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Biomedical subjects

M Federico

Publications and source records attributed to M Federico.

At least 37 records · Page 2Linked to original sources

Usefulness of breast MRI in a patient with genetic risk.

We describe an interesting case-report represented by a patient carrying BRCA1 mutation, recruited for the study "Multicenter evaluation of Magnetic Resonance Imaging (MRI) in early diagnosis and prevention of breast cancer in high risk population", diagnosed with breast cancer on the basis of MRI findings but not with conventional mammography and ultrasound (US). She was already affected at 53 years of age by a multifocal Ductal Infiltrating Carcinoma (DIC) in the left breast; then, she had an axillary and sovraclavear nodal recurrence of the disease, three years after the initial diagnosis. Since other relatives were affected by breast cancer (mother, sister and niece) and two arose at early age (< 40 years), BRCA1 mutational analysis was offered to the patient, identifying a nonsense mutation on the exon 13. Furthermore, this patient was recruited to study contralateral breast and at the second round, two little foci, suspicious of malignancy, were identified only with MRI, but not with mammography and ultrasonography. The final diagnosis was multifocal Ductal Carcinoma in situ (DCIS); the major focus measured 3 mm. In our patient MRI has shown a major sensitivity with respect to conventional radiology and US and has provided a very early diagnosis in this woman at genetic risk.

Biopsy, Needle↗

HIV-1 Nef activates STAT1 in human monocytes/macrophages through the release of soluble factors.

Monocytes/macrophages play a predominant role in the immunologic network by secreting and reacting to a wide range of soluble factors. Human immunodeficiency virus (HIV) infection leads to deep immunologic dysfunctions, also as a consequence of alterations in the pattern of cytokine release. Recent studies on in vivo models demonstrated that the expression of HIV Nef alone mimics many pathogenetic effects of HIV infection. In particular, Nef expression in monocytes/macrophages has been correlated with remarkable modifications in the pattern of secreted soluble factors, suggesting that the interaction of Nef with monocytes/macrophages plays a role in the pathogenesis of acquired immunodeficiency syndrome (AIDS). This study sought to define possible alterations in intracellular signaling induced by Nef in monocytes/macrophages. Results demonstrate that HIV-1 Nef specifically activates both alpha and beta isoforms of the signal transducer and activator of transcription 1 (STAT1). This was observed both by infecting human monocyte-derived macrophages (MDMs) with HIV-1 deletion mutants, and by exploiting the ability of MDMs to internalize soluble, recombinant Nef protein (rNef). STAT1-alpha activation occurs on phosphorylation of both C-terminal Tyr701 and Ser727 and leads to a strong binding activity. Nef-dependent STAT1 activation is followed by increased expression of both STAT1 and interferon regulatory factor-1, a transcription factor transcriptionally regulated by STAT1 activation. It was also established that Nef-induced STAT1- alpha/beta activation occurs through the secretion of soluble factors. Taken together, the results indicate that HIV-1 Nef could interfere with STAT1-governed intracellular signaling in human monocytes/macrophages.

Acquired Immunodeficiency Syndrome↗

Comparison of prognostic models in patients with advanced Hodgkin disease. Promising results from integration of the best three systems.

BACKGROUND: Several prognostic systems have been elaborated for patients with Hodgkin disease (HD) over the last 12 years, but early identification of a reasonably large group of both low and high risk, advanced stage patients remains unsatisfactory. METHODS: Seven well known models were applied to 516 patients with advanced HD, with 315 patients used for the study sample and 201 patients used for the test sample. Individual performances as well as joint performances were analyzed univariately and multivariately in relation to overall survival, recurrence free survival, and time to treatment failure by means of a proportional hazards model. RESULTS: None of the models identified a group containing > 10% of patients from the total population who had a failure risk of either < or = 10% or > or = 50%. The systems of the International Database on Hodgkin Disease, the Memorial Sloan-Kettering Cancer Center, and the International Prognostic Factor Project showed the best prognostic power; only these three, when analyzed together, predicted clinical outcome with a statistically significant fit to the clinical data. Integration of the three systems in a linear model dramatically improved their individual discriminatory capacity by identifying patients with 10% and 50% failure risks, respectively, in 23% and 24% of the study patient population and in 19% and 25% of the test population, respectively. CONCLUSIONS: As powerful and simple new prognostic factors are awaited that may improve our predictive ability, this integrated index is probably the best way to exploit the significance of those presently available. The program required for the calculations can be downloaded from the Internet at the web site http://www.unimo.it/gisl/default.htm.

