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BACKGROUND: The prognosis of patients with human immunodeficiency virus (HIV)-related non-Hodgkin lymphoma (NHL) is poor. In fact, despite a high complete response (CR) rate, approximately 50% of these patients die from progressive lymphoma. METHODS: From November 1994 to April 2000, the authors treated 40 patients with resistant or recurrent HIV-related NHL with a 96-hour continuous intravenous infusion of cyclophosphamide (187.5 mg/m(2) per day), doxorubicin (12.5 mg/m(2) per day), and etoposide (60 mg/m(2) per day). RESULTS: The median number of cycles administered was two (range, one to six cycles). A CR was documented in 4 of 40 patients (10%), and a partial remission (PR) was documented in 7 of 40 patients (18%). The CR median duration was 6 months (range, 4--30+ months), whereas PRs lasted for 5 months (range, 2--8 months). The overall median survival was 4 months (range, < 1--33 months), and the median survival for responding patients was 10 months. CONCLUSIONS: The current data confirm that infusional cyclophosphamide, doxorubicin, and etoposide is active in patients with refractory or recurrent HIV-related NHL. However, the median survival of these patients remains poor, and the other innovative approaches should be used.

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In the era of highly active antiretroviral therapy (HAART), systemic non-Hodgkin lymphoma (NHL) represented the most frequent cancer associated to HIV infection. In contrast to Kaposi's sarcoma and primary central nervous system lymphoma (PCNSL) which incidence have been declining after introduction of HAART, systemic NHL-HIV has relatively stable remained. Systemic HIV related NHL are markedly heterogeneous both histologically and clinically and this clinicophatological heterogenity reflects variability in the molecular lesions associated to these lymphomas and immunological status of these patients. The introduction of HAART has substantially modified the approach to HIV related lymphomas. The results of recent monoinstitutional study of Aviano Cancer's Institute on 235 patients have suggested that HAART would otherwise allow a long life expectancy with longer disease free survival and overall survival. In fact the reduced of morbidity of AIDS patients bought by HAART justified the use of aggressive antineoplastic therapies.

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The presence of a prominent tissue eosinophilia represents a typical histopathologic hallmark of Hodgkin's disease (HD). To evaluate the putative role of eosinophils on tumor cell regulation in HD, we have analyzed these cells for the functional expression of CD30 ligand (CD30L), a surface molecule able to transduce CD30-mediated proliferation signals on Hodgkin's (H) and Reed-Sternberg (RS) cells. The results demonstrate that circulating and tissue eosinophils from normal donors and patients with HD or hypereosinophilic syndrome (HES), display CD30L mRNA and express CD30L protein, as shown by immunostaining with a specific monoclonal antibody (M80) and with a biotinylated soluble CD30-Fc fusion protein. The surface density of CD30L on eosinophils from HD and HES patients was remarkably higher compared with healthy donors, probably reflecting a cytokine-mediated upregulation in these pathologic conditions. Accordingly, we provide evidence that cytokines regulating eosinophils proliferation and activation, ie, interleukin-5 (IL-5), IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF), are able to enhance the cellular density of CD30L on purified eosinophils from normal subjects. Finally, we show that native CD30L on human eosinophils is a functionally active surface structure able to transduce proliferative signals on CD30+ target cells, including cultured H-RS cells. Our data suggest that eosinophils may not merely represent innocent bystanders, but rather act as important elements in the pathology of HD by contributing to the deregulated network of CD30/CD30L-mediated interactive signals between H-RS cells and surrounding reactive cells.

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Bone remodeling requires cooperation between osteoclasts and other specialized or accessory bone cell populations by mechanisms that have not been completely elucidated. Here we describe the expression and functional role of the proto-oncogene c-kit and of its specific ligand stem cell factor (SCF) on human osteoclasts, osteoblasts, and stromal cells derived from different sources. Our results indicate that primary osteoclasts in imprints of metaphyseal bone and giant cell tumors (GCTs) of bone, as well as a bone marrow-derived preosteoclast cell line of human origin (FLG 29.1), expressed immunodetectable c-kit protein. In contrast, tissue osteoclasts did not react with anti-SCF antibodies, and barely detectable levels of SCF mRNA and protein were found in FLG 29.1 cells. Conversely, a strong expression of membrane bound-SCF was found in primary cultured bone marrow stromal cells, in a stromal cell line (C433) derived from the mononuclear component of GCT of bone, and in a human cell line with osteoblast features (Saos-2). FLG 29.1 preosteoclast cells displayed about 29,000 binding sites/cell of a single class of high affinity c-kit receptors (Kd 6.12 x 10(-10) mol/L) with a molecular weight of about 140 kDa, along with a structurally normal c-kit mRNA. Proliferation of FLG 29.1 preosteoclast cells was stimulated by exogenous SCF, indicating that c-kit was capable of transducing growth signals. Finally, in vitro adhesion of FLG 29.1 cells to primary bone marrow stromal cells, GCT-derived stromal cells (C433), and Saos-2 osteoblast cells was significantly inhibited by an excess of soluble SCF or by monoclonal antibodies recognizing SCF binding sites on the c-kit receptor. These results indicate that c-kit is constitutively expressed on human osteoclasts and that it may be directly implicated in cell contact-dependent interaction of osteoclasts with other specialized or accessory cell populations of the bone microenvironment. Our observations suggest a role for SCF in human diseases characterized by abnormal bone resorption and remodeling.

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Several pieces of evidence have shown that osteoclasts (OCs) are derived from progenitors originating from hemopoietic stem cells (1-3). More specifically, early OC precursors seem to be closely related to the colony-forming unit for granulocytes and macrophages (CFU-GM) (3-5. However, compared with other bone or marrow cells, OCs are found in extremely low numbers in normal adult bone. In addition, active OCs are strongly adherent to the bone surface. For these reasons, it is impossible to obtain pure or highly enriched cultures of intact OCs, although it is possible to obtain large numbers of OCs if good source tissue is available. OCs are found in large numbers only in bone undergoing extensive physiological remodeling (e.g., fetal bone and growing bone metaphyses) or pathological osteolysis (e g., fracture callus) Since human tissue is often difficult to obtain, most OC research has employed animal models, notably rabbit, rat, and chick.

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