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Biomedical subjects

C Nissen

Publications and source records attributed to C Nissen.

At least 37 records · Page 2Linked to original sources
PubMed1997

Effect of flt3 ligand on in vitro growth and expansion of colony-forming bone marrow cells from patients with aplastic anemia.

To determine the value of flt3 ligand (flt3L) in stimulating hematopoiesis in human hypoproliferative bone marrow disorders, we examined its in vitro effect on bone marrow cells from patients with aplastic anemia (AA). Growth response to flt3L, alone and in combination with other hematopoietic growth factors, was investigated in clonogenic methylcellulose assays, in long-term liquid and stroma cultures. Bone marrow cells were derived from 13 AA patients with persisting in vitro growth defect after immunosuppressive treatment and from nine normal bone marrow donors. In methylcellulose cultures, flt3L stimulated formation of hematopoietic colonies only weakly, whereas it had an additive effect when combined with erythropoietin (Epo), stem cell factor (SCF), interleukin-3 (IL-3), interleukin-11 (IL-11), or granulocyte colony-stimulating factor (G-CSF). Flt3L was less effective than SCF and did not further enhance the number of hematopoietic colonies formed in response to SCF-containing combinations of multiple cytokines. In long-term liquid suspension cultures, flt3L was less mitogenic than SCF but its effect on the maintenance of progenitors was superior that of SCF and of IL-3, IL-11, and G-CSF. The total number of clonogenic AA cells increased as much as four-fold during the first culture week and FACS analysis demonstrated expansion of the CD34+CD38+ progenitor cell subset. Despite this enhancement, survival of AA cells remained significantly poorer than that of normal cells, in which the primitive subset of CD34+CD38- cells was maintained up to 4 weeks when flt3L was used as a single factor. Both in normal and AA cultures, flt3L promoted differentiation of cells of the myeloid lineages. In cultures of bone marrow stroma, flt3L had almost no effect on growth and survival of AA progenitors, while in cultures of normal cells the number of colony-forming cells increased up to 10-fold. Although flt3L does not overcome the proliferative defect of AA precursors, we conclude that the ligand is capable of in vitro stimulation and expansion of the reduced progenitor cell pool in AA, when used in appropriate culture conditions. The in vitro effects of flt3L on AA cells differ in many aspects from those of the structurally related cytokine SCF, suggesting a benefit in use of a combination of these two early-acting growth factors.

Adult↗
PubMed1996

Flt3 ligand level reflects hematopoietic progenitor cell function in aplastic anemia and chemotherapy-induced bone marrow aplasia.

Flt3 ligand (flt3L) is a member of a small family of cytokines acting as tyrosine kinase receptor ligands that stimulate the proliferation of primitive hematopoietic progenitors in vitro. To gain insight into the physiological role of flt3L in early hematopoiesis, levels of flt3L were determined in serum of patients with multilineage bone marrow failure and related to the severity of stem cell depletion. In patients with aplastic anemia (AA) and in cancer patients with chemotherapy-induced transient suppression of hematopoiesis, flt3L fluctuated in an inverse relationship to the degree of bone marrow failure. In severe AA at diagnosis, levels of circulating soluble flt3L were highly elevated (2,653 +/- 353 pg/mL) as compared with normal blood serum values of 14 +/- 39 pg/mL. Flt3L returned to near normal levels within the first 3 months following successful bone marrow transplantation and in autologous remission induced by immunosuppressive therapy with antilymphocyte globulin (ALG; 100 +/- 31 and 183 +/- 14 pg/mL, respectively). In contrast, rejection of the graft or relapse of the disease after ALG was accompanied by an increase to high pretreatment concentrations of the circulating cytokine (3,770 +/- 2,485 and 1,788 +/- 233 pg/mL, respectively). Flt3L in serum inversely correlated with the colony-forming ability of AA bone marrow precursors in vitro (R = -.86), indicating that the concentration of the ligand reflects hematopoiesis at the progenitor cell level. Flt3L increased to 2,500 pg/mL in the serum of leukemia patients during chemoradiotherapy-induced bone marrow suppression and returned to normal values along with hematopoietic recovery. Expression of the membrane-bound form of flt3L was significantly elevated in mononuclear bone marrow and peripheral blood cells from patients with severe pancytopenia, suggesting de novo synthesis of the factor in response to bone marrow failure. The data provide a strong argument for the involvement of flt3L in the regulation of early hematopoiesis in vivo.

