[Characteristics of autoimmune hemolytic anemia in adults: retrospective analysis of 83 cases]

PURPOSE

To describe the main characteristics and outcome of adult's acquired immune hemolytic anemias (AIHA). To analyse the relevance of the complementary tests performed for the search of an underlying disease.

METHODS

Retrospective (1980-2000) monocentric study.

INCLUSION CRITERIA

age above 16, AIHA defined by an hemoglobin level below 12 g/dl in men and 11 g/dl in women, with hemolysis and/or a positive direct Coombs test and/or the presence of cold agglutinins (threshold 1/500) and/or in the absence of any other cause.

RESULTS

Eighty three patients included (56 women and 27 men), with a mean age of 56 years (+/- 22) at AIHA onset including: 72 patients (87%) with warm antibody AIHA and 11 (13%) with cold agglutinin disease. The mean follow-up was 48 months (median 22 months). Among the 72 patients with warm antibody AIHA, the specificity of autoantibodies was: IgG + complement (43%), IgG (32%) or complement alone (25%); cold agglutinins (titre from 1/60 to 1/512) were detected in 15 (20%) of the patients. Antinuclear antibodies were detected (threshold: 1/80) in 33% of the cases. Hypogammaglobulinemia on serum protein electrophoresis (SPE) was significantively associated with the presence of an underlying non-Hogkin lymphoma (NHL). The CT-scan of the the chest and abdomen which was performed in 50% of the patients, showed abnormalities other than a spleen enlargement in 25% of the cases. The medullar biopsy (MB) was abnormal in 7 of 26 cases (27%) but lead by itself to the diagnosis of NHL in a single case. Thrirty seven (51%) of warm antibody AIHA cases were finally considered to be "secondary" to an underlying disease namely: NHLs (n = 14), Hogkin's disease (n = 1) connective tissue disease (CTD) (n = 14), drug-induced AIHA (n = 3), miscellaneous (n = 5). In 6 out of 14 cases (43%) of NHL's associated AIHA, the onset of AIHA precedes the NHL from 22 to 66 months. The response rates to different therapeutic regimens did not significatively differ when "secondary" and "idiopathic" AIHA were compared. Overall, 13 patients (15.6%) died mainly from infectious complications (n = 5) or an underlying NHL (n = 5).

CONCLUSIONS

In more than half of the cases AIHA are associated with an underlying disease and AIHA may precede the onset of a NHL for a long period. In the absence of a clinically apparent underlying disorder, testing for the presence of antinuclear antibodies, a SPE and a CT-scan must be systematic. Conversely, if no abnormalities are found, the relevance of a systematic MB at AIHA onset seems very low.

[Autoimmune hemolytic anemia]

From the beginning of the century, autoimmune haemolytic anaemia (AIHA) was the first model of an auto-antibody mediated disease. Despite the variety of the clinical features, the diagnosis of AIHA provides few difficulties since the introduction of the popular Coombs' test. The clinical presentation of AIHA depends on the subclass type and on the thermal range activity of the causative auto-antibody, so that two main pictures occur usually: warm auto-antibody and cold auto-antibody types, the latter being less frequent than the former. In more than half the cases, AIHA is associated with another disease that must be considered more as the background of immune dysregulation than the cause of the disease. Systemic disorders, chronic lymphoid malignancy, primitive or acquired immunodeficiencies are the most common disorders associated with AIHA. Acute infections or drugs may give rise to acute transient AIHA. The clinical aspects and the links between AIHA and associated diseases are emphasised. No decisive advancement in therapy has arisen over the last decades. Some patients are still resistant to all therapeutic manoeuvres and may die. Much labour is to be done in order to discover more rational methods of therapy to restore a state of normal tolerance towards erythrocyte auto-antigens. Suppressing the production of pathogenic auto-antibodies by immunomodulation may be the first step of this task.

Quinine improves results of intensive chemotherapy (IC) in myelodysplastic syndromes (MDS) expressing P-glycoprotein (PGP). Updated results of a randomized study. Groupe Français des Myélodysplasies (GFM) and Groupe GOELAMS

We designed a randomized trial of IC with or without quinine, an agent capable of reverting the multidrug resistance (mdr) phenotype, in patients aged < or = 65 years with high risk MDS. Patients were randomized to receive Mitoxantrone 12 mg/m2/d d2-5 + AraC 1 g/m2/12 h d1-5, with (Q+) or without (Q-) quinine (30 mg/kg/day). 131 patients were included. PGP expression analysis was successfully made in 91 patients and 42 patients (46%) had positive PGP expression. In PGP positive cases, 13 of the 25 (52%) patients who received quinine achieved CR, as compared to 3 of the 17 (18%) patients treated with chemotherapy alone (p = 0.02). In PGP negative cases, the CR rate was 35% and 49%, respectively in patients who received quinine or chemotherapy alone (difference not significant). In the 42 PGP positive patients, median Kaplan-Meier (KM) survival was 13 months in patients allocated to the quinine group, and 8 months in patients treated with chemotherapy alone (p = 0.01). In PGP negative patients, median KM survival was 14 months in patients allocated to the quinine group, and 14 months in patients treated with chemotherapy alone. Side effects of quinine mainly included vertigo and tinnitus that generally disappeared with dose reduction. Mucositis was significantly more frequently observed in the quinine group. No life threatening cardiac toxicity was observed. In conclusion, results of this randomized study show that quinine increases the CR rate and survival in PGP positive MDS cases treated with IC. The fact that quinine had no effect on the response rate and survival of PGP negative MDS suggests a specific effect on PGP mediated drug resistance rather than, for instance, a simple effect on the metabolism of Mitoxantrone and/or AraC.

A prospective study of autologous bone marrow or peripheral blood stem cell transplantation after intensive chemotherapy in myelodysplastic syndromes. Groupe Français des Myélodysplasies. Group Ouest-Est d'étude des Leucémies aiguës myéloïdes

We prospectively assessed autologous stem cell transplantation for consolidation treatment in a trial of intensive chemotherapy in high risk myelodysplastic syndromes (MDS). In this trial, patients aged 55 years or less with no HLA-identical sibling and achieving CR were scheduled to receive unmanipulated autologous bone marrow transplantation (ABMT) preceded by a consolidation chemotherapy course. Forty-two of the 83 patients aged 55 years or less included in the trial (51%) achieved CR. Three were allografted in CR. Twenty-four of the remaining 39 patients who achieved CR (62%) received ABMT (16 patients) or autologous peripheral blood stem cell transplantation (APSCT) (eight patients). Indeed, as bone marrow harvest was often insufficient, APSCT was subsequently proposed after mobilization by consolidation chemotherapy followed by G-CSF. The conditioning regimen combined cyclophosphamide and busulfan. ABMT and APSCT were performed 1-7 months (median 3) after CR achievement. Hematological reconstitution occurred in all patients and tended to be faster after APSCT than ABMT although not significantly. Three patients died from the procedure, nine relapsed after 2-26 months and 12 (50%) were still in CR after 8-55 months. In autografted patients, median Kaplan-Meier disease-free survival and survival were 29 and 33 months from the autograft, respectively. Thus, ABMT or APSCT can be performed in almost two-thirds of MDS patients who achieve CR with intensive chemotherapy. PBSC collection may yield higher numbers of stem cells than marrow collection in some cases, and could improve the percentage of MDS patients autografted in CR. Longer follow-up is required to determine if autograft will prolong CR duration in at least some patients.

