Dual infection of the central nervous system by AIDS viruses with distinct cellular tropisms.

Human immunodeficiency virus (HIV) is the causative agent of the acquired immune deficiency syndrome (AIDS). A large number of AIDS patients show evidence of neurologic involvement, known as AIDS-related subacute encephalopathy, which has been correlated with the presence of HIV in the brain. In this study, two genetically distinct but related viruses were isolated from one patient from two different sources in the central nervous system: brain tissue and cerebrospinal fluid. Both viruses were found to replicate in peripheral blood lymphocytes, but only virus from brain tissue will efficiently infect macrophage/monocytes. The viruses also differ in their ability to infect a brain glioma explant culture. This infection of the brain-derived cells in vitro is generally nonproductive, and appears to be some form of persistent or latent infection. These results indicate that genetic variation of HIV in vivo may result in altered cell tropisms and possibly implicate strains of HIV with glial cell tropism in the pathogenesis of some neurologic disorders of AIDS.

Initial increase in blood CD4(+) lymphocytes after HIV antiretroviral therapy reflects redistribution from lymphoid tissues.

Previous studies proposed a dynamic, steady-state relationship between HIV-mediated cell killing and T-cell proliferation, whereby highly active antiretroviral therapy (HAART) blocks viral replication and tips the balance toward CD4(+) cell repopulation. In this report, we have analyzed blood and lymph node tissues obtained concurrently from HIV-infected patients before and after initiation of HAART. Activated T cells were significantly more frequent in lymph node tissue compared with blood at both time points. Ten weeks after HAART, the absolute number of lymphocytes per excised lymph node decreased, whereas the number of lymphocytes in the blood tended to increase. The relative proportions of lymphoid subsets were not significantly changed in tissue or blood by HAART. The expression levels of mRNA for several proinflammatory cytokines (IFN-gamma, IL-1beta, IL-6, and macrophage inflammatory protein-1alpha) were lower after HAART. After therapy, the expression of VCAM-1 and ICAM-1 -- adhesion molecules known to mediate lymphocyte sequestration in lymphoid tissue -- was also dramatically reduced. These data provide evidence suggesting that initial increases in blood CD4(+) cell counts on HAART are due to redistribution and that this redistribution is mediated by resolution of the immune activation that had sequestered T cells within lymphoid tissues.

Improved survival for patients with AIDS-related Kaposi's sarcoma.

PURPOSE: We retrospectively analyzed all patients with AIDS-related Kaposi's sarcoma (AIDS-KS) seen at one large California medical center to delineate factors that may have contributed to a relative decline in survival. METHODS: Potential prognostic factors were analyzed individually, using the Cox proportional hazards regression model, for their association with survival. After a stepwise Cox regression procedure was applied to those factors that showed a significant effect on survival, a subset of factors that best predicted survival was identified. We then quantified the effect of the year of diagnosis on survival using a univariate Cox model. Next, we combined the year of diagnosis with the subset of prognostic factors previously identified into the Cox model to examine survival after adjustment for the prognostic factors. Survival distribution was estimated by the Kaplan-Meier method, and the 95% confidence interval for the median survival was computed using the modified reflected method. RESULTS: In 688 patients, we identified four baseline variables that best predicted survival: CD4 cell number, hematocrit, number of KS lesions, and body mass index (BMI). Adjusted for these predictive factors, there was a significant improvement in survival for patients with AIDS-KS over the last 6 years. CONCLUSION: Contrary to prior reports, survival has increased for patients with AIDS-KS. The apparent increase in observed mortality is most likely due to a decline in the CD4 cell number at presentation.

Abnormal T-lymphocyte colonies (CFU-TL) following bone marrow transplantation.

