Immunologic abnormalities in homosexual men. Relationship to Kaposi's sarcoma

Flow Cytometric-Based Analysis of Defects in Lymphocyte Differentiation and Function Due to Inborn Errors of Immunity

The advent of flow cytometry has revolutionized the way we approach our research and answer specific scientific questions. The flow cytometer has also become a mainstream diagnostic tool in most hospital and pathology laboratories around the world. In particular the application of flow cytometry has been instrumental to the diagnosis of primary immunodeficiencies (PIDs) that result from monogenic mutations in key genes of the hematopoietic, and occasionally non-hematopoietic, systems. The far-reaching applicability of flow cytometry is in part due to the remarkable sensitivity, down to the single-cell level, of flow-based assays and the extremely user-friendly platforms that enable comprehensive analysis, data interpretation, and importantly, robust and rapid methods for diagnosing PIDs. A prime example is the absence of peripheral blood B cells in patients with agammaglobulinemia due to mutations in BTK or related genes in the BCR signaling pathway. Similarly, the development of intracellular staining protocols to detect expression of SAP, XIAP, or DOCK8 expedites the rapid diagnosis of the X-linked lymphoproliferative diseases or an autosomal recessive form of hyper-IgE syndrome (HIES), respectively. It has also become evident that distinct cohorts of PID patients exhibit unique “lymphocyte phenotypic signatures” that are often diagnostic even prior to identifying the genetic lesion. Flow cytometry-based sorting provides a technique for separating specific subsets of immune cells such that they can be studied in isolation. Thus, flow-based assays can be utilized to measure immune cell function in patients with PIDs, such as degranulation by cytotoxic cells, cytokine expression by many immune cells (i.e., CD4⁺ and CD8⁺ T cells, macrophages etc.), B-cell differentiation, and phagocyte respiratory burst in vitro. These assays can also be performed using unfractionated PBMCs, provided the caveat that the composition of lymphocytes between healthy donors and the PID patients under investigation is recognized. These functional deficits can assist not only in the clinical diagnosis of PIDs, but also reveal mechanisms of disease pathogenesis. As we move into the next generation of multiparameter flow cytometers, here we review some of our experiences in the use of flow cytometry in the study, diagnosis, and unraveling the pathophysiology of PIDs.

A Case of Classical Kaposi's Sarcoma in B-Cell Chronic Lymphocytic Leukemia (B-CLL)

We report a case of classical Kaposi's sarcoma (KS) in a patient affected by B-cell chronic lymphocytic leukemia for 2 years and who had not received any antiblastic treatment. At the ultrastructural analysis the leukemic cell showed rather immature features, and the immunologic phenotype (absence of detectable cytoplasmic Ig, and expression only of the DR, B2 and IgDλ molecules on the surface membrane) proved its intermediate level of maturity, its monoclonality and relative rarity. The patient presented a complex immunologic deficiency, revealed not only by the monoclonality of the B lymphocytes and their low degree of maturity, but also by the almost total absence of T helper lymphocytes, by the high reduction in NK activity, by the very scarce proliferative response to the polyclonal mitogens PHA, ConA and PWM, and by a complete anergy to the skin test of delayed reactivity. The search for antibodies against the viruses EBV, CMV, HTLV-I and HTLV-III in the serum was negative. At the HLA typing, the patient was DR5, as are most classical KS and/or B-CLL patients. The data are discussed in relation to documented non-casual association between B-CLL and KS. We stress that immunosuppression may play an important role in the pathogenesis of both diseases and the possibility of their being conditioned by common genetic HLA-associated factors of predisposition.

LIM kinase 1 modulates cortical actin and CXCR4 cycling and is activated by HIV-1 to initiate viral infection

Almost all viral pathogens utilize a cytoskeleton for their entry and intracellular transport. In HIV-1 infection, binding of the virus to blood resting CD4 T cells initiates a temporal course of cortical actin polymerization and depolymerization, a process mimicking the chemotactic response initiated from chemokine receptors. The actin depolymerization has been suggested to promote viral intracellular migration through cofilin-mediated actin treadmilling. However, the role of the virus-mediated actin polymerization in HIV infection is unknown, and the signaling molecules involved remain unidentified. Here we describe a pathogenic mechanism for triggering early actin polymerization through HIV-1 envelope-mediated transient activation of the LIM domain kinase (LIMK), a protein that phosphorylates cofilin. We demonstrate that HIV-mediated LIMK activation is through gp120-triggered transient activation of the Rack-PAK-LIMK pathway, and that knockdown of LIMK through siRNA decreases filamentous actin, increases CXCR4 trafficking, and diminishes viral DNA synthesis. These results suggest that HIV-mediated early actin polymerization may directly regulate the CXCR4 receptor during viral entry and is involved in viral DNA synthesis. Furthermore, we also demonstrate that in resting CD4 T cells, actin polymerization can be triggered through transient treatment with a pharmacological agent, okadaic acid, that activates LIMK and promotes HIV latent infection of resting CD4 T cells. Taken together, our results suggest that HIV hijacks LIMK to control the cortical actin dynamics for the initiation of viral infection of CD4 T cells.