Quinine improves the results of intensive chemotherapy in myelodysplastic syndromes expressing P glycoprotein: results of a randomized study

Intensive chemotherapy produces a lower complete remission (CR) rate in the myelodysplastic syndromes (MDS) than in de novo acute myeloid leukaemia (AML), possibly due in part to a higher incidence of P glycoprotein (PGP) expression in MDS blast cells. We designed a randomized trial of intensive chemotherapy with or without quinine, an agent capable of reverting the multidrug resistance (mdr) phenotype, in patients aged < or = 65 years with high-risk MDS. Patients were randomized to receive mitoxantrone 12 mg/m2/d days 2-5 + AraC 1 g/m2/12 h days 1-5, with (Q+) or without (Q-) quinine (30 mg/kg/d). 131 patients were included. PGP expression analysis was successful in 91 patients. In the 42 PGP-positive cases, 13/25 (52%) patients in the Q+ group achieved CR, compared to 3/17 (18%) patients in the Q- group (P = 0.02) and median Kaplan-Meier survival was 13 months in the Q+ group, and 8 months in the Q- group (P = 0.01). No life-threatening toxicity was observed with quinine. In conclusion, the results of this randomized study show that quinine increases the CR rate and survival in PGP-positive MDS cases treated with intensive chemotherapy.

[Myelodysplastic syndromes: unusual and mild forms]

Although the FAB classification of the myelodysplastic syndromes (MDS) allows to classify most patients, a few clinical patterns do not fit the FAB categories, including borderline forms with manifestations usually seen in other diseases and forms with atypical or unusual clinical or laboratory features that do not immediately suggest a MDS. Borderline forms are characterized by the presence of any of the following: high or very high platelet counts, myelofibrosis, bone marrow hypoplasia, eosinophilia, or systemic diseases such as relapsing polychondritis. Unusual or atypical forms include manifestations such as hemolysis, high reticulocyte counts, erythroblastopenia, or an abnormality of a single cell line such as isolated thrombocytopenia, isolated neutropenia, or isolated macrocytosis. The definitive diagnosis of these forms of MDS can require a number of investigations such as cytogenetic studies, bone marrow biopsy, and/or radionuclide evaluation, and may not be possible until the patient has been followed for some time.

Paroxysmal nocturnal haemoglobinuria: long-term follow-up and prognostic factors. French Society of Haematology

BACKGROUND

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired disorder of haematopoietic stem cells. Although knowledge about the pathophysiology of the disease is increasing, no multivariate analysis of factors influencing survival has been undertaken, mainly because the disease is rare. We undertook such an investigation.

METHODS

Data were collected on 220 patients with PNH diagnosed over a 46-year period (1950-1995) from participating French centres. Diagnosis of the disease required, at least, an unequivocally positive Ham's test.

FINDINGS

The Kaplan-Meier survival estimate was 65% (SE 4) at 10 years and 48% (6) at 15 years after diagnosis. 8-year cumulative incidence rates of the main complications (pancytopenia, thrombosis, and myelodysplastic syndrome) were 15% (3), 28% (4), and 5% (2), respectively. Demographic data, presenting features, initial treatment, complications, and causes of death were similar to those previously reported. In multivariate analysis, seven factors were significantly associated with survival in patients with PNH. Poor survival was associated with the occurrence of thrombosis as a complication (relative risk 10.2 [95% CI 6-17], p < 0.0001), evolution to pancytopenia (5.5 [2.8-11], p < 0.0001), myelodysplastic syndrome or acute leukaemia (19.1 [7.3-50], p < 0.001), age over 55 years at diagnosis (4 [2.4-6.9], p < 0.0001), need for additional treatment (2.1 [1.3-3.6], p < 0.003), and thrombocytopenia at diagnosis (2.2 [1.3-3.8, p < 0.003). Better survival was shown for patients in whom aplastic anaemia antedated PNH (0.32 [0.14-0.72], p < 0.02). Factors associated in multivariate analysis with a high risk of thrombosis during the disease course were thrombosis at diagnosis (5.1 [2.5-10.6], p = 0.0002), age over 54 years (2.6 [1.5-4.6, p = 0.0014), and infection at diagnosis (2.6 [1.3-5.2], p = 0.0099). The risk factors for progression to pancytopenia were absence at diagnosis of anaemia (4.03 [1.3-12.2], p = 0.03) and neutropenia (2.45 [1.1-5.7], p = 0.03). The risk factors for development of myelodysplastic syndrome or acute leukaemia were abdominal pain crisis at presentation (10.5 [2.5-44.0], p = 0.004) and year of diagnosis after 1983 (8.45 [1.8-40.7], p = 0.004).

INTERPRETATION

This large number of cases permitted a detailed analysis of prognostic factors for the first time, in this rare disease. Estimates of PNH prognostic factors may serve as baseline data in the assessment of current and future treatments for this disease.

Making choices in hospital resources allocation. The use of an assessment tool to decide which new projects are financed

We designed a scoring system to rank acute care hospital projects and allocate resources between them. The evaluation tool assessed projects on an ordinal scale; the criteria scored were medical interest, feasibility, interest for teaching and research, and compatibility with the hospital's strategy. Clinical and technical projects were ranked separately. In 1994, 25 new projects, representing a total cost of $1.4 million, were reviewed by two independent reviewers. The scores ranged from 30 to 18 over 36. Projects presented by clinical departments scored higher than projects presented by medicotechnical departments.

