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PubMed1995

Characterization of bone marrow after transplantation by means of magnetic resonance.

Magnetic resonance (MR) has become a new tool for noninvasive characterization of bone marrow in patients with hematological disorders in the past few years. Experiences gained from 1H MR imaging and spectroscopic investigations in 48 healthy volunteers and more than 130 patients with hematological disorders are reported and interpreted. Twenty-four of the patients underwent bone marrow transplantation (BMT) before the MR examinations. The findings in these studies provided noninvasive characterization and monitoring of vertebral marrow after BMT. Specifically, MR techniques were found to be suitable for studies of different aspects in physiological and pathological alterations of bone marrow: The water content within the marrow can be analyzed by chemical-shift selective-imaging techniques with good spatial resolution. Spectroscopic methods also allow more sensitive quantification of the signal fractions, as well as separate evaluation of the relaxation times of water and lipids. Relaxometry might be useful to characterize the cellular and extracellular portions of water molecules. Furthermore, the distribution of the magnetic field within small-volume elements of vertebral marrow can be measured. The field distribution is influenced by the trabecular density and the composition of the marrow. High amounts of hemosiderin in the marrow result in clearly broadened field distributions, demonstrated by increasing line widths in MR proton spectra. Magnetic resonance techniques can be used to assess not only the cellularity of the bone marrow, but also metabolic alterations in this compartment which result from cytotoxic treatment or immunological processes.

Bone Marrow↗

PubMed1995

Bone marrow, cytokines, and bone remodeling. Emerging insights into the pathophysiology of osteoporosis.

Both osteoblasts and osteoclasts are derived from progenitors that reside in the bone marrow; osteoblasts belong to the mesenchymal lineage of the marrow stroma, and osteoclasts to the hematopoietic lineage. The development of osteoclasts from their progenitors is dependent on stromal-osteoblastic cells, which are a major source of cytokines that are critical in osteoclastogenesis, such as interleukin-6 and interleukin-11. The production of interleukin-6 by stromal osteoblastic cells, as well as the responsiveness of bone marrow cells to cytokines such as interleukin-6 and interleukin-11, is regulated by sex steroids. When gonadal function is lost, the formation of osteoclasts as well as osteoblasts increases in the marrow, both changes apparently mediated by an increase in the production of interleukin-6 and perhaps by an increase in the responsiveness of bone marrow progenitor cells not only to interleukin-6 but also to other cytokines with osteoclastogenic and osteoblastogenic properties. The cellular activity of the bone marrow is also altered by the process of aging. Specifically, senescence may decrease the ability of the marrow to form osteoblast precursors. The association between the dysregulation of osteoclast or osteoblast development in the marrow and the disruption of the balance between bone resorption and bone formation, resulting in the loss of bone, leads to the following notion. Like homeostasis of other regenerating tissues, homeostasis of bone depends on the orderly replenishment of its cellular constituents. Excessive osteoclastogenesis and inadequate osteoblastogenesis are responsible for the mismatch between the formation and resorption of bone in postmenopausal and age-related osteopenia. The recognition that changes in the numbers of bone cells, rather than changes in the activity of individual cells, form the pathogenetic basis of osteoporosis is a major advance in understanding the mechanism of this disease.

Animals↗

PubMed1978

Bone marrow studies in myelomatosis.

The percentage of fat-cell areas in bone marrow particles from 22 patients with untreated myelomatosis was estimated. In only 1 patient was the mean fat cell area below 25% of the bone marrow area measured. A negative correlation was found between the area of fat cells and plasma cells, indicating a displacement of the fat cell area by the plasma cells. 28% of the patients had empty bone marrow deposits of iron. However, based on a normal iron saturation of S-transferrin and a normal sideroblast count in the bone marrow, the supply of iron to the erythropoiesis was considered sufficient. All patients but one had normoblastic bone marrows. Using a deoxyuridine suppression test in 10 patients, no biochemical defect could be demonstrated. To judge from the correlation coefficient a minor degree (9-14%) of the variation in Hb values could be predicted from the cellularity in the bone marrow while a major degree (70%) could be predicted from the renal glomerular filtration rate. The results do not support a displacement of blood-forming elements, iron deficiency, vitamin B12 or folic acid deficiency to be of general significance in the pathogenesis of anaemia, but agrees with a causal relationship between anaemia and renal failure.

