Myogenic commitment of human stem cells by myoblasts Co-culture: a static vs. a dynamic approach

An in-vitro model of human bone marrow mesenchymal stem cells (hBM-MSCs) myogenic commitment by synergic effect of a differentiation media coupled with human primary skeletal myoblasts (hSkMs) co-culture was developed adopting both conventional static co-seeding and perfused culture systems. Static co-seeding provided a notable outcome in terms of gene expression with a significant increase of Desmin (141-fold) and Myosin heavy chain II (MYH2, 32-fold) at day 21, clearly detected also by semi-quantitative immunofluorescence. Under perfusion conditions, myogenic induction ability of hSkMs on hBM-MSCs was exerted by paracrine effect with an excellent gene overexpression and immunofluorescence detection of MYH2 protein; furthermore, due to the dynamic cell culture in separate wells, western blot data were acquired confirming a successful cell commitment at day 14. A significant increase of anti-inflammatory cytokine gene expression, including IL-10 and IL-4 (15-fold and 11-fold, respectively) at day 14, with respect to the pro-inflammatory cytokines IL-12A (7-fold at day 21) and IL-1β (1.4-fold at day 7) was also detected during dynamic culture, confirming the immunomodulatory activity of hBM-MSCs along with commitment events. The present study opens interesting perspectives on the use of dynamic culture based on perfusion as a versatile tool to study myogenic events and paracrine cross-talk compared to the simple co-seeding static culture.

A case series of blastic plasmacytoid dendritic cell neoplasia

Blastic plasmacytoid dendritic cell neoplasm (BPDCN), an extremely rare and aggressive tumor, derives from plasmacytoid dendritic cell precursors and is characterized by CD4 and CD56 positivity accompanied by the expression of isolated myeloid, B- or T-cell lineage markers. Despite the recent introduction of specific targeted therapies, prognosis is still poor with a median overall survival of one year, and allogeneic bone marrow transplantation remains the only curative treatment in eligible patients. In this series, we described two cases of adult BPDCN treated with high dose cytarabine and methotrexate and autologous hematopoietic stem cell transplantation, or fludarabine, cytarabine, and idarubicin achieving the first a complete lasting remission, while the second only a transient improvement in skin lesions.

A Case Series of Blastic Plasmacytoid Dendritic Cell Neoplasia

Blastic plasmacytoid dendritic cell neoplasm (BPDCN), an extremely rare and aggressive tumor, derives from plasmacytoid dendritic cell precursors and is characterized by CD4 and CD56 positivity accompanied by the expression of isolated myeloid, B- or T-cell lineage markers. Despite the recent introduction of specific targeted therapies, prognosis is still poor with a median overall survival of one year, and allogeneic bone marrow transplantation remains the only curative treatment in eligible patients. In this series, we described two cases of adult BPDCN treated with high dose cytarabine and methotrexate and autologous hematopoietic stem cell transplantation, or fludarabine, cytarabine, and idarubicin achieving the first a complete lasting remission, while the second only a transient improvement in skin lesions.

Effects of Polyurethane Foam Dressings as an Add-on Therapy in the Management of Digital Ulcers in Scleroderma Patients

Digital ulcers (DUs) represent a severe and common complication occurring in patients affected by Systemic Sclerosis (SSc), with a consistent impact on the quality of life and often resulting in longer hospitalization than unaffected patients. Conventional treatment of SSc ulcers consists of both topical and systemic (oral or intravenous) pharmacological therapies. Several surgical options are also available, but there is overall a lack of official guidelines or recommendations. The aim of this study was to evaluate the efficacy of a novel local therapy based on polyurethane foam dressings, namely the Highly Hydrophilic Polyurethane Foam (HPF), in addition to the conventional pharmacological treatment, in a cohort of 41 SSc patients with at least one active ulcer. Our results showed that the addition of HPF to the conventional treatment based on systemic drugs induced i) a significant reduction in the number of active DUs (p=0.0034); ii) a significant reduction of the mean duration of ulcer-related hospitalization as compared with standard therapy (p=0.0001); iii) a significant improvement of patients' Quality of Life, as evaluated through the Scleroderma Health Assessment Questionnaire (SHAQ) (p=0.00011). Therefore, in our experience, the combined management of DUs can improve both the onset of new DUs and DU's healing thus leading to a better outcome.

Prolonged complete hematologic response in relapsed/refractory T-large granular lymphocyte leukemia after bendamustine treatment

T-large granular lymphocyte leukemia (T-LGLL) is a chronic clonal proliferation of effector memory cytotoxic CD3⁺CD57⁺CD56^- T cells and the current guidelines suggest immunosuppressive therapy as first-line therapy, but the treatment of refractory/relapsed patients is still challenging due to the lack of prospective studies. We describe a series of two refractory/relapsed T-LGLL patients successfully treated with bendamustine, a chemotherapeutic agent largely used for B-cell neoplasms, but poorly investigated for the treatment of T-cell diseases. Complete remission (CR) was achieved in 3 and 6 months, respectively, and maintained for at least 20 months. One patient relapsed after a 20-month CR, but she was responsive to bendamustine therapy again, obtaining a further prolonged CR. Bendamustine as single agent or in combination could be a feasible therapeutic option in refractory/relapsed T-LGLL, especially for elderly patients because of its safety profile.

In Vitro Apoptotic Effects of Farnesyltransferase blockade in Acute Myeloid Leukemia Cells

Farnesyltransferase inhibitors (FTIs) are a class of oral anti-cancer drugs currently tested in phase I-II clinical trials for treatment of hematological malignancies. The in vitro effects of various FTIs (alpha-hydroxyfarnesylphosphonic acid, manumycin-A and SCH66336) were tested on CD34⁺ KG1a cell line and in primary acute myeloid leukemia (AML) cells from 64 patients. By cell viability and clonogeneic methylcellulose assays, FTIs showed a significant inhibitory activity in CD34⁺ KG1a and primary bone marrow (BM) leukemic cells from 56% of AML patients. FTIs also induced activation of caspase-3 and Fas-independent apoptosis, confirmed by the finding that inhibition of caspase-8 was not associated with the rescue of FTI-treated cells. We concluded that other cellular events induced by FTIs may trigger activation of caspase-3 and subsequent apoptosis, but the expression of proapoptotic molecules, as Bcl-2 and Bcl-XL, and antiapoptotic, as Bcl-X(s), were not modified by FTIs. By contrast, expression of inducible nitric oxide synthase (iNOS) was increased in FTI-treated AML cells. Our results suggest a very complex mechanism of action of FTIs that require more studies for a better clinical use of the drugs alone or in combination in the treatment of hematological malignancies.

