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This review addresses various aspects of HIV infection pertinent to hematology, including the consequences of HIV infection on specific aspects of hematopoiesis and an update on the current biologic, epidemiologic and therapeutic aspects of AIDS-related lymphoma and Hodgkin's disease. The results of the expanding use of progenitor cell transplantation in HIV infected patients are also reviewed. In Section I, Dr. Scadden reviews the basis for HIV dysregulation of blood cell production, focusing on the role of the stem cell in HIV disease. T cell production and thymic function are discussed, with emphasis placed upon the mechanisms of immune restoration in HIV infected individuals. Results of clinical and correlative laboratory studies are presented. In Section II, Dr. Levine reviews the recent epidemiologic trends in the incidence of lymphoma, since the widespread availability of highly active anti-retroviral therapy (HAART). The biologic aspects of AIDS-lymphoma and Hodgkin's disease are discussed in terms of pathogenesis of disease. Various treatment options for these disorders and the role of concomitant anti-retroviral and chemotherapeutic intervention are addressed. Drs. Zaia and Krishnan will review the area of stem cell transplantation in patients with AIDS related lymphoma, presenting updated information on clinical results of this procedure. Additionally, they report on the use of gene therapy, with peripheral blood CD34+ cells genetically modified using a murine retrovirus, as a means to treat underlying HIV infection. Results of gene transfer experiments and subsequent gene marking in HIV infected patients are reviewed.

Introduction: Primary effusion lymphoma is a rare type of B-cell lymphoproliferative disorder which is mainly observed in patients with HIV infection. Lymphomatous cells bridge features of immunoblastic and anaplastic cells with a non-B non-T phenotype and are characterized by the presence of the human herpesvirus 8 genome. We report on the retrospective analysis of 12 cases., Patients and Methods: : Twelve HIV-infected patients with serous effusions containing large HHV8(+) lymphomatous cells were extensively evaluated to disclose associated visceral involvement. Clonality was assessed by IgH gene rearrangement PCR analysis (n = 11) or Southern blot (n = 1). EBV and HHV8 DNA sequences were detected by PCR analysis. Cytogenetics studies were performed in seven cases using RHG-banding., Results: Extraserous localizations of lymphoma were present in six cases (50%): mediastinal (n = 2), mesenteric (n = 2), pancreatic (n = 1), and bone marrow involvement (n = 1). A monoclonal rearrangement of IgH genes was demonstrated in six cases, an oligoclonal pattern in one, whereas no clonality could be detected in five. High HHV8 copy numbers were demonstrated in all effusion fluids, with EBV-co-infection in all cases but one. Cytogenetic analysis displayed a complex karyotype in all cases without recurrent abnormalities. Eight patients have died. Three patients are in complete remission at 28, 53 and 55 months after high-dose chemotherapy (n = 1), cidofovir and alpha-interferon combination therapy (n = 1), and antiretroviral therapy alone (n = 1)., Conclusion: The clinical and molecular pattern, as well as the response to therapy suggest that primary effusion lymphoma represents an heterogenous type of virus-induced B-cell lymphoproliferative disorder, sharing pathophysiological features with that induced by the Epstein-Barr virus and occurring in immunocompromised patients.

Objective: To review the current literature on HIV associated non-Hodgkin's lymphoma., Methods: A comprehensive Medline/Pubmed search of articles pertaining to HIV associated non-Hodgkin's lymphoma as well as personal experience from the treatment of over 200 patients at the Chelsea and Westminster Hospital, one of the largest centres for the management of HIV disease in Europe., Conclusion: High grade B cell non-Hogdkin's lymphoma is the second commonest tumour affecting people with HIV. The incidence of this tumour is not declining following the introduction of highly active antiretroviral therapy. Chemotherapy has been employed with modest success in this group of patients; however, the prognosis remains worse than for immunocompetent patients. Advances in molecular genetics and virology have led to a greater understanding of the biology of these tumours. However, these advances have yet to be translated into improvements in the clinical management of patients with AIDS associated non-Hodgkin's lymphoma.

Background and Objectives: Our hospital serves an area with a significant number of patients seropositive for the human immunodeficiency virus (HIV). Intravenous drug abuse and heterosexual exposure are by far the predominant risk factors for HIV and acquired immunodeficiency syndrome (AIDS). Seven percent of these patients develop malignancies. Our aim was to study the types of tumor, their distribution, and to evaluate the patients' outcome., Methods: Of 3,578 patients with HIV infection or AIDS treated between 1993 and 1998, 245 had 1 or more malignancies. Information was collected on age, sex, race, predisposing risk factors for AIDS, malignancies, symptoms at presentation, the time of the onset of AIDS, CD4 cell counts, pathology findings, and mortality., Results: Although aspects of our patients resembled those of previously studied groups of patients with AIDS, there also were ways in which our patients differed from those other groups. Of our patients, 21. 6% had non-AIDS-defining (NAD) invasive malignancies. This was considerably higher than the rate in most studies. Twenty-seven patients with such malignancies died during the study. Forty-two other patients had pre-invasive cancers. Among patients having AIDS-defining (AD) malignancies, 55.9% died, a fact that was related to patients' low CD4 cell counts and late presentation. Our 97 patients with Kaposi sarcoma included 22 women, a relatively high number that may be related to the fact that most of our patients were intravenous drug abusers or had become infected by heterosexual transmission of HIV., Conclusions: AIDS is associated with a high risk of malignancy and an unusual spectrum of tumors. Patients with invasive tumors have advanced disease at the time of initial presentation. Those with AD tumors have a worse prognosis than patients with NAD tumors. The impact of highly active antiretroviral therapy on both AD and NAD tumors needs to be further evaluated., (Copyright 2000 Wiley-Liss, Inc.)

