Human immunodeficiency virus and the hematopoietic repertoire: implications for gene therapy

A pre-HAART follow-up study of the hematologic manifestations in children with perinatal HIV-1 infection: suggestions for reclassification of clinical staging

Hematologic manifestations in perinatally human immunodeficiency virus-1-infected children have not been widely described in literature. Knowledge of the spontaneous evolution of this disease is essential for achieving optimum care of patients. We analyzed the main hematologic manifestations developed in the prehighly active antiretroviral therapy period of 1217 children, collected from the Italian Register for HIV infection. In 111 patients, the hematologic sign was the first clinical manifestation. Among anemic and neutropenic patients, the fraction of patients in clinical class C was significantly higher than the corresponding fraction in class B (76%, P<0.001 and 74%, P<0.01), and significantly lower in thrombocytopenic patients (42%, P<0.001). The overall progression from class B to C was overlapping to the control group; when separated, however, anemic patients progressed faster (P<0.0001), whereas thrombocytopenic patients had a slower progression, similar to the nonhematologic patients in class A. Anemic patients had a worse prognosis than the control group (P<0.0001), similar to the nonhematologic patients in class C. Finally, the negative prognostic value of anemia was independent from the immunologic condition. Anemia was associated with greater mortality risks. Thrombocytopenia appeared, paradoxically, to be a positive prognostic factor within class B. Centers for Disease Control and Prevention classification presently defines hematologic patients as a single entity; a finer distinction could improve its relevance for the rational design of prevention and therapy.

Retrovirus molecular conjugates: a versatile and efficient gene transfer vector system for primitive human hematopoietic progenitor cells

In principle, transient nongenetic modification of a noninfectious gene transfer virus enabling a one time infection and transduction of human cells could eliminate the risk of formation of replication competent virus. Formation of a molecular conjugate vector by conjugation of noninfective ecotropic murine Moloney leukemia virus to polylysine (eMMLV-PL) enabled high-efficiency transduction of human HPC using in vitro and in vivo assays. Xenotransplanted NOD-SCID mice durably expressed the transgene in human leukocytes and human progenitor cells with eMMLV-PL achieving three-fold increased transduction efficiency when directly compared to optimized amphotropic MMLV (aMMLV) transduction. Both aMMLV and eMMLV assembled conjugate vectors showed similar transduction efficiency indicating predominant polylysine-mediated uptake. Integration of retroviral sequences was determined from individual human HPC recovered from eMMLV-PL-xenotransplanted animals. This simple and versatile concept of conjugate gene transfer vectors has the potential to enhance transduction efficiency as well as to improve certain safety aspects of human gene therapy. Moreover, because it permits effective cellular internalization of particles, this concept of molecular conjugates can be used as research tool to investigate the interactions of otherwise noninfectious viruses or modified viral particles at the genomic level.

Haematological aspects of HIV infection

Multiple interacting factors contribute to the haematological manifestations of HIV disease. The effects of HIV-1 infection influence all haemopoietic cell lineages resulting in a spectrum of haematological abnormalities. Even in the absence of other pathological processes, bone marrow morphology is invariably abnormal, and anaemia, neutropenia and thrombocytopenia are all common during the course of disease. Intercurrent opportunistic infections may cause bone marrow suppression or induce specific cytopenias. Therapies used to treat HIV and its complications are frequently implicated as the cause of haematological dysfunction, and many have significant myelotoxic side-effects. Insights into the molecular basis for many of these abnormalities have permitted a clearer understanding of the pathophysiology of HIV-1 infection. Recombinant human growth factors that may be used to treat isolated cytopenias or to ameliorate the myelotoxic effects of other essential therapies. Lymph opoietic growth factors and the use of gene modified cells provide future therapeutic strategies that may alter the course of HIV disease.