Early Hematopoietic Reconstitution after Autologous Transplantation with Blood-Derived Stem Cells in a Patient with Advanced Lymphoma

A 30-year-old man with advanced non-Hodgkin lymphoma underwent repeated leukaphereses for harvesting blood-derived hemopoietic stem cells. Collection was started 8-10 days after the end of L-VAMP therapy (3 cycles). Nine procedures were performed and a total of 65.4× 109 mononuclear cells (0.87× 109/Kg) were collected, processed, cryopreserved and stored in liquid nitrogen. The yields of CFU-GM, BFU-E and CFU-GEMM were respectively 964× 104 (12.4× 104/Kg), 249× 104 (3.2× 104/Kg) and 798× 104 (10.4× 104). The patient received a myeloablative regimen consisting of fractionated total body irradiation (1200 cGy) and cyclophosphamide (120 mg/kg) followed by infusion of his own thawed cells. Early trilineage hematopoietic recovery was first observed on day +8; 1× 109/l WBC were reached on day + 11, 0.5× 109/l PMN on day + 13 and 50× 109/l platelets on day + 11. Course was uneventful and the patient was discharged from hospital on day + 21. Eight months after transplant the patient is in continuous unmaintained complete remission with normal blood cell counts. This reports suggests that complete and sustained engraftment can be achieved with peripheral stem cells recruited after “soft” chemotherapy.

Survival after PBSC Transplantation and Comparison of Engraftment Speed with Autologous and Allogeneic Marrow Transplantation: Results of a Multicenter Study

We have analyzed the results of a multicenter study on peripheral blood stem cell transplantation (PBSCT) performed on 55 patients suffering from various neoplastic diseases. After myeloablative therapy, they received a mediam of 6.8x108/kg MNC and 11.4x104/kg CFU-GM harvested by a median of 9 apheresis after mobilization with chemotherapy alone. As of date, 34 of the 55 patients are alive and 28 of them are in continuous complete remission after a follow-up of 30 months. The probability of survival was related to the disease status at transplant, CR/PR vs. PD (p= 0.0001) and the bone marrow involvement, BM-vs. BM+ (P=0.009). Furthermore, a comparative study on speed of engraftment and clinical management was conducted on the 55 PBSCT patients as well as on 41 autoBMT and 52 alloBMT patients. Days to reach WBC> 1.0x109/L, PMN> 0.5x109/L and PLT> 50x109/L was 12/14/33 for PBSCT, 17/20/23 for ABMT and 15/16.5/18 for BMT, respectively. Days with fever >38° C, systemic antibiotic therapy and length of hospitalization was 3/12/36 for PBSCT, 5/18.5/42 for ABMT and 9/25/46 for BMT respectively.

Concentration of Human Hematopoietic Stem Cells in Bone Marrow Transplantation: Results of a Multicenter Study Using Baxter CS 3000 plus Cell Separator

Preliminary BM processing to produce an enriched MNC fraction from large BM volumes improves subsequent pharmacological and/or immunological “ex vivo” treatment and cryopreservation. We detail on a multicenter study (6 Transplant Centers) performed to establish an effective and reliable protocol using a CS 3000 continuous flow separator on a large series of BM processed for autologous (96) and allogeneic (12) transplantation. The reduction in volume was 78.6+7.2% while 28.9+12.4% of the original nucleated cells were found in the final product. A mean of 84.3+13.2% of the starting MNC was yielded in a fraction containing over 81% MNC. Cloning efficiency indicated than the final graft was highly enriched in progenitor cells committed to the granulocyte/macrophage pathway (> 100%) as assessed in vitro (CFU-GM). Removal of RBC and PLT was 98.3+1.1 and 37.7+14.6%, respectively. The mean dose of MNC and CFU-GM was 0.6+0.37 x 108 and 0.96+1 x 108 recipient weight. The entire process was accomplished in 87.5+20 min. We concluded that this automated device is a simple and reproducible method for BM processing suitable as first step for further “ex vivo” automated negative and/or positive cell selections.