Post-transplant lymphoproliferative disorders (PTLD) share many of the features of human immunodeficiency virus (HIV)-related lymphomas, although important differences exist. PTLD ranges from hyperplastic lesions to aggressive lymphoma or multiple myeloma histology. The coexistence of multiple clones, and the strong association with the Epstein-Barr virus (EBV), represent a uniquely different mechanism for lymphomagenesis when compared with de novo lymphoma. The risk of PTLD increases as the duration of immunodeficiency lengthens, with unusual, newly described entities arising after prolonged immunosuppression. The risk is also strongly influenced by the specific anti-T-cell therapies used to prevent graft rejection, providing insight into the nature of immune surveillance. The presence or absence of bcl-6 mutations may be predictive of the reversibility of the PTLD with reduction in immunosuppressive therapy. The use of cytotoxic agents has been complicated by problems similar to those encountered with HIV-related lymphomas, but can nonetheless be very effective. Long-term remission has been achieved with anti-CD21 and anti-CD24 antibodies, although these have not been equally effective for all categories of PTLD. In vitro-expanded EBV-specific T cells have been effective both as treatment and as prophylaxis in the setting of PTLD occurring after marrow transplantation. EBV viral load measurement correlates with the emergence of PTLD, and may make clinical trials of screening, prophylaxis, or early intervention possible.

AIDS-related non-Hodgkin lymphomas (AIDS-NHL) consistently derive from B-cells and are characterized by extreme clinical aggressiveness. At histological level, AIDS-NHL are classified as AIDS-related Burkitt's lymphoma (AIDS-BL), AIDS-related diffuse large cell lymphoma (AIDS-DLCL) and AIDS-related primary effusion lymphoma (AIDS-PEL). The role of cytokines in the pathogenesis and management of AIDS-NHL has been studied to a certain extent. Production of large quantities of human IL-10 occurs frequently in AIDS-BL and correlates with latent EBV infection of the tumor clone. Lesser amounts of the cytokine are released in EBV negative cases. The pathogenetic role of IL-10 in AIDS-BL is suggested by the observation that IL-10 antisense oligonucleotides inhibit proliferation of the lymphoma. A significant fraction of AIDS-BL cell lines produce TNFbeta. Among AIDS-NHL, the release of TNFbeta appears to be specific for AIDS-BL. The pathogenetic relevance of TNFbeta in lymphomagenesis is suggested by the observation that some BL cell lines use TNFbeta as an autocrine growth factor. Some cases of AIDS-BL, particularly those carrying EBV infection, also secrete IL-6, IL-7 and IL-12. With respect to AIDS-DLCL, many cases express the IL-6R, rendering these cells responsive to the paracrine stimulation by the IL-6 produced by nearby T-cells, macrophages and endothelial cells which are frequently abundant in these tumor samples. The tumor clone itself, however, generally fails to release IL-6. AIDS-PEL is characterized by secretion of large amounts of IL-6 and IL-10. Some PEL cases also release oncostatin M. Apart from human IL-6, PEL also express viral IL-6, which is encoded by the HHV-8 genome. The biological relevance of both IL-6 and IL-10 in PEL proliferation and growth has been recently clarified in vitro and in vivo. Overall, these data suggest that activation of different cytokine loops clusters with different clinico-pathologic categories of AIDS-NHL and may represent the potential target of novel therapeutic strategies.

Acquired immunodeficiency syndrome (AIDS)-related lymphomas consistently display a B-cell phenotype and are histogenetically related to germinal center (GC) or post-GC B cells in the overwhelming majority of cases. The pathogenesis of AIDS-related lymphoma is a multistep process involving factors provided by the host, as well as alterations intrinsic to the tumor one. Host factors involved in AIDS-related lymphomagenesis include reduced immunosurveillance particularly against Epstein-Barr virus (EBV)-infected B cells, human immunodeficiency virus (HIV)-induced alteration of endothelial functions, B-cell stimulation and selection by antigen, HIV-induced deregulation of several cytokine loops, and possibly the host's genetic background. The molecular pathways of viral infection and lesions of cancer related genes associated with AIDS-related lymphoma vary substantially in different clinicopathologic categories of the disease and highlight the marked degree of biological heterogeneity of these lymphomas. Although the reasons for the heterogeneity of AIDS-related lymphoma are not totally clear, it is generally believed that the host's background selects for which specific molecular pathway of AIDS-related lymphoma is activated in a given patient.

