Pathogenesis of AIDS--related Kaposi's sarcoma. Evidence of a viral etiology

Variability of HHV8 LNA-1 Immunohistochemical Staining Across the 3 Histologic Stages of HIV-Associated Mucocutaneous Kaposi Sarcoma: Is There a Relationship to Patients' CD4 Counts?

The histologic diagnosis of Kaposi sarcoma (KS) can be confirmed with human herpes virus 8 (HHV8) latency-associated nuclear antigen (LNA)-1 immunohistochemistry, which may show variability in distribution and intensity. This retrospective study was aimed at addressing the factors that may contribute to this variability. All cases of mucocutaneous KS diagnosed in a 5-year period at the histopathology department at a tertiary hospital in South Africa with available patients' CD4 counts and HHV8 LNA-1 immunohistochemically stained slides were reviewed, and the biopsy stages of KS (patch/plaque/nodular), CD4 counts, immunohistochemistry staining method (manual vs. automated), and distribution (diffuse/focal) and intensity (strong/weak) of HHV8 LNA-1 staining were recorded. A total of 127 cases were reviewed. No relationship was demonstrated between the median CD4 count and the histologic stages of KS (P = 0.701) or the intensity and distribution of HHV8 immunohistochemical staining using either staining method. Multivariate analysis showed that method of immunohistochemical staining was a significant predictor of distribution (P = 0.006) and intensity (P = 0.044) of staining, and that stage was a significant predictor of distribution of staining (P = 0.033).

Otolaryngologic manifestations of human immunodeficiency virus infection

The otolaryngologist is uniquely positioned to detect and pursue manifestations of HIV in the head and neck. The presentation of problems subsequent to HIV infection is quite varied, but close investigation will often reveal treatable problems.

Human herpesvirus 8

Human herpesvirus 8 (HHV 8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV) is a g2 herpesvirus and the most recently identified human tumor virus. HHV 8 has been consistently implicated in the pathogenesis of all clinical variants of Kaposi's sarcoma, as well as in the plasma cell variant of multicentric Castleman's disease and primary effusion lymphomas. Pathogenicity of the virus is increased in the host who is immunosuppressed, either iatrogenically or through H1V-1 infection. The HHV 8 genome contains several homologues of cellular genes that regulate cell growth and differentiation, and the exact mechanisms of the virus' oncogenicity using molecular piracy are still being investigated and elucidated. In this article, the authors review the epidemiology, transmission, clinical manifestations, and molecular genetics of HHV 8 infection and provide a summary of the current treatment modalities available to the clinician.

Effect of treatment on health-related quality of life in acquired immunodeficiency syndrome (AIDS)-related Kaposi's sarcoma: a randomized trial of pegylated-liposomal doxorubicin versus doxorubicin, bleomycin, and vincristine

The purpose of this study was to determine whether health-related quality of life (HRQL) would be improved in patients with acquired immunodeficiency syndrome (AIDS)-related Kaposi's sarcoma treated by pegylated-liposomal doxorubicin (PLD) as compared to those treated by a conventional combination of doxorubicin, bleomycin, and vincristine (ABV). One hundred thirty-three patients received PLD and 125 patients received ABV every 2 weeks with a planned total of 6 cycles. Patients completed a 30-item AIDS-related HRQL questionnaire before beginning treatment (baseline), every 2 weeks while on treatment, and about 21 days after the end of treatment. Twenty-two items, involving nine domains, were analyzable. While on treatment, PLD-treated patients with partial clinical responses achieved statistically significant greater improvement (compared to baseline) in general health than did ABV-treated patients with partial clinical responses (rho = 0.008). By the end of treatment, the overall group of patients receiving PLD showed statistically significant greater improvement in pain and energy/fatigue than did the group receiving ABV (rho = 0.01-0.002). In addition, duration of clinically significant improvement in global QL was longer in the PLD arm.

