HEMATOPOIETIC ABNORMALITIES AFTER AUTOLOGOUS STEM-CELL TRANSPLANTATION IN LYMPHOMA PATIENTS

Haematopoietic reconstitution after autologous stem cell transplantati on (ASCT) was evaluated at different times in 26 lymphoma patients, Al l of the patients showed a significant decrease in the number of both committed (CFU-C) and more primitive progenitor cells (LTC-IC), The ex pansion of bone marrow progenitor cells in a 'stroma-free' long-term l iquid culture system supplemented with SCF, IL-3, IL-6 and GM-CSF from 19 transplanted patients was significantly reduced compared to normal controls, The stromal cell compartment, evaluated by means of a CFU-F assay, was also greatly reduced, The number of haematopoietic and str omal cell progenitors was, nevertheless, very similar to their pre-tra nsplant values, Bone marrow histology, which was evaluated at differen t times after transplant, showed an increase in reticulin fibres, the dilatation of parenchymal sinusoids and some morphological evidence of trilineage dysplasia in 11 patients; however, the same abnormalities were seen in the majority of pretransplant samples, No cytogenetic abn ormalities were observed in 15 patients before transplant, but four su bsequently developed persistent clonal karyotypic alterations and five showed non-clonal abnormalities that generally disappeared over time, Our data suggest that both the stromal and the haematopoietic compart ments are somehow damaged after ASCT for lymphoma; however, these defe cts generally pre-exist the transplant conditioning regimen and seem t o become less pronounced over time.