Primary effusion lymphoma (PEL) represents a peculiar type of B cell lymphoma which associates with HHV-8 infection and preferentially grows in liquid phase in the serous body cavities. In this report, we provide the detailed characterization of a newly established PEL cell line, termed CRO-AP/6. The cell line was obtained from the pleural effusion of a HIV-positive patient with PEL. Its derivation from the tumor clone was established by immunogenotypic analysis. Detailed phenotypic investigations defined that CRO-AP/6 reflects pre-terminally differentiated B cells expressing the CD138/syndecan-1 antigen. Karyotypic studies of CRO-AP/6 identified several chromosomal abnormalities, whereas genotypic studies ruled out the involvement of molecular lesions associated with other types of B cell lymphoma. Both CRO-AP/6 and the parental tumor sample harbored infection by HHV-8. Conversely, EBV infection was present in the parental tumor sample although not in CROAP/6, indicating that CRO-AP/6 originated from the selection of an EBV-negative tumor subclone. The pattern of viral (HHV-8 v-cyclin) and cellular (p27Kip1) regulators of cell cycle expressed by CRO-AP/6, together with the results of growth fraction analysis, point to abrogation of the physiological inverse relationship between proliferation and p27Kip1 expression. Also, both CRO-AP/6 and the parental tumor sample display biallelic inactivation of the DNA repair enzyme gene O6-methylguanine-DNA methyltransferase (MGMT) by promoter methylation. Overall, the CRO-AP/6 cell line may help understand cell cycle control of PEL cells, may clarify the relative contribution of HHV-8 and EBV to the disease growth and development and may facilitate the identification of recurrent cytogenetic abnormalities highlighting putative novel cancer related loci relevant to PEL.

Objectives: To identify risk factors for non-Hodgkin's lymphoma (NHL) in people with HIV infection., Design and Setting: Case-control study in Sydney, Australia., Participants and Methods: Two hundred and nineteen patients with AIDS-related NHL were compared with 219 HIV-infected controls without NHL, matched for CD4 positive cell count and date of specimen collection. Data on demographic, infectious, treatment-related and immunological factors were abstracted by medical record review. The association between demographic factors, sexually transmissible diseases, HIV-related opportunistic infections, anti-viral therapy, duration of immune deficiency and indices of immune stimulation and risk of NHL were derived for these groups., Results: In a multivariate model, there were two independent groups of predictors of NHL risk. The first was duration of immunodeficiency, as measured by longer time since seroconversion (P for trend 0.008), and lower CD4 positive cell count 1 year prior to the time of NHL diagnosis (P for trend 0.009). The second predictor was B-cell stimulation, as indicated by higher serum globulin (a surrogate marker for serum immunoglobulin, P for trend 0.044) and HIV p24 antigenaemia [odds ratio (OR) for p24 positivity, 1.82; 95% confidence interval (CI), 1.15-2.88]. Indices of B-cell stimulation preceded the diagnosis of NHL by several years. Factors not related to NHL risk included clinical indices of Epstein-Barr virus infection and receipt of individual nucleoside analogue antiretroviral agents. Combination therapy with these agents was associated with a non-significant reduction in NHL risk (OR, 0.68; 95% CI, 0.39-1.18)., Conclusions: Markers of long-standing immune deficiency and B-cell stimulation were associated with an increased risk of developing NHL. Unless the strongest risk factor for NHL, immune deficiency, can be reversed, NHL is likely to become proportionately more important as a cause of morbidity and mortality in people with HIV infection.

Viruses are etiologically linked to approximately 20% of all malignancies worldwide. Retroviruses account for approximately 8%-10% of the total. For human T-cell leukemia virus 1 (HTLV-I), the viral regulatory tax gene product is responsible for enhanced transcription of viral and cellular genes that promote cell growth by stimulating various growth factors and through dysregulation of cellular regulatory suppressor genes, such as p53. After a long latent period, adult T-cell leukemia/lymphoma (ATL) occurs in 1 per 1000 carriers per year, resulting in 2500-3000 cases per year worldwide and over half of the adult lymphoid malignancies in endemic areas. Human immunodeficiency virus 1 (HIV-1) accounts for a significant cancer burden, and its transactivating regulatory protein Tat enhances direct and indirect cytokine and immunological dysregulation to cause diverse cancers. Kaposi's sarcoma (KS) is a very rare tumor except after HIV-1 infection, when its incidence is greatly amplified reaching seventy thousand-fold in HIV-infected homosexual men. Human herpesvirus 8 (HHV-8), which is also known as Kaposi's sarcoma-associated virus (KSHV), is a necessary but not sufficient etiological factor in KS. The dramatic decline of KS since the introduction of highly active antiretroviral therapy (HAART) could be due to suppression of HIV-1 tat. B-cell non-Hodgkin's lymphoma occurs as their first acquired immunodeficiency syndrome-defining diagnosis in 3%-4% of HIV-infected patients. Hodgkin's lymphoma is also associated with HIV infection but at a lower risk. Human papillomaviruses are linked to invasive cervical cancer and anogenital cancers among HIV-infected patients. Human retroviruses cause malignancy via direct effects as well as through interactions with other oncogenic herpesviruses and other viruses.

The incidence of intermediate and high grade B-cell non-Hodgkin's lymphomas in HIV-infected individuals is approximately 60 times greater than in the general population. These AIDS-related lymphomas (AIDS-NHL) are a late manifestation of HIV infection and may increase in frequency as patients live longer with highly active antiretroviral therapy and effective prophylaxis of opportunistic infections. AIDS-NHL have unique clinical and pathological features that are different from non-Hodgkin's lymphomas in the general population. Histologically AIDS-NHL are either high (2/3) or intermediate (1/3) grade lymphomas. Clinically AIDS-NHL have a preponderance for extranodal involvement with central nervous system being the most common site for this. In addition to the clinical and pathological features of AIDS-NHL, a current knowledge of their pathogenesis and treatment options are presented in this review.