Rapid Diagnosis of Bacterial Contamination of Blood: Comparison of Three Automated Microbial Detection Systems

Rapid methods of determining microbial contamination are needed in suspecting contaminated banked blood or other blood products. In this study, we experimented contaminated blood units with 122 strains of bacteria and fungi. After innoculation, a comparison between ESP Blood Culture Sytem (Difco Laboratories Inc., Detroit Ml), BacT/Alert (Organon Teknica, Durham NC) and Bactec 9240 System was made for their efficiency in the detection of microbial contamination. Experimental data showed a diagnostic relevance of these automated systems with no significant differences in time detection of microbial contamination between the three methods under comparison.

Seven-day Storage of Single Donor Platelets in Polyolefin Bags: Clinical, Biochemical, Morphological and Microbiological Evaluation

We compared the in vitro and in vivo function of fresh and stored platelet concentrates (PCs) collected by an automated continuous-flow blood cell separator (CS 3000 Fenwal) in a closed-system apheresis kit in order to evaluate the possibility of extending the storage time to seven days with the polyolefin container (PL-732). The initial 220 ml platelet volume (5.14 ± 1.23 x 1011) was divided into two parts. Half was transfused and the other half was stored for 7 days. All cultured units were negative for bacterial contamination. Mean counts for fresh and stored platelets were respectively 2.34 ± 0.59 and 2.17 ± 0.50 x 1011/100 ml of PCs (mean recovery 88.7 ± 11.9%). The pO2 levels were maintained during storage (179.9 ± 30.5 mmHg) but pCO2, pH, LDH, osmolality, glucose consumption, bicarbonates, ATP, and osmotic stress values changed significantly after 7 days storage. From a clinical point of view, in 14 patients receiving a total of 38 PC transfusions no statistically significant change in corrected post-transfusional levels was observed between fresh and stored PC. Biochemical and morphological data and clinical results suggest that PCs collected with CS-3000 blood cell separator in a closed system and stored for 7 days in polyolefin bags (PL-732) can be satisfactorily employed in clinical practice.

Enrichment of Marrow Hemopoietic Progenitor Cells using a Blood Cell Processor

A total of 93 bone marrows (BM) from normal donors and patients were processed using the IBM-COBE 2991 blood cell washer to produce a concentrated buffy coat (BC) for either bone marrow transplantation (BMT) or cryopreservation for subsequent autologous BMT. The reduction in volume was 73.3 ± 8.5% and nucleated blood cells (NBC) recovery was 87.1 ± 9.1% of original marrow. Red blood cell (RBC) and platelet (PLT) contamination was reduced 64.5 ± 10.9% and 41.2 ± 24.1%, respectively. Clonogenic activity indicated that the NBC fraction was highly enriched in hematopoietic progenitor cells (> 100%) as assessed in vitro (CFU-GM). Results were not affected by diagnosis, initial marrow volume or cell count of the BM suspension. We conclude that this is a simple and reproducible method using blood bank, facilities and permits BC preparation from BM without significant loss of hematopoietic progenitor cells.

Malignancy: X-Linked Cytochrome B Positive Chronic Granulomatous Disease treated by Bone Marrow Transplantation

Chronic granulomatous disease is caused by a genetic defect in the oxidase of phagocytic cells which results in increased susceptibility to recurrent infections. Conventional treatment includes the use of antimicrobials and interpheron-gamma. This study was performed to assess the clinical efficacy of allogeneic bone marrow transplantation in definitively correcting the functional underlying defect of chronic granulomatous disease. An 8-year-old boy with a rare type X-linked cytochrome b positive chronic granulomatous disease underwent allogeneic bone marrow transplantation after conditioning with busulfan and cyclophosphamide. The patient's HLA identical sister was marrow donor. The post-transplant outcome was uneventful. During the 9 year follow-up period the patient has been constantly free of infections, maintained an excellent clinical performance with full correction of the granulocyte functional defect. This case confirms that allogeneic bone marrow transplantation is the only treatment capable to cure chronic granulomatous disease to those patients who cannot be optimally treated with conventional therapy.