The epidemiologic, pathologic, and clinical features of AIDS-associated pulmonary Kaposi's sarcoma

AIDS-related Kaposi's sarcoma (KS) occurs principally in homosexual or bisexual men infected with the newly identified human herpes virus-8, also called KS-associated herpes virus. Unlike classical forms of the disease, AIDS-associated KS is a multicentric entity that frequently involves lymph nodes and the GI tract. KS may also occur in the lung, commonly in the setting of extensive mucocutaneous disease and very rarely as an isolated event. The exact incidence of intrathoracic KS in patients with AIDS is unknown. Before the advent of highly active antiretroviral therapy (HAART), pulmonary KS had been reported in approximately 10% of patients with AIDS, 25% of patients with cutaneous KS, and in roughly 50% of postmortem examinations of patients with AIDS, KS, and respiratory infections. In the HAART era, the incidence of KS has declined precipitously in North America and Europe but not in third world countries where HAART is largely unavailable. Pulmonary KS may cause radiographic infiltrates and respiratory symptoms that mimic a variety of other infectious and neoplastic processes. An aggressive diagnostic evaluation of patients who have this condition is essential because chemotherapy and radiation therapy may provide significant palliation, particularly if used in conjunction with HAART. This review briefly explores the changing epidemiology of KS. The pathology and pathogenesis of KS is also reviewed, along with the clinical and radiographic presentation, diagnosis, and management of pulmonary KS.

Treatment of AIDS-related cutaneous Kaposi's sarcoma with topical alitretinoin (9-cis-retinoic acid) gel. Panretin Gel North American Study Group

BACKGROUND

Kaposi's sarcoma (KS) is the most frequent malignancy in patients with HIV. Given the promise that retinoids show in the treatment of various hyperproliferative skin disorders and in vitro evidence of inhibition of proliferation of KS cells, a randomized, controlled clinical trial was conducted.

METHODS AND RESULTS

A 12-week, multicenter, randomized, double-blind, vehicle-controlled safety and efficacy evaluation of topical alitretinoin 0.1% gel applied to cutaneous KS lesions was conducted in HIV-infected patients. The primary efficacy endpoint was the patient's response rate, as determined by evaluating six index lesions representative of the patient's overall KS cutaneous disease using AIDS Clinical Trials Group (ACTG) response criteria applied to topical therapy. Of 268 patients entered in the blinded treatment phase of the study (alitretinoin group, n = 134; vehicle group, n = 134), 47 patients (35%) treated with alitretinoin 0.1% gel had a positive response, compared with 24 patients (18%) treated with vehicle gel. Of 184 patients receiving open-label alitretinoin treatment following the blinded phase of the trial, 90 patients (49%) met criteria for a positive response. This superior efficacy of alitretinoin gel over vehicle gel was maintained when the data were adjusted or analyzed for age, race, Kamofsky scores, baseline CD4+ lymphocyte counts, number of raised lesions at baseline, and aggregate area of index lesions. Alitretinoin 0.1% gel was superior to vehicle gel regardless of the number of concurrent antiretroviral therapies. Most adverse events were mild to moderate in severity, limited to the application site, and reversible on reduction in frequency or suspension of application. Relatively few patients (7%) discontinued alitretinoin therapy because of to related adverse events.

CONCLUSIONS

The results show that alitretinoin gel application is safe and generally well tolerated, and they indicate the superiority of alitretinoin 0.1% gel over vehicle gel in the treatment of cutaneous AIDS-related KS lesions.

Modulation of the NF-kappa B pathway by virally encoded death effector domains-containing proteins

Death Effector Domains (DEDs) have been known to mediate the recruitment of Caspase 8 and its homologs to the aggregated death-inducing signaling complex (DISC), consisting of the death domain (DD)-containing receptors and various signaling proteins. In addition, several viruses were recently shown to encode proteins with DEDs (also called FLICE inhibitory proteins or vFLIPs) which have the ability of blocking cell death induced by DD-containing receptors. We provide evidence that vFLIPs can also modulate the NF-kappaB pathway and physically interact with several signaling proteins, such as the TRAFs, RIP, NIK and the IKKs. Modulation of the NF-kappaB pathway may play a role in the natural history of infection by these viruses.