When Epstein-Barr virus (EBV) infects B cells in vitro, the result is a proliferating lymphoblast that expresses at least nine latent proteins. It is generally believed that these cells are rigorously controlled in vivo by cytotoxic T cells. Consistent with this, the latently infected cells in the peripheral blood of healthy carriers are not lymphoblasts. Rather, they are resting memory B cells that are probably not subject to direct immunosurveillance by cytotoxic T lymphocytes (CTLs). When patients become immunosuppressed, the viral load increases in the peripheral blood. The expansion of proliferating lymphoblasts due to the suppressed CTL response is believed to account for this increase and is considered to be a major risk factor for posttransplant lymphoproliferative disease (PTLD) and AIDS-associated B cell lymphoma. Here we show that there is an increase in the numbers of latently infected cells in the peripheral blood of immunosuppressed patients. However, the cells are not proliferating lymphoblasts. They are all latently infected, resting, memory B cells-the same population of infected cells found in the blood of healthy carriers. These results are discussed in the context of a model for EBV persistence that explains why PTLD is usually limited to the lymph nodes.

Despite advances in antiretroviral therapy and in the treatment and prevention of opportunistic infections, oncological and consequent hematologic complications of human immunodeficiency virus (HIV) infection continue to occur and are of significant clinical importance. Virus-related tumors (e.g., Kaposi's sarcoma, induced by human herpesvirus 8; non-Hodgkin's lymphoma, linked to Epstein-Barr virus; and anogenital tumors, linked to human papillomavirus) are frequent in patients with HIV-induced immune deficiency. The incidence of AIDS-related Kaposi's sarcoma has declined among homosexual men, but this tumor remains problematic in many patients. Non-Hodgkin's lymphoma is 60 times more prevalent in HIV-positive persons than in others and typically presents as advanced-stage, high- or intermediate-grade B cell lymphoma, with frequent extranodal involvement. Primary central nervous system lymphoma is also common. Cervical carcinoma in HIV-positive women is also usually advanced at diagnosis. Anal carcinoma is increasing in both HIV-positive and HIV-negative populations. Chemotherapy for these tumors can result in dose-limiting cytopenia that can be well-controlled with hematopoietic growth factors, allowing patients to avoid transfusions and maintain the dose intensity of their chemotherapy regimens.

Syndecan-1 is a transmembrane proteoglycan expressed on the surface of tumor cells of various origins including myeloma, Hodgkin's disease, and certain human immunodeficiency virus (HIV) associated lymphomas. Functional studies in myeloma reveal that syndecan-1 may act as a multifunctional regulator of cell behavior in the tumor microenvironment; it mediates cell-cell adhesion, binding of myeloma cells to type I collagen, and inhibits tumor cell invasion into collagen gels. In addition, syndecan-1 is released from the surface of myeloma cells and this shed form of the molecule inhibits growth and induces apoptosis of myeloma cells and may modulate myeloma bone disease by inhibiting osteoclast formation and promoting osteoblast formation. In view of its effects on tumor cell growth, survival, adhesion and invasion and on bone cell differentiation, syndecan-1 may be an important potentially beneficial regulator of myeloma pathobiology. Further studies are needed to define the clinical significance of syndecan-1 in myeloma and to examine its functional significance in other lymphoid malignancies.

AIDS-associated primary central nervous system lymphomas are late events that have an extremely poor prognosis. Despite different hypotheses, the brain localization of these B cell lymphomas remains an enigma. To better define the cell origin of the lymphomas and the possible role of the B cell receptor (BCR) in the brain localization and/or in the oncogenic transformation, we analyzed the V region genes of the Ig heavy chain expressed by lymphoma cells in five randomly selected patients. After amplifying the rearranged VHDJH DNA by PCR, cloning, and sequencing of the amplified products, we observed that: 1) of the five lymphomas analyzed, four were clearly monoclonal; 2) there was no preferential use of one peculiar VH family or one peculiar segment of gene; 3) the mutation analysis showed that an Ag-driven process occurred in at least two cases, probably before the oncogenic event; and 4) there was no intraclonal variability, suggesting that the hypermutation mechanism is no longer efficient in these lymphoma B cells. Taken together, our results suggest that distinct Ags could be recognized by the BCR of the lymphoma cells in different patients and that, if the Ags are responsible for the brain localization of these B cells bearing mutated BCR, other factors must be involved in B cell transformations in primary central nervous system lymphoma.

In order to determine risk factors associated with the development of AIDS-associated lymphoma (AIDS-NHL) in individuals with haemophilia, we undertook a case-control study of 25 patients with AIDS-NHL identified prospectively in the multicentre Hemophilia Malignancy Study (HMS) and 100 haemophilia controls with AIDS matched 1:4 by age and date of AIDS diagnosis. Clinical, laboratory and lifestyle characteristics and blood product usage during the 2 years before seroconversion and AIDS or AIDS-NHL diagnosis were compared between cases and controls. AIDS-NHL cases had higher haemoglobin, platelets, %CD4 and white blood count, with the latter approaching significance, 5700 microL-1 vs. 4000 microL-1, P = 0.063. The proportion of cases receiving anti-retroviral treatment prior to diagnosis was similar to that of AIDS-controls, 72% vs. 86%, but a significantly lower proportion of cases had been treated with intravenous pentamidine, 4% vs. 26%, P = 0.048. There were no differences between cases and controls in prevalence of antibody to hepatitis B or hepatitis C, HIV-related symptoms, lifestyle characteristics, or in the type or amount of blood product usage. Thus, clinical, lifestyle characteristics, antiviral drug treatment and blood product usage appear to have little, if any, effect on the development of AIDS lymphoma in HIV(+) patients with haemophilia.