Adolescent↗

Treatment of B-cell non-Hodgkin's lymphoma with anti CD 20 monoclonal antibody Rituximab.

Rituximab is a chimeric anti CD-20 monoclonal antibody containing human IgG1 kappa constant regions, with murine variable regions. The anti-lymphoma effects of Rituximab are probably due to complement and antibody-dependent cell-mediated cytotoxicity, and induction of apoptosis. Phase II trials have demonstrated a strong activity of rituximab alone in indolent B non-Hodgkin lymphoma, especially in patients with follicular lymphoma. The most utilized dose-schedule is 375 mg/m(2) weekly x 4. The association with chemotherapy or with interferon-alpha increases Rituximab efficacy. More recently, Rituximab have showed activity also in diffuse large cell lymphoma, mantle cell lymphoma and in other B-malignancies. Good results have also been obtained utilizing Rituximab for in vivo purging. However, we are still far from having found a definite position for Rituximab in the treatment of lymphoproliferative disorders. The aim of future studies should be to develop new strategies that will hopefully produce the most effective Rituximab-based regimens in order to find the Rituximab key position in the treatment of B-malignancies

Antibodies, Monoclonal↗

Nef from human immunodeficiency virus type 1(F12) inhibits viral production and infectivity.

Human immunodeficiency virus type 1(F12) (HIV-1(F12)) interferes with the replication of other strains of HIV. Its accessory protein, Nef, is sufficient for this phenotype, where the production and infectivity of HIV are impaired significantly. The analysis of three rare mutations in this Nef protein revealed that these effects could be separated genetically. Moreover, the defect in virus production correlated with the lack of processing of the p55(Gag) precursor in the presence of Nef from HIV-1(F12). Importantly, the introduction of one of these mutations (E177G) into Nef from HIV-1(NL4-3) also created a dominant-negative Nef protein. Effects of Nef from HIV-1(F12) on virus production and Gag processing correlated with its altered subcellular distribution. Moreover, the association with two new cellular proteins with molecular masses of 74 and 75 kDa, which do not interact with other Nef proteins, correlated with the decreased virion infectivity. The identification of a dominant-negative protein for the production and infectivity of HIV suggests that Nef plays an active role at this stage of the viral replicative cycle.

CD8 Antigens↗

Risk-assessment in diffuse large cell lymphoma at first relapse. A study by the Italian Intergroup for Lymphomas.

BACKGROUND AND OBJECTIVES: Our aim was to identify risk factors in adults with diffuse large cell lymphoma at first relapse. DESIGN AND METHODS: We studied 474 patients observed at 45 centers in Italy. Median time from diagnosis to relapse was 395 days, median age at relapse was 55 years and median follow-up from relapse was 3.3 years. Salvage therapy consisted of polychemotherapy in 79% of patients, monochemotherapy and/or radiotherapy and/or surgery alone in 16%, and palliative therapy in 5%. Salvage treatment was intensified with high-dose chemotherapy + stem cell transplant in 20% of patients. OS and PFS were compared by sex, International Prognostic Index at diagnosis, histology, B/T phenotype, initial treatment, salvage therapy, and features at relapse: time from diagnosis, LDH, stage, performance status and bone marrow involvement. Cox models, adjusted for salvage therapy, were performed with factors related to overall survival (OS) and progression-free survival (PFS). RESULTS: Overall response (complete + partial) was 63%, OS at 3 years 35% and PFS at 3 years 26%. Relapse within 12 months from diagnosis, elevated serum lactic dehydrogenase (LDH), advanced stage and poor performance status were independent adverse factors for OS and PFS. The cumulative number of adverse factors is proposed as prognostic index for DLCL at first relapse since it identifies risk groups (p<0.0001) and has been validated (p=0.01). Moreover, it predicts OS and PFS in the selected group of patients with a responsive relapse (p<0.0001). INTERPRETATION AND CONCLUSION: Delay from initial diagnosis, LDH, stage and performance status at relapse should be balanced in comparative studies of salvage therapy of adults with DLCL. Patients with more than 2 adverse factors are one third of all cases and deserve more effective salvage treatments.