Adult↗

PubMed2001

Distribution of cellular isoform of prion protein in T lymphocytes and bone marrow, analyzed by wild-type and prion protein gene-deficient mice.

In this study, the authors investigated normal cellular prion protein (PrP(C)) expression on murine immune systems using prion protein gene-deficient mouse as negative control. Immunocytes expressing PrP(C) in adult and fetal mice were detected by flow cytometry with the monoclonal antibody against PrP(C), 6H4. Cells from thymus and bone marrow reacted positively with 6H4, while spleen cells, peritoneal cells, peripheral blood leukocytes, and intestinal intraepithelial lymphocytes were nonreactive. In thymus, PrP(C) was observed in CD4(-)CD8(-) double-negative thymocytes. PrP(C+) cells of double-negative thymocytes belonged to the CD3(-) subset, but not to the CD3(+) subset. Triple-negative PrP(C+) thymocytes expressed CD44 or CD25 antigens. Furthermore, PrP(C) was observed in c-kit(+) bone marrow cells. In fetuses, PrP(C+) cells were observed in the liver and thymus at day 16.0 and 15.0 of gestation, respectively. These results demonstrated that PrP(C) is expressed on immature immunocytes.

Animals↗

PubMed1986

Functional rearrangement of lymphohemopoietic system in heterochronically parabiosed mice.

This study examines some characteristics of the lymphohaemopoietic system of heterochronically parabiosed CBA mice. It was found that a decline of the primary immune response in a young mouse sutured with an old one is accompanied with the diminution of: bone marrow and thymus cellularity; thymus weight; haemopoietic stem cells (CFC-S) and granulocyte-macrophage precursor cells (CFC-C) contents in the femur, and stromal precursor cell (CFC-F) contents both in the femur and thymus. All the indices tested, including the immune response level, in old parabionts vs. old single mice remained unchanged. In the spleen, the considerable variations of splenic weights in the mice of different control and experimental groups have been found. At the same time, no significant changes in the cellularity and CFC-F number in the spleen of all examined groups of animals have been observed. The findings strongly indicate the considerable rearrangement of lymphohaemopoietic and stromal tissues in the central organs of the immune system, namely, bone marrow and thymus of young mice due to the parabiosis with old ones.

Aging↗

PubMed1985

Analysis of human bone marrow with monoclonal antibodies.

In order to study the antigenic phenotype of different hemopoietic cells, we used a series of monoclonal antibodies to investigate normal bone marrow in a standard immunofluorescence assay. The antibodies detected the following antigens: HLA-ABC, beta 2-microglobulin (beta 2m), HLA-DR (Ia), a lymphocyte subset and specific antigen (T and B) HuLy-m2, m3, T lymphocyte antigen (HuLy-m1), lymphocyte T200 antigen (HuLy-m4), a viral-associated antigen (HuLy-m5), and platelet-specific glycoproteins IIb-IIIa (HuPl-m1). The following results were obtained: (a) normoblasts were weakly HLA-ABC+, beta 2m+ and Ia-; all other lymphocyte and platelet antigens were not detected. (b) Myeloid cells at all stages of differentiation (promyelocytes, myelocytes, metamyelocytes, and neutrophils) were HLA-ABC+; beta 2m+; HuLy-m1-, m2-, m3+/- (20%), m4+, m5+/- (20%); HuPl-m1-; in addition, promyelocytes and myelocytes were Ia+ but neutrophils and metamyelocytes were Ia-. (c) Lymphocytes were HLA-ABC+, beta 2m+, Ia+/- (20-30%), HuLy-m1+/- (40-50%), m2+/- (60-70%), m3+, m4+, m5+; Pl-m1-. (d) Platelets and megakaryocytes were HLA-ABC+; beta 2m+; Ia-; HuLy-m1+-, m2-, m3-, m4-, m5-, HuPl-m1+, and the putative "megakaryocyte precursors" were HuPl-m1+, Ia-, HuLy-m1-. The different cell types in bone marrow could readily be distinguished, particularly cells of the myeloid series (Ia and HuLy-m4, m5), lymphocytes (Ia and HuLy-m1, m2, m3), and platelets and their precursor cells (HuPl-m1). This simple method of defining cellular phenotypes in bone marrow has demonstrated the practicality of using monoclonal antibodies to identify marrow cells and should be of diagnostic value.