Comparison of molecular changes in cervical intraepithelial neoplasia in HIV-positive and HIV-indeterminate subjects

OBJECTIVE

HIV infection is associated with an increased incidence of cervical malignancy and its precursor lesions (CIN, cervical intraepithelial neoplasia) compared with the general population. We studied the molecular abnormalities in the development of HIV-associated CIN and compared them with those present in CINs arising in HIV-indeterminate subjects ("sporadic CIN").

METHODS

We investigated the presence of human papilloma virus (HPV) sequences, loss of heterozygosity (LOH), and microsatellite alterations (MAs) at five 3p chromosomal regions using 17 polymorphic markers in precisely microdissected archival tissues from 16 HIV-positive CINs and compared them with those present in 39 sporadic CINs.

RESULTS

HPV sequences were detected in 36 of 55 (66%) CIN lesions, and high-risk oncogenic strains (HPV 16 and 18) accounted for 15 of them. No differences in the HPV frequencies were found between HIV-associated and sporadic CINs. Allelic losses at one or more chromosome 3p regions were frequently detected in CIN lesions (49%). The overall frequency of 3p LOH and the frequencies at all individual regions were similar in HIV-associated and sporadic CINs. The frequency of MA present in the HIV-associated CIN cases (0.093) was sixfold greater than in sporadic CINs (0.014; P = 0.0001). At least 1 MA was present in 11 (69%) of 16 HIV-associated vs. 5 of 39 (13%) sporadic CIN (P = 0.0006). Molecular changes were independent of the presence of HPV sequences.

CONCLUSION

Chromosome 3p deletions are frequently detected in the precursor lesions of cervical carcinoma (CIN) and there are no differences in the 3p LOH frequencies between HIV-associated and sporadic CIN lesions. Microsatellite alterations, which reflect widespread genomic instability, occur at greatly increased frequency in HIV-associated CIN. Although the mechanism underlying the development of increased MAs is unknown, it may play a crucial role in the development of many HIV-associated neoplasias.

Pathogenesis of non-AIDS-defining cancers: a review

As the AIDS epidemic advances, the number of HIV-infected subjects developing AIDS-related neoplasms is rapidly increasing, and the spectrum of malignancies encountered is expanding. Several non-AIDS-defining cancers are being reported at an increasing incidence in HIV-infected individuals, including anal, skin, oral mucosa, head and neck and lung carcinomas, testicular tumors, and pediatric soft-tissue sarcoma. There appears to be an emerging role for various concurrent viral infections in the HIV-infected host that are likely implicated in the pathogenesis of some nondefining-AIDS neoplasms. Our recent findings in HIV-associated lung cancers and in the precursor lesions of cervical carcinoma suggest that wide-spread genomic instability, as manifested by the development of increased numbers of microsatellite alterations (MAs), may occur frequently in HIV-associated tumors and they may play an important role in the pathogenesis of those neoplasms. Although the mechanism underlying the development of increased MAs is unknown, it may play a crucial role in the development of many HIV-associated tumors. It will be important to track the epidemiological and biological features of non-AIDS-defining cancers in HIV-infected patients, and compare them to those tumors in the general population. It is likely that further clues about malignant transformation and oncogenesis unraveled in the HIV setting will have broad clinical implications.

Sensitization of AIDS-Kaposi’s Sarcoma Cells to Apo-2 Ligand-Induced Apoptosis by Actinomycin D

