Algorithms utilizing peripheral blood hematopoietic progenitor cell counts in lieu of some CD34+ cell counts predict successful peripheral blood stem cell collections with substantial time and cost savings.

BACKGROUND AND OBJECTIVES: Hematopoietic progenitor cell (HPC) counts from Sysmex hematology analyzers have been shown to correlate with peripheral blood (PB) CD34+ cell counts by flow cytometry. Algorithms utilizing HPC counts to guide stem cell collections have been proposed but rarely tested. This study describes the development and validation of algorithms utilizing HPC and PB CD34+cell counts to predict adequate peripheral blood stem cell (PBSC) collections for chemomobilized and cytokine-mobilized individuals. MATERIALS AND METHODS: Utilizing a test set of 83 PB samples from chemomobilized or cytokine-mobilized PBSC collection patients, PB CD34+ counts were correlated with HPC counts and a receiver operating characteristic curve was constructed. Cut-offs of ≤0.5 HPC/µl and ≥7 HPC/µl were established to maximize sensitivity and specificity for using HPC to predict PB CD34+ ≥ 10 cells/µl. These cut-offs were subsequently validated using a separate prospective validation set of 88 HPC/CD34+ cell sample pairs. RESULTS: Using the algorithms, all patients in the prospective validation data set achieved adequate collections of ≥1 × 106 CD34+ cells/kg, and a 67% reduction in the number of CD34+ cell counts performed was achieved. This lead to a direct cost savings of at least $18,700 USD over a 21-month period (88% reduction in direct costs). CONCLUSION: Use of the algorithms provides significant time and cost savings for the laboratory while accurately predicting (i) timing of PBSC collections to obtain adequate CD34+ product yields for chemomobilized patients and (ii) when to administer plerixafor to cytokine-mobilized patients to improve the likelihood of achieving adequate collections.

Bone marrow mast cell morphologic features and hematopoietic dyspoiesis in systemic mast cell disease.

Systemic mast cell disease (SMCD) cannot be distinguished from reactive mastocytosis (RM) by quantitation of mast cells in aspirate smears, and few studies have analyzed systematically the morphologic features of mast cells in SMCD vs RM. In addition, although SMCD is associated with myeloproliferative disorders/myelodysplastic syndromes (MPD/MDS), it is not known whether subtle signs of dysplasia or MPD can be found in SMCD, suggesting most cases are part of a dysplastic or myeloproliferative process. We compared 18 bone marrow specimens with SMCD with 10 bone marrow specimens from patients with RM. Mast cells in SMCD were more likely to show cytoplasmic hypogranularity, uneven granule distribution, and fusiform morphologic features. Eight cases of SMCD (44%) demonstrated MPD/MDS, and 9 cases (50%) showed subtle evidence of dyspoiesis, with megaloblastic change, nuclear budding of erythroid precursors, and/or atypical megakaryocytes. Mast cells in SMCD appear morphologically different from those in reactive proliferations. Dyspoietic features were present in most cases of SMCD, suggesting that SMCD is part of a spectrum of chronic myeloproliferative/myelodysplastic disorders.

Acute lymphoblastic leukemia.

Over the last two decades, great strides have been made in the treatment of acute lymphoblastic leukemia (ALL). This progress has been paralleled by advances in diagnosis. In addition to morphology and cytochemistry, the diagnostic and prognostic importance of immunophenotypic and genetic features is becoming increasingly apparent. This article reviews the clinical and morphologic features, immunophenotypic classification, and karyotypic abnormalities of ALL, and discusses how these aspects relate to the diagnosis of ALL.

Special stains in the diagnosis of acute leukemia.

Special stains are used in the evaluation of bone marrow specimens to augment Wright-Giemsa preparations. This article details the common cytochemical stains available, and discusses their clinical use as indicators of hematopoietic lineage. Iron and reticulin stains, which are widely used in the general evaluation of the bone marrow, are also reviewed.

Neutrophils and low-grade inflammation in the seemingly normal aging human lung.