Antibodies, Monoclonal↗

PubMed1996

The development of cellular immunity to Epstein-Barr virus after allogeneic bone marrow transplantation.

Epstein-Barr virus-induced lymphoproliferative disease (EBV-LPD) is a potentially lethal complication during the first 6 months after allogeneic bone marrow transplantation (BMT). To determine whether deficiencies of EBV-specific cellular immunity contribute to EBV-LPD susceptibility and distinguish patients at risk, we performed limiting dilution analysis to quantify anti-EBV cytotoxic T-lymphocyte precursor (CTLp) frequencies in 26 recipients of unmodified or T-cell-depleted (TCD) grafts from EBV-seropositive donors. At 3 months post-BMT (n = 26), only five patients had EBV CTLp frequencies in the range of seropositive normal controls, irrespective of the type of transplant administered. By 6 months post-BMT, 9 of 13 patients tested had EBV CTLp frequencies within the normal range. The time period in which these patients had deficient cellular immunity to EBV corresponds to the period in which we have observed EBV-LPD in most prior patients. One patient with a low EBV CTLp frequency at 4 months post-BMT developed an EBV-LPD. Within 2 weeks of receiving an infusion of donor peripheral blood mononuclear cells (PBMC) providing less than 1,200 EBV-specific cytotoxic T-cell precursors, populations of EBV-specific CTL in the circulation were restored to levels detected in normal seropositive adults. Concurrently, the patient achieved a regression of the EBV-LPD, which has been sustained without further therapy. These studies indicate that recipients of both unmodified and TCD marrow grafts have profound deficiencies of EBV-specific T cell-mediated immunity early posttransplant, and that the period of risk for EBV-LPD closely corresponds to this interval of severe deficiency. Treatment of one patient with EBV-LPD with marrow donor-derived PBMC induced a rapid expansion of EBV-specific cytotoxic T-cell populations that occurred contemporaneously with the clinical regression of disease.

Adolescent↗

PubMed1990

Detection of Philadelphia chromosome-positive cells from glass slide smears using the polymerase chain reaction.

Southern and Northern blot hybridization studies and the polymerase chain reaction (PCR) have been used to analyze the bcr-abl gene complex in chronic myelogenous leukemia (CML). Because fresh or cryopreserved cells may not always be available for molecular analyses, we investigated the possibility of using routinely prepared glass slide smears of blood or bone marrow as our source of cellular material. Cellular RNA was prepared directly from the blood or bone marrow smears using a modified RNA extraction procedure. cDNA was synthesized from RNA and amplified with PCR using bcr and abl-specific primers. Using this procedure, the bcr-abl fusion gene was detected by PCR in 21 of 21 patients with CML. Three patients who had undergone allogenic bone marrow transplantation (BMT) for CML were also studied by PCR. bcr-abl was identified transiently in one patient, persisted in one patient after BMT for 2 years until relapse occurred, and was absent in one patient to 18 months after BMT. We have shown that PCR can detect the bcr-abl gene of CML using material from glass-slide smears. This technique may be useful as a general approach in evaluating archival hematologic specimens for the expression of critical gene products.

Bone Marrow Transplantation↗

PubMed1990

Gamma-irradiation response of cocultivated bone marrow stromal cell lines of differing intrinsic radiosensitivity.

