Myelodysplastic syndrome with increased marrow fibrosis: a distinct clinico-pathological entity

Seventeen cases of myelodysplastic syndrome (10 primary and seven secondary to previous radio-chemotherapy), characterized by trilineage dysplasia, severe bone marrow fibrosis and a high number of megakaryocytes, are described. All of these patients had similar clinical and prognostic features consisting of pancytopenia, modest or absent visceral enlargement and poor survival. The use of CD61 antibodies, which recognize megakaryocytic cells at all stages of maturation, confirmed that these patients had a higher number of these cells than either normal subjects or patients affected by myelodysplastic syndrome (MDS) without fibrosis. Furthermore, primary and secondary MDS with fibrosis, although clinically and histopathologically similar, differed in terms of the number of megakaryoblasts which were significantly higher in primary forms (P less than 0.02). We conclude that MDS with fibrosis may represent a clinicopathological entity which needs to be distinguished from other MDS subtypes as well as from idiopathic myelofibrosis or malignant myelosclerosis.     

Incidence and histological features of bone marrow involvement in malignant lymphomas

Summary Bone marrow biopsy (BMB) is a routine investigation in the diagnosis and staging of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL), and there is evidence supporting its prognostic importance in some histological varieties. The histological characteristics of BMB in 433 NHL and 155 HD patients were reviewed for clinicopathological correlations; 36 of these cases were also studied by means of immunohistochemistry. BM infiltrates were discovered in 171 NHL patients. In 36 cases, the diagnosis of NHL was directly established by BMB; a discordance between lymph node and BM histology was observed in 38 of the other 135 cases. BM-positive centroblastic and immunoblastic NHL were significantly associated with larger infiltrates, BM fibrosis, and megakaryocytic hyperplasia. Leukemization at diagnosis was more frequent in low-malignancy NHL. No correlation was found between histology and prognosis, although immunohistochemistry revealed a B-cell phenotype in all but two cases. BMB was positive in 18 of the 155 HD patients and directly diagnostic in two; Reed-Sternberg and Hodgkin cells were CD-30 positive and surrounded by T-cell infiltration. The concordance between BM and lymph node histology was fairly satisfactory, although the relationships between BM infiltration and other histological parameters may reflect peculiar interactions with BM microenvironmental factors. The usefulness of BMB in the diagnosis of malignant lymphomas has been demonstrated, and further progress can be expected from the availability of reliable immunohistochemical markers of clonality reacting on paraffin-embedded BM sections.     

Long-Term Results of Autologous Bone Marrow Transplantation in Adult Acute Lymphoblastic Leukemia

Autologous bone marrow transplantation (BMT) is widely performed in both adult and high-risk pediatric acute lymphoblastic leukemia (ALL). Nevertheless, there is still a lack of definitive data concerning its real effectiveness in prolonging the survival of these patients. Between 1984 and 1992, 20 ALL patients in first, second and third complete remission (CR) underwent autografting in the BMT Unit of the University of Milan. This series included 3 children in CR after one or more hematological relapses while all the other patients were adult. Autologous bone marrow was harvested during the same disease phase as that in which the autologous BMT was performed. The conditioning regimen included high-dose Ara-C, cyclophosphamide and TBI 1000 cGy. Successful engraftment occurred in all patients; no early deaths or deaths in CR were recorded, making disease-free survival and event-free survival (EFS) curves superimposable. The overall chance of EFS at 72 months was 41%: 57% for patients in first CR, 53% for patients autografted after one or more isolated meningeal relapse, 14% for patients autografted after one or more hematological relapse. The present data do not provide any evidence to support a role for autologous BMT in prolonging EFS in first CR ALL patients. Nevertheless, the results after meningeal relapse seem to be favourable when compared with the disappointing prospects of these patients after conventional chemotherapy. The EFS after hematological relapse revealed by this study does not significantly differ from that reported in the majority of other studies: the efficacy of autologous BMT in these ALL patients is doubtful.     