Haemorrhagic cystitis in haematopoietic stem cell transplantation (HSCT): a prospective observational study of incidence and management in HSCT centres within the GITMO network (Gruppo Italiano Trapianto Midollo Osseo)

Haemorrhagic cystitis (HC) is a recognised complication in patients undergoing allogeneic haematopoietic stem cell transplantation (HSCT). This study evaluates the incidence and severity of HC in patients undergoing allogeneic HSCT during hospitalisation and within the first 100 days following transplant, looking at the use of prophylaxis, management of HC, outcomes at 100 days post transplant, and to identify any correlations between development of HC and the different conditioning regimens for transplant or HC prevention methods used.

Fine needle aspiration cytology of lymphoproliferative lesions of the oral cavity

OBJECTIVE

Oral cavity non-Hodgkin lymphoma (OCL) is a rare condition that may be clinically and radiologically indistinguishable from other pathologies of the mouth. A complete excision or adequate biopsy of the OCL may be difficult. Fine needle aspiration (FNA) cytology has been successfully utilized in the pre-operative diagnosis of oral masses and in lymphoma involving other anatomical areas. Our experience with FNA pre-operative cytological diagnosis of 16 OCLs is reported herein.

METHODS

The results of FNA cytology on 16 consecutive lymphoproliferative lesions of the oral cavity collected over an 8-year period in three institutions were retrieved. Sampled lesions were submucosal masses of different sizes bulging into the oral cavity. Rapid on-site evaluation (ROSE) and routine cytological staining were performed. Immunocytochemistry (ICC), flow cytometry (FC) and polymerase chain reaction (PCR) of the IGH (immunoglobulin heavy) locus were performed on additional passes according to ROSE.

RESULTS

Fourteen OCLs, one myeloma and one florid reactive lymphoid hyperplasia (FRLH) were diagnosed by FNA. OCLs were diagnosed as large B-cell (eight cases) and small B-cell (six cases) lymphomas. Histology revealed eight diffuse large B-cell lymphomas (DLBCL), four lymphomas of mucosa-associated lymphoid tissue (MALT), two follicular lymphomas and one FRLH; no false-negative or false-positive results were diagnosed, but accurate subclassification was obtained in four cases only.

CONCLUSIONS

FNA diagnosis of OCLs may be hampered by the rare incidence, anatomical context and difficulties in obtaining a sufficient amount of cells. Ancillary techniques should be used according to ROSE; a pre-operative FNA cytology diagnosis can avoid unnecessary extensive surgery and speed up the institution of therapeutic procedures.

Immunological derangement in hypocellular myelodysplastic syndromes

Hypocellular or hypoplastic myelodysplastic syndromes (HMDS) are a distinct subgroup accounting for 10-15% of all MDS patients, that are characterized by the presence of bone marrow (BM) hypocellularity, various degree of dysmyelopoiesis and sometimes abnormal karyotype. Laboratory and clinical evidence suggest that HMDS share several immune-mediated pathogenic mechanisms with acquired idiopathic aplastic anemia (AA). Different immune-mediated mechanisms have been documented in the damage of marrow hematopoietic progenitors occurring in HMDS; they include oligoclonal expansion of cytotoxic T lymphocytes (CTLs), polyclonal expansion of various subtypes of T helper lymphocytes, overexpression of FAS-L and of the TNF-related apoptosis-inducing ligand (TRAIL), underexpression of Flice-like inhibitory protein long isoform (FLIPL) in marrow cells as well as higher release of Th1 cytokines, such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). It has also been documented that some HMDS patients have higher frequency of polymorphisms linked both to high production of proinflammatory cytokines such as TNF-α and transforming growth factor-β and to the inhibition of T-cell mediated immune responses such as interleukin-10, further suggesting that immune-mediated mechanisms similar to those seen in AA patients may also operate in HMDS. Clinically, the strongest evidence for immune-mediated hematopoietic suppression in some HMDS is the response to immunosuppression including mainly cyclosporine, anti-thymocyte globulin and/or cyclosporine, or alemtuzumab. Here we review all these immune mechanisms as well as the influence of this deranged cellular and humoral immunologic mileau on the initiation and possible progression of MDS. All these observations are pivotal not only for a better understanding of MDS pathophysiology, but also for their immediate clinical implications, eventually leading to the identification of MDS patients who may benefit from immunosuppression.

OPSI threat in hematological patients

Overwhelming post-splenectomy infection (OPSI) is a rare medical emergency, mainly caused by encapsulated bacteria, shortly progressing from a mild flu-like syndrome to a fulminant, potentially fatal, sepsis. The risk of OPSI is higher in children and in patients with underlying benign or malignant hematological disorders. We retrospectively assessed OPSI magnitude in a high risk cohort of 162 adult splenectomized patients with malignant (19%) and non malignant (81%) hematological diseases, over a 25-year period: 59 of them splenectomized after immunization against encapsulated bacteria, and 103, splenectomized in the previous 12-year study, receiving only life-long oral penicillin prophylaxis. The influence of splenectomy on the immune system, as well as the incidence, diagnosis, risk factors, preventive measures and management of OPSI are also outlined. OPSI occurred in 7 patients (4%) with a median age of 37 years at time interval from splenectomy ranging from 10 days to 12 years. All OPSIs occurred in non immunized patients, except one fatal Staphylococcus aureus -mediated OPSI in a patient adequately immunized before splenectomy. Our analysis further provides evidence that OPSI is a lifelong risk and that current immune prophylaxis significantly decreases OPSI development. Improvement in patients' education about long-term risk of OPSI and increased physician awareness to face a potentially lethal medical emergency, according to the current surviving sepsis guidelines, represent mandatory strategies for preventing and managing OPSI appropriately.

Accelerated bone mass senescence after hematopoietic stem cell transplantation

Osteoporosis and avascular necrosis (AVN) are long-lasting and debilitating complications of hematopoietic stem cell transplantation (HSCT). We describe the magnitude of bone loss, AVN and impairment in osteogenic cell compartment following autologous (auto) and allogeneic (allo) HSCT, through the retrospective bone damage revaluation of 100 (50 auto- and 50 allo-HSCT) long-term survivors up to 15 years after transplant. Current treatment options for the management of these complications are also outlined. We found that auto- and allo-HSCT recipients show accelerated bone mineral loss and micro-architectural deterioration during the first years after transplant. Bone mass density (BMD) at the lumbar spine, but not at the femur neck, may improve in some patients after HSCT, suggesting more prolonged bone damage in cortical bone. Phalangeal BMD values remained low for even more years, suggesting persistent bone micro-architectural alterations after transplant. The incidence of AVN was higher in allo-HSCT recipients compared to auto-HSCT recipients. Steroid treatment length, but not its cumulative dose was associated with a higher incidence of bone loss. Allo-HSCT recipients affected by chronic graft versus host disease seem to be at greater risk of continuous bone loss and AVN development. Reduced BMD and higher incidence of AVN was partly related to a reduced regenerating capacity of the normal marrow osteogenic cell compartment. Our results suggest that all patients after auto-HSCT and allo-HSCT should be evaluated for their bone status and treated with anti-resorptive therapy as soon as abnormalities are detected.