Lung function deteriorates with age and is associated with elastin loss, loss of elastic recoil and decline in diffusing capacity for carbon monoxide. To determine whether increased numbers of neutrophils can be found in the lower respiratory tract in healthy, clinically normal individuals who are more advanced in age, we performed bronchoalveolar lavage (BAL) on individuals in three discontinuous age groups (Group I, 19-36 years; Group II, 45-55 years; Group III, 64 83 years). We found that neutrophils were increased in many individuals in Group III compared to Group I. The neutrophil cell differential count was 1.44+/-0.18% (mean+/-S.E.M.) for Group I versus 3.88+/-0.81% for Group III (P < 0.01) and neutrophils x 10(3)/ml BAL fluid was 1.7+/-0.2 versus 7.2+/-1.7 for Group I versus Group III, respectively (P < 0.01). Similarly, interleukin-8 (IL-8) (8.5+/-1.7 vs 36.8+/-9.4 pg/ml, P < 0.01) and neutrophil elastase (NE) complexed to alpha1-antiprotease (1.2+/-0.1 vs 16.6+/-7.1 ng/ml, P < 0.02) were significantly elevated in the oldest versus youngest age group, although alpha1-antiprotease (582+/-86 vs 1178+/-148 ng/ml, P < 0.01) and elastase inhibitory capacity (EIC) (8.1+/-1.3 vs 17.7+/-1.9 micromol/ml, P < 0.01) were also significantly increased in the oldest age group. This cross-sectional investigation suggests that low-grade inflammation exists in the air spaces of many clinically normal, older individuals.

Pediatric bone marrow cellularity: are we expecting too much?

PURPOSE: Accurate assessment of marrow cellularity is necessary for establishing diagnoses and monitoring the effects of treatment in a large number of malignant and nonmalignant pediatric illnesses, and for evaluating sibling donors for transplantation. However, normal values for age-related bone marrow cellularity in pediatric patients have not been well established. This study was designed to better define pediatric normal values for bone marrow cellularity. PATIENTS AND METHODS: A retrospective review of 448 bone marrow core biopsy or clot specimens, including 45 samples from healthy donors, were taken from the posterior iliac crest of patients aged from younger than 1 to 18 years (55% male). All samples were collected and fixed in a standardized fashion. Patients with hematopoietic malignancies and other systemic conditions known to impact marrow cellularity were excluded. RESULTS: The mean cellularity of the entire sample was 65.4%. Cellularity was similar in boys and girls, but varied (p < 0.001) with age. Cellularity was highest in patients younger than 2 years (79.8%), and declined in patients 2 to 4 years old (68.6%) and 5 to 9 years old (59.1%). Cellularity remained stable in older patients (60.1% and 61.1%, respectively, in patients 10 to 14 and 15 to 18 years of age). Adjusting for age and gender, mean cellularity was similar in patients with an underlying nonhematologic malignancy compared to health donors but was roughly 6% higher in patients with hematopoietic disorders. CONCLUSIONS: This study demonstrates that average cellularity during the first two decades of life, using current techniques of marrow collection and standardized analysis, is lower than previously estimated. In addition, cellularity declined with age until the age of 5 years, but was similar thereafter. After adjusting for age, differences according to diagnosis were relatively small.

Bone marrow biopsy findings in childhood anemia: prevalence of transient erythroblastopenia of childhood.

OBJECTIVE: Bone marrow examination is rarely required for the diagnosis of childhood anemia, and its diagnostic utility in this setting is unknown. DESIGN: Marrow specimens from 25 children aged 11 days to 12 years were reviewed to determine the cause of unexplained anemia. RESULTS: These samples comprised only 2% of pediatric marrow examinations. Hematocrits ranged from 0.12 to 0.31 (mean 0.23). Marrow findings included erythroid hypoplasia (12 of 25, 48%) and hyperplasia (11 of 25, 44%), dyserythropoiesis (2 cases), ringed sideroblasts (2 cases), lymphocytosis (3 cases), and megaloblastic change (1 case). Final diagnoses were transient erythroblastopenia of childhood (15 cases, 60%); iron deficiency and sideroblastic anemia (2 cases each); and congenital dyserythropoietic anemia, anemia of chronic disease, hereditary spherocytosis, and intra-abdominal hemorrhage (1 case each). In two patients, a definitive diagnosis was never made. CONCLUSIONS: Marrow examination contributed to a specific diagnosis in childhood anemia in 92% of cases; the most common diagnosis in this population was transient erythroblastopenia of childhood.

Transient increase in blasts mimicking acute leukemia and progressing myelodysplasia in patients receiving growth factor.

