LTMC). We have also assessed some aspects regarding the composition of the hematopoietic microenvironment developed in vitro. As compared to normal subjects, BMT recipients showed decreased numbers of myeloid, erythroid, and multipotent progenitor cells. Interestingly, progenitor levels were significantly lower in GVHD patients (7% of the levels in normal marrow) than in those without GVHD (44% of the levels in normal marrow). When marrow cells from BMT recipients were cultured in LTMC, hematopoiesis was sustained at lower levels and for shorter periods of time, as compared to cultures from normal subjects. The hematopoietic deficiencies observed in this in vitro system were also more pronounced in GVHD patients. In terms of the microenvironment elements, reduced numbers of fibroblastic progenitors and adherent stromal cells were observed in BMT recipients, as compared to normal subjects, who showed 7 colony-forming unit fibroblast (CFU-F)/10(5) marrow cells and 320,000 adherent cells in LTMC. Again, GVHD patients showed more severe deficiencies (0.16 CFU-F/10(5) marrow cells and 34,000 adherent cells in LTMC) than patients without GVHD (2 CFU-F/10(5) marrow cells and 122,000 adherent cells in LTMC). Our results demonstrate that the hematopoietic system of BMT recipients is impaired, both in terms of its in vitro composition and function, and that these deficiencies are clearly more pronounced in patients with GVHD than in those without GVHD. Finally, although the evidence is still preliminary, our results also indicate that the severity of the hematopoietic alterations may be greater in acute GVHD than in chronic GVHD.

Immune Reconstitution After Allogeneic Haematopoietic Cell Transplantation: From Observational Studies to Targeted Interventions

“…Of note, progenitor levels were significantly lower in patients with GvHD (7% of normal marrow levels in patients with GvHD vs. 44% of normal marrow levels in patients without GvHD). These findings corresponded with the severely reduced numbers of fibroblastic progenitors and adherent stromal cells observed in long-term marrow culture in patients with GvHD vs. those without (135).…”

Effect of Graft-versus-Host Disease Prophylaxis Regimens on T and B Cell Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation

“…Thus, lower KREC levels coincided with the onset period of classic aGVHD, whereas lower TREC levels were associated with a period of increased incidence of cGVHD. It was previously shown that hematopoietic dysfunction can be exacerbated during GVHD [37][38][39], and hematopoietic cells express both class I and class II HLA proteins, which represent potential targets for direct immunocompetent cell responses. Mensen et al [40] reported that T cell bone marrow infiltration during aGVHD may be associated with delayed B cell recovery and function after HSCT, and a toxic bone marrow microenvironment impairing donor-derived hematopoiesis (eg, B cell output) also could result from GVHD-related cytokine release [41].…”

Concise Review: The Bone Marrow Niche as a Target of Graft Versus Host Disease

“…Irrespective of the clinical occurrence of GvHD, HSCT itself has been shown to result in long‐lasting reductions in bone marrow cellularity, persistent alterations in T‐ and B‐cell development and functionality, and profound declines in the self‐renewal capacities of hematopoietic stem cells (HSC), although these alterations are not necessarily accompanied by a reduction in the peripheral blood cell counts . Furthermore, these pathologies also occur in patients with complete donor chimerism, indicating that engraftment and graft function are regulated by distinct pathways.…”