Impact of magnetic resonance imaging on the diagnosis of abdominal complications of paroxysmal nocturnal hemoglobinuria

Magnetic resonance (MR) imaging is a method of choice for assessing vascular patency and parenchymal iron overload. During the course of paroxysmal nocturnal hemoglobinuria (PNH), it is clinically relevant to differentiate abdominal vein thrombosis from hemolytic attacks. Furthermore, the study of the parenchymal MR signal intensity adds informations about the iron storage in kidneys, liver, and spleen. Twelve PNH patients had 14 MR examinations of the abdomen with spin-echo T1- and T2-weighted images and flow-sensitive gradient echo images. Vessels patency and parenchymal signal abnormalities--either focal or diffuse--were assessed. MR imaging showed acute complications including hepatic vein obstruction in five patients, portal vein thrombosis in two patients, splenic infarct in one patient. In one patient treated with androgens, hepatocellular adenomas were shown. Parenchymal iron overload was present in the renal cortex of eleven patients with previous hemolytic attacks. On the first MR study of the remaining patient with an acute abdominal pain showing PNH, no iron overload was present in the renal cortex. Follow-up MR imaging showed the onset of renal cortex iron overload related to multiple hemolytic attacks. Despite the fact that all our patients were transfused, normal signal intensity of both liver and spleen was observed in three of them. MR imaging is particularly helpful for the diagnosis of abdominal complications of PNH.

[Managing of an innovation in health care: the case of polyvalent intravenous immunoglobulins at the Assistance-Publique-Hôpitaux de Paris]

Managing new innovations in medicine is a particularly timely subject. There is an abundant history concerning over expectations resulting from the development of new treatments or diagnostic procedures, some shown to be less effective than promised, others even found to be dangerous. A new aspect to the question is the importance of economic pressures which require rational investment decisions when diffusing innovating technologies. In 1991, the Commission for the evaluation and diffusion of innovating technologies (CEDIT) at the University Hospitals of Paris (Assistance Publique-Hôpitaux de Paris) developed a programme aimed at better managing the distribution and use of polyvalent intravenous immunoglobulins (IgIV), a new promising therapeutic tool with both a high cost and a certain number of risks. The programme was designed to assist prescribers in elaborating better therapeutic strategies and to help hospital managers rationalize expenditures for IgIV. The results of this experience are presented here together with certain conclusions concerning the way management decisions can be applied to the diffusion of an innovation in health care.

Evolution of bacterial susceptibility to antibiotics during a six-year period in a haematology unit

A knowledge of the bacterial ecology of a haematology unit should help in the management of the febrile patient with or without neutropenia. We studied the prevalence and the susceptibility profiles of bacteria isolated during a six-year period among patients hospitalized in a 44-bed haematology unit. Antibiotic use over this period was also studied. The most prevalent bacteria were coagulase-negative staphylococci (CNS) (35.1%), Escherichia coli (11.4%), Staphylococcus aureus (9.9%), Enterococcus spp. (8.2%), and Pseudomonas aeruginosa (7.5%). The susceptibility of CNS to oxacillin decreased from 67-44% over six years, while that of enterobacteriaceae to amoxycillin and piperacillin was reduced by about 50%. P. aeruginosa susceptibility to ceftazidime remained remarkably stable at around 90%, despite extensive empirical use. Imipenem and ciprofloxacin were used restrictively and ceftazidime-resistant P. aeruginosa remained susceptible to these two agents in most cases. Our antibiotic policy was found to be compatible with the frequency of the bacterial strains isolated in our department and with their susceptibility profiles.

Exhaustive analysis of the P53 gene coding sequence by denaturing gradient gel electrophoresis: application to the detection of point mutations in acute leukemias

We report the set-up of a denaturant gradient gel electrophoresis (DGGE) assay to screen for mutations in the whole coding sequence of the p53 gene. These DGGE experimental conditions were applied to the analysis of the p53 gene in acute leukemias. Forty adults with acute myelogenous leukemia (AML) and 21 with acute lymphoid leukemia (ALL) were investigated. Eleven of the AML patients were investigated at the time of the initial diagnosis and at relapse. In contrast with most reports based on amplified fragments analyzed by single-strand conformation electrophoresis and focusing on exons 5 to 8, we analyzed the whole coding sequence of the gene. Two of the 40 AML patients displayed a point mutation in exon 7; it was either an A to G substitution that converted Tyr-234 to Cys, or a G to A change that converted Arg-248 to Gln. The screening procedure led to the discovery of several intronic and exonic polymorphisms. These results confirm the low incidence of p53 mutations in acute leukemias and suggest a limited role of the p53 protein in leukemogenesis. The computerized modeling and electrophoresis parameters presented here provide a powerful tool for the exhaustive characterization of p53 mutants in all kinds of malignancies.

[Chronic anemia: diagnostic tools and approach]

Anaemia is frequently encountered in daily practice. With full knowledge of its pathophysiology a rational classification is possible allowing a suitable approach for diagnostic investigations. In a first stage, the data provided by blood counts, erythrocyte constants and reticulocyte counts guide the diagnostic rationale. In cases with microcytic and hypochromic anaemia, measurement of ferritin level separates iron deficiency anaemia from the so-called "inflammatory" anaemias. A high number of reticulocytes points to haemolytic anaemia. Among the many causes of haemolysis, one must first look for autoimmune haemolysis. Elsewhere, the clinical context and morphological red cell abnormalities point to a hereditary disease affecting the erythrocyte membrane, enzymes or globin content. Although rare, microangiopathic anemia with schizocytosis and paroxysmal nocturnal haemoglobinuria must not be misdiagnosed. Bone marrow examination remains the clue in non-regenerative normochromic, normo- or macrocytic anaemias. In difficult cases, other investigations, such as cytogenetics, isotopic examination and progenitor culture, may help in characterizing the anaemia. Serum erythroproietin essays and plasma transferrin receptor counts will soon figure among the methods used to explore anaemias.

Danazol in autoimmune haemolytic anaemia

Ten adult patients with warm antibody haemolytic anaemia at initial presentation and seven other patients with either refractory AIHA (two patients) or who relapsed after an initial response to prednisone (five patients) were treated with both Danazol and prednisone. 80% of the first group, but also 60% of the second group displayed long-lasting responses (mean follow up 21 months). Minimal side-effects occurred. Finally, addition of Danazol at presentation in warm AIHA may decrease the duration of prednisone therapy and markedly reduce the necessity of second-line splenectomy which is usually required in many patients.

A multicentric randomised study of alpha 2b interferon (IFN) and hydroxyurea (HU) with or without cytosine-arabinoside (Ara-c) in previously untreated patients with Ph+ chronic myelocytic leukemia (CML): preliminary cytogenetic results

The CML 88 study was designed to evaluate the efficacy of maintenance therapy in a multicentric randomised protocol using IFN combined with low-dose Ara-C versus IFN alone, following an induction with IFN + HU. Between April 1988 and February 1991, 237 patients from 36 French Hematology Centres were entered in the study. Preliminary cytogenetic results show a slightly higher, although not statistically significant, proportion of major chromosomal responses, including complete cytogenetic remissions, in the IFN + Ara C arm.