Adult↗

Clinical activity and safety of combination immunotherapy with IFN-alpha 2a and Rituximab in patients with relapsed low grade non-Hodgkin's lymphoma.

BACKGROUND AND OBJECTIVES: To determine the clinical activity and safety of the combination immunotherapy of the chimeric anti-CD20 antibody, Rituximab, and Interferon (IFN)- alpha 2a DESIGN AND METHODS: Sixty-four patients with relapsed low-grade or follicular B-cell non Hodgkin's lymphoma received 4 infusion of Rituximab (375 mg/m(2) x dose) after priming and simultaneous treatment with IFN- alpha 2a. RESULTS: The overall response rate was 70% with 33% complete responses. Median for duration of response is 19 months, after a median follow-up of 22 months. By univariate analysis none of the most common prognostic factors predicted for response to therapy. After treatment 10 patients become bcl-2 negative in the bone marrow, but no correlation between molecular and clinical response was found. Fifty-three patients (83%) had drug related or unknown origin adverse events. The number of adverse events per patient varied from 1 to 21. Considering all 272 events, 231 (85%) were grade 1 or 2, 36 (13%) grade 3 and 5 (2%) grade 4. Twenty-three patients required reduction in the dose and/or short discontinuation of IFN treatment, either during priming or subsequent treatment. The most frequent adverse events were leukopenia, fever, neutropenia, hypotension and thrombocytopenia. INTERPRETATION AND CONCLUSIONS: this report shows that combination immunotherapy Rituximab + IFN- alpha 2a is active and relatively well tolerated. The overall response rate of 70% and the median duration remission of 19 months compare favorable with the results obtained with Rituximab alone in similar subset of patients. Randomized trials, investigating Rituximab versus combination immunotherapy are needed.

Adult↗

Comparability issues of survival data.

This study examines the level of homogeneity in cancer registration and follow up techniques adopted by each registry, in order to ensure a correct evaluation of the data and of the geographical differences observed within Italy. A quality check was performed on the registration techniques, assuring that they met the international standards and yielded correct data, and on follow up methods. Difficulties concerning the assessment of certain tumours emerged from international debates. Thus, registries were requested to fill in a questionnaire to thoroughly examine differences in the management of tumour cases with difficult biological and clinical assessment (e.g. in situ and urinary bladder tumours). Some discrepancies in registration methods were observed. The most significant problems concern urinary bladder tumours, especially in coding procedures of in situ and uncertain behaviour tumours and the proportion of short-term survivors proportions for some geographical areas. Good quality and comparability indices were generally observed (microscopic verification, follow up management). In conclusions, quality standards in cancer registration appear good and allow for a correct geographical comparability. Some important problems regard only a small number of cancer sites (namely urinary bladder), whose results should be examined with caution.

Female↗

Prognosis of follicular lymphoma: a predictive model based on a retrospective analysis of 987 cases. Intergruppo Italiano Linfomi.

Patients (n-987) with a histologically confirmed diagnosis of follicular lymphoma were studied with the aim of developing a prognostic model specifically devised for this type of lymphoma. We collected information on age, sex, Ann Arbor stage, number of extranodal disease sites, bone marrow (BM) involvement, bulky disease, B symptom criteria (fever, night sweats, and weight loss), performance status (PS), serum lactate dehydrogenase (LDH) level, serum albumin level, hemoglobin level, and erythrocyte sedimentation rate (ESR). In the training sample of 429 patients with complete data, multivariate analysis showed that age, sex, number of extranodal sites, B symptoms, serum LDH level, and ESR were factors predictive for overall survival. Using these 6 variables, a prognostic model was devised to identify 3 groups at different risk. The 5- and 10-year survival rate was 90% and 65% for patients at low risk, respectively; 75% and 54% for patients at intermediate risk; and 38% and 11% for those at high risk (log-rank test, 86.62; P <. 0001). The model was also predictive (P =.0001) in the validation sample of 265 patients with complete data only for the 6 variables used in the development of the model and even in the group of 210 patients from the validation sample uniformly treated with doxorubicin-containing regimens (P =.0001). The prognostic model appears to be very useful in identifying patients with follicular lymphoma at low, intermediate, or high risk.

Adult↗

BRCA1 mutations and clinicopathological features in a sample of Italian women with early-onset breast cancer.