Among patients with congenital and acquired immunodeficiencies, non-Hodgkin's lymphoma (NHLs ) are the most common tumors of the immune system. In the setting of human immunodeficiency virus (HIV) infection, as many as 10% to 20% of people ultimately developed NHLs. These tumors are clinically aggressive, frequently involve extranodal sites, and often exhibit unique features that distinguish them from NHL arising in individuals with other forms of immunosuppression. Important in the development of HIV-associated NHL are cytokines and other factors that induce B-cell proliferation and increase the likelihood of mutations of c-myc, bcl-6, and other tumor-suppressor genes with carcinogenic potential. Specific forms of HIV-associated NHL are linked to expression of Epstein-Barr virus (EBV)-latent proteins; the newly described DNA virus, Karposi's sarcoma-associated herpesvirus/human herpesvirus-8 (KSHV/HHV-8); and perhaps HIV. Elucidation of the factors that contribute to the high incidence of NHL among patients infected with HIV provides insights into important elements of lymphomagenesis.

We describe the anatomic and histologic presentation and prognosis of non-Hodgkin's lymphoma (NHL) among people with AIDS (PWA) and determine their contribution to the NHL burden. We linked AIDS and cancer registries in selected areas of the United States and compared NHL sites and histologies in PWA and non-PWA, after adjusting for age, sex and ethnicity. Among 51,033 PWA, we found 2,156 cases of NHL (4.3%). Half of NHL cases occurring post-AIDS were not reported to AIDS registries. NHL was part of an AIDS-defining condition for 3.2% of all PWA; the relative risk of NHL with 3.5 years of another AIDS diagnosis was 165-fold compared to non-PWA within the cancer surveillance system. Of NHLs, 39% were high grade (vs. 12% among non-PWA), 60% were nodal (vs. 74% among non-PWA) and 15% had brain primaries (vs. 1% among non-PWA). Excluding brain sites, extranodal sites were still 20% more common than expected. Relative risk was elevated for all histologic types, with the risk ranging from 652-fold for high-grade diffuse immunoblastic tumors and 261-fold for Burkitt's lymphomas to 113 for intermediate-grade lymphoma to 14-fold for low-grade lymphoma. Survival among PWA with NHL was poor, and tumor grade had little impact. In high-risk AIDS areas, AIDS-related NHLs constitute a major share of the NHL burden. We conclude that NHL risk is considerably under-estimated in AIDS registry data. The major differences between PWA and non-PWA were the high frequency of brain lymphoma and the increase in high-grade lymphomas in PWA. However, the grade of NHL did not influence the prognosis among PWA with lymphoma. The increasing risk of NHL in PWA has contributed substantially to the general increase in NHL rates in the United States since 1981.

To assess the frequency of malignancy-associated 30-bp deletion variants of the latent membrane protein 1 (LMP-1) in benign conditions, a comparative sequence analysis was done using samples from 20 American children with acute infectious mononucleosis and 16 Swiss children with chronic tonsillar hyperplasia. The 30-bp deletion variant (LMP-1-del) was present in 66% of patients (12/20 with infectious mononucleosis and 12/16 with tonsillar hyperplasia). Two additional patients had a 3-bp deletion and an inframe insertion of 18 nucleotides, respectively. All but 1 isolate had numerous nonsilent point mutations. These data identify a hypervariable region within the C-terminus of LMP-1, in a domain required for maximal stimulation of NF-kappaB activity. These data demonstrate that LMP-1-del variants are frequent in acute infectious mononucleosis and tonsillar hyperplasia and identical to those observed in Epstein-Barr virus-associated AIDS-related lymphoma.

During the past few years the neoplasms defining the diagnosis of AIDS are in apparent evolution and a new distribution of specific tumors is currently reported in the literature. Besides the Kaposi's sarcoma, non-Hodgkin's lymphomas, and uterine cervical carcinoma, other malignancies are frequently diagnosed in HIV+ population, particularly during the advanced stages of the infection. The pathogenesis of such an increase of tumor diffusion is apparently related to the persistence of several herpes viruses including HHV8 and HPV whose molecular interaction with HIV may contribute to the genetic variations suitable for tumor development. The epidermoid anal carcinoma is a tumor whose appearance is increasingly recurrent in HIV+ patients, although it is not considered as an AIDS-defining neoplasia. This tumor is prevalent in HIV+ homosexual men, in particular during the full-blown immunodeficiency disease. Here we report the case of a patient whose diagnosis of AIDS was emphasized by the concurrent presence of the anal tumor.

Recently, a novel DNA virus has been molecularly cloned from Kaposi's sarcoma (KS) tissue, a tumour common in acquired immune deficiency syndrome (AIDS). Analysis of the viral genome confirms that it is a relative of human herpesviruses and the virus has been designated HHV-8. Epidemiological evidence suggests a strong aetiological link between the presence of HHV-8 DNA and/or antibodies against the virus, and KS. Additional sequence analysis suggests that the HHV-8 genome contains sequences which encode a D type cyclin and a number of other genes potentially implicated in growth deregulation which may be relevant to its proposed role as a transforming virus.