Usefulness of consensus conferences: the case of albumin

The usefulness of consensus conferences has been questioned. We have assessed the impact of a 1989 consensus conference about the treatment of hypovolaemia on prescribing practice at our hospital. Data available from the blood bank enabled us to follow albumin use and costs by department between 1987 and 1991. Medical journals, direct mail, and meetings were used to disseminate the recommendations of the consensus conference, which were that the only indications for albumin are massive haemorrhage, plasmapheresis, massive hypoalbuminaemia, and volume expansion in pregnancy; for hypovolaemia caused by septic shock or vasoplegia, fluid gelatins and crystalloids should be used. In the year after the conference, and in subsequent years, albumin use and costs were 40% lower than before the conference, even though total medical expenditure continued to rise and numbers of patients admitted did not change. We believe that consensus conferences can be a useful means of improving medical practice. The features that ensured success in this programme were the small number of prescribers, the homogeneous setting, and the frequent restatement of the recommendations.

Induction of cytolytic function in resting peripheral blood CD8+/Leu-7+ T cells through IL2/p 75 IL2-receptor interaction: a study in the allogeneic human bone marrow transplantation model

CD8+/Leu-7+ T cells which circulate in increased proportions in the blood of long-term surviving BMT patients are for the most part high-density resting lymphocytes lacking IL2R-alpha (p55) expression. We show that they can be induced by IL2 to manifest cytolytic function after 24-48 hr stimulation by using rather high concentrations of IL2 (at least 50 U/ml). This function was much more readily induced in high-density CD8+/Leu-7+ T cells than in high-density CD8+/Leu-7+ T cells and occurred in the presence of minimal cell proliferation. Other cytokines involved in primary CTL differentiation (IFN-gamma, IL4 and IL6) were without effect suggesting that CD8+/Leu-7+ T cells are, in the BMT model, in vivo preactivated CTL ready to differentiate into cytolytic effectors under the sole IL2 stimulus. TU27 Mab directed at IL2R-beta (p75) subunit almost completely prevented IL2-induced cytolytic function of CD8+ T cells while 33B3.1 Mab directed at IL2R-alpha (p55) subunit was ineffective, suggesting that the signal for this function has its origin in IL2R-beta chains constitutively expressed by these cells.

Abnormally expanded CD8+/Leu-7+ lymphocytes persisting in long-term bone marrow-transplanted patients are resting pre-cytotoxic T-lymphocytes

We analyzed the functional status of the small CD8+/Leu-7+ T-lymphocytes that circulate in increased proportions in the blood of many allogeneic bone marrow transplant (BMT) patients. Purified CD8+/Leu-7+ T cells were tested for their effect on T-cell proliferative responses. In contrast to CD8+/Leu-7-T-lymphocytes, such cells behaved as suppressor cells for lectin-induced mitogenic responses of the donor's peripheral blood lymphocytes. However, they did not interfere with the in vitro responsiveness to specific stimuli such as protein purified derivative (PPD) or alloantigens. We demonstrate that CD8+/Leu-7+ T cells are resting pre-cytotoxic T-lymphocytes (CTL) that can be induced by mitogenic lectins to express their cytolytic program in a non-specific, non-major histocompatibility complex-restricted manner against phytohemagglutinin-treated lymphoblasts or K562 target cells. The lectin-triggered cytotoxicity was achieved within a few days, together with limited cell division. Our results suggest that circulating CD8+/Leu-7+ T cells from BMT recipients are in vivo primed CTL awaiting cellular activation.

Central nervous system relapses after bone marrow transplantation for acute lymphoblastic leukemia in remission

This study defines the risk of central nervous system (CNS) relapse in patients undergoing bone marrow transplantation (BMT) for acute lymphoblastic leukemia (ALL) in remission, with no posttransplant prophylactic CNS therapy. Ninety-two consecutive patients in complete remission received BMT for ALL (n = 82) or high-grade non-Hodgkin's lymphoma with poor prognostic factors at diagnosis (n = 10). Sixty-six patients received allogeneic BMT (Allo-BMT) and 26 patients, without an identical sibling, underwent autologous BMT (Auto-BMT). Fifteen patients had CNS involvement at diagnosis and underwent BMT in first remission. Eight patients experienced CNS relapse after BMT, corresponding to a probability of 11% at 3 years. Apart from a history of prior CNS involvement, no patient characteristic evaluated statistically influenced CNS relapse after BMT. The probability of CNS relapse was 5.5% for the 70 patients without history of CNS involvement and 27.5% for the 22 patients with prior CNS involvement. However, subgroup analysis showed that the increased risk of CNS relapse is mainly observed in Auto-BMT patients with history of prior CNS involvement, particularly in patients undergoing BMT in first remission (three of five Auto-BMT versus one of ten Allo-BMT). Taking into account the multiple factors which influence the occurrence and the treatment of CNS leukemia, the results on this retrospective study suggests that (1) for patients without CNS involvement at diagnosis and for whom BMT is performed in first remission, cranial irradiation before BMT and posttransplant prophylactic CNS therapy can be omitted because of the low probability of CNS relapse after BMT (3.4%), when total-body irradiation (TBI) is included in the conditioning regimen; and (2) the difference observed between Allo-BMT and Auto-BMT patients with previous CNS involvement and undergoing BMT in first remission could indicate that graft-versus-host leukemia acts even in the CNS in Allo-BMT patients.

[Mixed lympho-epidermal cell cultures: value in bone marrow grafts]

Graft-versus-host disease (GVHD) is the major complication of allogeneic HLA-identical bone marrow transplantation. GVHD is induced by the activation of mature T cells in the graft which react against minor antigens of the recipient. Mixed epidermal cell-lymphocyte cultures (MELC), which constitute an in vitro model of epidermal cell-lymphocyte interactions, make it possible to study the presentation of antigens to the lymphoid cells by epidermal Langerhans cells. We performed MELC in 66 patients who had received an HLA-identical bone marrow transplant for malignant blood disease. The bone marrow received by 29 recipients had been depleted of mature T cells, whereas 37 recipients had received a non-depleted bone marrow. A complete, uni- and multivariate statistical analysis was carried out on recipients of non-depleted bone marrow to evaluate the risk factors for acute and chronic GVHD. This study showed that MELC between donor and recipient was the most predictive parameter for the occurrence of GVHD. Other factors were a history of previous pregnancies in female donors and a diagnosis of chronic myelogenous leukaemia. These results may be of value in the selection of donors and for a better determination of the need for bone marrow depletion.