Breast cancer in young women is uncommon and often presents with unfavourable biopathological features. Although early age at onset could suggest a genetic susceptibility to cancer, the appropriateness of BRCA1 testing for women with early-onset breast cancer and modest family history (FH) is controversial. 40 Women diagnosed with breast cancer at the age of 35 years or less, unselected for FH, were screened for germ line BRCA1 mutations by automated sequencing of exons 2, 5, 6, 11, 13 and 20. Overall, deleterious mutations were evidenced in 6 (15%) patients. With regard to FH, mutations were detected in 14%, 11% and 29% of women with none, weak and strong FH, respectively. Large tumour size, grade 3, lack of oestrogen receptors and high proliferation rate were significantly more common in mutation carriers (MC). Our data support both the appropriateness of testing young breast cancer patients and the frequency of unfavourable features in BRCA1-related breast cancer. It is hypothesised that BRCA1 mutations partially justify the high rate of aggressive breast cancer in young patients and that combining age and breast cancer phenotype could help to identify probable MC.

Adult↗

cis expression of the F12 human immunodeficiency virus (HIV) Nef allele transforms the highly productive NL4-3 HIV type 1 to a replication-defective strain: involvement of both Env gp41 and CD4 intracytoplasmic tails.

F12 human immunodeficiency virus type 1 (HIV-1) nef is a naturally occurring nef mutant cloned from the provirus of a nonproductive, nondefective, and interfering HIV-1 variant (F12-HIV). We have already shown that cells stably transfected with a vector expressing the F12-HIV nef allele do not downregulate CD4 receptors and, more peculiarly, become resistant to the replication of wild type (wt) HIV. In order to investigate the mechanism of action of such an HIV inhibition, the F12-HIV nef gene was expressed in the context of the NL4-3 HIV-1 infectious molecular clone by replacing the wt nef gene (NL4-3/chi). Through this experimental approach we established the following. First, NL4-3/chi and nef-defective (Deltanef) NL4-3 viral particles behave very similarly in terms of viral entry and HIV protein production during the first replicative cycle. Second, no viral particles were produced from cells infected with NL4-3/chi virions, whatever the multiplicity of infection used. The viral inhibition apparently occurs at level of viral assembling and/or release. Third, this block could not be relieved by in-trans expression of wt nef. Finally, NL4-3/chi reverts to a producer HIV strain when F12-HIV Nef is deprived of its myristoyl residue. Through a CD4 downregulation competition assay, we demonstrated that F12-HIV Nef protein potently inhibits the CD4 downregulation induced by wt Nef. Moreover, we observed a redistribution of CD4 receptors at the cell margin induced by F12-HIV Nef. These observations strongly suggest that F12-HIV Nef maintains the ability to interact with the intracytoplasmic tail of the CD4 receptor molecule. Remarkably, we distinguished the intracytoplasmic tails of Env gp41 and CD4 as, respectively, viral and cellular targets of the F12-HIV Nef-induced viral retention. For the first time, the inhibition of the viral life cycle by means of in-cis expression of a Nef mutant is here reported. Delineation of the F12-HIV Nef mechanism of action may offer additional approaches to interference with the propagation of HIV infection.

Alleles↗

Impairment of human immunodeficiency virus type 1 (HIV-1) entry into Jurkat T cells by constitutive expression of the HIV-1 vpr protein: role of CD4 down-modulation.

Jurkat T-cell clones, stably expressing the human immunodeficiency virus type 1 (HIV-1) Vpr protein, exhibited an impaired susceptibility to HIV-1 infection. A marked down-modulation of surface CD4 receptors was detected in Vpr-expressing clones with respect to control cells. Likewise, a reduced CD4 expression was also observed in parental Jurkat cells infected with wild-type but not with Vpr-mutant HIV-1. Notably, Vpr-expressing clones were fully susceptible to infection with a vesicular stomatitis virus G protein-pseudotyped HIV-1 virus, indicating that a block at the level of viral entry was responsible for the inhibition of viral replication. The effect exerted by Vpr on HIV replication and CD4 expression suggests that this protein can regulate both the establishment of a productive HIV-1 infection and CD4-mediated T-cell functions.

CD4 Antigens↗

Detection of circulating tumor cells by reverse transcriptase polymerase chain reaction of maspin in patients with breast cancer undergoing conventional-dose chemotherapy.