[Efficacy of estrogen-progestin replacement therapy after bone marrow transplantation]

Ovarian failure is a common consequence of chemotherapy and radiotherapy in women undergoing bone marrow transplantation. The longer survival in these women has raised, during the past years, the need for a better quality of life. The objective of the present study has been to evaluate perspectively the potential benefit of hormonal replacement therapy in 24 women who underwent bone marrow transplantation. The data obtained indicated that hormonal replacement therapy results effective in preventing and/or relieving the multiple manifestations of gonadal failure, including amenorrhea, hot flashes, atrophy of genital apparatus, osteoporosis and cardiovascular disease.

Growth and endocrine function following bone marrow transplantation for thalassemia

Twenty two patients with thalassemia major who received successful bone marrow transplantation (BMT) were followed to verify the impact of the transplant procedure on subsequent growth and development. The transplant preparative regimen consisted of busulphan and cyclophosphamide. Growth and endocrinological function were assessed during the first 4 years following BMT. At the time of transplant most patients showed growth retardation. The median difference between chronological age and bone age was -9.5 months for the boys and -8.5 months for the girls. Patients > 7 years old at the time of BMT showed a significant worsening of their growth delay at 48 months following BMT compared with 12 months before transplantation. Patients < 7 years at the time of BMT had their growth retardation constant over time span after transplantation. Moreover six of 11 younger patients showed an improvement of their growth delay compared with one of 11 older patients. The outcome of height standard deviation score at 24 and 48 months following BMT was strictly correlated with the level of serum transaminases and ferritin. Sixteen patients had impaired growth hormone secretion after a provocative test evaluated at 24 months after transplant. At 48 months there was no significant increase in the mean peak GH levels. This study confirms that the growth retardation of patients with thalassemia major is multifactorial.

CD8 serum levels in acute graft-versus-host disease diagnosis

Attempts to identify an early and discriminating marker of acute graft-versus-host disease (aGvHD) have been unsuccessful. The levels of soluble CD4 and soluble CD8 in serum correlate with T cell subset activation and may be important in monitoring and characterizing immunological processes. We determined serum soluble CD4 (sCD4) and sCD8 levels with a two-site sandwich enzyme immunoassay on patients' serum samples collected prior to bone marrow transplantation and weekly after transplantation until day +28. No significant increment of sCD4 was documented in each determination. sCD8 rose significantly before diagnosis or development of maximal clinical symptoms in patients with grade II-III aGvHD than grade 0-I aGvHD [at day +21--median value 447 IU/ml; range 94-713; versus 1136 IU/ml, range 790-1416 (P = 0.002); at day +28--median value 443 IU/ml, range 73-992, versus 1164 IU/ml, range 625-1960 (P = 0.005)]. On the day of marrow infusion the sCD8 levels were significantly higher in patients who subsequently developed grade II-III than in patients with grade 0-I aGvHD (median value 155 IU/ml, range 10-332, versus 350 IU/ml, range 283-830; P = 0.003). Careful monitoring of sCD8 is a useful tool for a prompt aGvHD diagnosis and may be used in a clinical bone marrow transplantation setting.

Amebiasis after bone marrow transplantation

A patient undergoing BMT for acute non-lymphocytic leukemia (ANLL) developed bloody diarrhea due to amebiasis. The infection was successfully treated with intensive and prolonged antiparasitic therapy.