Cost of allogeneic bone marrow transplantation in four diseases

The cost of bone-marrow transplantation is compared in 4 diseases: acute myelogenous leukaemia, severe combined immunodeficiency, severe aplastic anaemia and chronic granulocytic leukaemia. Hospital cost components directly related to the clinical protocols applied are valorized. Results confirm the well-known fact that bone-marrow transplantation is a costly technique. The unit cost of a transplantation can vary from 1 to 2 between departments for the sole reason that patients treated are not suffering from the same illness. For one disease, the unit cost may vary from 1 to 2.7 when post-graft complications arise. Furthermore, in the health-care sector, as well as in every other economic sector, costs do not remain stable: they vary in time most especially when treatment protocols evolve. This type of cost information is the basis for management control systems without which physicians, hospital managers and health-care authorities cannot communicate effectively. In countries where health care is largely financed by the community, what is at stake is the future of advanced technologies in medicine.

In vitro inhibition of normal human hematopoiesis by marrow CD3+, CD8+, HLA-DR+, HNK1+ lymphocytes

We previously demonstrated that after allogeneic bone marrow transplantation (BMT) a subset of CD8, HNK1, and DR-positive T lymphocytes are able to inhibit CFU-GM and BFU-E growth with an HLA-DR restriction. In this study we investigated whether these cells, present in normal marrow in low concentration (less than 1%), play the same role. HNK1-positive sorted marrow cells forming rosettes (E+C) were able to inhibit BFU-E and CFU-GM growth when added back to the marrow E-C at a ratio of 1:10 (HNK1+ E+C/E-C) in a range from 40% to 60%. This inhibitory effect was also detected for a cellular ratio of 1:100, which is the normal marrow value for this subset of T cell. HNK1+ DR+-sorted E+C after double-immunofluorescent labeling also showed the same inhibitory activity as the HNK1+ E+C, whereas the negative fraction including all the other E+C had no detectable inhibitory activity. CD3 and CD8 antigens were also present on the membrane of these cells, as demonstrated in two cases by double-immunofluorescent labeling performed with anti-CD3 or anti-CD8 monoclonal antibodies (MoAbs) and HNK1 MoAb, respectively, and subsequent cell sorting. Blocking experiments, performed by adding in culture anti-CD4 and anti-CD8 MoAbs to HNK1+ T cells showed that only the last MoAb was able to prevent inhibition of hematopoietic colony growth. These results confirmed that one subset of CD3+, CD8+, HNK1+, and DR+ T cells was responsible for in vitro inhibition of normal hematopoiesis. In addition, this inhibition was genetically restricted to HLA-class II antigens, since in three co-culture experiments with unrelated bone marrow cells inhibition occurred only when cells with one haplo-identical HLA-DR antigen was added back to the culture. Indeed, this effect was really HLA-DR restricted, since in blocking experiments with different anti-HLA class II MoAbs (anti-DR, anti-DP, and anti-DQ MoAbs) only an anti-HLA-DR MoAb was able to prevent the colony growth inhibition by CD3+ HNK1+, or CD8+ HNK1+ E+C. In conclusion, the CD3+, HNK1+, CD8+, DR+ cells may be the T-cell subset able to inhibit normal hematopoiesis with an HLA-DR restriction.

Immunophenotype of leukemic blasts with small peroxidase-positive granules detected by electron microscopy

Forty-three cases of undifferentiated leukemias by light microscopy examination were diagnosed as acute myeloblastic leukemias by ultrastructural revelation of peroxidase and were subsequently studied by immunological markers. In 41 of these cases, blasts were labeled by at least one of the antimyeloid MoAbs (My 7, My 9, and 80H5). An antimyeloperoxidase polyclonal antibody was used in 23 cases and was clearly positive in 11 of them, while cytochemistry by light microscopy was negative. These myeloblasts were frequently mixed with a minority of blasts from other lineages especially promegakaryoblasts. It is noteworthy that in 6 cases myeloid and lymphoid markers (E rosette receptor, common acute lymphoblastic leukemia antigen (cALLA), CD 9, CD 19 antigens (anti-B4 MoAb] were detected on a fraction of blast cells, suggesting a bilineage leukemia. However, in double labeling experiments, blasts with myeloperoxidase coexpressed lymphoid and myeloid markers including cALLA and CD 19 antigen. In one case, blasts had a typical non-B, non-T acute lymphoblastic leukemia phenotype (HLA-DR, CD 9, CD 19, cALLA positive) without staining by any of the antimyeloid MoAbs. However, 70% of the blasts were labeled by the antimyeloperoxidase antibody and expressed peroxidase-positive granules at ultrastructural level. In conclusion, most of the AML undiagnosed by optical cytochemistry are identified by antimyeloid antibodies. Some of these cases are also stained by some antilymphoid MoAbs. Use of antibodies against myeloperoxidase may improve the diagnosis of difficult cases of acute myeloblastic leukemia.

Hepatic vein thrombosis in paroxysmal nocturnal hemoglobinuria. A spectrum from asymptomatic occlusion of hepatic venules to fatal Budd-Chiari syndrome

In a series of 40 patients with Budd-Chiari syndrome, 5 (12%) were found to be afflicted with paroxysmal nocturnal hemoglobinuria. The clinico-pathological features in these 5 patients and in 26 well-documented previously reported cases could be ascribed to three groups of increasing severity: thrombosis limited to small-sized hepatic veins with no or transient ascites, partial thrombosis of large-sized hepatic veins with chronic ascites, and complete thrombosis of large-sized hepatic veins with a life-threatening course. These three groups did not differ with regard to sex, age, and duration and characteristics of paroxysmal nocturnal hemoglobinuria. In view of the relationship between prognosis and the extent of hepatic vein obstruction, we suggest that early therapy directed toward limiting the extension of thrombosis, or toward dissolving formed thrombi, should improve the prognosis of this severe complication of paroxysmal nocturnal hemoglobinuria.

Ultrastructural and cytochemical characterization of blasts from early erythroblastic leukemias

Among nine cases of early erythroblastic leukemia previously diagnosed using a panel of antibodies, two patients have erythroid blasts expressing glycophorin A, seven patients have blasts with a more immature phenotype. These immature blasts were labeled by the FA6-152 monoclonal antibody when studied with the immunogold technique. The blasts exhibited large nucleoli, and their cytoplasm contained numerous ribosomes and large mitochondria. In the Golgi apparatus several granules resembled the theta granules as previously described and contained ferritin molecules in the absence of rhopheocytosis. A large proportion of these blasts exhibited a platelet peroxidase (PPO)-like activity. As the blasts from the two other patients with a more mature phenotype and glycophorin A reactivity lacked this PPO, this enzyme seems to be restricted to the more immature cells. Since in these leukemic samples immature erythroid blasts were admixed to promegakaryoblasts, immunogold labeling was also performed with antiplatelet antibodies. This latter population which was labeled with C17, a monoclonal antibody to platelet glycoprotein IIIa, showed strong PPO activity but lacked theta granules and ferritin. In the normal bone marrow enriched by panning for CFU-E (8%) and depleted in progenitors of other lineages, blast cells showing characteristics similar to leukemic erythroid blasts were seen. They exhibited theta granules and ferritin and a proportion of them also had a PPO-like activity. Thus, a PPO reaction is not restricted to the platelet-megakaryocyte line. In conclusion, a PPO-like activity and ferritin molecules were present in immature leukemic erythroid blasts. Similar cells could be identified from normal bone marrow.