Expansion of dendritic cells derived from human CD34+ cells in static and continuous perfusion cultures

We examined the effects of different cytokine combinations and culture conditions on the expansion and modulation of cell surface antigens of CD34⁺ derived dendritic cells (DCs), the most efficient antigen-presenting cells capable of stimulating resting T cells in the primary immune response. Cells with a dendritic morphology and expressing HLA-DR, CD1a, S100 and CD83 were maximally expanded under serum-free conditions with the addition of SCF, GM-CSF, TNF-α, TGF-β and Flt-3 ligand (fold increase of CD1a⁺ cells = 102 ± 32 after 2 weeks of culture). CD34⁺ cells were also grown under continuous flow conditions in an artificial capillary system; after 14 d of culture, the expansion in the total cell number was lower than that of the static cultures (3.3 ± 2 v 18.9 ± 4) but the percentage of CD1a⁺/CD83⁺/CD80⁺ cells was considerably higher, whereas the CD14⁺ cells were significantly reduced (8.9 ± 2 v 26 ± 13). In continuous perfusion cultures, low levels of DC precursors and of LTC-IC were still present up to day 14. The DCs generated under flow conditions stimulated the mixed leucocyte reaction (MLR) more than the cells grown in static cultures. By electron microscopy, cells grown in the continuous flow system showed an increased number of large cells with numerous dendritic processes and abundant multilamellar complexes. The cells expanded under these conditions were sorted on the basis of their light-scatter properties into two fractions: one containing a predominance of CD1a⁺/S100⁺/CD83⁺/CD80⁺/CD14^?‘large cells’ with great internal complexity (mature DCs); the second including ‘small cells’ either CD33⁺/CD14⁺, CD33⁺/CD15⁺ or CD33⁺/CD13^±/CD14^?. The DCs generated and selected with this method are therefore particularly well suited for immunotherapeutic protocols.     

Unrelated donor marrow transplantation for chronic myelogenous leukaemia

Between January 1989 and July 1995 the search for an unrelated donor (UD) was started for 379 consecutive Italian patients with Philadelphia positive (Ph⁺) chronic myelogenous leukaemia (CML). 89 (23%) were transplanted. The overall probability of transplant before and after December 1991 was 16% and 49%, respectively (P = 0.0001), and average interval between search activation and graft was 23 months and 13 months, respectively (P = 0.0001). Disease-free survival (DFS) following 60 consecutive transplants performed before February 1996 was 41.5% at 48 months and was 64% for patients grafted after January 1993. In univariate analysis, five variables had a favourable effect on DFS: year of bone marrow transplantation (BMT) after 1993 (P = 0.0002), HLA-DRB1 donor/recipient (D/R) match (P = 0.0006), total body irradiation (TBI) containing regimen (P = 0.0006), graft-versus-host disease (GvHD) prophylaxis including ‘early’ cyclosporin before the transplant, and a marrow cell dose > 3 × 10⁸/kg of recipient body weight (P = 0.04). Multivariate analysis confirmed that HLA identity (P = 0.006), TBI-containing regimen (P = 0.0001) and ‘early cyclosporin’ (P = 0.04) were associated with higher DFS. Transplant-related mortality (TRM) was 67% in patients grafted before January 1993 and 30% in patients grafted subsequently (P = 0.002). Multivariate analysis confirmed DRB1 identity (P = 0.03) and TBI-containing regimen (P = 0.0005) to be independent factors predictive of low TRM. This suggests that the outcome of patients transplanted from an HLA DRB1 matched donor, after a TBI-containing preparative regimen, is similar to results recently reported in patients transplanted from geno-identical siblings. These results indicate that the search should be initiated at diagnosis for patients < 45 years of age and UD BMT should be considered early in the disease course for those with an available DRB1-matched unrelated donor.     

Bone marrow stroma in humans: anti-nerve growth factor receptor antibodies selectively stain reticular cells in vivo and in vitro

Two anti-nerve growth factor receptor (LNGFR or p75NGFR) antibodies, Me20.4 and Me8211, label stromal cells with dendritic features in fresh smears and in formalin-fixed, paraffin-embedded human bone marrow (BM). The LNGFR+ cells have an oval nucleus, a scanty cytoplasm with long dendrites that intermingle with the hematopoietic cells, line the abluminal side of sinus endothelial cells, and provide the scaffold for the hematopoietic marrow. At the electron microscopy level, the immunogold tag labels the body and the long branching dendrites of fibroblast-like cells with scanty cytoplasm containing mitochondria, endoplasmic reticulum, and dense bodies. The LNGFR+ cells are positive for alkaline phosphatase, reticulin, collagen III, vimentin, TE-7, and CD13 but negative for endothelial (vWF, CD34, Pal-E), neural (CD56, neurofilament) and leukocyte markers (CD45, CD68). The LNGFR+ stromal cells appear in the fetal BM before the hematopoietic activity begins, originate from the vessel adventitia, and radiate in the Bm cavity. Long-term BM culture (LTBMC) in vitro contain LNGFR+ stromal cells. We document the presence of RNA message for the low- (LNGFR) and the high- affinity NGF receptor (NTRK1) by using RT-PCR on fresh BM aspirate and on LTBMC. BM biopsies from patients with hematologic fibrogenic diseases and in cytokine-treated cancer patients are evaluated for LNGFR+ cells: the amount of stained cells is correlated with the traditional reticulin stain in cases of myelofibrosis, therapy-related myelodysplasia, leukemia, and detected an increase of stromal cells in cytokine-treated patients. The anti-LNGFR antibodies represent a specific membrane marker for the adventitial reticular cells (ARC) of the human marrow and allow precise evaluation and quantitation of this important BM microenvironment component in vivo and in vitro.     