The Role of Hemapheresis Technology in Allogeneic Bone Marrow Transplantation

In this paper the impact of hemapheresis technology on 238 allogeneic bone marrow transplants performed in Pescara from 1982 through 1993 is described. Granulocyte transfusions were limited to patients with neutrophil level <0.2x109/L. An average of 4 units of packed red blood cells were required to maintain adequate hemoglobin levels. Patients with major ABO incompatibility showed an increased requirement of red blood cell support as compared to patients ABO-matched and ABO minor mismatched. For platelet support single-donor platelets collected on a blood-cell separator were given. A total of 1548 platelet transfusions were examined. The median number of platelet transfusions for each patient was 5. Platelet refractoriness occurred in 44% of patients. The hemorrhage related mortality was 0.9%.

The advancement made in the field of hemapheresis technology, as well as the improved transplant technique, have contributed to increase the post-transplant survival from 17% in the early experience (1976-1982) to 88% in the recent years (1992-1993).

Detection of minimal residual disease by polymerase chain reaction in patients with different hematologic diseases treated by bone marrow transplantation

Thirteen male patients affected by different hematologic diseases who underwent bone marrow transplantation (BMT) with female donors were investigated by cytogenetic analysis and polymerase chain reaction (PCR) amplification of a DNA sequence specific for the Y chromosome. In six of these patients, PCR showed the presence of the Y chromosome-related sequence; in only three of these did cytogenetic analysis confirm the presence of mixed chimerism. In the remaining three patients, the results of the PCR were confirmed by in situ hybridization on cell nuclei with a probe for the alpha-satellite of the Y chromosome. We compare results obtained with the two methods and discuss the meaning of the minimal residual disease detected by PCR in patients submitted to BMT.

Occurrence of bacteremia in hematologic patients

In the present study we reviewed eighty-six episodes of bacteremia occurred in 60 neutropenic patients and thirty-one episodes occurred in 30 non-neutropenic patients. Twenty-four out of 60 neutropenic patients suffered from multiple episodes of bacteremia, while only one out of 30 non-neutropenic patients presented multiple episodes. In neutropenic patients, 29 episodes of bacteremia were polymicrobial, whereas only one non-neutropenic patient had polymicrobial bacteremia. Intravascular catheters were the most common source of bacteremia (23.2%) in neutropenic patients, as compared with infections of the genito-urinary tract (45.1%) among non-neutropenic patients. In both groups, aerobic gram-positive cocci were the microorganisms most frequently isolated (71.6%). Anaerobic microorganisms showed an higher incidence in polymicrobial episodes than in monomicrobial episodes x 2 = 5.39 p = 0.02 OR = 2.97 95% CI (1.2-7.7).

Leukemic evolution in three patients with myelodysplastic syndrome and unusual chromosome changes

The authors describe three patients with myelodysplastic syndrome without a history of exposure to chemical agents and who showed many chromosome rearrangements not previously reported in this hematologic disorder, and a rapid outcome of the disease. The authors discuss the significance of the chromosome changes, suggesting, in agreement with others, that patients with complex rearrangements have a poor prognosis.

AIDS-related complex treated by antiviral drugs and allogeneic bone marrow transplantation following conditioning protocol with busulphan, cyclophosphamide and cyclosporin

A 26-year-old man with AIDS-related complex (ARC) was treated with high-dose busulphan and cyclophosphamide, followed by allogeneic bone marrow transplantation. For 3 months before transplantation he received a combination of four drugs considered active against human immunodeficiency virus (HIV) to reduce the viral burden: zidovudine, acyloguanosine, fusidic acid and phenylidantoin. Although in reduced doses in coincidence with marrow engraftment, zidovudine therapy was scheduled after transplantation in order to protect donor cells from infection with HIV. Engraftment rapidly occurred and was documented by cytogenetic analyses. The post-transplant course was characterized by severe acute GvHD with irreversible hepatorenal failure. The patient died on day 48 after transplantation. Polymerase chain reaction analyses for detecting HIV DNA showed the persistence of positivity at day +30 and +45 after transplantation. Antibodies to specific HIV proteins evaluated with Western blot testing also persisted at days +21 and +35 after transplantation. Circulating immunocomplexes disappeared on day +31, and an increase in the CD4/CD8 ratio occurred. The short survival of the patient, affected by chronic hepatitis too, does not allow final conclusions about the role of BMT in HIV disease.