Successful management of pulmonary mucormycosis with liposomal amphotericin B and surgery treatment: a case report

Mucormycosis is an increasingly recognized invasive fungal infection (IFI) in patients with acute myeloid leukemia (AML) and after allogeneic (allo) stem cell transplantation (HSCT); it is mainly due to the severe and prolonged neutropenia related to high-dose chemotherapy. In such patients, the lung is the most frequently involved site in mucormycosis. Since rapidly progressive dissemination may occur after pulmonary mucormycosis in hematologic malignancies, early diagnosis and prompt initiation of an effective antifungal therapy is mandatory for a successful outcome. We report the case of a young AML patient who developed, early after the onset of neutropenia in the first induction phase of chemotherapy, a rapidly progressive pulmonary IFI, successfully treated with liposomal Amphotericin-B (LAmB) and then with a limited open toracothomy biopsy, clearly establishing diagnosis of mucormycosis and removing lung infiltrate. Secondary prophylaxis with LamB, applied during both consolidation therapy and myeloablative sibling allogeneic HSCT, was effective to prevent IFI recurrence despite the development of grade I acute graft-versus-host disease (GVHD) and limited chronic GVHD requiring immunosuppressive treatment. Our case report further provide evidence that the combined surgical and LAmB therapy is an effective and safe choice for the management of pulmonary mucormycosis in hematological immunocompromised patients.

The urokinase-receptor in infectious diseases

Cell migration through the extracellular matrix (ECM) or endothelial cells is a basic process in several physiological and pathological events, including the immune host response to pathogens, both in the case of innate and adaptive immunity. The urokinase-type plasminogen activator (uPA) receptor (uPAR) is a GPI-anchored cell-surface receptor largely expressed on most of leukocytes, including monocytes/macrophages, granulocytes, immature dendritic cells. uPAR has been detected also in soluble and cleaved forms, which are increased in several pathologies. uPAR focuses the proteolytic activity of its ligand, the serine-protease uPA, on the cell membrane, thus promoting localized plasminogen activation and allowing the cell to degrade surrounding ECM and to move across physical barriers. However, the discovery that uPAR can bind with high affinity a component of the ECM, vitronectin (VN), and associates to cell surface molecules to activate signalling pathways inside the cells, largely expanded the role that uPAR can play in cell proliferation/survival and adhesion/migration, which are crucial events for an efficient immune response to infectious agents. This review is focused on the expression and possible functions of the various forms of uPAR in infectious diseases.

Hp(2-20) peptide of Helicobacter pylori and the innate immune receptors: specific role(s) of the formyl peptide receptors

Helicobacter pylori (H. pylori) is a microaerophilic, Gram-negative bacterium that affects more than half of the world's population. H. pylori has co-evolved with humans to be transmitted from person to person and to persistently colonize the stomach. A well-choreographed equilibrium between bacterial effectors and host responses permits microbial persistence and health of the host but confers risk of serious diseases. During its long coexistence with humans, H. pylori has evolved complex strategies to limit the degree and extent of gastric mucosal damage and inflammation as well as immune effector activity. In this complex strategy an important role is played by the interaction of H. pylori with a specific class of innate immune receptors, named N-formyl peptide receptor family (FPRs). In the last years several virulence factors have been studied in an effort to correlate bacterial phenotype with specific gastric manifestations and to clarify the pathogenetic mechanisms. Several peptides produced by H. pylori appear to be involved in inflammation associated with the infection. A particular interest has been focused on the Hp(2-20) peptide derived from the bacteria. Thus, aim of the article is to comment on some advances in the elucidation of specific interactions between the Hp(2-20) peptide and FPRs.

Non lymphomatous clonal B-Cell populations in enlarged lymph nodes in acquired immunodeficiency syndrome

Clonal B-cell populations in non-lymphomatous processes have been sporadically reported in enlarged reactive lymph nodes and mucosa-associated lymphoid cell populations. These generally small clones are considered non-malignant proliferations of B-lymphocytes determined by an abnormal response to bacterial or viral antigen stimulation. In cases reported in literature, clonality was detected by light chain assessment and or by polymerase chain reaction (PCR) analysis of immunoglobulin heavy chain (IgH) gene in histologically and clinically proven non lymphomatous processes. In this study the clinical, cytological, phenotypical and pathological features of three HIV patients in which non-lymphomatous clonal B-cell populations detected in enlarged lymph nodes are reported. All the patients complained for later cervical lymph nodes enlargement, positive at the FDG-positron emission tomography scan. Fine needle cytology, coupled with flow cytometry showed atypical lymphoid cell proliferations and kappa (2 cases) or lambda (1 case) light chain restriction. Reactive, non lymphomatous nature of these processes were then proven by histological control in two cases and by clinical follow-up in the last one; corresponding clinical and pathological aspects are discussed. Clonal B-cell populations in non-lymphomatous processes can sporadically occur in enlarged reactive lymph nodes in immunodeficiency as well as in autoimmune processes. Awareness of the phenomenon and attention should be paid in the evaluation of corresponding pathological features and in the clinical management of corresponding patients.

67 kDa laminin receptor: structure, function and role in cancer and infection

The 67 kDa high affinity laminin receptor (67LR) is a non integrin cell surface receptor for the extracellular matrix whose expression is increased in neoplastic cells and directly correlates with an enhanced invasive and metastatic potential. 67LR derives from homo- or hetero-dimerization of a 37 kDa cytosolic precursor (37LRP), by fatty acid acylation. Interestingly, 37LRP is a multifunctional protein involved in the translational machinery and has also been found in the nucleus, where it is tightly associated with nuclear structures. Acting as a receptor for laminin is not the only function of this protein; indeed, 67LR also acts as a receptor for viruses, such as Sindbis virus and Dengue virus, and is involved in the internalization of the prion protein. Here, we review the current understanding of the structure and function of this molecule, highlighting its role in cancer and infection diseases.

Low-dose valgancyclovir as cytomegalovirus reactivation prophylaxis in allogeneic haematopoietic stem cell transplantation

The efficacy and safety of low dose oral valgancyclovir (VGCV) as cytomegalovirus (CMV) reactivation prophylaxis was retrospectively evaluated in 32 consecutive patients which underwent allogeneic HLA-matched related and unrelated hematopoietic stem cell transplantation (HSCT). Thirty HSCT recipients showed pretransplant CMV seropositivity. Fifteen received a myeloablative conditioning regimen, while seventeen patients received a reduced-intensity conditioning regimen. Twenty-one patients received graft-versus-host disease (GVHD) prophylaxis with cyclosporin A (CsA) and methotrexate (MTX), and the others CsA with MTX and anti-thymocyte globulin. CMV infection was monitored weekly using polymerase chain reaction (PCR). VGCV was administered orally at a dose of 450 mg daily for six months. Six patients developed a positive CMV-PCR on average 56 days after HSCT successfully treated with VGCV at 1800 mg/day, except one who developed fatal gastrointestinal CMV disease. At the time of CMV reactivation, four patients had been affected by grade II-IV acute GVHD and two by an extensive chronic GVHD. No significant specific VGCV-related toxicity was encountered. Seven patients presented hematological toxicity which did not require drug discontinuation. Our data suggest that low dose VGCV is safe and effective as CMV reactivation prophylaxis in allogeneic HSCT recipients. These results require further validation in prospective randomized studies.