We studied the presence of peripheral-blood- and bone-marrow-derived T-lymphocyte colony formation (CFU-TL) in 28 bone marrow transplant recipients from 1 month to six years after transplantation. Peripheral blood leukocyte and lymphocyte counts were generally normal, and all had morphologic evidence of engraftment without leukemia at the time of study. Both peripheral-blood- and bone-marrow-derived CFU-TL were markedly reduced after transplantation as compared to normal controls, which included bone marrow donors (14.2 +/- 5/4 X 10(4) vs 313 +/- 100/4 X 10(4) [p less than 0.001] and 26 +/- 4/2 X 10(5) vs 1004 +/- 60/2 X 10(5) [p less than 0.001]). Among the patients, four had no detectable bone-marrow-derived CFU-TL when tested less than six months after transplantation. Peripheral blood CFU-TL, while present in all patients, was markedly decreased for more than 12 months after transplantation. After two years, the number of CFU-TL returned to normal in several patients. The abnormalities in CFU-TL were unrelated to diagnosis, age, sex, graft-versus-host disease (GVHD), pretransplant conditioning, or posttransplant immunosuppressive treatment. Patients receiving autologous bone marrow transplants also had decreased CFU-TL. Cocultures of normal peripheral-blood- or bone-marrow-derived mononuclear cells with recipients' mononuclear cells or sera did not inhibit normal CFU-TL growth. Furthermore, the addition of mononuclear cells or sera from normal individuals, or of exogenous interleukin 1 or interleukin 2, did not correct the deficiency of CFU-TL growth by recipient cells. Depletion of T-lymphocytes from bone marrow or peripheral blood in transplant recipients by physical techniques or with a monoclonal antibody (CT-2) and complement had no effect on CFU-TL recovery. Similarly, addition of recipients' T cells to normal peripheral blood or bone marrow mononuclear cells did not suppress CFU-TL. These data indicate that most transplant recipients have a marked reduction in CFU-TL which persists for up to two years after transplantation. This reduction in the growth of T-cell colonies appears to be due to deficient numbers of these cells or an intrinsic defect in their responsiveness to T-cell lymphokines, rather than a result of growth suppression by inhibitory cells or serum factors. This observed defect in CFU-TL may have implications for therapeutic attempts to facilitate immune reconstitution after bone marrow transplantation.

The potential role of interleukin-2 in HIV.

Interleukin-2 (IL-2) is a secretory cytokine produced by activated T cells that stimulates T cells, B cells, and natural killer cells to proliferate and release cytokines. In addition, IL-2 slows apoptosis of HIV-infected cells. Clinical studies have demonstrated that exogenous human recombinant IL-2 can be safely administered concurrently with potent antiretroviral therapy to HIV-infected patients. It was further demonstrated that recombinant human IL-2 therapy produces sustained increases in CD4+ cell number and function in patients with both early and late HIV disease. Further evaluation of the clinical efficacy of IL-2 in HIV-infected patients is expected to provide important information on the utility of recombinant human IL-2 in HIV disease.

Phase I AIDS Clinical Trials Group (075) study of adriamycin, bleomycin and vincristine chemotherapy with zidovudine in the treatment of AIDS-related Kaposi's sarcoma.

OBJECTIVE: To determine the toxicity and maximum tolerated dose of doxorubicin (adriamycin) in combination with fixed doses of bleomycin, vincristine (ABV) and zidovudine in patients with advanced AIDS-related Kaposi's sarcoma. PATIENTS AND METHODS: Twenty-six HIV-seropositive men with Kaposi's sarcoma were treated daily with 100 mg zidovudine orally every 4 h, along with combination chemotherapy using bleomycin 10 U/m2 and vincristine 1.4 mg/m2 (maximum, 2 mg) given intravenously in 2-week cycles. In addition, three successive cohorts of eight patients received escalating doses of doxorubicin each beginning with no doxorubicin (level I), doses of 10 mg/m2 (level II), and 15 mg/m2 (level III). RESULTS: The major dose-limiting toxicity experienced with the combination therapy was severe neutropenia in eight patients, four of whom received level III doxorubicin (15 mg/m2). Therefore, 10 mg/m2 of doxorubicin in combination with zidovudine and BV chemotherapy was defined as the maximum tolerated dose. Other dose-limiting toxicities included neuropathy (n = 2), cutaneous toxicity associated with bleomycin (n = 1), and diarrhea (n = 1). Seventeen patients (71%; 95% confidence interval, 46-85) experienced either partial (n = 13) or clinical complete remission (n = 4) to therapy after a median of five cycles (range, 2-9). CONCLUSION: The maximum tolerated dose of doxorubicin is 10 mg/m2 when given in combination with zidovudine and BV chemotherapy. Response rates observed with the combined antiretroviral and chemotherapy regimen are similar to those previously reported with ABV chemotherapy alone.

Activity of the soft gelatin formulation of saquinavir in combination therapy in antiretroviral-naive patients. NV15355 Study Team.

