Disseminated Kaposi's sarcoma in AIDS: histogenesis-related populations and influence of long-term treatment with rIFN-alpha A

Progressive HHV-8-positive classic Kaposi's sarcoma: rapid response to interferon alpha-2a but persistence of HHV-8 DNA sequences in lesional skin

The pathogenesis of Kaposi's sarcoma (KS) is often attributed to an infectious agent. In particular, the human herpesvirus 8 (HHV-8) was currently shown to be closely related to all known KS types, including HIV-associated KS, European classic KS, African endemic KS and iatrogenic KS. We report here on an HIV-negative, German patient of neither Jewish nor Mediterranean descent with disseminated classic KS showing unusual rapid progression into the tumour stage. After systemic administration of interferon alpha-2a over 4 weeks all tumour lesions cleared completely. Interestingly, HHV-8 DNA sequences detected by nested polymerase chain reaction in KS lesions before the onset of treatment were still present in lesional skin after complete remission of the tumour. No recurrence was seen after a follow-up period of 6 months.

Factor-XIIIa-expressing dermal dendrocytes in Kaposi's sarcoma

The histogenetic origin of Kaposi's sarcoma is a matter of controversy, with recent reports claiming it to derive from the factor-XIIIa-positive dermal dendrocyte rather than endothelial cells. We investigated the potential role of factor-XIIIa-positive dermal dendrocytes in the genesis of both classical (endemic) and immunosuppression-associated Kaposi's sarcoma. Thirteen cases of classical and 16 cases of immunosuppression (mostly AIDS)-associated Kaposi's sarcoma were immunostained with antibodies to factor XIIIa and to the blood-group antigen H, recognizing endothelial cells. Factor-XIIIa-positive cells were consistently antigen-H-negative and represented only a small percentage (usually less than 10%) of the proliferative cells. Their relative density tended to be decreased in immunosuppression-associated Kaposi's sarcoma when compared with that of the classical form. These results do not support the view that dermal dendrocytes may be the cells of origin of Kaposi's sarcoma; conversely, their decreased density in cases of immunosuppression-associated Kaposi's sarcoma could be related to immunosuppression and may account for more rapid tumour growth.

Changes in Kaposi's sarcoma induced by dapsone

The authors describe the clinical and histological changes in well-established classic Kaposi's sarcoma lesions during 2-years therapy with dapsone. Both the patients noted a great improvement in their symptoms. Clinical examination did not show significant modifications of the lesions. Histology showed a striking reduction in the spindle-cell component and an increase in the number of mature vessels. Immunohistochemistry with an endothelial cell marker (FVIIIRAg) confirmed the presence of an increased number of mature vessels after treatment. This study seems to confirm that dapsone can modify well-established lesions of classic Kaposi's sarcoma.

Long-term therapy of HIV-associated Kaposi's sarcoma with recombinant interferon alpha-2a

Five young male patients with HIV-associated Kaposi's sarcoma (KS) were treated with recombinant interferon alpha 2a (rIFN-alpha-2a) over a period of 2-2.5 years. An IFN dose of 18 x 10(6) IU was given subcutaneously every day during the first 3 months of treatment and then on alternate days. Additional treatment with radiotherapy and laser therapy was given and, in some cases, isolated skin nodules were excised. Within 7 months of initiation of therapy one patient had a complete remission of his tumours, however, tumour progression recurred after the patient discontinued treatment. In another patient the tumour cleared within 9 months of rIFN therapy, and after 52 months he is still free of KS. The condition of a third patient tended to become stabilized during the first 6 months of therapy, but after 60 months there has been a slow progression. The fourth and fifth patients died 25 and 28 months, respectively, after the histological diagnosis of KS and the initiation of treatment. While on therapy with rIFN-alpha-2a, no life-threatening opportunistic infections occurred. The side-effects were mostly well tolerated, and no severe changes in haematological parameters were caused by the therapy.

Effects of rIFN alpha, beta, and gamma on the morphology, proliferation, and cell surface antigen expression of human dermal microvascular endothelial cells in vitro

The influence of recombinant human interferon alpha 2a (rIFN alpha), recombinant human interferon beta 1 (rIFN beta), and recombinant human interferon gamma (rIFN gamma) on human dermal microvascular endothelial cells (HDMEC) cultured in vitro was studied in various rIFN concentrations (0.1 IU/ml-10(4) IU/ml) over 2, 3, 4, 6, 8, and 10 d. Cell morphology and ultrastructure, cell proliferation, expression of class II alloantigens (HLA-DR and HLA-DQ), and intercellular adhesion molecule-1 (ICAM-1) were investigated using an in vitro technique established in our laboratory. All rIFN tested induced alterations of typical HDMEC morphology; the cells became spindle-shaped and fibroblastoid, although they maintained their endothelial cell marker expression. Also, all IFN dose- and time-dependently inhibited the proliferation of HDMEC in vitro (rIFN alpha greater than beta greater than gamma), whereby rIFN alpha exerted the strongest growth-inhibitory effect. Alkaline phosphatase anti-alkaline phosphatase (APAAP) immunocytochemistry of the cultured cells showed dose- and time-dependent stimulation of ICAM-1 and class II antigen expression only by rIFN gamma (HLA-DR greater than HLA-DQ), rIFN alpha and beta did not exert any immunomodulatory activity on HDMEC in vitro. These results indicate that HDMEC are an important target for the action of IFN. Besides growth inhibition, it seems that rIFN gamma in particular may be involved in the modulation of leucocyte adhesion and trafficking by altering the immunophenotype of the endothelial cell population.