PURPOSE: To establish, in patients with breast cancer subjected to primary conventional chemotherapy and enrolled in a prospective study, the mobilizing effect of therapy on potentially neoplastic cells by means of a reverse transcriptase polymerase chain reaction (RT-PCR) assay for mRNA of maspin, a protein related to the serpin family of protease inhibitors. PATIENTS AND METHODS: Peripheral-blood samples were collected from 30 patients with histologically proven breast cancer before and 4 and 8 days after conventional chemotherapy for three consecutive courses. A total of 216 samples were screened for the presence of maspin mRNA by RT-PCR. RESULTS: Before therapy, all samples but one were negative. After chemotherapy, 11 patients (38%) had positive samples. No difference in the rate of positivity was observed between groups defined according to initial stage, type of chemotherapy, Ki-67-related proliferative activity, or CA 15.3 expression. CONCLUSION: Our results confirm that RT-PCR for maspin mRNA is a sensitive assay for the study of circulating potentially neoplastic mammary cells in patients with breast cancer. Moreover, our findings indicate a marked effect of conventional-dose chemotherapy on the mobilization of these cells in breast tumors. In our series of patients, this phenomenon does not seem to be associated with other known risk factors. Finally, the data suggest, without proving, an association between the presence of circulating maspin positive cells and a higher risk of disease progression. If this association could be confirmed, then the assay could have prognostic significance. However, larger confirmatory studies are necessary.

Adult↗

Comparison between genotype and phenotype identifies a high-risk population carrying BRCA1 mutations.

Hereditary breast carcinomas constitute about 10% of all malignant mammary tumors, but the selection criteria to identify a high-risk population carrying BRCA1 mutations are not yet well-defined. We have collected 51 pedigrees of familial breast cancer, 16 pedigrees of familial breast and ovarian cancer, and 30 cases of early-onset breast cancer (<35 years of age) without any family history of breast cancer. The index cases of the 97 selected families were further subdivided into three groups based on histopathological parameters: group A (n = 19) was characterized by tumor grade III, negative estrogen and progesterone receptors, and high proliferative rate; group B (n = 20) was characterized by grade I-II tumors, positive hormonal receptors, and low proliferative rate; and group C (n = 58) was not homogeneous for the histopathological criteria. The aim of our study was to evaluate, in patients with a family history of breast cancer or with early diagnosis of breast cancer, the incidence of BRCA1 mutation on the basis of tumor phenotype. We found the highest rate of BRCA1 mutations in group A (53%), and low frequencies in groups B (5%) and C (0%). Our data strongly indicate that an aggressive tumor phenotype in patients with a positive family history or early diagnosis identifies a population with high probability of carrying BRCA1 mutations. Genes Chromosomes Cancer 27:130-135, 2000.

Adult↗

Validation of the international prognostic index in working formulation group A low-grade non-Hodgkin's lymphoma: retrospective analysis of 137 patients from the Gruppo Italiano per lo Studio dei Linfomi registry.

BACKGROUND AND OBJECTIVE: The subset of non-follicular non-Hodgkin's lymphoma (NHL) includes patients with varied prognoses, thus suitable for different therapeutic approaches. The International Prognostic Index (IPI), originally proposed for aggressive NHL, has been demonstrated to be of prognostic relevance also in follicular NHL. The main aim of the study was to validate the IPI in this histologic category; in addition, the specific prognostic classification, currently employed in the Gruppo Italiano per lo Studio dei Linfomi (GISL) prospective therapeutic trials and based on different features, more similar to those applied to chronic lymphocytic leukemia, was analyzed. DESIGN AND METHODS: The present series consists of 137 evaluable patients affected by Working Formulation group A NHL out of 256 cases referred to the GISL Registry. The retrospective prognostic study included the evaluation by both univariate and multivariate analyses of overall survival, response to therapy and response duration. The IPI was applied as originally proposed. The GISL definition of indolent and aggressive disease at diagnosis was based on the presence of B symptoms, bulky disease, anemia and thrombocytopenia. RESULTS: The distribution of patients in IPI risk groups was rather unbalanced with 18%, 47%, 28% and 7% of cases classified as low (L), intermediate-low (IL), intermediate-high (IH) and high (H) risk, respectively. The median overall survival was not reached in either L or IL risk groups, and was 84.1 and 7.4 months for IH and H risk groups, respectively (p=0. 0005). A simplified IPI model was designed merging patients in both intermediate risk groups and the statistical difference of survival retained its significance. GISL prognostic stratification was demonstrated to have a significant association with survival, with a median survival of 71.3 months in aggressive disease and a median survival not reached at 152 months in indolent disease. Both the simplified IPI model and the GISL risk definition retained their significance in multivariate analysis for overall survival, while for response to therapy only the simplified IPI model resulted to be of statistical significance. In addition, the GISL prognostic stratification identified patients with different outcomes within the IPI intermediate risk group, with a median survival of 70.2 months for patients with aggressive disease wheras the median survival for those with indolent disease was not reached. Finally, a prognostic score resulting from the integration of the simplified IPI and the GISL system was statistically validated. INTERPRETATION AND CONCLUSIONS: The retrospective analysis of this series demonstrates the validity of the IPI in non-follicular indolent NHL and the usefulness of integrating the IPI parameters with disease specific prognostic variables.