OBJECTIVE: A Phase II, open-label, randomized, parallel-arm, multicentre trial to compare the antiviral activity and safety of two formulations of saquinavir (SQV), soft gelatin (SQV-SGC) and hard gelatin (SQV-HGC) capsules, in combination with two nucleoside reverse transcriptase inhibitors (NRTI), in antiretroviral-naive, HIV-1-infected individuals. PARTICIPANTS: A total of 171 people of > or = 13 years, with plasma HIV-1 RNA levels > or = 5000 copies/ml, who had received no protease inhibitor therapy, < or = 4 weeks NRTI therapy and no antiretroviral treatment within 28 days of screening. Eighty-one people were randomized to the SQV-HGC group and 90 to the SQV-SGC group. A total of 148 patients completed 16 weeks of therapy. INTERVENTION: Therapy for 16 weeks with either SQV-SGC 1200 mg or SQV-HGC 600 mg, both three times a day, in combination with two NRTI. RESULTS: Using an on-treatment analysis, patients taking SQV-SGC had a larger reduction in plasma HIV-1 RNA than those taking SQV-HGC (-2.0 versus -1.6 log10 copies/ml). Eighty per cent of those on SQV-SGC had < 400 copies HIV RNA/ml, compared with 43% in the SQV-HGC group (P = 0.001). A statistically significant difference in the area under the curve (AUC) values between the SQV-SGC and SQV-HGC arms (-1.7 versus -1.5 log10 copies/ml, respectively; P = 0.0054) was observed when withdrawals prior to week 12, major protocol violators and patients with < 75% compliance were excluded from the analysis; however, the difference between the values for the intent-to-treat population was not significant (P = 0.1929). Adverse events (mostly mild) included diarrhoea and nausea. CONCLUSIONS: SQV-SGC was generally well tolerated and gave significantly more potent suppression of plasma HIV-1 RNA in antiretroviral-naive patients than SQVHGC.

Interferon-alpha 2a in the treatment of acquired immunodeficiency syndrome-related Kaposi's sarcoma.

In a series of studies, recombinant interferon-alpha 2a (rIFN alpha 2a, Roferon-A) was administered alone (273 men) or combined with vinblastine (91 men) to patients with acquired immunodeficiency syndrome (AIDS)-related Kaposi's sarcoma (KS). Patients were treated with daily doses of rIFN alpha 2a ranging from 3 to 54 million international units (I.U.) administered intramuscularly. A dose of 36 million I.U. daily for approximately 10 weeks followed by a three times weekly maintenance schedule with the same dose resulted in the best overall therapeutic benefit. An escalating-dose regimen of 3, 9, and 18 million I.U. daily, each for 3 days, followed by 36 million I.U. daily, produced equivalent therapeutic benefit with amelioration of acute toxicity in some patients. Response was more likely in patients without a history of opportunistic infection or B symptoms (fever, night sweats, or weight loss). Response rate increased with increasing baseline CD4 lymphocyte count and was 45.5% in patients with a CD4 count of greater than 400/mm3. Responding patients with a CD4 count of greater than 200/mm3 had a distinct survival advantage over patients who had similar CD4 counts but whose tumors did not regress with therapy. The addition of vinblastine increased toxicity and did not improve the response rate or prolong survival. Side effects included fatigue, fever, chills, myalgias, headaches, anorexia, nausea, diarrhea, and dizziness. Mild abnormalities in hematologic and liver function tests occurred in some patients. Most adverse effects diminished or resolved with continued therapy. We conclude that rIFN alpha 2a offers important therapeutic benefit in a select group of patients with AIDS-related KS.

AIDS-related Kaposi's sarcoma: a review of its pathogenesis and treatment.

One of the most unusual manifestations of the acquired immunodeficiency syndrome is the cutaneous tumor, Kaposi's sarcoma. This rare and indolent tumor was once thought of as an interesting curiosity in Europe and Africa prior to the recognition of AIDS. Currently, however, this tumor accounts for approximately one quarter of all cases of AIDS recognized in the United States, and while not the proximate cause of death in most cases, Kaposi's sarcoma may cause severe physical and psychological morbidity in many patients. Treatment approaches must incorporate an understanding of the severe immunologic impairment in these individuals as well as their relatively poor tolerance to the myelosuppressive effects of many therapeutic agents. Treatment for Kaposi's sarcoma includes chemotherapy and radiation therapy, and more recently antiretroviral agents and immunomodulators in patients with indolent disease. Prophylactic treatment for Pneumocystis carinii pneumonia as well as nutritional and psychological support, and pain control are also important aspects of the care of these patients. This review will focus on the pathogenesis and natural history of Kaposi's sarcoma and review the treatment approaches and limitations of therapy for this tumor.

Intravenous recombinant tumor necrosis factor in the treatment of AIDS-related Kaposi's sarcoma.