Kaposi's sarcoma (KS) and non-Hodgkin's lymphomas (NHL) are common consequences of HIV infection. These tumours appear to be precipitated by herpesviruses. Epstein-Barr virus (EBV) is implicated as a cause of up to 50% of systemic NHLs and up to 100% of central nervous system lymphomas in patients with AIDS. KS may be a consequence of the newly identified gamma-herpesvirus KSHV (KS-associated herpesvirus or HHV-8). This herpesvirus is found in all KS biopsies from different epidemiologic forms of this disease. KSHV is also implicated in the pathogenesis of a rare form of B cell lymphoma called body-cavity based lymphoma or primary effusion lymphoma (PEL).

Objective: This study reports the main clinical and histological features, and the treatment and outcomes of six HIV-associated oral lymphomas., Subjects: During the period 1991-1995, six cases of lymphoma presenting in the oral cavity were diagnosed in this clinic. All six patients were men ranging in age from 36 to 62 years with CD4 counts below 100 cells mm-3., Results: In five patients, oral lymphoma was the first AIDS defining disease. Four lesions occurred on the gingiva, one on the palate and one on the tongue. The duration of symptoms prior to presentation ranged from 2 weeks to 14 months. In all but one patient, the lesions presented as red, exophytic masses and were diagnosed clinically as Kaposi's sarcoma. None of the five lesions presenting on the palate or gingiva showed radiographic evidence of bone destruction. Metastatic work-up failed to diagnose lymphoma elsewhere in the five cases where this was performed. Histological diagnoses included two small, non-cleaved (Burkitt's type) lymphomas, two immunoblastic lymphomas, one large cell lymphoma and one small, non-cleaved (non-Burkitt's) lymphoma., Conclusion: These findings highlight the uncommon clinical presentation of this disease and despite its relative rarity, demonstrate the need to maintain a high degree of suspicion in any unusual oral lesion in this group of patients.

The pediatric AIDS epidemic began in the U.S.A. between 1983 and 1985. Hemophilia patients were among the first victims of this disease with the majority of these patients infected prior to 1984. At the South Texas Hemophilia Center 69 of 108 patients less than 21 years of age demonstrated serologic evidence of infection. Of these patients, 6 subsequently developed malignancies between 1987 and 1994. Between 1992 and 1996 data was subsequently accumulated on the development of malignancy in HIV positive patients through the Pediatric Oncology Group, which to date has enrolled 24 HIV positive children with malignancy. In these studies the majority of patients had B cell, non-Hodgkin's lymphomas, however approximately 20% of the patients were identified with leiomyosarcomas. Histologic studies of tumors of 6 children with AIDS and leiomyosarcomas or leiomyoma identified the EBV receptor or CD 21 in the tumor using immunoperoxidase techniques, whereas similar staining was not seen in smooth muscle tumors from HIV negative children. In situ hybridization techniques identified EBV-EBER probe in the tumors from HIV positive patients. In 2 patients with adequate tumor tissue EBV genome was present in high concentration using PCR techniques and Southern blot studies showed a monoclonal and biclonal proliferation. Other laboratories have reported similar EBV findings in lymphomas from AIDS patients. Thus EBV appears to be an important cofactor in development of malignancy in pediatric AIDS patients.

Human herpesvirus type-8 (HHV-8) is a lymphotropic herpesvirus originally identified in Kaposi's sarcoma. Among lymphoproliferative disorders, HHV-8 infection is restricted to body-cavity-based lymphoma (BCBL) and multicentric Castleman's disease (MCD). BCBL are B-cell lymphomas growing in liquid phase in the body cavities and most frequently associated with AIDS. BCBL express indeterminate phenotypes, in all cases are associated with HHV-8 infection, and frequently carry Epstein-Barr virus genomes in the absence of c-MYC rearrangements or other genetic lesions characteristic of B-cell lymphomas. The clinical outcome of BCBL is poor with a median survival of only few months. MCD is an atypical lymphoproliferative disorder which displays marked vascular hyperplasia and is commonly associated with Kaposi's sarcoma. HHV-8 infection occurs in 100% of AIDS-related MCD and in approximately 40% of AIDS-unrelated cases. Overall, the consistency of HHV-8 infection in BCBL and MCD, its selectivity throughout the spectrum of lymphoproliferative disorders and the high copy number of HHV-8 DNA sequences in infected cells suggest that the virus plays a pathogenetic role in these disorders.

A case-control study of 913 black cancer patients (aged 15-50 years) was undertaken to measure the association between human immunodeficiency (HIV) infection and cancers believed to have an infective aetiology. Controls were patients with cancers believed not to be infective in origin. The prevalence of HIV in the controls of 7.3% (24 of 325) was similar to the background HIV seropositivity in this population. Odds ratios (ORs) and 95% confidence intervals (CI) adjusted for age, year of diagnosis, marital status and sex were calculated. There was a strong association between HIV infection and Kaposi's sarcoma (KS), with 27 of 33 cases being HIV seropositive, OR = 61.8 (95% CI 19.7-194.2) and an elevated association with non-Hodgkin's lymphoma (NHL), with 27 of 40 cases being HIV seropositive [OR = 4.8 (95% CI 1.5-14.8)]. The elevated odds ratio for KS associated with HIV infection accords with the observed increases in the incidence of KS in several sub-Saharan African countries where the prevalence of HIV is high. The odds ratio for NHL associated with HIV infection was lower than that reported in developed countries, and the reason for this is not clear. No other cancers, including cervical and liver cancers, showed significantly elevated odds ratios associated with HIV infection.