Ultrastructural study of leukemic cell phagocytosis using the myeloperoxidase reaction.

The phagocytosis (in the absence of serum factors) of zymosan particles by peripheral leukocytes isolated from ten patients with acute leukemia (AMbL, AMoL, AMML, AUL, ALL and CML-BC) was studied at the electron microscope. An evident phagocytic activity was observed only in the cells in which cytochemical and ultrastructural features suggested that the blast elements belonged to the monocytic series. However, no phagocytosis by unclassifiable leukemic blasts was observed, even though they had some submicroscopic characteristics of the monocytic series. These findings suggest that phagocytic capacity develops during the course of cell differentiation, becoming striking only when the blast cell acquires the ultrastructural features of the pro-monocytic stage. Using the myeloperoxidase reaction, this study also demonstrates a morphological alteration in the degranulation process after the ingestion of zymosan particles in both the blasts and the mature PMN cells of leukemic patients. This defect could be related to the susceptibility to severe infections usually found in subjects with hematological malignancies.     

A6--a new 45RO monoclonal antibody for immunostaining of paraffin-embedded tissues.

The authors report on the extensive characterization, on normal and pathologic tissues, of the T-cell-specific monoclonal antibody (MoAb) A6, which the authors previously found to identify a fixation- and paraffin-embedding-resistant epitope. A6 reacted with most T lymphocytes, macrophages, and Langerhans' cells of normal tissues and with peripheral T-cell lymphomas (31 of 34), Ki-1+ lymphomas (12 of 18), and T-cell leukemias (1 of 5). All cases of X and non-X histiocytosis examined and monocytic leukemias with mature phenotype only were A6 positive. Three of 47 cases of B-cell lymphoma and leukemia were labeled. Hairy cell leukemias, multiple myelomas, and Hodgkin's and Reed-Sternberg cells were negative. The A6 reactivity was preserved with different fixatives (formalin, Bouin's fluid, Carnoy's fixative, and B5) and decalcification procedures and was slightly enhanced by trypsin digestion. The pattern of reactivity of A6 was similar to that obtained with MoAb UCHL-1, recognizing the CD45RO determinant of leukocyte common antigen; however, in pathologic tissues, A6 labeled a higher percentage of cells than UCHL-1. Cross-blocking and enzyme digestion studies (Pronase E [Sigma Chemical, St. Louis, MO] and neuraminidase [Sigma Chemical]) indicated that the two MoAbs may identify close epitopes on the same molecule. In conclusion, the authors' study indicates that A6 is an excellent reagent for detection of the CD45RO molecule on paraffin-embedded normal and pathologic tissues.     

Cytogenetic and myelodysplastic alterations after autologous hemopoietic stem cell transplantation

Secondary myelodysplastic syndrome/acute myelogenous leukemia (MDS/AML) are today considered a primary complication of autologous hematopoietic stem cell transplantation. In our Center, 83 autografted patients underwent bone marrow (BM) biopsy and cytogenetic analysis at fixed intervals. Twelve patients developed non-clonal cytogenetic abnormalities and 10 patients clonal abnormalities, five of whom (three - 7, one - 5 and one t(9;11)) developed secondary MDS/AML. MDS was also diagnosed in two patients with a normal karyotype. In brief, seven patients (three males, four females; median age 36 years) developed MDS/AML 12-48 months (median 14) after autografting. The FAB diagnosis was AML-M2 in one, chronic myelomonocytic leukemia in two and refractory anemia with excess of blasts in transformation in four cases. Two patients presented a BM biopsy picture of MDS with fibrosis; none of them experienced leukemic transformation. Four MDS patients died, three of leukemic transformation and one of BM insufficiency; the two remaining patients are still living and untransformed. Our data underline the leukemogenic role of previous treatments, even if it is not possible to exclude that underlying disease and/or conditioning therapy may be involved.