Anemia, Aplastic↗
PubMed1996

[Transplantation of allogeneic peripheral hematopoietic progenitor cells instead of bone marrow].

In a pilot study we tested the feasibility and safety of peripheral blood precursor cells instead of bone marrow cells for allogeneic transplantation. 13 patients, 7 male and 6 female between 24 and 52 years of age with hematological malignancies (10 with acute leukemias, 3 with myeloproliferative syndromes-were conditioned for bone marrow transplantation with VP-16, cyclophosphamide and total body irradiation followed by graft-versus-host disease prophylaxis with cyclosporin and methotrexate. Precursor cells were mobilized in the donors by granulocyte colony stimulating factor (G-CSF, Neupogen) 10 micrograms/kg s.c. from day-5 on. A total of 14.05 x 10(8) nucleated cells/kg recipient body weight (range 9.52-20.23 x 10(8)/kg), corresponding 6.82 x 10(6)/kg CD 34+ cells (range 1.43-15.84 x 10(8)/kg) or 113.9 x 10(4) CFU/kg (range 45.15-431.64 x 10(4)/kg) were collected by 3 phereses (1 patient 5 phereses) of 27-45 liters and infused without further manipulation. All patients engrafted with a recovery of total white blood cell count > 1 x 10(9)/l on day 15 (day 10-26) and of platelets > 20 x 10(9)/l on day +18 (day 12-39). 11 of the 12 patients developed aGvHD, 8 with grade II, 3 with grade > or = II. 9 of 13 patients are alive and well +4 to +16 months posttransplant, 3 patients died of aGvHD, one of veno-occlusive disease. These preliminary results confirm the capacity of peripheral blood precursor cells for rapid and complete engraftment in the allogeneic setting. Whether they induce more or equal aGvHD is an open question. Their value in allogeneic transplantation is currently under investigation in prospective randomized trials.

Adult↗
PubMed1996

[Autologous transplantation of hematopoietic precursor cells following CD34 selection].

Peripheral blood is increasingly used instead of bone marrow as a source of hemopoietic precursor cells for transplantation. The optimal technique still needs to be defined. Selection of CD34+ cells in transplant material may be of benefit in allogeneic and autologous peripheral blood precursor cell transplantation (PBPCT), since it allows elimination of unwanted CD34-negative cells, such as T-cells and contaminating tumor cells. We have evaluated the feasibility of CD34 selection in PB transplants and studied hemopoietic reconstitution after autologous transplantation of CD34 selected precursor cells. Between August 1994 and June 1995 CD34 selection was performed on 12 transplants for 9 patients with malignant disease (non-Hodgkin lymphoma [n = 5]; Ewing sarcoma [n = 1]; chronic lymphocytic leukemia [n = 1]; breast cancer [n = 1]; multiple myeloma [n = 1]). PBPC were collected with a Fenwall CS 3000 harvester after stimulation with G-CSF. For selection of CD34+ cells the Ceprate LC34 system (CellPro) was used. A median CD34 purity of 73% (range 40-94%) was achieved. The median number of CD34 positive cells per transplant was 4.8 x 10(6)/kg body weight (range 0.7-15.8). The median number of colony forming cells per transplant was 31 x 10(4)/kg body weight (range 1.5-131.3). For autologous PBPCT the minimal number of CD34 positive cells required in the transplantate was arbitrarily set at 1.0 x 10(6)/kg body weight. This number was achieved in 10 of the 12 transplants. The median loss of CD34+ cells during selection was 1.5 x 10(6)/kg body weight (range 0.2-6.4). In 2 patients the total number was reduced to below the critical value of 1.0 x 10(6)/kg. 7 of the 9 patients received the CD34 selected transplant after intensive chemotherapy and irradiation. The median follow-up time after PBPCT was 196 days (range 62-278). All 7 patients are now alive and with normal hemopoietic function. A granulocyte count above 0.5 x 10(9)/l and a platelet count above 20 x 10(9)/l was achieved on day 14 (median), and on day 19 after PBPCT. We conclude that CD34 selection is technically feasible and that CD34 selected cells can be used for PBPCT. The procedure is time consuming and expensive; it requires complex organization at laboratory level, and the benefit of CD34 selection with regard to T-cell depletion and tumor purging still needs to be proven. However, CD34+ selection is likely to open new perspectives in transplantation medicine.