Achievements and limitations of complement inhibition by eculizumab in paroxysmal nocturnal hemoglobinuria: the role of complement component 3

Paroxysmal nocturnal hemoglobinuria (PNH) is a hematological disorder characterized by complementmediated hemolytic anemia, thrombophilia and bone marrow failure. The clinical hallmark of PNH is evident chronic hemolysis due to the absence of the complement regulators CD55 and CD59 on PNH erythrocytes. Intravascular hemolysis drives the major clinical features of PNH, including anemia, hemoglobinuria, fatigue and other hemolysisrelated disabling symptoms, such as painful abdominal crises, dysphagia and erectile dysfunction. A peculiar thromboembolic risk has been associated with the hemolysis in PNH, but its pathophysiologic cause remains unclear. The treatment of PNH has remained supportive until a few years ago, when the first complement inhibitor, designated eculizumab, became available. Chronic treatment with eculizumab results in sustained control of intravascular hemolysis, leading to hemoglobin stabilization and transfusion independence in half of the patients. However, residual anemia may persist in a substantial fraction of patients. Recent observations by different groups, including our own, have demonstrated that residual hemolysis may be due to persistent activation of the early phases of the complement cascade, leading to progressive C3-deposition on PNH erythrocytes and possible subsequent extravascular hemolysis through the reticuloendothelial system. Here we critically review the available clinical results of eculizumab treatment for PNH patients, pointing out the recent insights into the pathophysiology of the disease. We discuss the role of the different components of the complement cascade leading to hemolysis, in both the absence and presence of the terminal effector pathway inhibition by eculizumab. Finally, we provide a theoretical rationale for the development of novel strategies of complement inhibition which could in the future further improve on the already substantial efficacy of eculizumab.

Impact of immunogenetic polymorphisms in bone marrow failure syndromes

AIM

To explore whether predisposition to bone marrow failure syndromes (BMF), such aplastic anemia (AA), paroxysmal nocturnal hemoglobinuria (PNH) and myelosysplastic syndromes (MDS), is found in killer cell immunoglobulin-like receptor (KIR) and human leukocyte antigen (HLA) ligand (KIR-L) gene variations or cytokine polymorphisms.

PATIENTS

We studied a cohort of 77 patients with AA, 129 with MDS and 285 healthy controls for the frequencies of KIR-L and KIR genotypes and 22 selected single nucleotide polymorphisms (SNPs) located within 10 cytokine (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL12, IFN- γ, TNF- α, TGF- β) and 3 cytokine receptor (IL-1R, IL-1RA, IL-4Rα) genes.

RESULTS

In AA we found a decreased frequency of inhibitory KIR-2DL3 genes. In MDS, no difference in the frequency of KIR genotype was identified; however, a decreased frequency of 2DL3 was found in hypocellular MDS. Analysis of the KIR genotype in correlation with the corresponding KIR-L profile, revealed a decreased frequency of stimulatory 2DS1/C2 mismatch both in AA and MDS. In AA and MDS cohorts, compared to controls, we found a higher frequency of TT codon 10 variant and of GG codon 25 variant of TGF- β gene, consistent with a high secretory phenotype. This relationship was even more pronounced in PNH and hypocellular MDS. We confirm that the hypersecretory genotype T/T at position -874 of INF-γ gene was overrepresented only in AA and correlates with presence of a PNH clone. Instead in MDS patients, the frequency of G/A polymorphism at position -308 on the TNF- α gene promoter, which correlates with higher TNF- α production, was found significantly higher. Moreover, hypocellular MDS was characterized by a higher prevalence of IL-10 GCC/GCC haplotype, which is functionally associated with a low secretor phenotype.

CONCLUSION

Our findings suggest that alterations in KIR/KIR-L matching, such as increased 3DL2 and decreased 2DS1 mismatch, and in the polymorphisms of TGFβ1, IFN-γ, TNF- α and IL-10 may account for the propensity to immunemediated killing of hematopoietic stem cells and/or ineffective hematopoiesis characteristic of AA and MDS. Further studies are needed to elucidate whether these immunogenetic traits may be involved in increased risk of developing immune-mediated BMF.

Cryptozoospermia with normal testicular function after allogeneic stem cell transplantation: a case report

One of the most frequent consequences of allogeneic haemopoietic stem cell transplantation (allo-SCT) in both males and females is gonadal insufficiency. We report the case of a 27-year-old myelodysplastic male who developed azoospermia after allogeneic transplantation of haemopoietic stem cells from his HLA-identical sister. Post-transplant azoospermia was alternated with intermittent severe oligospermia. The patient had a normal endocrine pattern and evidence of mild chronic graft-versus-host disease (cGVHD). Normal intratesticular spermatogenesis was revealed by bilateral fine needle aspiration (FNA) cytology. Inflammation was evident at semen analysis, but no infection was detected by microbiological examination and sperm culture. These findings, together with the re-appearance of sperm cells at semen analysis after a low-dose immunosuppressive treatment, suggested the presence of cGVHD of the urogenital tract, causing a reversible obstruction of the spermatic tract and cryptozoospermia. This is the first case report documenting a severe impairment of sperm count because of a reversible obstruction of the seminal tract, likely caused by cGVHD, in a long-term survivor of allo-SCT with normal endocrine pattern. An important practical consequence of this case report is the fact that azoospermia was cured using low-dose immunosuppressive therapy, and this allowed us to avoid expensive stimulatory treatments with gonadotrophins, which remain, however, ineffective if the obstruction of spermatic tracts is not removed. A spontaneous uncomplicated pregnancy occurred in the partner of the patient 3 months after the corticosteroid treatment withdrawal.

Effects of various antireabsorptive treatments on bone mineral density in hypogonadal young women after allogeneic stem cell transplantation

Ovarian failure after allogeneic stem cell transplant (allo-SCT) is an important risk factor for development of osteoporosis. We investigated the effects of various antiresorptive treatments in long-term surviving females with ovarian failure after allo-SCT. A total of 60 women with osteoporosis or osteopenia were divided randomly into four groups of 15 women each. Group 1 was treated with calcium and vitamin D alone, group 2 received the same treatment in combination with hormone replacement therapy (HRT), group 3 received risedronate (35 mg weekly, orally for 1 year) and group 4 zoledronic acid (3 monthly doses of 4 mg (intravenous)). All groups were similar for age, body mass index, underlying disease and time elapsed from transplant. Lumbar and femoral bone mineral density (BMD) were measured at baseline and after 12 months, together with serum osteocalcin and urinary hydroxyproline. At 12 months, a significant decrease in lumbar and femoral BMD was observed in group 1 and a milder decrease in group 2. Risedronate treatment increased significantly lumbar BMD and prevented bone loss at the femoral neck. Zoledronic acid increased significantly both lumbar and femoral BMD. In groups 3 and 4 the hydroxyproline excretion was significantly reduced, while osteocalcin mildly increased only in group 4. In conclusion, bisphosphonate administration is useful to prevent and treat bone demineralization in young adult women after allo-SCT.