Lymphoma, Non-Hodgkin↗

Lineage-specific expression of human immunodeficiency virus (HIV) receptor/coreceptors in differentiating hematopoietic precursors: correlation with susceptibility to T- and M-tropic HIV and chemokine-mediated HIV resistance.

Human immunodeficiency virus (HIV) entry is mediated not only by the CD4 receptor, but also by interaction with closely related molecules that act as membrane coreceptors. We have analyzed mRNA expression and/or cell membrane exposition of the coreceptors most widely used by diverse HIV-1 strains (CXCR4, CCR5, and CCR3) on purified hematopoietic progenitor cells (HPCs) induced in liquid suspension culture to unilineage differentiation/maturation through the erythroid (E), granulocytic (G), megakaryocytic (Mk), and monocytic (Mo) lineages. Reverse transcriptase-polymerase chain reaction (RT-PCR) and cytofluorimetric analysis showed the presence of both CXCR4 and CCR5 in quiescent HPCs, but failed to detect CCR3-specific transcripts. Chemokine expression in HPC progenies showed that CXCR4 receptor is detected on the majority of MKs from early to late stages of maturation, whereas it is moderately decreased in the Mo lineage. In the G pathway, two distinct cell populations, CXCR4(+) and CXCR4(-), were observed: morphological analysis of the sorted populations showed that the CXCR4(+) cells were largely eosinophils and the CXCR4(-) were granulocytes of the neutrophilic series. Furthermore, in the E pathway, CXCR4 was almost completely absent. CCR5 expression is restricted to Mo cultures, ie, approximately 30% to 80% cells throughout all monocytopoietic differentiation/maturation stages. Finally, CCR3 mRNA is always absent in all the unilineage cultures. Evaluation of CD4 expression by flow cytometry on both quiescent HPCs and differentiating unilineage precursors showed that the CD4 receptor is present on approximately 15% of the starting CD34(+) HPC population, highly expressed in the Mo lineage up to 80% at terminal maturation, present on 20% to 30% of maturing Mks, and not detectable in either the E or G lineage. Expression of CD4 receptor together with CXCR4 and/or CCR5 coreceptor in the four lineages correlates with hematopoietic precursor susceptibility to T-lymphotropic and macrophage (M)-tropic HIV strains infection: (1) CD4(-) G and E cells were resistant to both M-tropic and T-lymphotropic strains; (2) HPC-derived Mks were susceptible to T-tropic, but resistant to M-tropic, infection; (3) Mo differentiating cells efficiently replicate both HIV strains. Furthermore, we showed that the CXCR4 and CCR5 ligands (stromal-derived factor 1 and macrophage-inflammatory protein-1alpha [MIP-1alpha], MIP-1beta and RANTES, respectively) inhibit HIV replication in both maturing Mo and Mk cells. Taken together, our data show a lineage-specific modulation of chemokine receptor/coreceptor during hematopoietic cell differentiation and extend previous observations on the relationship between the expression of HIV receptor/coreceptors, susceptibility, and chemokine-mediated resistance to HIV infection.

Adult↗

Lentiviruses as gene delivery vectors.

Lentivirus vectors are already used as effective gene delivery tools in cells from liver, retina, skeletal muscle and the central nervous system. In the past year, new and exciting data from gene transfer experiments in human hematopoietic progenitor cells have been obtained. Furthermore, new generations of HIV-1 based lentivirus vectors as well as new potentially less pathogenic HIV-2 based vectors have been described; however, old and new obstacles remain to be cleared.

Animals↗