Adolescent↗
PubMed1996

Deficiency of CD34+ c-kit+ and CD34+38- hematopoietic precursors in aplastic anemia after immunosuppressive treatment.

To characterize the persistent abnormalities of hematopoiesis in aplastic anemia (AA) after immunosuppression with antilymphocyte globulin (ALG), we analyzed the quantity, phenotype, and growth properties of hematopoietic progenitor cells in 13 patients who received ALG treatment. Flow cytometry (FACS) revealed a deficiency of CD34+ cells in bone marrow (BM) of all patients. This deficiency was most severe (40-fold) in 4 patients in AA relapse. In 9 patients in remission, CD34+ cells were reduced 2-10-fold and showed no correlation with the ALG-induced improvement of peripheral blood cell counts. The proportion of CD34+ cells carrying c-kit receptors was abnormally low (2-10-fold below normal) in 5 of 13 AA patients. These patients also displayed low levels of c-kit mRNA by reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, the CD34+ cell population was almost completely depleted of CD34+CD38- early hematopoietic progenitors in all AA patients. The proportion of CD34+ cells expressing lineage differentiation antigens CD33, CD71, and CD45RA in AA was increased, as compared to control BM. Formation of hematopoietic colonies by FACS-purified CD34+ cells was nearly absent in 4 relapsed patients, normal in 4 of 9, and decreased (up to 10-fold) in 5 of 9 patients in remission. The degree of impairment of colony-forming ability by AA progenitors correlated well with the reduction of CD34+ c-kit+ cells. The best proliferative response of CD34+ cells was observed in the presence of stem cell factor and, in some cases, fit3 ligand. Our results indicate that the disease process in AA depletes immature BM progenitors, thus providing a plausible explanation for persistent defects in colony-forming ability and long-term regenerative capacity of AA marrow after immunosuppression. Analysis of the immunophenotypes and the proliferative properties of purified progenitors may be useful for estimating degree of hematopoietic recovery in ALG-treated patients.

ADP-ribosyl Cyclase↗
PubMed1996

Splenectomy as an adjuvant measure in the treatment of severe aplastic anaemia.

The role of splenectomy in aplastic anaemia (AA) is controversial. The hazards of operating on a severely pancytopenic patient, the fear of compromising the patient's immune function, and the improvement of non-surgical treatment have made splenectomy unpopular in this disease. We have evaluated positive and adverse effects of splenectomy in 80 patients with severe aplastic anaemia (SAA) treated with antilymphocyte globulin (ALG) (group A), using 52 nonsplenectomized ALG patients as controls (group B). All patients survived the operation. Nonfatal complications of surgery occurred in 10 (12.5%). Splenectomy induced a significant increase of peripheral blood neutrophils, reticulocytes and platelets within 2 weeks, followed by a continuous increase of all values over the following weeks. 28/132 patients (21%) developed a late clonal disorder of haemopoiesis, paroxysmal nocturnal haemoglobinuria (PNH) or myelodysplastic syndrome (MDS), or both. Their incidence was identical in groups A and B. 13/28 (59%) died, 10/17 (59%) in group A and 3/11 (27%) in group B (not significant (n.s.)). Overall probability of survival at 18 years after ALG was 51+/-6% for group A and 61+/-7% for group B (n.s.). We conclude that splenectomy in AA is safe. It induces an immediate increase of peripheral blood counts and, thereafter, a continuous improvement of haemopoiesis. It does not increase the incidence of late clonal complications but has a borderline effect on mortality from these disorders. Splenectomy should be reconsidered in selective nontransplanted patients who have prolonged transfusion requirements despite otherwise optimal treatment.