Allogeneic bone marrow transplantation restores IGF-I production and linear growth in a gamma-SCID patient with abnormal growth hormone receptor signaling

Severe combined immunodeficiency (SCID) is a heterogeneous group of disorders characterized by a severe defect of both T- and B-cell immunity, which generally require allogeneic bone marrow transplantation (BMT) within the first years of life. We previously reported a patient affected with an X-linked SCID due to L183S hemizygous missense gamma chain mutation, whose severe short stature was due to a peripheral growth hormone (GH) hyporesponsiveness associated to abnormal GH receptor (GH-R) signal transduction. In this study, we report the effect of BMT on the GH-R/insulin-like growth factor I (IGF-I) axis. After BMT, the patient showed a significant improvement in linear growth and normalization of basal- and GH-stimulated IGF-I values, which paralleled a fully competent immunological reconstitution. This suggests that cells derived from the hematopoietic stem cell may exert an unexpectedly significant role in producing IGF-I. This may also suggest that stem cell-based therapies may be useful for the correction of non-hematopoietic inherited disorders, such as those of GH-R/IGF-I axis.

Beneficial treatment with risedronate in long-term survivors after allogeneic stem cell transplantation for hematological malignancies

In this prospective randomized study we evaluated the effect of risedronate, an aminobisphosphonate, on bone mass and turnover in patients who had undergone allogeneic stem cell transplant (SCT) for hematological malignancies. Thirty-four patients (18 females, 16 males, age 32+/-10 years) with bone mineral density (BMD) </=-1.5 SD as a T-score at least 6 months after SCT were treated with calcium 1 g/day and vitamin D 800 IU/day and randomized to receive ( n=17, group 1) or not receive ( n=17, group 2) oral risedronate 5 mg/day. The duration of treatment was 12 months. After 6 months, lumbar BMD increased by 4.4+/-1.6% in patients of group 1 and decreased by 4.3+/-1.5% in those of group 2 ( P<0.05); at the femoral neck, BMD did not change significantly in patients of group 1 (+1.2+/-1.2%), while it decreased in those of group 2 (-4.3+/-2.1%; P<0.05). After 12 months, lumbar BMD further increased (+5.9+/-1.7%, P<0.05), compared to baseline in group 1 and slightly increased (+1.1+/-1.4%) in group 2. No further changes were observed at femoral neck in both groups. In conclusion, treatment with risedronate for 12 months increased BMD significantly at the lumbar spine and prevented further bone loss at the femoral neck in long-term survivors after allo-SCT.

Extramedullary involvement at relapse in acute promyelocytic leukemia patients treated or not with all-trans retinoic acid: a report by the Gruppo Italiano Malattie Ematologiche dell'Adulto

PURPOSE

Recent reports of extramedullary disease (EMD) at recurrence in acute promyelocytic leukemia (APL) have raised increasing concern about a possible role of retinoic acid (RA) therapy.

PATIENTS AND METHODS

We analyzed the risk of developing EMD localization at relapse in APL patients enrolled onto two consecutive studies of the Gruppo Italiano Malattie Ematologiche dell'Adulto. The studies investigated chemotherapy alone (LAP0389) versus RA plus chemotherapy (AIDA).

RESULTS

When all relapse types were taken into account, 94 (51%) of 184 patients and 131 (18%) of 740 patients who attained hematologic remission underwent relapse in the LAP0389 and AIDA studies, respectively (P < .0001). EMD localization was documented in five (5%) of 94 and 16 (12%) of 131 patients (P = .08). Hematologic and/or molecular relapse was diagnosed concomitantly in all but two patients with EMD in the AIDA study. For patients in the LAP0389 and AIDA series, the probability of EMD localization of any type at relapse was 3% and 4.5%, respectively (P = .79), while the probability of CNS involvement was 0.6% and 2% (P = .28). No significant differences were found with regard to mean WBC count and promyelocytic leukemia/retinoic acid receptor-alpha junction type in comparisons of patients with EMD and hematologic relapse.

CONCLUSION

APL patients receiving all-trans retinoic acid in addition to chemotherapy have no increased risk of developing EMD at relapse as compared with those treated with chemotherapy alone.

Sustained long-term hematologic recovery despite a marked quantitative defect in the stem cell compartment of patients with aplastic anemia after immunosuppressive therapy

Previously, we reported that patients with aplastic anemia (AA) have profoundly decreased numbers of hematopoietic progenitor and stem cells as measured in the long-term culture initiating cell (LTC-IC) assay (Blood 1996;88:1983-1991). We now present results of a long-term prospective study of LTC-IC numbers in peripheral blood (PB) and bone marrow (BM) of patients treated with antithymocyte globulin and cyclosporin A. Numbers of secondary colony forming cells (secondary CFC) in long-term bone marrow culture (LTBMC) were used to quantitate LTC-IC. BM (N = 35) and PB (N = 41) secondary CFC from both untreated severe AA patients and responders to immunosuppressive therapy who were sampled up to 6 years after initial treatment were compared. Normal controls showed 148 +/- 38 (N = 17) and 16 +/- 3 (N= 14) secondary CFC per 10(6) in BM and PB, respectively. In cross-sectional analysis, prior to therapy, AA patients showed 2.6 +/- 1 (mean +/- SD) secondary CFC/10(6) BM MNC; within the first year after initial treatment (N = 14), secondary CFC number rose modestly to 8.2 +/- 2.2/10(6) MNC, and further increased to 15.8 +/- 7 (N = 17) at 2 years and 16.2 +/- 7/10(6) MNC (N = 25) 3 years after treatment. There was no further improvement in the secondary CFC numbers at 4, 5, and > or =6 years (N = 37). Thus, while BM secondary CFC increased about 6-fold at 3 years post-therapy compared to presentation, they remained about only 10% of normal despite hematologic recovery. Similar data were obtained for PB, with approximately 4-fold increase in secondary CFC numbers within 2 years of therapy, to about 15% of normal values. We confirmed these observations in patients studied serially over a period of 4 years: initial secondary CFC were 2.35 +/- 1/10(6) BM MNC and 0.11 +/- 0.1/10(6) PB MNC improving to an average of 6 +/- 1. 2 (BM; N = 12) and 2.4 +/- 1/10(6) MNC (PB; N = 14). In many cases of partial recovery, PB counts improve but do not normalize. When we studied secondary CFC numbers only in patients who achieved complete normalization of PB counts (ANC >1,500/mm(3); platelets >10(5)/mm(3) and absolute reticulocytes >5 x 10(4)/mm(3)), BM secondary CFC were significantly higher than in patients with partial recovery; the PB secondary CFC number was modestly increased but remained below the normal values. Within the group of patients with complete recovery, there was no correlation between the secondary CFC and time after initial treatment. In addition, there also was no correlation between the secondary CFC number at presentation and the quality of hematopoietic recovery. Despite a limited expansion potential of a severely reduced stem cell pool, their numbers are sufficient to provide a long-term supply of mature blood cells. Am. J. Hematol. 65:123-131, 2000. Published 2000 Wiley-Liss, Inc.