Immunological abnormalities in massive cutaneous hyalinosis

Immunological studies in a patient with massive cutaneous hyalinosis, a disease characterized by principally dermal and subcutaneous accumulations of monoclonal kappa light chains and a gliadin-binding mannose-rich 90 kD glycoprotein, show that the ratio of helper to suppressor T cells is decreased and the proliferative responses of the peripheral mononuclear cells to T cell and T cell-dependent B cell mitogens are depressed. High levels of circulating immune complexes were demonstrated by C1q-binding and rheumatoid factor enzyme linked immunoassays. IgM and IgA class antibodies against the hyalin components, the mannosyl-90 kD glycoprotein and type I collagen, and against keratin and gluten were present in high titres. The reactivity of mononuclear cells to phytohemagglutinin normalized and the antibody levels to hyalin proteins, keratin and gluten fell during low-dose steroid therapy. However, the concanavalin A response was not reversed, neither did the levels of circulating immune complexes and anti-intercellular substance antibodies decrease. The results demonstrate a very complex dysfunction of the immune system in massive cutaneous hyalinosis.

AIDS-related cancer in the era of highly active antiretroviral therapy (HAART): a model of the interplay of the immune system, virus, and cancer. "On the offensive--the Trojan Horse is being destroyed"--Part A: Kaposi's sarcoma

The introduction of highly active antiretroviral therapy (HAART), aimed at controlling human immunodeficiency virus (HIV), has been associated with a dramatic decrease in the incidence of acquired immunodeficiency syndrome-Kaposi's sarcoma (AIDS-KS) and the clinical manifestations of KS appear to be less aggressive. The pathogenesis of AIDS-related KS is related to a system of cytokines (e.g., interleukin-6) driven by autocrine and paracrine loops. More recently, human herpesvirus 8 (HHV-8), was discovered to be the putative etiological agent of this disease. This virus encodes several unique open reading frames that are homologs of human cellular proteins involved in cellular regulations, cell proliferation, apoptosis, and immune regulation. The treatment of this disease depends on whether it is "limited" disease or "extensive" disease. For "limited" disease, local therapy or non-bone marrow suppressive agents should be used. For "extensive" disease, new chemotherapeutic agents, such as liposomal anthracycline, which are active and have little adverse reactions, are indicated. The control of HIV infection continues to be essential. Knowledge of the pathogenesis of the disease has led to the development of novel treatment strategies, aimed at the inflammatory or angiogenesis cytokines necessary for growth or at HHV-8 as the target of therapy.

What can oncologists learn from HIV?

Developments in HIV-related medicine have significant implications for the practice of oncology. Although HIV is a relatively new discipline within medicine, the identification and therapeutic targeting of HIV has been rapid. Furthermore, political lobbying has sculpted scientific research and patient care. Rational drug design has reduced morbidity and mortality to such an extent that the development of predictive surrogate endpoints has been necessary to enable randomised assessments of new protocols to continue. These studies now include the routine detection of resistance to tailor specific therapies to the patient. The involvement of affected communities in dynamically modelled studies have shown the efficacy of new, preventive strategies and debates about such approaches have improved the standard of care. In this review, we discuss what oncologists can learn from the HIV epidemic.

Update on Kaposi's Sarcoma: A Gammaherpesvirus- induced Malignancy

Since the beginning of the AIDS epidemic, Kaposi's sarcoma (KS) has been one of the most visible manifestations of this disease and one of the most distressing for affected patients. The discovery in 1994 of a new gammaherpesvirus, called Kaposi's sarcoma-associated herpesvirus, has led to increased understanding of the pathogenesis of this disease and the potential for new specific therapy. In addition, the development of highly active antiretroviral therapy has had a substantial impact on the incidence of KS in countries where it is available and on the course of established disease. Finally, recent advances in our understanding of angiogenesis have the potential of leading to new KS therapies. In this article we review some of the recent advances in the epidemiology and pathogenesis of KS, review the current treatment of this disease, and discuss several therapeutic approaches that are now under development.