Tumor necrosis factor (TNF) has demonstrated antitumor activity against a variety of tumors and is particularly cytotoxic to capillary endothelial cells, which are the presumed cell of origin of Kaposi's sarcoma. We evaluated the toxicity and clinical antitumor and antiretroviral effects of recombinant TNF administered at a once weekly dose of 100 micrograms/m2 intravenously for 8 weeks in five men with AIDS-related Kaposi's sarcoma and without prior opportunistic infection. One patient was removed from study at week 4 due to rapid progression of Kaposi's sarcoma, another patient with stage IV disease and a pretreatment CD4 count of 11 developed fever, hypotension, and pneumonia at week 7 and died 8 days after discontinuing recombinant TNF. No pathogenic organisms were isolated. He had marked eschar formation of his Kaposi's sarcoma lesions, particularly in areas previously exposed to radiation therapy. Uniform toxicities included fevers, rigors, and headaches during drug infusion that were ameliorated by prophylactic meperidine hydrochloride and acetaminophen. All experienced fatigue and three had arthralgias. One patient had transient hypotension which corrected with i.v. fluids. No significant hematologic, hepatic, or renal toxicities were seen. All patients had some progression of their Kaposi's sarcoma on study. There was no change in CD4 or CD8 count or in CD4:CD8 ratios. Serum human immunodeficiency virus (HIV) p24 antigen levels increased greater than 50% in three patients. We conclude that, as a single agent, at a dose of 100 micrograms/m2 recombinant TNF by i.v. infusion has no obvious antitumor or antiretroviral effects in patients with AIDS-related Kaposi's sarcoma.

Phenotypically defined memory CD4+ cells are not selectively decreased in chronic HIV disease.

Simultaneous measurements of phenotypically defined memory CD4+ cells and in vitro proliferation to three recall antigens (Ags; tetanus toxoid, influenza, and Candida albicans) were performed in 53 HIV-seropositive subjects and 39 HIV-seronegative controls. The results indicate that the low proliferative responses to recall Ags of those who were HIV infected could be partly, but not fully, explained by a decrease of phenotypically defined memory CD4+ cells. This is, to our knowledge, the first report of experiments that simultaneously measured memory CD4+ cell numbers and function and then examined whether the low responses observed in seropositive subjects could be explained by low numbers of phenotypically defined memory CD4+ cells. A central finding of the study, which argues against prevailing dogma, was that within the CD4+ lymphocyte population, the proportion of cells displaying the memory phenotype was not selectively decreased in HIV-seropositive subjects as compared with the proportion of these cells in seronegative homosexual controls. An entirely new finding of the study was that AIDS patients, many of whom were unresponsive to all three recall Ags tested, actually had a significant increase in the proportion of CD4+ cells with the memory phenotype, and this fraction approached 100% in subjects with CD4+ cell numbers that were near zero. A final observation of the study, possible because some patients were on zidovudine (ZDV), was that there was no evidence that ZDV treatment led to an increased proliferative response to recall Ags in vivo. An in vitro study also found no effect of ZDV, dideoxycytidine (ddC), or azido-dideoxyuridine (AZU) on proliferative responses to recall Ags.

Eleven lymphoid phenotypic markers in HIV infection: selective changes induced by zidovudine treatment.

HIV infection induces substantial changes in the expression of many lymphocyte phenotypic markers as well as depletion of CD4 lymphocyte numbers. A comprehensive study was undertaken to determine whether seven lymphocyte phenotypic changes associated with HIV infection (increased CD38, HLA-DR, CD57, and CD71 and decreased CD11b, CD45RA, and leu-8) are altered by zidovudine (ZDV) administration. Levels of the four major lymphoid subsets (CD4, CD8, B, and NK cells) and changes in the serum activation markers neopterin and beta 2-microglobulin (beta 2M) were also measured. Elevated pretreatment expression of CD38 and CD71 was reduced significantly toward normal at 2 weeks by ZDV; however, CD38 and CD71 returned to pretreatment levels at different rates. The kinetics of CD38 reduction and the return to pretreatment levels were similar to those of serum neopterin and beta 2M. HLA-DR decreased in many but not all subjects. CD4 lymphocytes showed a transient increase, most evident at 8 weeks of treatment. Lymphoid phenotypes that did not show significant changes after ZDV therapy included CD57, CD11b, CD45RA, and leu-8 markers as well as CD8 T cells, CD20 B cells, and CD56 NK cells. The fact that some lymphocyte phenotypic markers change toward normal with ZDV treatment and others do not indicates that complex processes underlie immune perturbations of HIV infection. Several phenotypic markers (CD38, CD71, and HLA-DR) that are susceptible to short-term effects of ZDV (but with changes that differ from CD4 T cell changes) are surrogate marker candidates for evaluation in anti-HIV treatment.