There is evidence for differences in the gamma-irradiation response of different cellular lineages within the bone marrow microenvironment. We previously reported that heterogeneity is demonstrable in the gamma-irradiation response of five clonal stromal cell lines, derived from one human bone marrow specimen, despite morphological, histochemical, cytogenetic, and functional similarity. In the present study we tested whether one stromal cell line could affect the intrinsic radiosensitivity of another. Two clonal stromal cell lines, which display distinct gamma-irradiation responses relative to dose rate were used: KM 101, which shows the same radiosensitivity at a low dose rate of 5 cGy/min (LDR) and a high dose rate of 120 cGy/min (HDR) and KM 104 which shows significant gamma-irradiation resistance at LDR. To facilitate the study of the gamma-irradiation response of each cell line during cocultivation, we derived stable subclones of each, expressing the transfected neomycin resistance (neo-r) gene, which confers resistance to the neomycin analog: G 418. Introduction of the neo-r gene did not alter cell lines radiosensitivity. The results show that cocultivation of stromal cell lines before, during, and after gamma-irradiation induces changes in repair of radiation-induced damage, with a dominant effect of a resistant cell line at LDR. In fact, the radiation survival curves of cocultivated stromal cell lines were always characteristic of KM 104, and a dose rate effect was observed, even when KM 101 was present in large excess. Moreover, our results are consistent with preferential killing of the more radiosensitive stromal cell line: both LDR and HDR Do values of the neo-r KM 101, cocultivated with the parent KM 104 for 24 hr before, and during gamma irradiation were significantly lower compared to the neo-r subclone irradiated alone. The LDR Do value of the neo-r KM 104 cocultivated for 24 hr before, and during gamma irradiation with excess of parent KM 101, was significantly higher, compared to the neo-r cells irradiated alone.

Bone Marrow↗

PubMed2000

Heterogeneity of isolated mononuclear cells from patients with acute myeloid leukemia affects cellular accumulation and efflux of daunorubicin.

BACKGROUND AND OBJECTIVE: Pharmacologic studies on blasts from patients with leukemia are generally performed on density gradient isolated blood or bone marrow cells. Thereby, cellular drug accumulation and efflux are determined as mean values of the entire cell population. The objective of the present study was to characterize the heterogeneity in the accumulation and efflux of daunorubicin in various subpopulations of mononuclear cells isolated from patients with acute myeloid leukemia (AML). DESIGN AND METHODS: Mononuclear cells from 33 patients with AML were isolated from peripheral blood by density gradient centrifugation on Lymphoprep (1. 077 g/mL). Cellular accumulation of fluorescent daunorubicin was determined by flow cytometry after incubation of the cells at +37C for 1 hour. Thereafter, the cells were washed and reincubated in drug-free medium. Kinetics of drug efflux were determined by frequent determination of cellular fluorescence during 30 min. Daunorubicin accumulation and efflux were compared in the total isolated mononuclear cell population and in the various blast cell populations gated on FSC/SSC according to the results of immunophenotyping. RESULTS: In 8 of these 33 (24%) patient samples, two distinct blast cell populations could be identified. In 7 out of 8 these cases the more immature blasts had a lower drug accumulation and in 6 out of the 8 cases also a higher efflux rate than the differentiating cell population. Cyclosporin A increased daunorubicin accumulation and reduced efflux in the immature blast population. In the differentiating cell population cyclosporin A increased both the accumulation and the efflux. In patients with a single blast cell population, the gated blast cells had a significantly lower drug accumulation but also a lower drug efflux rate than the total cell population. INTERPRETATION AND CONCLUSIONS: The results imply that drug transport studies on cells isolated from patients with AML give somewhat different results depending on the cell population studied. Some, but not all, of these differences in daunorubicin accumulation and efflux as well as in the effect of cyclo-sporin A can be explained by a heterogenous expression of the mdr1-gene. The observed heterogeneity may be of special relevance with regard to drug resistance. The presence of even a small resistant cell clone may jeopardize the effect of the chemotherapy due to expansion resulting in relapse of disease.