Adolescent↗
PubMed1996

Peripheral blood pressure cells transplants across a major histocompatibility barrier in rabbits: positive effects of a higher number of precursor cells?

Peripheral blood precursor cells (PBPCs) are used with increasing frequency for hematopoietic transplants and have more or less replaced autologous bone marrow transplants. First clinical and experimental reports document the feasibility of PBPCs as a source for allogeneic transplants. Few data exist on the optimal procedure and the ideal number of cells for the transplant. We have previously shown in rabbits that PBPCs can be used for transplants even across a major histocompatibility barrier. We used this model to test whether the number of transplanted precursor cells would influence graft outcome. Adult outbred Red Burgundy rabbits were used as donors, New Zealand White rabbits of the opposite sex as recipients. One individual donor was taken for one individual recipient. Conditioning consisted of single-dose total body irradiation of 10 Gy followed by a short course of cyclosporine to enhance engraftment. Donor animals were treated with recombinant human granulocyte-colony-stimulating factor, 10 micrograms/kg subcutaneously daily from day -2 until day +9. PBPCs were obtained from the artery of the donor animal by repetitive centrifugation of 2 x 40 ml heparinized blood on each day of donation, i.e. days 0, +2, +3, +6, +8, and +10 and infused without further manipulation. Eight animals underwent transplantation. Seven took the grafts, six died of graft-versus-host disease and pneumonia between days 12 and 55 (median survival of all animals: 34 days). One animal was still alive after 120 days. Transplanted nucleated cells varied from 7.3 to 15.4 x 10(8)/ kg (median 9.2 x 10(8)/kg) and CFU-GM from 12.3 to 176.8 x 10(4)/kg (median 42 x 10(4)/kg). Survival tended to increase with more CFU-GM) r = 0.716, p = 0.0704). These data confirm that allogeneic PBPCs can engraft across a major histocompatibility barrier and suggest that a higher number of CFU-GM might be advantageous.

Animals↗
PubMed1996

Treatment of Aplastic Anemia.

There is general agreement that in children and adolescents with an HLA-identical or syngeneic sibling, bone-marrow transplantation (BMT) should be performed without delay. More controversial are young-to-middle-aged adults with an HLA-identical sibling. Because of comparable survival rates, some centers advocate BMT; others advocate immunosuppression as primary treatment. BMT cures severe aplastic anemia (SAA), but has a higher early mortality. Immunosuppression usually induces hemopoietic improvement and has hardly any early mortality. However, there are late problems. After immunosuppression, there may be relapse and clonal hematopoietic disease. After BMT, there may be late graft failure, severe or even fatal chronic graft-versus-host-disease (GVHD). Both procedures are followed by a slight increase in second malignancies. Retrospective studies show no significant differences in long-term survival between the two treatment modalities. In patients over the age of 40, immunosuppression is favored by most centers because in this age group there is a very high transplant-related mortality with BMT. Androgens and hematopoietic growth factors have hardly any role in therapy of SAA. Splenectomy helps some patients with severe thrombocytopenia and problems with supportive care, but does not improve the overall prognosis. BMT with unrelated donors has usually been performed in late stages of the disease with disappointing results.

Journal Article↗
PubMed1996

Allogeneic peripheral blood precursor cell transplants in rabbits.