The effect of zidovudine treatment on serum neopterin and beta 2-microglobulin levels in mildly symptomatic, HIV type 1 seropositive individuals.

Sixty-one subjects with mildly symptomatic human immunodeficiency virus (HIV) infection were included in a double-blind, randomized, placebo-controlled trial of zidovudine (part of AIDS Clinical Trials Group protocol 016, ACTG 016) to evaluate changes in the serum immune activation markers neopterin and beta 2-microglobulin (beta 2M) as early markers of the antiviral effect of zidovudine on HIV type 1 (HIV-1) infection. The mean values of serum neopterin and beta 2M levels in 27 placebo-treated subjects tended to increase with time. The mean value of neopterin in 34 subjects receiving zidovudine decreased at 4 weeks (15.76 nmol/L before treatment to 12.73 nmol/L, p = 0.001). The maximum reduction was seen at 8 weeks of treatment (10.78 nmol/L, p less than 0.0001). Subsequently, the mean value of serum neopterin increased but remained below the pretreatment value for more than a year. Serum beta 2M levels decreased (from 3.01 to 2.69 mg/L at 4 weeks, p = 0.01) and reached the lowest level at 8 weeks (2.45 mg/L, p = 0.0002) in zidovudine recipients. The mean beta 2M level returned to pretreatment value at approximately 24 weeks of the treatment. There was a close correlation between changes from baseline in serum neopterin and beta 2M during the first 16 weeks of the zidovudine therapy, but not later. Subjects with greater reductions of serum neopterin or beta 2M tended to maintain lower levels of these markers with continued zidovudine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Gene therapy for the treatment of AIDS: animal models and human clinical experience.

Although antiretroviral drug therapy has had a significant impact on the natural history of HIV infection, complete virus eradication still remains an unattainable goal. Drug-mediated virological control only occurs transiently, in part as a result of the development of drug resistance. Gene therapy for the treatment of AIDS is a promising area of research that has as its goal the replacement of the HIV-infected cellular pool with cells engineered to resist virus replication. A variety of anti-HIV genes have been designed and tested in laboratory systems, and available results from pilot clinical trials demonstrate the safety and feasibility of this approach. Obstacles to effective application of this technology include partial protection of HIV resistance genes, lack of effective vectoring systems, and unregulated gene expression. Herein, we review recent advances in transduction methods, data from in vivo preclinical studies in relevant animal models, and emerging results derived from pilot clinical gene therapy studies.

Clinical variants and staging of Kaposi's sarcoma.

Kaposi's sarcoma (KS) in the acquired immunodeficiency syndrome (AIDS) is a new and aggressive presentation of a previously rare malignancy. Variation in the clinical course of this disease and its response to treatment suggest that clinical or immunologic parameters may be important in its prognosis. A review of the clinical staging systems for epidemic (AIDS-related) KS (EKS) suggests an improved survival with lower tumor stages, the lack of prior opportunistic infections, and the absence of systemic symptoms. In addition, retrospective analysis of 16 immune parameters for their prognostic value showed that total CD4 (T4) cell numbers and the CD4:CD8 ratio correlated most closely with survival. Response to treatment with recombinant alpha-interferon did not correlate with tumor stage, but was more frequent in patients without systemic symptoms or prior opportunistic infections. Several studies suggest that treatment response is associated with a greater degree of intact T cell function. These findings point out the importance of cellular immunity in the prognosis of patients with EKS.

Simultaneous occurrence of Hodgkin's disease and Kaposi's sarcoma in a patient with the acquired immune deficiency syndrome.

Kaposi's sarcoma and Hodgkin's disease have each been associated with abnormalities in T lymphocyte function and occur with increased frequency in the immunosuppressed host. Although the association of Kaposi's sarcoma with lymphoreticular disorders has long been recognized, only sporadic cases of Hodgkin's disease have been described in patients with the acquired immune deficiency syndrome (AIDS) in contrast to the frequent occurrence of non-Hodgkin's lymphoma in these patients. The simultaneous occurrence of Kaposi's sarcoma and Hodgkin's disease in the same lymph node is described in a patient with AIDS. This case suggests an association of AIDS with both Kaposi's sarcoma and malignant lymphomas and raises the question of a common pathogenetic mechanism.