Sustained long-term hematologic recovery despite a marked quantitative defect in the stem cell compartment of patients with aplastic anemia after immunosuppressive therapy

Previously, we reported that patients with aplastic anemia (AA) have profoundly decreased numbers of hematopoietic progenitor and stem cells as measured in the long-term culture initiating cell (LTC-IC) assay (Blood 1996;88:1983-1991). We now present results of a long-term prospective study of LTC-IC numbers in peripheral blood (PB) and bone marrow (BM) of patients treated with antithymocyte globulin and cyclosporin A. Numbers of secondary colony forming cells (secondary CFC) in long-term bone marrow culture (LTBMC) were used to quantitate LTC-IC. BM (N = 35) and PB (N = 41) secondary CFC from both untreated severe AA patients and responders to immunosuppressive therapy who were sampled up to 6 years after initial treatment were compared. Normal controls showed 148 +/- 38 (N = 17) and 16 +/- 3 (N= 14) secondary CFC per 10(6) in BM and PB, respectively. In cross-sectional analysis, prior to therapy, AA patients showed 2.6 +/- 1 (mean +/- SD) secondary CFC/10(6) BM MNC; within the first year after initial treatment (N = 14), secondary CFC number rose modestly to 8.2 +/- 2.2/10(6) MNC, and further increased to 15.8 +/- 7 (N = 17) at 2 years and 16.2 +/- 7/10(6) MNC (N = 25) 3 years after treatment. There was no further improvement in the secondary CFC numbers at 4, 5, and > or =6 years (N = 37). Thus, while BM secondary CFC increased about 6-fold at 3 years post-therapy compared to presentation, they remained about only 10% of normal despite hematologic recovery. Similar data were obtained for PB, with approximately 4-fold increase in secondary CFC numbers within 2 years of therapy, to about 15% of normal values. We confirmed these observations in patients studied serially over a period of 4 years: initial secondary CFC were 2.35 +/- 1/10(6) BM MNC and 0.11 +/- 0.1/10(6) PB MNC improving to an average of 6 +/- 1. 2 (BM; N = 12) and 2.4 +/- 1/10(6) MNC (PB; N = 14). In many cases of partial recovery, PB counts improve but do not normalize. When we studied secondary CFC numbers only in patients who achieved complete normalization of PB counts (ANC >1,500/mm(3); platelets >10(5)/mm(3) and absolute reticulocytes >5 x 10(4)/mm(3)), BM secondary CFC were significantly higher than in patients with partial recovery; the PB secondary CFC number was modestly increased but remained below the normal values. Within the group of patients with complete recovery, there was no correlation between the secondary CFC and time after initial treatment. In addition, there also was no correlation between the secondary CFC number at presentation and the quality of hematopoietic recovery. Despite a limited expansion potential of a severely reduced stem cell pool, their numbers are sufficient to provide a long-term supply of mature blood cells. Am. J. Hematol. 65:123-131, 2000. Published 2000 Wiley-Liss, Inc.

The role of FAS-mediated apoptosis in chronic myelogenous leukemia

Clinical observation and laboratory evidence suggest that immune mechanisms play an important role in the natural control of evolution of the Ph+ clone in chronic phase as well as during progression of chronic myelogenous leukemia (CML). The understanding of these mechanisms could facilitate development of innovative therapeutic approaches. Due to bcr-abl translocation, CML cells carry an intrinsic resistance to apoptotic signals. However, resistance to apoptosis is not absolute and can be overcome through enhancement of immune-mediated pathways, e.g., during graft vs. leukemia reaction after allogeneic bone marrow transplantation, or during interferon-alpha (IFN-alpha) therapy. Among the effector mechanisms, T-lymphocyte-mediated killing of target cells via Fas-receptor (Fas-R) triggering plays an important role in the elimination of malignant cells, including CML cells. Although CML Ph+ progenitor cells express Fas-R, the expression levels are variable and do not correlate with clinical parameters. In addition, CML progenitor cells also express functional Fas-ligand (Fas-L), which may be an important immune surveillance escape factor. IFN-alpha can greatly upmodulate Fas-R expression, an effect that seems to be more pronounced in CML compared to normal cells, while Fas-L expression levels are not affected by IFN-alpha, thereby improving their susceptibility to elimination by the immune system. Responsiveness to Fas-induced apoptosis following stimulation with IFN-alpha correlates with the clinical effects of IFN-alpha therapy. This effect seems to be associated with decreased bcr-abl protein levels, which are influenced by Fas via posttranscriptional modulation. In comparison to the chronic phase, CML cells derived from patients in blast crisis are refractory to Fas-mediated apoptosis, regardless of the expression levels of Fas, suggesting that an immune-mediated selection pressure could result in acquisition of Fas-resistance. In the future, enhancement of immunological recognition and elimination of CML cells may prove to be an effective therapeutic approach directed towards the cure of CML.

Prolonged response to cyclosporin-A in hypoplastic refractory anemia and correlation with in vitro studies

BACKGROUND AND OBJECTIVE

Lymphocyte abnormalities in myelodysplastic syndromes (MDS) have been widely described, but the role of the immune system in the pathogenesis of these clonal disorders remains controversial. An active role of lymphocytes in suppressing normal hematopoiesis may be implicated in MDS with hypoplastic marrow. We have studied in vitro and in vivo activity of cyclosporin-A (CSA) on hematopoiesis in patients affected by hypoplastic MDS without blast excess.

DESIGN AND METHODS

Nine consecutive patients with hypoplastic refractory anemia (RA), followed up in our out-patient unit, were treated with CSA at daily doses of 1-3 mg/kg for at least three months. Low dose steroids or danazol were transiently added in 7/9 patients. Differences between pre- and post-treatment parameters were studied by the Student's t-test. In vitro effect of CSA on circulating hematopoietic progenitors was studied by the methylcellulose colony assay.