Previous studies of the hematologic effects of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) have emphasized the morphologic changes induced by these growth factors, but few have reported increases in blasts. Here, we report six cases in which growth factor treatment resulted in a marked but temporary increase in peripheral and bone marrow blasts that led to diagnostic confusion with acute leukemia and high-grade myelodysplastic syndromes. Five of the six patients were receiving treatment for hematologic malignant neoplasms, and one patient had an optic nerve germinoma. Growth factor treatment included single agent therapy with G-CSF (three patients), GM-CSF (one patient), or simultaneous therapy with G-CSF and GM-CSF (two patients). In two patients, there was a dramatic increase in blasts in the peripheral blood (39% and 20%), whereas four had substantial increases in blasts on the aspirate smear (8%-41%). One patient had a medium-sized blast cluster shown on the core biopsy specimen. The blasts decreased after removal of growth factor in all patients. The findings indicate that growth factor therapy can cause a substantial transient increase in blasts in the bone marrow and peripheral blood that may be confused with relapse of acute leukemia or progression of a myelodysplastic syndrome.

Degradation of annexin I in bronchoalveolar lavage fluid from patients with cystic fibrosis.

Annexin I is a 36 kilodalton (kD) calcium-dependent phospholipid-binding protein which may have anti-inflammatory properties. Previous investigations which sampled lower respiratory tract epithelial lining fluid (ELF) via bronchoalveolar lavage (BAL) have demonstrated that annexin I can be degraded in inflammatory lung disease. We analyzed BAL fluid from patients with cystic fibrosis (CF) to determine the effects of lung inflammation on the structure and activity of annexin I. Intact annexin I was absent in 17 out of 20 BAL fluid samples from patients with CF, due largely to degradation to a 33 kD protein. The three CF BAL fluids in which annexin I was detectable had very little or no unopposed neutrophil elastase activity in contrast to the 17 in which no annexin I was detectable. Annexin I was present in all BAL fluid samples from 10 normal volunteer (NV) subjects and 12 patients with interstitial lung disease (ILD). The 33 kD annexin I breakdown product was not detectable in samples from NV, but was detectable only in ILD patients with relatively high percentages of neutrophils on BAL differential cell counts. Annexin I appeared to be cleaved by neutrophil elastase at the N-terminal portion between Val-36 and Ser-37 to yield the 33 kD protein. Cleavage of the N-terminal portion of annexin I was accompanied by a marked change in the annexin I isoelectric point (pI) value (from 6.0 to 8.5-9.0) and greatly diminished annexin I functional activity. Our findings demonstrate that annexin I degradation in epithelial lining fluid is closely related to lung inflammation.

Myelodysplastic syndromes and acute myeloid leukemia in connective tissue disease after single-agent chemotherapy.

Cytopenias are typical of patients with connective tissue disease (CTD) and are usually related to autoimmune phenomena. In some cases, cytopenia may be the result of treatment with cytotoxic agents. Although multi-drug therapy is known to produce myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) in patients with CTD, treatment with single-agent therapy, particularly methotrexate, has rarely been associated with secondary MDS or AML. Blood and marrow samples were studied from 3 men and 5 women with rheumatoid arthritis (5 cases), Behcet's disease (2 cases), and systemic lupus erythematosus (1 case) developing MDS or AML after methotrexate (5 cases), chlorambucil (2 cases), and cytoxan (1 case). The durations of CTD ranged from less than 6 months to more than 10 years. Five patients (63%) presented with MDS including refractory anemia (RA), refractory thrombocytopenia (RT), refractory anemia with excess blasts (RAEB), chronic myelomonocytic leukemia (CMML), and RAEB in transformation. Patients with RT, CMML, and RAEB in transformation developed AML. Of six patients presenting with or developing AML, four had AML with differentiation (FAB M2), one acute myelomonocytic leukemia (FAB M4), and one M4Eo. Inv 16 was seen in the M4Eo and t(8;21) in one case of M2. Four of six patients are alive up to 6 years after diagnosis of AML. One of three patients with MDS is alive 6 months after diagnosis of MDS. Cytopenias in patients with CTD may be due to therapy-related MDS or AML occurring in a setting of single-agent chemotherapy, including methotrexate.

Mantle cell lymphoma. Morphologic findings in bone marrow involvement.