Kaposi’s sarcoma (KS) is the most frequent malignancy associated with HIV infection (AIDS-KS), a complication that leads to high mortality and morbidity. AIDS-KS cells are resistant to killing by chemotherapeutic drugs/NK cells and Fas-induced apoptosis, suggesting that the acquisition of antiapoptotic characteristics by AIDS-KS cells may contribute to their prolonged survival. Apo-2 ligand (Apo-2L)/TNF-related apoptosis-inducing ligand, a new member of the TNF family, has been identified as an apoptosis-inducing molecule. In this study we examined the sensitivity of 10 different AIDS-KS isolates to Apo-2L-mediated cytotoxicity. AIDS-KS cells were relatively resistant to Apo-2L; however, Apo-2L and actinomycin D (Act D) used in combination synergistically potentiated the induction of cell death in nine of the 10 isolates. Apo-2L induced apoptosis in >80% of AIDS-KS cells pretreated with Act D. The caspase inhibitors, zIETD-fmk and zDEVD-fmk, inhibited apoptosis in AIDS-KS by sApo-2L, suggesting that caspase 3-like and caspase 8 or 10 activities are essential for Apo-2L-mediated apoptosis. Act D treatment of AIDS-KS cells markedly and selectively down-regulated Bcl-xL expression, while the expressions of decoy receptors 1 and 2, Bax, cellular FLICE (Fas-associated death domain protein-like IL-1-converting enzyme) inhibitory protein, FADD (Fas-associated death domain protein), procaspase 8, and p53 were not affected. These findings suggest the possible involvement of Bcl-xL in Act D-induced sensitization of AIDS-KS cells to Apo-2L-mediated apoptosis. Furthermore, Act D did not sensitize PBMC or fibroblast cells to Apo-2L. Thus, Apo-2L and Act D used in combination may be of therapeutic value in the treatment of AIDS-KS.

Clinical overview: issues in Kaposi's sarcoma therapeutics

Four questions are posed that are critical to the development of improved therapeutic and prophylactic strategies for Kaposi's sarcoma (KS). 1) Can we predict who will develop KS? Accurate identification of high-risk factors for KS development is essential for the development of KS prophylaxis trials. 2) Can developing insights into KS pathogenesis be translated into improved therapeutic and/or new prophylactic strategies for patients at high risk? Several approaches are being developed that target new blood vessel development, inflammatory cytokines, and the viruses that are implicated in KS pathogenesis. 3) How does the improved prognosis for human immunodeficiency virus (HIV)-infected patients affect KS treatment strategy? Improved anti-HIV therapy has implications for the timing of KS therapy, the choice of therapeutic approaches, and the potential for adverse drug interactions. 4) How can we best evaluate benefits from KS treatment? More rigorous, standardized criteria are in development and will be essential not only for accurate documentation of objective tumor regression, but also for assessment of tumor-associated symptom relief in a quantitative, function-oriented way.

Regression of acquired immunodeficiency syndrome-related pulmonary Kaposi's sarcoma after highly active antiretroviral therapy

Kaposi's sarcoma (KS) is the most common neoplasm affecting people with the human immunodeficiency virus (HIV) infection. The skin is the most common site of disease; however, KS can also involve visceral organs such as the lungs, leading to severe morbidity and contributing to death in almost 30% of patients with the acquired immunodeficiency syndrome (AIDS). New antiretroviral strategies incorporating combination nucleoside analogues with a protease inhibitor lead to increased circulating CD4+ lymphocyte counts, decreased plasma levels of HIV, and decreased mortality from AIDS-defining opportunistic infections. The effects of highly active antiretroviral therapy (HAART) on AIDS-associated KS remain largely unknown. Herein the case of an antiretroviral-naive man with advanced AIDS (CD4+ helper T-lymphocyte count, 35/mm3; HIV viral RNA quantification, more than 800,000 copies/mL), and symptomatic pulmonary KS is described. After HAART was initiated, his CD4+ cell count increased fourfold, his HIV-viral load decreased to nondetectable levels, and the pulmonary KS regressed dramatically. To my knowledge, this report represents the first documented case of pulmonary KS regression after the initiation of HAART. Although this finding is preliminary, if confirmed by other clinicians, the effect of potent antiretrovirals on KS growth and development will have important implications on the manner in which KS is staged and treated.

Kaposi's sarcoma and human herpesvirus-8

KS is a major cause of morbidity and mortality among AIDS patients and a treatment problem in the sporadic cases that are not associated with HIV. All four forms of the disease are linked to a newly described herpesvirus, HHV-8 or KSHV, via strong epidemiologic associations and biologic plausibility as a causal agent. HHV-8 is also epidemiologically associated with body cavity-based lymphomas, which are almost unique to AIDS, and Castleman's disease. Existing radiation and chemotherapeutic treatments of KS are only partially effective and cause significant adverse effects. New preventive approaches and therapies aimed at inhibiting HHV-8 may be effective. New treatments that interfere with the molecular mechanisms that drive KS may, in the future, provide the best opportunities to control the disease.