Acute Disease↗

PubMedDate not supplied

Low-field magnetic resonance imaging of bone marrow in the lumbar spine, pelvis, and femur in the adult dog.

The purpose of this study was to describe the appearance of normal bone marrow in seven adult dogs using low-field (0.3T) magnetic resonance (MR) imaging. The areas imaged included the lumbar spine, pelvis, and femur. T1-weighted, fast spin-echo T2-weighted, and short tau (T1) inversion recovery (STIR) sequences were obtained at all locations. Histopathology was performed on sections from the sixth lumbar vertebral body, the wing of the ilium, and the femur (head and neck, mid-diaphysis, and condyle) for evaluation of cellularity and fat content. The lumbar spine and pelvic marrow MR images were similar in all dogs. The lumbar vertebral bone marrow was uniform, intermediate signal intensity, and isointense to muscle on all sequences. There was variation between dogs in the bone marrow distribution with MR imaging of the femur. In the proximal and mid-diaphysis of the femur there was patchy high-signal intensity on T1- and T2-weighted images, and hypointense foci on the STIR images. The distal femoral metaphysis had a variable pattern ranging from intermediate-to-high signal on T1- and T2-weighted images and intermediate-to-low signal on STIR images. The femoral condyles were uniformly high signal on T1- and T2-weighted images and hypointense on STIR images. Histopathologically there was a normal variation in the bone marrow cellularity. The marrow was normocellular (25-75% cellularity) for all sites examined except the femoral condyles, which were hypocellular (<25% cellularity).

Adipose Tissue↗

PubMed2000

Functional disturbances in hemopoietic microenvironment in various forms of myelodysplastic syndrome.

We studied the ability of stromal sublayer of long-term bone marrow cultures and peripheral blood macrophages from patients with various forms of myelodysplastic syndrome to maintain the growth of normal granulocyte-macrophage colony-forming units in mixed cultures. There were changes in the hemopoietic microenvironment in these patients: decreased cellularity of the bone marrow and impaired formation of sublayers in long-term bone marrow cultures, production of growth factors, maintaining the growth of normal granulocyte-macrophage precursors by stromal cells. Dysfunction of macrophages in the stromal microenvironment was probably related to the presence of pathological macrophages./Abstract>

Bone Marrow↗

PubMed1968

Bone marrow as source of cells in reactions of cellular hypersensitivity. II. Identification of allogeneic or hybrid cells by immunofluorescence in passively transferred tuberculin reactions.

The precise origin of cells infiltrating tuberculin skin reactions was studied with the technique of immunofluorescence. Thymectomized, irradiated Lewis rats were restored with bone marrow from allogeneic or F(1) donors. They were passively sensitized to tuberculin by a subsequent transfer of Lewis lymph node cells and were given intradermal skin tests with tuberculoprotein. In 24 hr reactions the majority of cells were shown to be derived from the infused marrow. These results were the same regardless whether the lymphocyte transfer was performed on the day of irradiation and marrow injection or 7 days later. The cells in the tuberculin reactions, marrow, spleen, and lymph nodes not derived from the bone marrow were found to originate in the transferred lymph node cells. The relative percentages of marrow-derived and lymph node-derived cells in the tuberculin reactions remained the same during the 9-24 hr period following skin test.

Animals↗

PubMed1979

Bone marrow culture in vitro. A technique for analysis and permanent recording of cellular composition.

The in vitro cloning of haematopoietic progenitor cells derived from blood or bone marrow is now an established technique for the study of normal and abnormal blood formation. In semi-solid agar the results are conventionally recorded as the number of clusters or colonies that grow on the plate under controlled culture conditions. However, the demonstration of detailed morphology within these cellular aggregates remains unsatisfactory. Aspiration techniques are cumbersome and invariably disturb cellular relationships within the supporting matrix while supravital staining is limited by variable uptake of dye by the agar. We describe a method in which the entire cell-containing layer is removed from the Petri dish, fixed, and after mounting on a glass-slide, is air-dried. This preparation stains well with a wide variety of biological dyes, is minimally influenced by background colouration of the culture medium and excellent demonstration of morphologic detail is possible. A permanent record of the cellular composition of the culture is easily obtained by mounting the stained agar disc.