In vitro inhibition of hematopoiesis by HNK1, DR-positive T cells and monocytes after allogeneic bone marrow transplantation

Blood CFU-GM and BFU-E, grown from 17 patients who had undergone allogeneic bone marrow transplantation (BMT), were studied by the plasma-clot technique before day 45, and at a time when their blood count was approximately normal. The number of colonies varied from one patient to another, but was always lower than in normal subjects. Removal of cells forming rosettes with sheep erythrocytes (E+C) increased colony growth in four out of eight cases, whereas removal of adherent cells (AC) had the same effect in five out of six cases. Addition of E+C or AC after their initial removal restored the inhibition of colony growth. This suppression was noted at a 1:1 to 8:1 cellular ratio and ranged from 25% to 75%. The phenotype of the suppressive cells was further characterized by complement-mediated lysis with monoclonal antibodies (MoAbs) and fluorescent labeling. Two types of cells associated with inhibition of colony growth were identified: the first were E+C positive, characterized by the T3, HNK1, DR, and T8 determinants; the second were identified by the MO2 MoAb, indicating their monocytic origin, together with their properties of adherence. Similar suppressor cells of CFU-GM were found in the marrow of two other allogeneic BMT patients. A direct suppressive effect of the two types of cells was demonstrated in one experiment when MO2+ and/or HNK1+ cells collected by cell sorting were added back to cultures depleted in MO2+ and HNK1+ cells by complement-mediated lysis and were both found to decrease colony growth. Purified HNK1+ cells led to moderate inhibition of colony growth, which was not enhanced by increasing their concentration. This suppressive effect of hematopoiesis could be the consequence of an allogeneic reaction, since no inhibition was affected by T cells or monocytes in seven autologous BMTs and one syngeneic BMT.

Expression of blood group A antigen during erythroid differentiation in A1 and A2 subjects

The expression of blood group A antigen on marrow and blood cells from A1 and A2 subjects was investigated by the binding of Helix pomatia and Dolichos biflorus lectins using immunofluorescence. These two lectins stained BFU-E-derived colonies from A subjects in the early days of culture before the expression of glycophorin. The erythroid origin of these cells was ascertained by the coexpression of two other very early erythroid markers. In bone marrow, the ultrastructural immunogold method revealed that the entire erythroid lineage including proerythroblasts was labeled by HPA, whereas no staining was observed on granulomonocytic cells including myeloblasts. Platelets from A subjects were HPA-labeled and so were platelets from an O subject preincubated in A plasma. Megakaryocytes obtained in CFU-MK-derived colonies were weakly and heterogeneously labeled by the HPA lectin. Cultures from A1 and A2 subjects were the reflection of the genetic differences only when investigations were performed on mature erythroblasts. In contrast, the great majority of immature erythroblasts both from A2 and A1 subjects were equally labeled by both lectins; during further erythroid maturation, binding of both lectins markedly diminished only on A2 erythroblasts. When marrow erythroblasts were investigated at electron microscopic level, heterogeneity of labeling among all stages of maturation was clearly observed in A2 subjects, with staining stronger on immature than on mature erythroblasts. Therefore, the genetic differences between A1 and A2 subjects are revealed during terminal erythroid differentiation.

Treatment of adult acute lymphoblastic leukemia. Preliminary results of a trial from the French Group

We present here the results of a cooperative trial in 244 adult patients with acute lymphoblastic leukemia. Induction therapy with vincristine, cytoxan, and prednisone (VCP) gave the same complete remission rate after one course as more aggressive induction with vincristine, rubidazone, araC, and prednisone (VRAP) due to increased toxic death in the aggressive arm. Because of high efficacy of salvage therapy with VRAP regimen in patients failing to achieve CR with VCP regimen, patients initially randomized to receive VCP had a significantly higher CR rate than patients initially receiving VRAP (87% vs. 73%, p = 0.01). Patients randomized to receive postremission consolidation using adriamycin, araC, and asparaginase (AAA) prior to maintenance had a significantly longer remission than patients not receiving consolidation (p less than 0.005). At the time of analysis allogeneic bone marrow transplantation does not significantly increase disease-free survival when compared with intensive consolidation chemotherapy.

T-cell lymphoma revealed by a peripheral neuropathy. A report of two cases with an immunohistologic study on lymph node and nerve biopsies

In two patients a peripheral neuropathy was the presenting symptom of a noncutaneous peripheral T-cell lymphoma. In the first patient, the neuropathy had a relapsing and remitting course, the symptoms improved under corticosteroid therapy. The second patient suffered from a relentless neuropathy. In both cases the lymphoma infiltrated the peroneal nerve with an angiocentric and perivascular pattern resembling that observed in central nervous system lymphomas. The characterization of T-cell subsets in the lymph node showed cells with the helper/inducer and suppressor/cytotoxic phenotype in the first case and a predominance of cells with the helper/inducer phenotype in the second case. In the nerve, lymphocytes beard the helper/inducer phenotype antigen. A typical paraneoplastic vasculitis of nerve showed clearly different immunologic features.

Mixed epidermal cell-lymphocyte reaction in prediction of acute graft-versus-host disease in bone marrow recipients

Peripheral blood lymphocytes (PBL) and epidermal cells (EC) of 44 patients to be grafted with bone marrow from an HLA-identical sibling have been used as stimulator cells in primary cultures with effector PBL of one or several potential donors. Proliferative responses against PBL did not differ from those obtained with effector cells cultured in medium alone, whereas EC induced clearly positive proliferation in 21/53 (40%) of the pairs tested. Evaluation of 30 patients followed for more than 3 months after the graft shows that a high level of response in the mixed epidermal cell lymphocyte reaction is directly correlated with the incidence of acute graft-versus-host disease.