This report summarizes a series of experiments undertaken to evaluate the role of mobilized peripheral blood precursor cells (PBPC) for transplantation across a major histocompatibility barrier. Adult outbred red Burgundy rabbits were used as donors, New Zealand white rabbits of the opposite sex as recipients. Conditioning consisted of single dose total body irradiation (TBI) of 10 Gy supported by a short course of cyclosporine to enhance engraftment. Human recombinant G-CSF at a dose of 10 micrograms/kg was used for mobilization of precursor cells. Three methods of PBPC transplants were tested initially in 5 animals each. PBPC were collected and infused at once on day 0; collected initially, cryopreserved for one month, infused on day 0 and followed by 3 additional fresh donations or collected and infused on 6 occasions between days 0 and + 11. 13 animals engrafted, 2 became complete, longterm chimeras. Survival was best in the group given repetitive infusions (39 days median, 12 days to > 180 days, range). 10 additional animals were transplanted as in the last group and the number of transplanted nucleated cells (10.5 x 10(8)/kg median, 7.3 - 15.7 x 10(8)/kg range) and colony forming units CFU-GM (42 x 10(4)/kg median, 12.3 - 176.8 x 10(4)/kg range), were compared with outcome. Median survival of the 10 animals was 29 days (12 - 55 days range; 1 autologous reconstitution). Survival did not correlate with total nucleated cells per kg (r = 0.10; p = 0.79), but there was a trend to prolong survival with higher numbers of CFU-GM per kg (r = 0.47; p = 0.19). These data show that allogeneic PBPCT can engraft across a major histocompatibility barrier, that the high number of CFU-GM per kg might be advantageous, but also that additional methods are warranted to reduce acute GvHD.

Animals↗
PubMed1995

[Bone marrow transplantation].

Bone marrow transplantation (BMT) has evolved from an experimental undertaking to an established therapeutic strategy for hematological neoplasias, severe aplastic anemia, congenital immunological and metabolic disorders and some solid tumors. This report summarizes the main indications for autologous and allogenic transplants, the prerequisites and potential techniques, early and late complications as well as preventive and therapeutic strategies. The results of 397 BMT, 357 allogeneic and 40 autologous transplants, performed in Basel between 1973 and 1995, illustrate the present potential and main prognostic factors: stage of disease, age and histocompatibility. 50% of the patients treated with an allogeneic BMT from an HLA-identical sibling early in the disease are alive 15 years post BMT, 80% free of disease and reintegrated into work and family. New strategies are testing the use of unrelated HLA-compatible volunteer donors and the potential of mobilized peripheral blood precursor cells instead of bone marrow for allogeneic and autologous transplants.

Bone Marrow Transplantation↗
PubMed1995

Recombinant human interleukin-3 in refractory severe aplastic anaemia: a phase I/II trial.

In a prospective open-labelled phase I/II trial we tested efficacy and tolerability of recombinant human interleukin-3 (rhIL-3) alone in patients with refractory severe aplastic anaemia (SAA). 15 patients with idiopathic (12 patients) or secondary (one post-hepatitic, one drug induced, one dyskeratosis congenita) SAA, refractory or relapsing after one to three courses of antilymphocyte globulin were included. 14 patients were transfusion dependent (RBC 14, platelet 12). RhIL-3 was planned for three patients each at five escalating dose levels of 1, 2, 4, 8 and 16 micrograms/kg, given daily as 24 h continuous infusion for 21 d. RhIL-3 was prematurely withdrawn at days 10 and 11 for adverse events in two patients. 9/15 patients showed an increase in WBC; 2/6 at the 1-2 micrograms/kg and 7/9 at the 4-16 micrograms/kg level, but no sustained effects were seen. No patient showed a response in platelet counts. Additionally, platelet and RBC transfusion requirements were unchanged pre and post study. All patients experienced one or more adverse event, mainly fever (15 patients), bleeding (nine patients), and headache (six patients). Occurrence of adverse events was dose related and the maximum tolerated dose was reached with 8 micrograms/kg. Five patients suffered serious adverse events. RhIL-3 as single growth factor and used alone is of minimal benefit in severe aplastic anaemia.

Adolescent↗
PubMed1995

Persistent growth impairment of bone marrow stroma after antilymphocyte globulin treatment for severe aplastic anaemia and its association with relapse.