Animals↗

PubMed1999

Comparison of touch imprints with aspirate smears for evaluating bone marrow specimens.

We compared the differential counts of normal and abnormal bone marrow from touch imprints with those from aspirate smears to determine whether the touch imprint was reliable for independent routine use in the examination of bone marrow and the classification of hematologic abnormalities. Normocellular bone marrow specimens were obtained from 87 patients without hematologic abnormality. Abnormal bone marrow specimens were obtained from 173 patients with treated or untreated neoplastic hematologic disease, including acute myeloid leukemia, myelodysplastic syndrome, chronic lymphocytic leukemia, non-Hodgkin lymphoma, hairy cell leukemia, myeloma, and acute lymphoblastic leukemia. We found no diagnostic difference in the differential counts from touch imprints and aspirate smears of normocellular bone marrow, and although we found some difference between the differential counts in certain cases of diseased bone marrow, the touch imprint proved to be a reliable diagnostic tool for determining the cellular composition of normal bone marrow and more reliable for the diagnosis of bone marrow involved by a neoplastic hematologic disease. Our findings suggest that evaluating touch imprints should be considered a standard practice in examining bone marrow.

Bone Marrow Cells↗

PubMedDate not supplied

Prospective hematologic and clinicopathologic study of asymptomatic cats with naturally acquired feline immunodeficiency virus infection.

Prospective studies were performed over a 28- to 77-month period (median, 66 months) on 5 cats with naturally acquired feline immunodeficiency virus (FIV) infection in an attempt to correlate hematologic and clinicopathologic changes with the emergence of clinical disease. On presentation, all cats were asymptomatic; free of opportunistic infections; and had normal complete blood counts, bone marrow morphologies, marrow progenitor frequencies, and progenitor in vitro growth characteristics. During study, 2 cats remained healthy, 2 cats showed mild clinical signs, and 1 cat developed a malignant neoplasm (ie, bronchiolar-alveolar adenocarcinoma). Although persistent hematologic abnormalities were not observed, intermittent peripheral leukopenias were common. In 3 of 5 FIV-seropositive cats, lymphopenia (< 1,500 lymphs/microL; normal reference range, 1,500 to 7,000 lymphs/microL) was a frequent finding and the absolute lymphocyte counts had a tendency to progressively decline. One of the other 2 cats had consistently low to low-normal absolute neutrophil counts (1,300 to 4,800 segs/microL; mean, 2,730 segs/microL; normal reference range, 2,500 to 12,500 segs/microL), and the remaining cat had consistently normal leukograms, except for a transient period (ie, 11 months) of benign lymphocytosis (7,200 to 13,430 lymphs/microL) early in the study. Periodic examinations of bone marrow aspirates revealed normal to slightly depressed myeloid-to-erythroid ratios with normal cellular morphology and maturation. Bone marrow abnormalities observed late in the study included mild dysmorphic changes (ie, megaloblastic features) in 2 cats, and a significant decrease (60% of controls, P < .001) in the frequencies of burst-forming units erythroid (BFU-E) in marrow cultures of FIV-seropositive cats compared with uninfected control cats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2005

Critical early events in hematopoietic cell seeding and engraftment.