HLA-DR restriction in suppression of hematopoiesis by T cells from allogeneic bone marrow transplants

Three allogeneic bone marrow transplantation patients who exhibited a suppressive subset of T cells for in vitro hematopoiesis have been investigated to determine whether this T cell suppressive effect was genetically restricted. In the three cases, T cells separated by sheep red cell rosetting inhibited blood colony-forming units granulocyte-monocyte (CFU-GM) and burst-forming unit erythroid (BFU-E) growth from the patients and from the bone marrow donors who were HLA identical, but not from randomly chosen unrelated subjects. In one case, cocultures were performed between the patient T cells and the T-depleted cells from eight siblings and from the mother. A marked inhibition (30 to 60%) of CFU-GM and BFU-E growth was found in the relatives who shared a haplo-identical HLA-DR 5. The same degree of suppression was found with respect to whether the siblings were homozygous or heterozygous for the HLA-DR 5 antigen, and whether or not they shared common class I antigens. This inhibition was totally abolished when a monoclonal antibody against HLA-DR was added, whereas a monoclonal antibody against class I histocompatibility antigen had no effect. To additionally demonstrate that this inhibition was mediated by a single HLA-DR haplotype, T cells from the patient were co-cultured with cells from three normal unrelated individuals, one with a phenotypically identical DR and two with only one haploidentical DR. Inhibition was similarly found in the subject exhibiting complete DR identity, and the subject with only the DR 5 haploidentical phenotype. These results demonstrate that a unique subset of T cells present in allogeneic bone marrow transplants specifically suppress differentiation of hemopoietic progenitors that bear one phenotypically haplo-identical HLA-DR antigen.

HLA-DR restriction in suppression of hematopoiesis by T cells from allogeneic bone marrow transplants

Three allogeneic bone marrow transplantation patients who exhibited a suppressive subset of T cells for in vitro hematopoiesis have been investigated to determine whether this T cell suppressive effect was genetically restricted. In the three cases, T cells separated by sheep red cell rosetting inhibited blood colony-forming units granulocyte-monocyte (CFU-GM) and burst-forming unit erythroid (BFU-E) growth from the patients and from the bone marrow donors who were HLA identical, but not from randomly chosen unrelated subjects. In one case, cocultures were performed between the patient T cells and the T-depleted cells from eight siblings and from the mother. A marked inhibition (30 to 60%) of CFU-GM and BFU-E growth was found in the relatives who shared a haplo-identical HLA-DR 5. The same degree of suppression was found with respect to whether the siblings were homozygous or heterozygous for the HLA-DR 5 antigen, and whether or not they shared common class I antigens. This inhibition was totally abolished when a monoclonal antibody against HLA-DR was added, whereas a monoclonal antibody against class I histocompatibility antigen had no effect. To additionally demonstrate that this inhibition was mediated by a single HLA-DR haplotype, T cells from the patient were co-cultured with cells from three normal unrelated individuals, one with a phenotypically identical DR and two with only one haploidentical DR. Inhibition was similarly found in the subject exhibiting complete DR identity, and the subject with only the DR 5 haploidentical phenotype. These results demonstrate that a unique subset of T cells present in allogeneic bone marrow transplants specifically suppress differentiation of hemopoietic progenitors that bear one phenotypically haplo-identical HLA-DR antigen.

Carbonic anhydrase I is an early specific marker of normal human erythroid differentiation

The expression of carbonic anhydrase (CA) as a marker of erythroid differentiation was investigated by immunologic and enzymatic procedures. A polyclonal anti-CA antibody was obtained by immunizing rabbits with purified CA I isozyme. This antibody is reactive with CA I but not with CA II. Within blood cells, CA I was only present in erythrocytes, whereas CA II was also detected in platelet lysates by enzymatic assay. Concerning marrow cells, identifiable erythroblasts and some blast cells expressed CA I. Most of the glycophorin A-positive marrow cells were clearly labeled by the anti-CA I antibody. However, rare CA I-positive cells were not reactive with anti-glycophorin A antibodies. We therefore investigated whether these cells were erythroid precursors or progenitors. In cell sorting experiments of marrow cells with the FA6 152 monoclonal antibody, which among hematopoietic progenitors is reactive only with CFU-E and a part of BFU-E, was performed, CA I+ cells were found mainly in the positive fraction. The percentage of CA I+ cells nonreactive with anti-glycophorin A antibodies contained in the two fractions was in the same range as the percentage of erythroid progenitors identified by their capacity to form colonies. In addition, the anti-CA I antibody labeled blood BFU-E-derived colonies as early as day 6 of culture, whereas in similar experiments with the anti-glycophorin A antibodies, they were stained three or four days later. No labeling was observed in CFU-GM- or CFU-MK-derived colonies. The phenotype of the day 6 cells expressing CA I was similar to that of erythroid progenitors (CFU-E or BFU-E): negative for glycophorin A and hemoglobin, and positive for HLA-DR antigen, the antigen identified by FA6 152, and blood group A antigen. Among the cell lines tested, only HEL cells expressed CA I, while K562 was unlabeled by the anti-CA I antibody. In contrast, HEL and K562 cells expressed CA II as detected by a biochemical technique. Synthesis of CA I, as with other erythroid markers such as glycophorin A and hemoglobin, was almost abolished after 12-O-tetradecanoyl-phorbol-13 acetate treatment of HEL cells. In conclusion, CA I appears to be an early specific marker of the erythroid differentiation, expressed by a cell with a similar phenotype as an erythroid progenitor.

The iron-chelating agent picolinic acid enhances transferrin receptors expression in human erythroleukaemic cell lines

Picolinic acid, a metal chelating molecule, was administered to human erythroleukaemic cell lines (K 562 and HEL) that were grown in serum-containing media. Picolinic acid inhibited both iron uptake and cell growth. Furthermore, picolinic acid was shown to markedly decrease the level of ferritin in the cells. In spite of the inhibition of cell growth, picolinic acid induced a marked increase in the transferrin-binding capacity of the cells. This phenomenon was due to a two-five-fold enhancement of the rate of transferrin receptor biosynthesis. Other iron-chelating compounds, capable of reducing the level of intracellular iron, also elicited a marked enhancement of the transferrin-binding capacity of the cells. However, the addition of iron, as ferric ammonium citrate, in the culture medium elicited a marked increase in the level of ferritin and a strong decrease in the transferrin-binding capacity of the cells. On the basis of these data we propose that a feed-back mechanism is involved in the regulation of transferrin receptors: when the cells accumulate iron they decrease the number of transferrin receptors in order to prevent further accumulation of iron; when no or low iron is available to the cells, the number of transferrin receptors markedly increases as a compensatory mechanism.