Meningitis due to penicillin-resistant Streptococcus pneumoniae in patients with chronic graft-versus-host disease

Two episodes of meningitis due to penicillin-resistant Streptococcus pneumoniae occurring in two patients with chronic graft-versus-host disease (GVHD) are reported. Both patients were treated with ceftazidime. The first patient died, unresponsive to therapy. The second patient showed clinical improvement, reverting to her baseline mental status. This report draws attention to the fact that in chronic GVHD patients: (1) bacterial prophylaxis does not ensure protection against encapsulated bacteria; (2) rapid microbiological investigation is recommended with any upper respiratory tract infections.

Evaluation of four different methods for platelet freezing. In vitro and in vivo studies

This report describes our experience with various techniques for the freezing of platelet-rich plasma, removed from the final product after leukapheresis procedures performed on 14 hematological patients. A total of 194 platelet units were frozen for subsequent autologous transfusion, by the following four methods: (1) 6% dimethyl sulfoxide (DMSO); (2) a combination of 5% DMSO/6% hydroxyethyl starch; (3) 3% glycerol; (4) 5% glycerol/4% glucose. Each technique was evaluated by measuring the percentage of platelet recovery, malondialdehyde (MDA) production, and lactate dehydrogenase release. To investigate the safety and therapeutic effectiveness of the previously frozen platelets, in vivo comparison of four platelet freezing methods was made in 8 thrombocytopenic patients, using corrected platelet increment (CCI), determined at 24 h. Our in vitro results indicate that the cryopreservation with 6% DMSO, without controlled cooling rate, provides significantly (p less than 0.05) greater platelet recovery (75%) as compared to other systems. The decrease of MDA production and the increase in plasma lactate measured after the thawing process was less in the DMSO-frozen units than in the other platelet units. When platelets, cryopreserved by this method, were subsequently transfused into patients, a significantly better CCI (greater than 5,000/microliters) was obtained. In our series, 6 patients were entirely supported with frozen autologous platelets. It appears from this study that a better understanding of the physical and biochemical events occurring during the freezing process will improve platelet cryopreservation, allowing a more systematic use of frozen platelets in the support of thrombocytopenic patients.

Cytogenetic survey of 80 patients with acute nonlymphocytic leukemia

The authors report a cytogenetic survey of 80 patients with acute nonlymphocytic leukemia. The prognostic value of chromosome aberrations has been evaluated with three methods. The first one showed that patients with NN or AN bone marrow cellularity have a significantly better prognosis than those with AA cellularity; the second method confirmed the relatively good prognosis for patients with t(8;21) and abnormal 16 and a poor one for those with rearrangements of chromosomes 5 and/or 7. The authors also noted, surprisingly, that patients with hyperdiploidy had a significantly poorer prognosis than those with hypodiploidy and especially pseudodiploidy. The third method showed that patients with very complex karyotypes and a worse outcome than those with simple changes. Finally, they discuss the prognostic value of unusual and/or undeciphered chromosome changes detected in 18 patients, with a mean survival of 9.6 months, showing that these changes have a negative prognostic significance.

Patterns of infection in 41 patients with idiosyncratic drug-induced agranulocytosis

We examined the patterns of infection in 41 consecutive patients with idiosyncratic drug-induced agranulocytosis observed during the past 15 years. All patients were nursed in reverse isolation and treated prophylactically with oral antimicrobials and antifungal compounds. Nine of 41 patients remained without fever and did not need any parenteral antibiotic treatment for full recovery. The other 32 patients developed fever during the period of agranulocytosis and were treated with empirical antimicrobial therapy. Febrile episodes were documented microbiologically in 16 patients (eight with and eight without bacteremia) and clinically in six patients. In the other ten cases the fever was of unexplained origin. The observed pattern of infection was in accordance with the type of infection as reported in cancer patients during the granulocytopenic phase induced by cytotoxic drugs. Ten of 32 febrile patients showed improvement after empirical antimicrobial therapy, whereas three patients died, two of them of a lower respiratory tract infection and one of a massive hemorrhage due to necrosis of the carotid artery. In ten patients the signs and symptoms of infection resolved only after adjustment of the initial empirical scheme. In nine patients the fever persisted even after additional empirical antifungal therapy but subsided after recovery of the granulocytopenia.

