Comparative characteristics of bone marrow cell composition, stroma, and trabecular bone in allogenic hematopoietic stem cell transplantation in patients with primary myelofibrosis

Abstract

Introduction. Primary myelofibrosis (PMF) is a clonal disease violating the cell composition, histological topography and stroma in bone marrow (BM). Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is a curative therapy in PMF.Aim — description of change in the haematopoietic tissue cell composition and stroma, as well as in trabecular bone in allo-HSCT patients with fibrotic PMF.Materials and methods. We studies 24 trephine biopsy samples from nine PMF patients with allo-HSCT at the intervals: I — 1 month prior to, II — past 1–3 months and III — past 4–6 months from allo-HSCT. BM trephine biopsy slides were prepared in a standard histological assay with haematoxylin—eosin and additional staining with Gomori’s silver and Masson’s trichrome. Morphological change was evaluated in reticulin and collagen stroma, bone trabeculae, cellularity and topography of haematopoietic tissue.Results. The BM trephine biopsies of interval I were morphologically distinguished in three types by haematopoietic cellularity, stromal and trabecular sclerotic change. Post-transplant intervals II and III (3–6 months after allo-HSCT) did not reveal these types but showed an evident myelofibrosis and osteosclerosis reduction and signs of a restoring bone remodelling cycle. Myelopoietic lineages recovered in stages: the erythroid germ restored in three, granulocytic — in six months, and megakaryocytic cellularity did not fully recover in six months. Myelopoietic cellularity recovery outpaced blood recovery, which may be due to induced myelodysplasia or disruption of stromal niches.Conclusion. Allo-HSCT leads to the disappearance of PMF-pathognomonic BM morphology reflecting a histological remission. The reduction of myelofibrosis and osteosclerosis and normalisation of the trabecular bone remodelling cycle in post-transplant periods indicates an impact of cell microenvironment on PMF pathogenesis and warrants research into the composition and histological topography of cell microenvironment in PMF.