Although mantle cell lymphoma (MCL), has been well described in lymph nodes, involvement of blood and bone marrow has not been well defined. The authors reviewed involved blood and marrow specimens from 13 patients with MCL to determine patterns of infiltration. These findings were compared to marrow involvement by follicular small cleaved cell lymphoma (SCCL) and small lymphocytic lymphoma (SLL). Peripheral blood involvement by MCL was present in 5 patients (38%). The circulating lymphoma cells were small (7-10 mu) with slightly folded nuclei. Marrow involvement ranged from 5% to 90% of the marrow space and was predominantly intertrabecular, including nodules and interstitial infiltrates (9 cases each; 68%). Paratrabecular aggregates (6 cases; 46%) and diffuse replacement by lymphoma (3 cases; 23%) were also seen. In SCCL, paratrabecular involvement was seen as were interstitial nodules. Cases of SLL showed diffuse, interstitial or nodular involvement without paratrabecular localization. Cytologic comparison showed nuclei that were angulated in SCCL, round in SLL, and slightly irregular in MCL, with considerable overlap among the groups. The architectural and cytologic findings in marrow involved by MCL show features of both SCCL and SLL, and cannot be used to definitively diagnose MCL.

An unusual case of autoimmune hemolytic anemia with reticulocytopenia, erythroid dysplasia, and an IgG2 autoanti-U.

BACKGROUND: Autoantibodies with anti-U specificity, usually in combination with autoantibodies of other specificities, have occasionally been identified in association with autoimmune hemolytic anemia. A case of life-threatening autoimmune hemolytic anemia, characterized by several atypical features, including apparent intravascular hemolysis associated with an IgG2 anti-U, reticulocytopenia, and bone marrow dyserythropoiesis is described. CASE REPORT: A 36-year-old man with a severe case of acute-onset autoimmune hemolytic anemia was admitted to another hospital; he had a hematocrit of 15 percent, elevated bilirubin and lactate dehydrogenase, and positive direct and indirect antiglobulin tests. He received 7 units of incompatible red cells without improvement in hematocrit, and he was transferred to University Hospitals of Cleveland (OH). He was jaundiced and became syncopal in the sitting position. His serum was reddish pink; he had a hematocrit of 11.8 percent and a reticulocyte count of 2.5 percent. No spherocytes were observed in the peripheral blood smear. Shortly after admission, the hematocrit fell to 6.9 percent. He was given 3 units of "least-incompatible" red cells and was started on prednisone, with little improvement. An IgG2 autoanti-U was detected in his serum. Seven units of U- red cells were transfused over the next 4 days. The hematocrit improved to 23 percent and continued to rise without further transfusion. A bone marrow examination, initially revealing erythroid hyperplasia accompanied by dyserythropoiesis, became morphologically normal. Drug studies failed to show evidence of drug-related hemolysis. He remains well 2 years after discharge without evidence of recurrent hemolysis. CONCLUSION: Severe life-threatening autoimmune hemolytic anemia, in this instance induced by an autoanti-U, may be associated with IgG2 autoantibody and characterized by apparent intravascular hemolysis and bone marrow dyserythropoiesis. Early treatment with U- blood, in addition to steroids, may be beneficial.

Immune dysregulation in the aging human lung.

Aging has been associated with diminished lung function and increased susceptibility to lung infection. To determine whether changes suggestive of immune dysregulation and inflammation appear in the lungs of clinically normal individuals as a function of advancing age, we performed bronchoalveolar lavage (BAL) on discontinuous age groups (20-36, 45-55, and 65-78 yr old) of clinically normal volunteer subjects. We measured immunoglobulin (IgG, IgA, IgM), albumin, interleukin-6 (IL-6), and interleukin-10 concentrations in BAL fluid. Bronchoalveolar cell profiles, cell surface antigen expression, and superoxide anion production were also measured. A significant increase in total cell concentration, neutrophils, and BAL immunoglobulin content was observed in the oldest age group compared with the youngest age group. Mean lymphocyte subset (CD4+/CD8+) ratios were significantly increased in blood (2.6 +/- 0.4 versus 1.6 +/- 0.1; p<0.03) and to a greater degree in BAL (4.8 +/- 1.0 versus 1.9 +/- 0.2; p<0.01) for the oldest versus youngest age groups. Similarly, BAL-derived cells displayed significantly increased phorbol myristate acetate-stimulated release of superoxide anion (8.8 +/- 1.3 versus 4.5 +/- 0.7 nmol/5 x 10 5 cells/h; p<0.01) for the oldest versus youngest subject group, and mean BAL IL-6 concentrations were significantly elevated in the oldest age group (0.86 +/- 0.13 ng/ml) compared with the youngest age group (0.53 +/- 0.03 ng/ml; p<0.01). Our observations suggest that altered inflammatory cell profiles and low-grade inflammation exist in the lower respiratory tracts of many asymptomatic, clinically normal volunteers of advanced age.