Bone marrow from 65 patients with aplastic anaemia (AA) was tested for stroma growth in short term cultures (2 weeks) and for colony formation by haemopoietic precursor cells during the course of their disease. In 18 untreated patients, mean stroma growth was 30% of normal and colony formation was virtually absent. After treatment with immunosuppression (IS), as estimated from 90 examinations in 54 patients, stroma growth was approximately 50% and colony growth approximately 10% of normal. Growth impairment of stroma and haemopoietic precursors persisted for 10 and more years after IS. Results of 2-week stroma cultures were compared with results of long term bone marrow cultures in 10 AA patients and 4 controls. At 2 weeks, growth of aplastic marrow was delayed compared to normal, but this difference became less evident with prolonged incubation time. In vitro growth abnormalities were compared with the clinical evolution after IS. The development of late haematological complications (paroxysmal nocturnal haemoglobinuria (PNH)) and myelodysplastic syndrome (MDS), did not correlate with the degree of stroma growth impairment. However, relapse of aplasia was associated with poor stroma growth: 8/29 patients with stroma confluence of < or = 30% during haematological remission versus 1/25 with stroma confluence of > 30% relapsed. We conclude that (i) the haematopoietic microenvironment is frequently coinvolved in the disease process of AA, (ii) a defect is detected in short term rather than in long term stroma cultures and, (iii) relapse is more frequent in patients with poor stroma growth.

Adolescent↗
PubMed1995

Stem-cell factor in aplastic anemia: in vitro expression in bone marrow stroma and fibroblast cultures.

In vitro expression of stem-cell factor (SCF) by bone marrow (BM) cells of 30 patients with aplastic anemia (AA) has been analyzed at the mRNA and protein levels. While no deficiencies were found in SCF mRNA expression, low levels of soluble SCF protein were measured in poorly growing AA stroma cultures. The SCF protein concentration in the supernatant and the confluence of AA stroma growth were found to correlate (R = 0.70). Defective proliferation was observed in the majority (20/30) of AA stroma cultures and was paralleled by poor growth of homogeneous cultures of fibroblasts from the same marrow sample. AA stroma growth was enhanced by addition of exogenous SCF in combination with interleukin-11 (IL-11), leukemia inhibitory factor (LIF), and basic fibroblast growth factor (bFGF). Our results demonstrate that deficient growth of stroma cells results in decreased production of SCF. Therefore, SCF and other stroma-derived cytokines may be of therapeutic value in AA patients with documented defects within the BM microenvironment.

Adolescent↗
PubMed1995

Transplantation of G-CSF mobilized allogeneic peripheral blood stem cells in rabbits.

Mobilized peripheral blood precursor cells (PBPC) are used with increasing frequency to restore autologous hematopoiesis following high-dose radio-chemotherapy. The success of this method has aroused interest in the use of mobilized PBPC for allogeneic transplants. This approach would eliminate the need for marrow aspiration and general anesthesia. In this project we tested the feasibility of allogeneic histoincompatible PBPC transplants in rabbits. Adult outbred Red Burgundy rabbits were used as donors, histoincompatible New Zealand White rabbits of the opposite sex as recipients. One individual donor was used for one individual recipient. Conditioning consisted of 10 Gy total body irradiation (TBI). Donor animals were pre-treated with recombinant human granulocyte colony-stimulating factor (rh G-CSF) given s.c. at 10 micrograms/kg daily. Three schedules of PBPC collection and reinfusion were tested in 3 groups of animals, each consisting of 5 donor recipient pairs: (A) PBPC were collected either on days -2, -1 and 0, and infused at once after TBI on day 0; (B) collected and infused on days 0, +2, +4, +7, +9, and +11; (C) collected on 3 consecutive days, cryopreserved for 1 month and infused on day 0 followed by 3 fresh donations on days +4, +8 and +11. The median amount of blood processed from donor animals was 470 ml (312-602) containing about 10 x 10(8) (5-71 x 10(8)) nucleated cells. Recipient animals received a median of 2.7 x 10(8) cells/kg equivalent to 9.6 x 10(4) colony-forming units granulocyte-macrophages (CFU-GM)/kg (data derived from Group C of the animals).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Late clonal complications in severe aplastic anemia.