Comparison of five methods for concentrating progenitor cells in human marrow transplantation

Enrichment of bone marrow (BM) aspirates is an important prerequisite prior to in vitro treatment or cryopreservation. In this regard, we have analyzed the results obtained on 190 BM processed by the following 5 techniques: HES sedimentation with centrifugation; COBE 2991 blood cell processor; Ficoll/hypaque (F/H) gradient centrifugation; Continuous flow cell separator (CS 3000 Fenwal); Semicontinuous blood cell separator (Dideco T 90). Each procedure was evaluated by measuring the recovery of nucleated marrow cells (NC), mononuclear cells (MNC), committed progenitor cells (CFU-GM), the reduction of BM volume and the removal of red blood cells (RBC) and polymorphonuclear cells (PMN). The results of this comparative study show that F/H gradient on a COBE 2991 cell washer provides the most efficient system for purifying a MNC fraction (89% recovery) from unwanted cells (RBC less than 2% and PMN less than 2%) in a very small volume (98% reduction) with a good recovery of CFU-GM (80%).

Karyotypic changes identified by HaeIII restriction endonuclease banding in a patient with M2 acute non-lymphoblastic leukemia

A patient with acute non-lymphoblastic leukemia, FAB type M2, showed a complex karyotype involving chromosomes 1 and 11. The breakpoints could not be exactly identified by GTG and QFQ banding. A subsequent analysis with Alul and HaeIII restriction enzyme staining allowed the detection of a translocation of the heterochromatic region of chromosome 1 to 11q21.

Reconstitution of normal neutrophil function in chronic granulomatous disease by bone marrow transplantation

Allogeneic bone marrow transplantation was carried out on an 11-year-old boy with chronic granulomatous disease and severe chronic pulmonary insufficiency of restrictive type. After preparative regimen with busulfan (13 mg/kg) and cyclophosphamide (200 mg/kg), the patient received marrow cells from his HLA-identical and MLC-nonreactive sister. Durable sustained engraftment of donor hematopoietic and lymphoid populations occurred, as documented by analysis of genetic markers and complete reversal of the neutrophil function defect. No episode of infection occurred in the post-transplant course and, currently, 40 months after transplantation the patient is in excellent health and growing normally and showing an increasing improvement of his respiratory capacity. The successful outcome in this patient demonstrates that marrow transplantation is at present the only curative approach for this congenital disorder of neutrophil function.

Early hematopoietic reconstitution after autologous transplantation with blood-derived stem cells in a patient with advanced lymphoma

A 30-year-old man with advanced non-Hodgkin lymphoma underwent repeated leukaphereses for harvesting blood-derived hemopoietic stem cells. Collection was started 8-10 days after the end of L-VAMP therapy (3 cycles). Nine procedures were performed and a total of 65.4 x 10(9) mononuclear cells (0.87 x 10(9)/Kg) were collected, processed, cryopreserved and stored in liquid nitrogen. The yields of CFU-GM, BFU-E and CFU-GEMM were respectively 964 x 10(4) (12.4 x 10(4)/Kg), 249 x 10(4) (3.2 x 10(4)/Kg) and 798 x 10(4) (10.4 x 10(4]. The patient received a myeloblative regimen consisting of fractionated total body irradiation (1200 cGy) and cyclophosphamide (120 mg/kg) followed by infusion of his own thawed cells. Early trilineage hematopoietic recovery was first observed on day +8; 1 x 10(9)/l WBC were reached on day +11, 0.5 x 10(9)/l PMN on day +13 and 50 x 10(9)/l platelets on day +11. Course was uneventful and the patient was discharged from hospital on day +21. Eight months after transplant the patient is in continuous unmaintained complete remission with normal blood cell counts. This reports suggests that complete and sustained engraftment can be achieved with peripheral stem cells recruited after "soft" chemotherapy.