RESULTS

Before treatment, fewer circulating hematopoietic progenitors were found in all patients as compared to normal subjects. The number of CD34+ cells was about halved, while circulating erythroid and myeloid colony-forming cells (CFC) were reduced to one-fifth. After a mean period of 22 months of CSA treatment (median: 14.5 months), hemoglobin was significantly and persistently increased in two patients, platelets in one, platelets and hemoglobin in two. Two patients showed transient responses, one patient did not tolerate the treatment and one patient is close to a significant response. At in vitro CSA concentrations similar to those achieved in vivo after oral administration the drug significantly increased cell colony growth in hypoplastic RA. This test correctly predicted a positive clinical response to CSA in 3/5 cases and treatment failure in 4/4 cases.

INTERPRETATION AND CONCLUSIONS

About one half of hypoplastic RA patients benefited from CSA treatment. A larger study could verify whether in vitro culture of hematopoietic progenitors in the presence of CSA can predict the clinical response and whether this treatment could prolong patients' survival.

Therapy of molecular relapse in acute promyelocytic leukemia

Fourteen patients with PML/RARalpha-positive acute promyelocytic leukemia (APL) were given salvage therapy at the time of first molecular relapse. All patients had achieved first molecular remission after the AIDA protocol (all-trans retinoic acid [ATRA] + idarubicin) and were being prospectively monitored by reverse transcriptase-polymerase chain reaction (RT-PCR). Molecular relapse was defined as reappearance of RT-PCR-positivity for the PML/RARalpha fusion (sensitivity 10(-4)) in 2 successive marrow samples collected during postconsolidation monitoring. The median duration of first molecular remission was 7.5 months (range, 2 to 25). Salvage therapy consisted of oral ATRA for 30 days followed by 4 daily courses of chemotherapy (CHT) with cytarabine 1 g/m(2)/d and mitoxantrone 6 mg/m(2)/d. Second molecular remission was obtained in 12 of 14 patients (86%). Seven of these 12 attained molecular remission after ATRA alone. Of the 2 patients who persisted PCR(+) after CHT, 1 died in remission and 1 progressed to hematologic relapse. Of 12 patients PCR(-), 8 received consolidation with autologous bone marrow transplantation (ABMT), and 4 received ATRA-containing maintenance. Ten patients in this group are in sustained second molecular remission at a median time of 9.5+ months (range, 4 to 22+) and 2 underwent hematologic relapse 6 and 13 months, respectively, after transient second molecular remission. The 2-year Kaplan and Meier survival estimate from time of relapse was 92% (95% confidence interval [CI]: 61% to 98%) in this series, and 44% (95% CI: 35% to 52%) in a previous series of 37 patients who received the same treatment at the time of hematologic recurrence (P <.05, by log-rank test). This study suggests that early administration of salvage therapy is advantageous in APL and represents the first experience on therapy of molecular relapse in acute leukemia.

BCR/ABL mRNA and the P210(BCR/ABL) protein are downmodulated by interferon-alpha in chronic myeloid leukemia patients

The BCR/ABL hybrid gene plays a central role in the pathogenesis of the chronic phase of chronic myeloid leukemia (CML). We used a very sensitive quantitative reverse transcriptase-polymerase chain reaction to investigate the levels of hybrid BCR/ABL mRNA in bone marrow cells of 20 patients with Philadelphia positive (Ph(+)) CML treated with interferon-alpha (IFN-alpha) as a single agent. Bone marrow samples were collected at diagnosis and at hematologic remission induced by IFN-alpha, or by hydroxyurea in case of resistance to IFN-alpha. The mean levels of BCR/ABL transcripts in bone marrow mononuclear cells of patients who showed a complete hematologic response to IFN-alpha were significantly reduced with respect to those at diagnosis (48 x 10(3) v 168 x 10(3); P <.001), whereas no difference was detected between the values at diagnosis and at hematologic remission in patients resistant to IFN-alpha. In cell culture experiments, IFN-alpha priming significantly reduced the levels of BCR/ABL hybrid transcripts in a dose-dependent manner in Ph+ bone marrow precursors obtained at diagnosis from patients who subsequently responded to IFN-alpha treatment (P < .005). No downmodulation was observed in bone marrow precursors from patients who subsequently proved to be IFN-resistant. These results indicate that downmodulation of BCR/ABL gene expression could be one of the mechanisms involved in the response of CML patients to IFN-alpha treatment.

Interferon-alpha induces apoptosis in human KB cells through a stress-dependent mitogen activated protein kinase pathway that is antagonized by epidermal growth factor

We have demonstrated that interferon-alpha2-recombinant (IFNalpha) at growth inhibitory concentrations enhances the expression and signalling activity of the epidermal growth factor receptor (EGF-R) in human epidermoid carcinoma KB cells. Here we report that KB cells exposed to IFNalpha underwent apoptotic cell death and this effect was antagonized by EGF. We have also found that IFNalpha enhanced the expression of heat shock proteins (HSP) HSP-70, HSP-90 and HSP-27 and activated the NH2-terminal Jun kinase-1 (JNK-1) and p38 mitogen activated protein kinase, the target enzymes of a stress-dependent intracellular transduction pathway. Moreover, the overexpression of the wild-type JNK-1, obtained through plasmid transfection of KB cells, induced apoptosis which was potentiated by the exposure of wild-type JNK-1 (JNK-1wt)-transfected cells to IFNalpha. All these effects were neutralized by the addition of EGF to parental and JNK-1wt-transfected KB cells exposed to IFNalpha. In conclusion, EGF has a protective effect on KB cells from apoptosis while antagonizing a stress response elicited by IFNalpha and targeted on the stress pathway terminal kinases.

Spleen sizing by ultrasound scan and risk of pneumococcal infection in patients with chronic GVHD: preliminary observations

Encapsulated bacteria infections (EBI) can cause severe complications after BMT, usually occurring in patients with chronic GVHD (cGVHD) and attributed to functional hyposplenism. Using ultrasound (US) scan, we measured spleen size in 22 patients transplanted from HLA identical siblings, with or without cGVHD. No patient had received TBI, spleen irradiation or penicillin prophylaxis. Results were correlated with occurrence of EBI during a mean follow-up of 55 months (range 7-93). In the group without cGVHD, the difference between pre- and post-BMT spleen longitudinal diameters was not significant, and no patient developed EBI. In the cGVHD group, post-BMT spleen longitudinal diameters were significantly smaller than those pre-BMT (9.1+/-1.6 vs. 12.3+/-2.2; P = 0.0005). Out of four patients with cGVHD who showed a major spleen size reduction, two developed a severe infection (an overwhelming sepsis and a pneumococcal meningitis). In our small series, we found a borderline relationship between spleen size reduction and duration of cGVHD (P = 0.06), as well as an increased risk of life-threatening infection in patients with extensive cGVHD and hyposplenism as detected by US scan. We conclude that US scan may be useful to detect spleen size reduction following allogeneic BMT and that penicillin prophylaxis is to be strongly recommended in patients with extensive cGVHD and spleen size reduction, even in those who have not received total body or spleen irradiation.