One hundred and seventy patients with severe aplastic anemia (SAA) were treated in Basel, from 1976 to 1992. Forty one underwent bone marrow transplantation (BMT) and 129 antilymphocyte globulin (ALG) therapy. As of January 1, 1993, 99 of the 170 patients are alive (58% +/- 7%) and the probability to be alive at 15 years is 54% +/- 4%. Until now, 29 patients have developed a clonal complication. All occurred within the ALG group. Nine patients developed a myelodysplastic syndrome (MDS), 16 patients paroxysmal nocturnal hemoglobinuria (PNH) and 4 patients both, PNH and MDS. The cumulative risk of developing a clonal complication after ALG-therapy is 42% +/- 13% at 15 years; for MDS this risk is 26% +/- 8% and for PNH 25% +/- 5%. The development of a clonal disease directly affects long term prognosis. The survival of the patients with stable disease is 81% +/- 10% and 36% +/- 13% for those with clonal evolution (p = 0.001). The most important risk factor is the type of treatment. In contrast to patients treated with ALG, none of the patients treated with BMT developed MDS or PNH (p < 0.001). No other clinical parameter, such as age, sex, etiology of SAA, severity of the disease and splenectomy correlate with an increased risk of developing this complication. In contrast, morphological parameters at the time of diagnosis, during bone marrow regeneration and at remission are indications in this respect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Glycosylation of recombinant human granulocyte colony stimulating factor: implications for stability and potency.

The production of recombinant human granulocyte colony stimulating factor (HuG-CSF) by gene cloning has made this growth factor available in large quantities for clinical application. There is accumulating evidence to suggest that the glycosylation of HuG-CSF confers advantages in terms of in vitro stability to temperature, pH and degradation by proteases, and a recent report attributes a greater biological potency, in the absence of larger biological mass, to the property of glycosylation. In this study, the biological potency of glycosylated rHuG-CSF (lenograstim) was compared with that of non-glycosylated rmetHuG-CSF (filgrastim) and a non-glycosylated rHuG-CSF (non-commercial preparation), using duplicate assays of neutrophil and erythroid colony formation in three human bone marrows. Serial doubling dilutions of each rHuG-CSF resulted in a concentration range of 0.008-128 ng/ml. Qualitative (number) and quantitative (size) assessments of colonies were performed at day 14 of culture. Lenograstim proved twice as potent as filgrastim (and non-commercial rHuG-CSF) at maximal colony stimulation, and 20 times more potent than both at half-maximal colony stimulation (P = 0.0001). Incubation with lenograstim also produced a higher proportion of colonies with > 200 cells than either of the other preparations. In conclusion, glycosylated rHuG-CSF (lenograstim) had a greater qualitative and quantitative potency than the non-glycosylated rHuG-CSFs (filgrastim and non-commercial rHuG-CSF), indicating that glycosylation confers a potency advantage on lenograstim.

Colony-Forming Units Assay↗
PubMed1994

Graft rejection and second bone marrow transplants for acquired aplastic anaemia: a report from the Aplastic Anaemia Working Party of the European Bone Marrow Transplant Group.

Six hundred and eighteen patients with acquired aplastic anaemia grafted from an HLA-identical sibling donor between 1976 and 1990 in eight European centres were reported to the Working Party for Severe Aplastic Anaemia (SAA) Registry and were evaluable for analysis of the incidence of graft failure/rejection and the outcome of second bone marrow transplants (BMT). The number of patients experiencing graft rejection declined significantly over the study period from 32% to 8% (p < 0.0001). This coincided with the introduction of cyclosporine to the conditioning regimen for BMT. The graft rejection rate in the post-hepatitis SAA group was significantly lower than in the group with idiopathic SAA (4% vs 20%) (p = 0.001). The use of irradiation in the conditioning regimen significantly reduced the number of patients experiencing graft rejection (7% vs 21%) (p = 0.004). Age, sex and severity of disease did not influence the rate of sustained engraftment. Of the 85 patients experiencing graft rejection, 41 received a second transplant: their survival is 33% vs 8% for patients not transplanted a second time (p = 0.003). The major factor predicting the outcome of second BMT for SAA was the interval from first BMT. Patients receiving a second BMT within 60 days from the first BMT had a significantly poorer outcome.

Adolescent↗