Autologous bone marrow transplantation in acute leukemia

We evaluated the therapeutic efficacy of autologous bone marrow transplantation (ABMT) in 49 patients with acute leukemia, using ex-vivo-treated marrow with mafosfamide. This report summarizes data collected from 8 italian centers, involving 27 cases with acute lymphoid leukemia (ALL) and 22 cases with acute nonlymphoid leukemia (ANLL). The analysis of the results shows that the disease-free survival of ALL and ANLL are similar (45 and 52%, respectively) and no significant difference can be demonstrated between patients transplanted in CR1 or CR2, although there is a trend in favor of ABMT in CR1.

Cytogenetics and bone marrow transplantation

The authors report hematologic and cytogenetic data on 19 patients treated with allogeneic bone marrow transplantation (BMT) for severe hematologic disorders: 8 patients with chronic myelogenous leukemia, 6 with acute leukemia, 3 with severe aplastic anemia, 1 with refractory anemia, and 1 with beta-thalassemia major. Cytogenetic assays were performed on marrow cells before conditioning, 30 days after BMT, and at subsequent times. The authors discuss the role of cytogenetic studies in the evaluation of bone marrow engraftment, leukemic transformation of the graft, and disease relapse.

Cytochemical characteristics of leukopoietic differentiation in murine erythroleukemic (Friend) cells

The 3BM-78 murine Friend erythroleukemia cell line was obtained by in vitro transformation of bone marrow cells of DBA/2J mice by the polycythemic Friend virus complex. Thirty-five subclones have been isolated and tested for their ability to express various markers of blood and bone marrow cells. Upon dimethyl sulfoxide treatment, the cells differentiated along the erythroid pathway as shown by morphological evidence and by their increased synthesis of hemoglobin and spectrin. In addition, a high proportion of dimethyl sulfoxide-induced cells stained positive for specific esterase, a marker characteristic of granulocytic cells. Of these cells, about 20% stained positive for both hemoglobin-peroxidase and specific esterase. Analysis of the subclones showed that the expression of these markers for erythroid and leukopoietic differentiation was uncoordinated. Further dissection of expression was obtained by the use of two potent tumor promoters, 12-O-tetradecanoylphorbol-13-acetate and phorbol-12,13-benzoate, which in general inhibited specific esterase more than hemoglobin peroxidase expression. Inhibition was related to the structure of the phorbol diester and was unrelated to toxicity. No evidence was found for other markers characteristic of different pathways of differentiation, such as Fc and C3 receptors, cell surface immunoglobulins, theta antigen, or the capacity to phagocytose inert particles. All cells stained positive for nonspecific esterase activity in both the presence and the absence of dimethyl sulfoxide. This staining was only partially fluoride sensitive. In unstimulated cultures, a few cells also reacted for myeloperoxidase, Sudan black staining and, very rarely, alkaline phosphatase staining. These findings support the view that 3BM-78 cells are leukemic cells which, despite a prevalent commitment to erythroid differentiation, retain the genetic determinants for some traits of leukopoietic differentiation. These traits may be expressed under suitable culture conditions.

Hereditary haemolytic ovalocytosis with defective erythropoiesis

Patients belonging to four families with 'atypical elliptocytosis' have been investigated. Clinical, haematological, erythrokinetic and enzymatic characteristics as well as the effect of splenectomy are discussed. These studies appear to define the fundamental features of a particular disorder or a variety of hereditary elliptocytosis; characterized by a genetic autosomal dominant character, moderate degree of RBC eccentricity, erythroid dysplasia with relative marrow failure and incomplete response to splenectomy.