Durable hematopoietic stem cell engraftment requires efficient homing to and seeding in the recipient bone marrow. Dissection of cellular and molecular mechanisms by retrospective analysis of functional engraftment studies imposes severe limitations on the understanding of the early stages of this process. We have established an experimental approach for in vivo functional imaging of labeled cells at the level of recipient bone marrow in real time. The adhesive interaction of hematopoietic cells with the bone marrow stroma evolves as the most important early event. Adhesion to the marrow, rather than the vascular endothelium, determines the efficiency of both homing and seeding, and is absolutely essential to maintain cell viability in the marrow. Seeding and engraftment may be improved either by bypassing homing or by localized transplant of a large number of cells in a relatively small marrow space. There is functional redundancy in the molecular pathways that mediate the cell-stroma interaction, such that blockage of a single pathway has only minor effect on homing and seeding. We hypothesize that successfully seeding-engrafting cells undergo extensive phenotypic changes as a consequence of interaction with the stroma, without engaging in rapid proliferation. Surprisingly, Fas-ligand appears to promote hematopoietic cell engraftment by immunomodulatory and trophic effects.

Animals↗

PubMed2001

The value of bone marrow histology in differentiating between early stage Polycythemia vera and secondary (reactive) Polycythemias.

BACKGROUND AND OBJECTIVES: The diagnostic criteria of the Polycythemia Vera Study Group (PVSG), although generally acknowledged as the gold standard for establishing a diagnosis of polycythemia vera (PV), do not consider bone marrow features. It may, therefore, be speculated that initial-early stages of PV are overlooked. In this retrospective study we tried to investigate whether bone marrow morphology of patients with an only borderline to slight increase in hemoglobin/hematocrit not conforming with the postulates of the PVSG enabled a clear-cut differentiation between PV and secondary (reactive) polycythemias (SP). DESIGN AND METHODS: From a series of 348 patients with a borderline to pronounced erythrocytosis and representative pre-treatment bone marrow trephine biopsies a cohort of 86 cases was selected showing only a borderline increase in hemoglobin (males < 18.5 g/dL, females < 16.5 g/dL). Biopsies and clinical records were evaluated independently and following histologic and clinical work-up a straightforward consensus was reached. The diagnostic impact of histologic findings was tested by means of discriminate analysis of 20 standardized morphologic features based on histochemical and immunohistochemical staining techniques. RESULTS: Bone marrow histopathology in 47 patients diagnosed as having SP was characterized by a minimal to slight increase in cellularity with predominance of the erythroid lineage. Neutrophil granulocytopoiesis was prominent and left-shifted and small to medium-sized megakaryocytes without maturation defects were scattered throughout the bone marrow. There was an increased number of eosinophils, marked perivascular plasmacytosis, histiocytic reticular cells with accumulated cell debris and many iron-laden macrophages. Contrasting this appearance in SP our 39 patients with initial-early stage PV revealed a hypercellular bone marrow with trilineage proliferation (pan-myelosis) showing confluent sheets of erythropoiesis and loose clusters of megakaryocytes. Megakaryocytopoiesis was characterized by a pleomorphous appearance, i.e. giant cells were lying adjacent to small ones, but lacked an obvious cytologic abnormality. There was usually no prominent inflammatory reaction of the interstitial compartment. In ten patients lymphoid nodules were found, but no conspicuous iron deposits and in six patients a borderline to minimal increase in reticulin fibers was present. Following stepwise discriminate analysis of histologic features a set of parameters emerged including increase in megakaryocyte size, perivascular plasma cells, overall bone marrow cellularity and cellular debris. This pattern exerted a significant impact on separation (Wilks' lambda statistics = 0.110, p < 0.0001) of early stage PV from SP. Most patients with SP had an underlying bronchopulmonary condition, frequently associated with heavy smoking or rarely renal pathology. In addition to the histopathologic features, splenomegaly, thrombocyte count, LDH, LAP and erythropoietin levels proved to be different in the two groups of patients. INTERPRETATION AND CONCLUSIONS: Initial-early PV is characterized by a specific pattern of bone marrow histopathology. Clinical features of distinctive impact include splenomegaly, thrombocyte count, LDH, LAP and in particular erythropoietin level. Taking these clinical and histologic findings into consideration, reactive-secondary causes of polycythemia (SP) are clearly distinguishable from autonomous ones (PV).

Adult↗