Characterization of a distinct subgroup of high-risk persons with Kaposi's sarcoma and good prognosis who present with normal T4 cell number and T4:T8 ratio and negative HTLV-III/LAV serologic test results.

Three homosexual male patients with biopsy-proved Kaposi's sarcoma were classified as having the acquired immune deficiency syndrome (AIDS) by Centers for Disease Control criteria when first seen in 1983 and 1984. These patients, however, differed from most patients with AIDS and Kaposi's sarcoma in having normal CD4 cell numbers and normal CD4:CD8 ratio. Furthermore, these immunologic parameters remained normal for eight to 24 months of follow-up, and the disease did not progress. Results of recent testing of serum from these patients were negative for HTLV-III/LAV antibodies. The Kaposi's sarcoma was limited to skin (stage I tumors) and the patients did not have persistent lymphadenopathy, fever, night sweats, or weight loss. In contrast to AIDS, the serum immunoglobulin levels (IgG, IgA, IgM) and number of B cells that were spontaneously forming immunoglobulin were within normal range with no evidence of polyclonal activation. The lymphocyte proliferative responses to phytohemagglutinin and Candida were reduced in two of the three patients, and skin test anergy was observed in the two patients tested. These findings are not frequently encountered in other healthy, homosexually active men or in classic Kaposi's sarcoma. They may be indicative of functional T cell changes (without numerical changes) induced by factors other than HTLV-III/LAV virus, which made these homosexually active men susceptible to development of low-grade Kaposi's sarcoma lesions.

Detection of non-HLA antigens: effect of lymphocyte priming and amplification signals.

We studied three potential mechanisms that might account for the difficulty in detecting non-HLA antigenic disparities between HLA-identical siblings: (1) a low frequency of antigen-reactive cells; (2) the failure of antigen recognition to trigger proliferation or cytotoxicity; and (3) the development of suppressor cells or factors. In vitro sensitization was used to increase the frequency of antigen-reactive cells. Allogeneic lymphocytes or supernatants from mixed lymphocyte cultures were used to provide nonspecific proliferative signals. Neither approach was successful in facilitating the detection of proliferation or cytotoxicity between HLA-identical siblings. Furthermore, we found no evidence for the development of antigen-specific suppressor cells or factors. These data indicate that other mechanisms must underlie the difficulty in detecting non-HLA antigens in vitro.

Human T-cell leukemia virus infection in non-intravenous drug using HIV seropositive men in Los Angeles.

Sera from 634 homosexual men with Western blot-confirmed human immunodeficiency virus (HIV) infection were subjected to radioimmunoprecipation assay (RIPA) using an HTLV-I-infected human T-cell line (SLB-I). Sera obtained from Japanese adult T-cell leukemia patients, noninfected healthy individuals served as positive and negative controls. HIV-infected groups were comprised of asymptomatic homosexuals (n = 131), AIDS-related complex (n = 115), Kaposi's sarcoma (n = 300), AIDS-defining opportunistic infections (n = 76), and high-grade lymphomas (n = 12). Only two patients were known to be intravenous drug users. No instances of dual retroviral infection were detected. As a corollary, no cross reactivity between HTLV and HIV gene products was noted by RIPA. We conclude that HTLV infection is uncommon among select groups of HIV seropositive homosexuals who do not engage in intravenous drug abuse. Additional studies examining the seroprevalence and consequence of HTLV infection in broader based populations at risk for retroviral infection are required.

Kaposi's sarcoma in the acquired immunodeficiency syndrome.

Kaposi's sarcoma is the most common malignancy seen in association with AIDS. Although the pathogenesis of AIDS-KS has not been clearly established, the clinical course and prognosis are closely related to the patient's immune status, prior history of opportunistic infection, and hematologic status. Treatment methods include local or regional radiation therapy, cytotoxic chemotherapy, and interferon therapy. Evaluation of the results of clinical therapeutic studies in this tumor should consider its natural history and peculiar biologic behavior and associated complications of AIDS. Effective treatment strategy would take into account the immune status of the patient, the rate of progression of tumor, the presence or risk of developing life-threatening opportunistic infections, associated hematologic or neurologic abnormalities, the toxicities of treatment, and the desire of the patient for treatment. Investigations of antiviral, antiproliferative, and immunomodulating agents singly or in combination currently are in progress. Additionally innovative approaches with biologic response modifies, adjunctive hematopoietins, and growth factor modulators may lead to newer approaches to the control of this malignancy.