Long-term follow-up of 120 patients with AIDS-related Kaposi's sarcoma treated with interferon alpha-2a

One hundred and twenty patients suffering from an AIDS-related Kaposi's sarcoma treated by 18 million units of recombinant alpha-2A-interferon daily were followed prospectively for a period of between one and six years. An overall complete response was observed in 35% of these patients; the figure was significantly higher in those who did not have a visceral localization or opportunistic infections. Total lymphocyte count, CD4 lymphocyte count, and CD4/CD8 ratio were significantly higher, and beta-2-microglobuline significantly lower, in the responders than in the non-responders. A multivariate analysis showed that localization of KS and CD4 count had independent predictive value, with an odds ratio of 35 for patients who had more than 300 CD4 cells at the onset of treatment versus those with less than 150. Patients whose initially negative p24 antigenemia remained negative during treatment had the highest frequency of complete response. Among patients with initially positive p24 antigenemia, those whose percentage decrease in antigenemia levels was greatest had a higher frequency of complete response. The cumulative probability of survival in responders was 62% at four years. These results demonstrate an anti-tumoral and anti-viral effect and prolonged survival in a group of patients whose initial immune parameters were relatively well preserved. However, these results do not permit us to conclude whether these well-responding patients were treated at the onset of illness, or whether their illness was naturally less evolutive.

Biologic effects of interferons

If one were to review articles on IFN published between 1957 and 1967 it would become apparent that virtually none of the tenets held then are still valid today. Whereas IFN was long considered to be a specific antiviral substance without any effect on normal cellular metabolism, we accept today that it affects normal cell division and many specialized cellular functions. In this respect it is not unique; IFN is a prototype of a family of similar substances now called cytokines that all appear to function as regulatory molecules. It was held that the production of IFN constituted a specific response to a viral infection. Today we believe that IFN is an integral part of a cytokine network and that they and other cytokines may be produced constitutively at low levels. These substances exert multiple effects on virtually all cells. They play an important role in host defense against viral and parasitic infections, and in the resistance to experimental tumors. IFN can be shown to exert effects on the immune system and on lymphocyte circulation. Lastly, because of the multiplicity of their biologic effects, they may even contribute to the pathogenesis of certain diseases. Thus, when large amounts of IFN are administered or induced in newborn mice they can cause liver, kidney, and pulmonary disease. The field of IFN and cytokine research continues to expand and there is an increasing number of therapeutic applications. Twenty years from now, scientists and clinicians may be surprised that we understood so little of how IFN act and how inadequately we used them to treat disease.

Non-AIDS-associated Kaposi's sarcoma (classical and endemic African types): treatment with low doses of recombinant interferon-alpha

In the treatment of the classical and endemic African forms of Kaposi's sarcoma (KS), radiation therapy and chemotherapy have been widely used with varying degrees of success and morbidity. We here report our preliminary experiences with low doses of recombinant interferon alfa-2b (rIFN alpha-2b) in the treatment of these types of KS, non-linked to the acquired immunodeficiency syndrome (AIDS). Ten consecutive patients (eight patients with classical and two with endemic KS) with a median age of 62 years were treated long-term with 5 X 10(6) units of rIFN alpha-2b (Introna) given subcutaneously three times weekly for at least 6 months. Of the 10 patients, six presented with cutaneous disease only, and four had additional visceral involvement. After 6 months of treatment, seven of the 10 patients had a major response of the cutaneous lesions, and three patients showed stable skin diseases. Of the four patients with additional visceral disease, one patient showed a complete regression of an intramyocardial tumor involving the right atrium and ventricle, whereas in the three other patients stabilization of the visceral lesions with marked symptomatic improvement occurred. On the whole, the long-term results over a median duration of 12 months (range, 7 to 30) are also satisfactory: IFN-alpha continued to control KS in all patients. The treatment was generally well tolerated; no serious side effects were observed. Our preliminary data suggest that low-dose rIFN alpha-2b regimens are effective in classical and endemic African KS. However, further studies are needed to establish the exact role for IFN-alpha as alternative to radiation and chemotherapy.

Disseminated Kaposi's sarcoma not associated with HIV infection in a bisexual man

We report a 42-year-old white bisexual man with disseminated Kaposi's sarcoma limited to the skin and gastrointestinal tract. Results of several serum tests for human immunodeficiency virus (HIV) antibodies have been negative. The CD4/CD8 ratio has remained normal, and his Kaposi's sarcoma has had a benign clinical course during 30 months of follow-up. Similar reports of disseminated Kaposi's sarcoma with a benign clinical course in homosexual or bisexual men without demonstrable HIV infection are reviewed. Some cellular immune impairment that might be more prevalent in the homosexual population may be implicated in the pathogenesis of this type of Kaposi's sarcoma.

Pseudo-Kaposi's sarcoma occurring after placement of arteriovenous shunt. A case report with DNA content analysis

Pseudo-Kaposi's sarcoma developed in a 51-year-old man 2 years after placement of an arteriovenous shunt for hemodialysis. Data from histopathologic, immunohistologic, and histochemical studies, electron microscopy, and DNA-cytometric analysis are presented.