Primary CNS lymphoma is recognized as one of the criteria of AIDS. The incidence is 0.4 to 0.56% of AIDS complications. Non-Hodgkin's lymphomas appear as multicentric tumours, mostly located in the hemispheres; they have a B phenotype and have a high grade of malignancy. They are sometimes associated with opportunistic infections. Survival is around 4 to 5 months. The presence of EBV in these tumours is an argument to propose a synergistic role of this virus in the pathogenesis of these tumours. Secondary lymphomas are observed in 40 to 47% of these tumours and must be systematically looked for. Hodgkin's disease is rare. It is mostly diagnosed as secondary compressive epidural tumors.

Lymphomagenesis in HIV positive patients is a complex phenomenon not yet completely understood (Karp and Broder, 1992). The great majority of NHL are of the B cell type. Burkitt lymphoma seems to develop early during the evolution of HIV infection in patients with a CD4 count above 200/microliter. MYC is rearranged in the majority of the cases. EBV latent infection is observed in 30-45%. EBV status is characterized by a negativity for EBNA2 and LMP1 The main sites of the tumour are the lymph node and the bone marrow. Diffuse large cell lymphomas, mostly represented by immunoblastic lymphomas with plasmacytoid differentiation and by centroblastic lymphomas rich in immunoblasts, are a late event in HIV infection, in patients with a low CD4 count (often below 50/microliter). The prognosis is worse than in Burkitt and Burkitt like lymphoma. MYC is rearranged in about 30-40% of the cases, whereas more than 70% are EBV positive. EBV status is characterized by a positivity for both EBNA2 and LMP1. B type ALC lymphomas are more frequently associated with EBV than in the general population and exhibit the same EBV status as diffuse large cell lymphomas. HD occurs at any stage of HIV infection. The majority of patients are in clinical stage III or IV at the time of diagnosis, and HIV associated HD shows a more aggressive course than non-HIV HD. Many cases remain difficult to classify; instead, the immunophenotype of neoplastic cells is similar to that in HD occurring in the general population. Histiocytes and epithelioid cells are even more numerous than T lymphocytes, and the CD4:CD8 ratio is low. Neoplastic cells are EBV positive in most or all cases, although they are consistently HIV negative by in situ hybridization. Lymphomagenesis seems to be very complex, with multiple agents acting together or successively. EBV, other viruses, rearrangement of various genes and production of cytokines all seem to have major roles in addition to immune deficiency.

There are few reports of salvage chemotherapy for HIV-related non-Hodgkin's lymphoma (NHL). We report a relapsed HIV-related high-grade NHL which was treated successfully with ESHAP chemotherapy followed by high-dose chemotherapy and autologous bone marrow transplantation (ABMT). ABMT may later have triggered opportunistic infections in this patient.

The incidence of NHL is greatly increased in HIV-infected individuals. The vast majority are clinically aggressive B cell-derived neoplasms exhibiting BL, IBL, or LCL histology. Approximately 80% arise systemically (nodal and/or extranodal), and the remaining 20% arise as primary CNS lymphomas. A small proportion are body cavity-based lymphomas associated with KSHV infection. Possible factors contributing to lymphoma development include HIV-induced immunosuppression, chronic antigenic stimulation, and cytokine overproduction. These alterations are associated with the development of oligoclonal B-cell expansions. The appearance of NHL is characterized by the presence of a monoclonal B-cell population displaying a variety of genetic lesions, including EBV infection, c-myc gene rearrangement, bcl-6 gene rearrangement, ras gene mutations, and p53 mutations/deletions. The number and type of genetic lesions varies according to the anatomic site and histopathology. In the case of BL, virtually 100% exhibit c-myc gene rearrangements, two thirds display p53 gene mutations, one third contain EBV, and none exhibit bcl-6 gene rearrangements. In contrast, in the case of IBL, virtually 100% contain EBV, 25% display c-myc gene rearrangements, 20% display bcl-6 gene rearrangements, and very few exhibit p53 gene mutations. These findings suggest that more than one pathogenetic mechanism is operational in the development and progression of AIDS-related NHLs. Further work will be necessary to develop a complete understanding of the etiology and pathogenesis of NHL in the setting of HIV infection. AIDS-related NHL remains an important biologic model for investigating the development and progression of high-grade NHLs as well as NHLs that develop in immune-deficient hosts.

As many as 40% of individuals infected with HIV will be diagnosed with a malignancy during the course of their illness. Although neoplasms of all organ systems have been reported in infected patients, Kaposi's sarcoma (KS), non-Hodgkin's lymphoma (NHL), primary central nervous system (CNS) lymphoma, and invasive squamous cell cervical carcinoma are considered to be diagnostic of AIDS in the presence of HIV infection. The rapidity with which these malignancies are diagnosed can affect the morbidity experienced by patients. The management of patients with AIDS-related malignancies poses several challenges for oncology nurses. First, most such patients are treated with either chemotherapy or radiotherapy, and use of these modalities is complicated by the underlying HIV infection. Second, patients with AIDS-related malignancies experience numerous symptoms, and again, management of these symptoms is compounded by the underlying disease. By applying their knowledge and experience, oncology nurses can greatly lessen morbidity in these patients.