Expression of the 67-kDa laminin receptor in acute myeloid leukemia cells mediates adhesion to laminin and is frequently associated with monocytic differentiation

Lodgement, proliferation, and migration of leukemic cells within bone marrow (BM) microenvironment involves adhesion of these cells to the BM extracellular matrix molecules fibronectin and laminin. The 67-kDa laminin receptor (67LR) is a nonintegrin protein with high affinity for laminin, which plays a critical role in basement membrane invasion and metastasis of cancer cells. By Western blotting, we documented that 67LR was strongly expressed in myelomonocytic THP1 and histiocytic U937 cells and was weakly expressed in promyelocytic HL-60 cells. In HL-60 cells, 67LR expression almost disappeared after retinoic-induced granulocytic differentiation, whereas it strongly increased after phorbol ester-induced monocytic differentiation. We did not detect 67LR expression in normal BM hematopoietic cells, in precursor-B acute lymphoblastic leukemia, in chronic lymphocytic leukemia, or in chronic myeloid leukemia in chronic phase. By contrast, we detected enhanced 67LR expression in 40% of 53 de novo acute myeloid leukemias (AMLs), which frequently exhibited monocytic or myelomonocytic morphology and expressed CD14 and CD11a (P < 0.05). Using a colorimetric assay, we found that the expression pattern of this receptor corresponded to a higher adhesion to laminin; the adhesion was specific because in vitro addition to laminin-coated wells of recombinant 37-kDa laminin receptor precursor (37LRP), which is the cytoplasmic precursor containing both laminin-binding domains of cell surface 67LR, significantly reduced laminin binding of AML cells. The expression of 67LR on AML cell surface did not correlate with other differentiation and integrin antigens such as CD7, CD13, CD33, CD34, CD11b, CD11c, CD49d, CD49e, CD45RA, and CD45RO. In contrast with 67LR behavior in solid tumors, no statistically significant difference was found between 67LR expression and any hematological characteristic of the disease at diagnosis, nor between 67LR expression and outcome of the disease as measured by complete remission rate, disease-free survival, or overall survival. In conclusion, our results indicate that 67LR expression mediates specific adhesion to laminin and that the detection of this molecule may be a valuable addition to other lineage-associated antigens in identifying monocytic-oriented AML.

Long-lasting decrease of marrow and circulating long-term culture initiating cells after allogeneic bone marrow transplant

We investigated bone marrow (BM) and circulating (PB) hematopoietic progenitor cells in 37 normal donors and in 25 patients 1 to 8 years after successful allogeneic bone marrow transplant. At the time of testing, transplanted patients had normal blood counts and bone marrow cellularity. By flow cytometry, BM CD34+ cells were found to be three- to four-fold decreased in transplanted patients compared to normal donors, while the number of PB CD34+ cells was the same as in normal donors. Using a methylcellulose colony assay, primary BM colony-forming cells (CFU-GM) were decreased 2.1-fold, whereas PB CFU-GM were only marginally decreased. In a long-term culture initiating cell (LTC-IC) assay, an eight-fold decrease of early progenitor cells was observed in the marrow of transplanted patients compared to normal donors, and a five-fold decrease was documented in peripheral blood. We found that the BM LTC-IC cell number correlated with concurrently determined BM CD34+ cells and committed progenitor cell number (measured as CFU-GM) and with PB LTC-IC number, but not with PB CFU-GM and CD34+ cells. We conclude that marrow and circulating early stem cell compartments, as measured by the LTC-IC assay, are greatly and permanently depressed following bone marrow transplant. The correlation between BM and PB LTC-IC indicates that the enumeration of circulating LTC-IC can be used as a measure of the stem cell compartment in the bone marrow after transplant. It seems that the deficiency of the most immature progenitor cells persists forever after successful bone marrow transplant; this means that a complete hematopoietic reconstitution can be sustained by a reduced stem cell pool.

Early detection by ultrasound scan of severe post-chemotherapy gut complications in patients with acute leukemia

BACKGROUND AND OBJECTIVE

Acute leukemia patients may develop life-threatening gut complications after intensive chemotherapy. We evaluated the role of abdominal and pelvic ultrasound (US) examination in early detection of these complications.

DESIGN AND METHODS

A cohort of twenty adult acute leukemia patients undergoing intensive chemotherapy for remission induction entered the study. All chemotherapy regimens included cytarabine by continuous i.v. infusion for several days.

RESULTS

Three patients had severe gut complications: 2 cases of enterocolitis and 1 case of gall bladder overdistension in the absence of calculi. In all cases the abnormality was documented by US examination: US scan showed thickening of the intestinal wall (two cases), and gall bladder overdistension with biliary sludge (one case). Immediate medical care included bowel rest, a broad-spectrum antibiotic, antimycotic treatment, and granulocyte colony-stimulating factor. All patients recovered from the complication.

INTERPRETATION AND CONCLUSIONS

We believe that the favorable outcome obtained in our small series can be attributed to early diagnosis followed by appropriate treatment. Early recognition by US and immediate medical management can lead to complete recovery of severe intestinal complications in patients with acute leukemia undergoing intensive chemotherapy.

Fanconi's anemia cells are relatively resistant to H2O2-induced damage

BACKGROUND AND OBJECTIVE

Fanconi's anemia (FA) is a rare autosomal recessive syndrome characterized by skeletal abnormalities, late onset bone marrow failure and susceptibility to neoplasias. Reduced defense against oxidative stress is thought to be one of the cell damaging mechanisms. We investigated in vitro the effects of oxidative stress on red blood cells (RBC) and on hematopoietic progenitor growth of normal donors and of FA patients.

DESIGN AND METHODS

The effects of hydrogen peroxide (H2O2) on RBC and hematopoietic progenitors were studied in vitro by erythrophagocytosis assay and by hematopoietic progenitor colony assay, respectively.

RESULTS

In an erythrophagocytosis assay using normal monocytes, RBC from nine FA patients showed increased binding index (defined as the percentage of monocytes with adherent or phagocytosed RBC) compared to that obtained with RBC from nine normal controls. Upon exposure to H2O2, the binding index of normal RBC increased, while that of FA RBC remained unchanged. In a set of different experiments, H2O2 treatment of peripheral blood mononuclear cells (PBMNC) caused a significant decrease of the number of colonies from circulating progenitor cells in all normal subjects; the inhibition was dose-dependent and direct as proven by using normal purified CD34+ cells. In nine FA patients colony assays from intact cells showed a decreased number of circulating progenitors as compared to normal subjects; however, H2O2 treatment of FA PBMNC did not cause any further decrease of the plating efficiency.

INTERPRETATION AND CONCLUSIONS

Untreated FA cells behave as normal cells after exposure to the toxic effects of H2O2. However, since H2O2 exposure is inoffensive to circulating FA RBC and hematopoietic progenitors, it seems that a selection for cells resistant to further oxidative stress has taken place in the residual hematopoiesis of FA patients. We may surmise that the survival of cells that have suffered from oxidative damage may have increased the risk of their leukemic transformation.