Presence of the Tn antigen on hematopoietic progenitors from patients with the Tn syndrome

The Tn syndrome is an acquired clonal disorder characterized by the exposure of a normally hidden determinant, the Tn antigen, on the surface of human erythrocytes, platelets, granulocytes, and lymphocytes. Two distinct populations, Tn positive (Tn+) and Tn negative (Tn-), of mature hemopoietic cells are present in Tn patients. To determine whether the Tn antigen is already expressed on erythroid, myeloid, and pluripotent progenitors, light-density mononuclear blood cells from two patients with this syndrome were separated by fluorescent-activated cell sorting and by affinity chromatography into Tn+ and Tn- fractions, using their binding properties to Helix pomatia agglutinin (HPA). Burst-forming-unit erythroid (BFU-E), colony-forming-unit granulocyte/macrophage (CFU-GM), cells were assayed in plasma clot cultures. After 12-14 d of culture, colonies were studied by a double fluorescent labeling procedure. First, a fluorescein-conjugated HPA permitted evaluation of the presence or absence of the Tn antigen at the surface of the cells composing each colony, and second, the binding of a murine monoclonal antibody against either glycophorin A (LICR-LON-R10) or against a myeloid antigen (80H5), revealed by an indirect fluorescent procedure, was used to establish the erythroid or myeloid origin of each cell. The Tn+ fraction obtained by cell sorting gave rise to nearly 100% Tn+ colonies composed exclusively of cells bearing this antigen. The reverse was observed for the Tn- cell fraction. These results demonstrate that in the Tn syndrome, BFU-E, CFU-GM, and CFU-GEMM of the Tn+ clone express the Tn antigen at this early stage of differentiation.

Expression of SSEA-I antigen (3-fucosyl-N-acetyl-lactosamine) on normal and leukaemic human haemopoietic cells: modulation by neuraminidase treatment

Several mouse monoclonal antibodies (MoAbs) considered specific for the myeloid lineage recognize the same carbohydrate structure (3-fucosyl-N-acetyl-lactosamine) which is similar to the murine antigen SSEA-I. We have investigated the expression of this antigen with six different well-characterized murine IgM MoAbs on normal, leukaemic, and cultured cells by immunofluorescence and immunoelectron microscope cytochemistry. The cells were studied before and after neuraminidase treatment since epitopes recognized by these MoAbs may be masked by sialic acid. Among the recognizable normal marrow or blood cells, all these MoAbs specifically labelled the granulocytic lineage from the promyelocyte to the polymorph. After neuraminidase treatment, monocytes became labelled. All the other lineages remained unstained. Several cell lines were studied. Six of eight lymphoblastoid cell lines were stained by these MoABs; reactivity was increased by neuraminidase. One Burkitt cell line and two T cell lines were also found to be positive. These antibodies were tested on leukaemic cells. In acute non-lymphocytic leukaemia they usually labelled promyelocytes, more mature granulocytic and monocytic precursors but did not label myeloblasts; after neuraminidase treatment, these myeloblasts became stained. No labelling was observed on leukaemic proerythroblasts and promegakaryoblast before and after neuraminidase treatment except in one case of promegakaryoblastic leukaemia in which the SSEA-I antigen and platelet peroxidase were expressed in the same cell. In addition, six cases of common acute lymphoblastic leukaemia were studied; the blasts became positive after desialylation. Two examples of T cell acute leukaemia were essentially negative. We conclude, therefore, that the reactivity of haemopoietic cells with these MoAbs alone does not represent a criterion sufficient to sustain their myeloid origin since the SSEA-I antigen may be expressed at the surface of all cell lineages in the early phases of haemopoietic differentiation.

Effect of phorbol esters on iron uptake in human hematopoietic cell lines

We have investigated the effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on iron uptake into human hematopoietic cell lines K562, U937, and HL-60. TPA inhibited both cell growth and iron uptake by these cell lines. This effect was rapid, which is typical of phorbol esters which are biologically active, and it occurred at very low concentrations of TPA. This effect of TPA was dependent upon an inhibition of the transferrin-binding capacity as estimated on intact cells. However, experiments with transferrin binding on cell samples dissolved in 1% Triton X-100 showed that TPA-treated cells exhibited a transferrin-binding capacity similar to that of control cells. On the basis of this result, it is suggested that TPA modified a part of transferrin receptors present in the cells; as a result of this modification, these receptors became unavailable for binding transferrin, but they remained physically present in the cell. Other compounds capable of inducing the differentiation of leukemic cells, such as dimethyl sulfoxide, butyrate, retinoic acid, and 1 alpha,25-dihydroxy-vitamin D3, did not acutely inhibit iron uptake. We also investigated the effect of TPA on transferrin receptors in a cellular system in which phorbol esters stimulate cell proliferation. At 16 X 10(-9) M, TPA markedly stimulated the proliferation of T-lymphocytes. However, in spite of this marked stimulation of cell proliferation, TPA-stimulated lymphocytes exhibited a transferrin-binding capacity much inferior to cells stimulated by other mitogens, such as phytohemagglutinin.

The role of iron in the growth of human leukemic cell lines

The growth requirements of three human leukemic cell lines (K 562, HEL, U937) have been studied in the absence of serum. For growth in serum-free medium, the cells require insulin, transferrin, and albumin. Two highly water-soluble iron salts, ferric ammonium citrate and ferric ammonium sulfate, may completely replace transferrin for supporting the growth of these cell lines. Similar results were obtained when mitogen-stimulated lymphocytes were grown in serum-free media. Iron containing compounds, such as hemin or hemoglobin, were also able to replace transferrin. Experiments using 42/6 monoclonal antibody strongly suggest that free-iron salts are taken up by the cells by a mechanism that is completely independent from transferrin-receptors.

Regulation of transferrin receptors in human hematopoietic cell lines

Cells grown in the presence of ferric ammonium citrate or hemin exhibited a concentration and time-dependent decrease in 125I-transferrin (Trf) binding. In contrast, cells grown in the presence of protoporphyrin IX or picolinic acid (an iron chelator) exhibited a marked increase in Trf binding. The decrease or increase in binding activity observed under these different conditions of culture reflected, respectively, a reduction or increase in receptor number rather than an alteration in ligand receptor affinity. Growth of the cells in the presence of saturating concentrations of apotransferrin only induced a slight reduction in receptor number. Investigation of the Trf receptors' turnover and biosynthesis clearly showed that iron and hemin decreased the synthesis of Trf receptors without any modification of the receptor turnover; in contrast, protoporphyrin IX and picolinic acid markedly increased the synthesis of Trf receptors. Our results suggest that hemin, iron, and protoporphyrin IX may represent the main molecules involved in the regulation of Trf receptors.

High dose intravenous gammaglobulin and platelet transfusions in leukaemic HLA-immunized patients

3 aplastic patients with acute leukaemia, strongly HLA-immunized and refractory to platelet transfusions, received polyvalent gammaglobulin i.v. infusions (0.4 g/kg/d for 5 or 6 d) in association with daily random platelet transfusions. Platelet recovery was obtained in 2 patients. The 3rd patient did not show any significant rise in platelet count. The ability of gammaglobulin to prolong the life-span of incompatible transfused platelets could facilitate the management of HLA-immunized patients.