Tryptophan metabolism in chronic inflammatory lung disease.

Induction of indoleamine 2,3-dioxygenase (IDO), an enzyme expressed by mononuclear phagocytes and some fibroblast cell lines in response to interferon-gamma, leads to enhanced degradation of tryptophan to kynurenine. Because inflammatory lung diseases are generally associated with activation of pulmonary macrophages, we investigated tryptophan metabolism in patients with interstitial lung disease by measuring circulating levels of tryptophan and kynurenine in peripheral blood and by measuring the IDO activity of bronchoalveolar cells. IDO activities were increased for bronchoalveolar lavage (BAL) cells obtained from patients with interstitial lung disease (115.4 +/- 30.4, n = 37) when compared with BAL cells from normal subjects (15.2 +/- 7.4, n = 14; p < 0.05), and messenger RNA for IDO was present in BAL cells from patients with interstitial disease but was not present in BAL cells from normal volunteer subjects. Patients with inflammatory lung disease also had decreased tryptophan and increased kynurenine concentrations in serum. The ratio of serum tryptophan levels to serum kynurenine levels was significantly depressed for patients with idiopathic pulmonary fibrosis (18.4 +/- 1.7, n = 29; p < 0.0001), patients with fibrosing alveolitis associated with collagen vascular disease (13.1 +/- 1.6, n = 18; p < 0.0001), or patients with sarcoidosis (21.0 +/- 1.1, n = 50; p < 0.0001), as compared with the ratio for normal subjects (31.8 +/- 2.3, n = 18). Patients with fibrotic disease had the highest levels of BAL cell IDO activity, and patients with collagen vascular disease associated fibrosing alveolitis had the most depressed levels of serum tryptophan and the greatest elevations in serum kynurenine. Measurement of tryptophan and kynurenine concentrations in serum may provide a useful measure of disease activity in chronic inflammatory parenchymal lung diseases such as sarcoidosis and idiopathic pulmonary fibrosis.

Ex vivo expansion and subsequent infusion of human bone marrow-derived stromal progenitor cells (mesenchymal progenitor cells): implications for therapeutic use.

We report a phase I trial to determine the feasibility of collection, ex vivo culture-expansion and intravneous infusion of human bone marrow-derived progenitor stromal cells (mesenchymal progenitor cells (MPCs)). Ten milliliter bone marrow samples were obtained from 23 patients with hematologic malignancies in complete remission. Bone marrow mononuclear cells were separated and adherent cells were culture-expanded in vitro for 4-7 weeks. Autologous MPCs were reinfused intravenously and a bone marrow examination repeated 2 weeks later for histologic assessment and in vitro hematopoietic cultures. Patient age ranged from 18 to 68 years and 12 subjects previously had undergone an autologous or syngeneic bone marrow transplant 4-52 months prior to collection of MPCs. A median of 364 x 10(6) nucleated bone marrow cells (range: 103 to 1004 x 10(6)) were used for ex vivo expansion. Median number of MPCs which were obtained after ex vivo culture expansion was 59.0 (range: 1.1 to 347 x 10(6)) representing a median cell doubling of 16,000-fold (13 doublings). Fifteen of 23 patients completed the ex vivo expansion and underwent MPC infusion. Time to infusion of MPCs after collection ranged from 28 to 49 days. Five patients in each of three groups were given 1, 10 and 50 x 10(6) MPCs. No adverse reactions were observed with the infusion of the MPCs. MPCs obtained from cancer patients can be collected, expanded in vitro and infused intravenously without toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Promyelocytic blast crisis of chronic myelogenous leukemia. A rare subtype associated with disseminated intravascular coagulation.

Two patients with chronic myelogenous leukemia (CML) developed blast crisis that morphologically appeared to be the microgranular variant of acute promyelocytic leukemia. This represented 8% of CML patients developing blast crisis from 1984 to 1993. Cytogenetic studies revealed translocation 15;17 in addition to translocation 9;22 that had been documented at initial diagnosis. Both patients had evidence of disseminated intravascular coagulation at the onset or during treatment of blast crisis, which was not documented in any other patients with CML blast crisis. One patient died of sepsis during intensive chemotherapy. The second returned to a chronic phase of the disease after therapy. Although rare, a promyelocytic blast crisis of CML can occur which, as in de novo acute promyelocytic leukemia, has a propensity to produce disseminated intravascular coagulation.