The magnitude for and risk factors of the two most important AIDS neoplasm, Kaposi's sarcoma and non-Hodgkin's lymphoma, are reviewed in detail. The association between AIDS and other cancers is mostly speculative because surveillance biases tend to favor detecting associations that may be spurious. The overall relative risk of other cancers appears, however, to be only twofold above that in the general population, with associations being most convincing for anal (but not cervical) cancer and leiomyosarcoma and possible also for Hodgkin's disease, testicular cancer, and conjunctival cancers.

Most AIDS-related non-Hodgkin's lymphomas can be categorized into one of three histologic subtypes: large-cell immunoblastic, small non-cleaved cell (Burkitt's or Burkitt's-like) and diffuse large cell. Rare histologies include Ki-1 anaplastic large cell lymphoma, angiotropic large cell lymphoma, mucosa-associated lymphoid tissue, primary pulmonary T-cell lymphoma, and Sézary syndrome. Although the role of Epstein-Barr virus remains uncertain, a new herpes virus, human herpes virus 8, has been identified in the rare subset of effusion-based lymphomas. Overexpression of the cytokines interleukin-6 and interleukin-10 may have a role in pathogenesis, and they may serve as potential therapeutic targets. In addition, chronic antigenic stimulation may correlate with elevated serum CD22 levels and may serve as a tool for early detection. Novel investigational therapies in clinical development include new chemotherapy-based regimens, immune modulators, antibody therapy, as well as cellular therapy.

In a previous study, we described a cell line (BRG-P) derived from a woman with Burkitt's lymphoma (BL) and acquired immunodeficiency syndrome that shared the same characteristic cytogenetic abnormalities as the patient's malignant cells. This cell line contained subclones that displayed an isotype switch from IgM to IgA1 and an accumulation of point mutations in the Vh region genes. Because these two features suggested an antigen-driven process, we began a search for the antigen responsible for the stimulation of the malignant B cells. Specifically, we hypothesized that because the patient's tumor had presented as a lymphomatous infiltration of the breast, the malignant B cells were recruited to this site because of the reactivity of their surface lg with breast tissue. A hybridoma (BRG-H) was obtained by fusing BRG-M cells (an IgM producing subclone of the BRG-P cell) with an appropriate cellular partner. The monoclonal antibody (BRG MoAb) produced by this hybridoma reacted strongly with two of five breast cancer cell lines and stained normal and malignant ductal epithelial cells on breast tissue sections. The antigen recognized by the BRG MoAb consisted of a single, minimally glycosylated polypeptide chain of 45 kD (p45). The BRG MoAb failed to react with a panel of human cell lines from different tissues, except for one cell line from a uterine cervical carcinoma. No reactivity was detected for a panel of exogenous antigens from various pathogens, including human immunodeficiency virus and self-antigens frequently recognized by polyspecific antibodies. Experiments were performed to investigate the functional consequences of the interaction of surface IgM with its specific ligand. Coculture of BRG-M cells with p45+, but not with p45-, breast cells caused apoptosis of BRG-M cells. The specificity of the interaction was shown by the observation that apoptosis was prevented by pretreatment of BRG-M cells with a monovalent F(ab') fragment of rabbit IgG antibody to human mu chains. Moreover, only BRG-M cells, but not other BL cells, underwent apoptosis after exposure to p45+ breast cells. The interaction between the CD40 molecule expressed by BRG-M cells and its specific ligand (CD40L) prevented p45-induced cell apoptosis. Because this interaction mimics that occurring in vivo between T and B cells during immune responses, our data suggest that various events contributed to the emergence of the BL, in this particular patient, including antigenic stimulation possibly assisted by T-cell help.

The etiology of non-Hodgkin's lymphomas (NHL) remains a controversial matter, but, in the last few years, considerable evidence suggests that aberrations of the immune system and viruses may act as etiologic agents, in at least some cases of NHL. In fact, patients with primary immuno-deficiencies, or those suffering from diseases characterized by autoimmune dysfunction, show an increased risk for the development of NHL. Several viruses have been identified as possible etiologic agents for NHL; one of the best studied is the Epstein-Barr virus, which was detected in cultures of tumor cells from patients with Burkitt's lymphoma. The pathogenetic potential of this virus is illustrated by its association with an increasing number of malignant diseases. In addition, the human T-cell lymphotropic virus family (HTLV), was also recognized as possible etiologic agents for several lymphomas, such as cutaneous T-cell lymphoma and T-cell leukemia-lymphoma syndrome (HTLV-I), and T-cell hairy cell leukemia (HTLV-II). Recently, the presence of hepatitis C virus infection has also been recognized in several hematological malignancies such as mixed cryoglobulinemia, low-grade malignant lymphomas and Waldenström's disease. The possible etiopathogenetic role of this virus in non-Hodgkin's lymphomas is discussed on the basis of molecular, clinical, and epidemiological considerations.

There are a variety of HIV-related neurologic complications that have numerous causes. HIV-related neurologic illnesses are specific to the stage of HIV infection, although the greatest burden of neurologic disease and the most disabling syndromes occur in the more advanced stages. As the number of HIV-infected persons continues to increase worldwide and as antiretroviral and other anti-infective therapies improve patient survival in the advanced stages of HIV infection, the burden of neurologic disease will continue to increase.