Failure to engraft after bone marrow transplantation: bone marrow morphologic findings.

Few studies have explored bone marrow findings in patients with graft failure or delayed engraftment after bone marrow transplantation (BMT). The authors retrospectively identified 4 patients of 165 transplant recipients who underwent bone marrow examination after BMT because peripheral blood counts had not recovered to expected levels. All patients were women who were 21- to 49-years old (mean 37 years). Three patients underwent autologous BMT; the fourth received peripheral stem cell infusion. Transplants were performed for treatment of Hodgkin's disease, breast carcinoma, and follicular small cleaved cell lymphoma. Three patients received GM-CSF after marrow infusion. The time between transplant and biopsy ranged from 19 to 40 days (mean 22 days). White cell counts ranged from 0.1 to 0.6 x 10(9)/L, hematocrits from .25 to .41, and platelet counts from 10 x 10(9)/L to 39 x 10(9)/L. Aspirate smears were markedly hypocellular in all cases, and markedly hypocellular, and all contained histiocytes with foamy eosinophilic cytoplasm diffusely throughout the biopsy. Acid-fast and Gomori's methenamine-silver (GMS) stains were negative. Serous fat atrophy and marrow fibrosis were not seen. Delayed engraftment after BMT may be associated with a profuse histiocytic proliferation similar to that seen in immunodeficiency, some hematologic disorders, and storage diseases.

msd is required for mesoderm induction in mice.

Mesoderm induction is fundamental for establishing the basic body plan of the vertebrate embryo and mutations are critical for dissecting this process. Mouse embryos lacking msd (mesoderm deficiency) do not produce mesoderm but have well-defined extraembryonic and thickened embryonic ectoderm. Distribution of transcripts indicate that temporal regulation of gene expression relevant to gastrulation has begun but primitive-streak formation and mesoderm induction are blocked. Both msd-deficient embryos and embryonic stem (ES) cells fail to form highly differentiated structures of mesoderm origin, but are capable of ectodermal differentiation. Thus, the effects of the msd mutation are restricted to mesoderm formation and could result from the inability to respond to an inducing signal.

Reactive plasmacytosis and lymphocytosis in acute myeloid leukemia.

The association of plasmacytosis and lymphocytosis with acute myeloid leukemia (AML) has been documented in isolated case reports. We examined 149 cases (134 adults, 15 children) of newly diagnosed AML and found 9 adults (6%) with > or = 5% plasma cells and 1 child and 1 adult with > or = 20% lymphocytes. Lymphocytes constituted 25% and 42% of marrow cellularity in the adult and child respectively and persisted throughout remission in the child's marrow. The percentage of morphologically normal plasma cells ranged from 5% to 13% (mean 7%). Monoclonal immunoglobulins were not detected with immunostaining or flow cytometry. Hypergammaglobulinemia was present in 3 cases, and a monoclonal increase in IgG-kappa in 1. Plasmacytosis was not seen in remission marrows from these patients (n = 4). Lymphocytosis or plasmacytosis occurs in approximately 7% of patients with AML, appears reactive in nature, and may represent an immunological response to tumor. Monoclonal paraproteins may occur without other evidence of B-cell neoplasia.

Marrow cellularity as a predictor of adequate cell yield for transplantation.

Clear correlations have not been established between bone marrow cellularity before or at marrow harvest and marrow cell yield for transplantation. The authors therefore retrospectively reviewed 204 marrow donations to ascertain whether biopsy cellularity was predictive of nucleated cell yield at harvest, as measured by final cell counts (FCC)/kg body weight. Preharvest and intraoperative biopsy cellularity were highly correlated with each other; moderate correlation was found between intraoperative biopsy cellularity and FCC. Mean cellularity was slightly but significantly higher in samples yielding an FCC greater than 2 x 10(8) nucleated cells/kg (P < 0.01). Biopsy cellularity less than 20%, seen in 4% of specimens, did not consistently correlate with low FCC, defined as less than 2 x 10(8) nucleated cells/kg. More than 2 x 10(8) cells/kg were consistently obtained only when biopsy cellularity was 65% or more. Marrow biopsies performed before harvest can be used to predict intraoperative cell counts at the time of marrow donation, although a cell yield of more than 2 x 10(8) nucleated cells/kg can be assured only with high marrow cellularity.