Effect of protease therapy on cytokine secretion by peripheral blood mononuclear cells (PBMC) from HIV-infected subjects

The viral load reduction seen in patients with late stage HIV infection treated with the protease inhibitor, ritonavir, is accompanied by increases in the in vitro proliferative responses generated by PBMC. The present study was undertaken to investigate which lymphocyte subsets generated these responses and the effects of therapy on cytokine production. Lymphoproliferation following phytohaemagglutinin (PHA) stimulation was studied by thymidine incorporation, and production of IL-2, interferon-gamma (IFN-gamma) and IL-4 was assessed by ELISA in 12 patients receiving ritonavir and seven receiving placebo in the context of randomized, blinded clinical trials. CD4+ cell-depleted and CD8+ cell-depleted subsets were obtained from PBMC by immunomagnetic bead depletion. At week 4 of therapy a two-fold or greater increase in proliferative responses was observed in 9/12 subjects receiving therapy, compared with 0/7 receiving placebo. Similarly there was a significant increase in IL-2 and IFN-gamma production of 2.7-fold (P = 0.02) and 1.7-fold (P = 0.03), respectively, in the treatment group compared with those receiving placebo. No change in IL-4 production was observed. Despite these increases, cytokine responses post-therapy were still reduced compared with both healthy controls and asymptomatic HIV-infected subjects. Increases in proliferative response and IL-2 production were greater in the CD8+ cell-depleted population than in the CD4+ cell-depleted population, whereas increases in IFN-gamma production were derived from the CD4+ cell-depleted population.

Effect of HIV infection on the frequency of cytokine-secreting cells in human peripheral blood

A selective decrease in type 1 cytokine secretion by in vitro stimulated peripheral blood cells is reportedly associated with disease progression in HIV-infected individuals. To examine whether a similar change in cytokine secretion occurs under physiologic conditions in vivo, sensitive and specific ELIspot assays were used to compare the phenotype and frequency of PBMC spontaneously producing interleukin (IL)-2, IL-4, IL-10, and interferon-gamma (IFN-gamma) in 83 HIV-infected subjects and 60 normal controls. Phenotypic analysis of freshly isolated cytokine-secreting cells showed that T cells were the primary source of IL-2, IL-4, and IFN-gamma while CD14+ macrophages/monocytes were the dominant source of IL-10 in vivo. The number of peripheral blood mononuclear cells (PBMC) spontaneously secreting both type 1 and type 2 cytokines was significantly reduced in HIV-infected patients versus controls. The magnitude of this decrease did not correlate with disease severity. Changes in IL-2-secreting cell number correlated with CD4 count, while changes in the frequency of IFN-gamma-secreting cells correlated with disease duration. These findings do not support the contention that a selective reduction in type 1 cytokine production correlates with disease progression.

In vitro anti-HIV-1 antibody production in subjects in different stages of HIV-1 infection

We evaluated the in vitro antibody production from peripheral blood mononuclear cells (PBMC) against HIV-1 proteins in infected adults. Fifty-four HIV-1 infected patients (four recent seroconverters, 15 asymptomatics with a CD4 count higher than 500/microliters, 27 asymptomatics with a CD4 count between 200 and 500/microliters and eight symptomatic patients) were tested. PBMC were incubated in the presence or absence of 1% pokeweed mitogen (PWM) at 37 degrees C for 8 days. Western blot assay, p24 antigen ELISA and anti-p24 antibody ELISA were performed on serum and culture supernatants. Spontaneous production of anti-env antibody in culture supernatants was evidenced in all subjects. All the positive supernatants for anti-core antibodies (18/54) were derived from asymptomatic patients. PBMC from recent seroconverters and from symptomatic patients did not produce any anti-core antibody. Antibody production decreased after stimulation with PWM. The concentration of p24 antigen did not significantly increase in p24 positive supernatants following acidification (P = 0.1), suggesting that the inability to detect p24 antibody was not due to the anti-p24 antibody complexed to p24 antigen in culture supernatants. In vitro production of anti-p24 antibodies was significantly more frequent in asymptomatic subjects with high CD4+ cell counts (P = 0.02) and was absent in recent seroconverters. This last finding suggests that during the initial phases of the infection, anti-p24 antibody production may be restricted to cells residing in lymphoid organs. In addition, the lower percentage of anti-core antibody in people with low CD4+ cell counts is not merely a consequence of the binding of the antibody to an increased amount of antigen, but probably reflects an impaired production or a sequestration of producing cells in lymphoid tissue during the late stages of the infection.

HIV type 1 Tat protein induces immunoglobulin and interleukin 6 synthesis by uninfected peripheral blood mononuclear cells

Tat is a potent trans-activating protein encoded by the HIV genome. It is essential for viral replication, but has pleiotropic effects on host cells as well. We demonstrated that exogenous recombinant Tat increases immunoglobulin (Ig) and interleukin 6 (IL-6) production in vitro by normal uninfected peripheral blood mononuclear cells by 100-500%. The optimal Tat concentration was 100 ng/ml, but even a low concentration of 1 ng/ml induced a response in most subjects. The observed induction was inhibited by monoclonal anti-Tat antibodies and 2,3-dimercapto-1-propanol. Both anti-IL-6 antibodies and IL-6 antisense oligonucleotides inhibited Tat-induced IgG and IgA synthesis to some degree, whereas induction of IgM appeared to be independent of IL-6. We conclude that Tat can function in vitro in the absence of any other viral structures and induce Ig and IL-6 production; the clinical significance of these findings remains as yet undetermined.

Immunization with recombinant gp160 prolongs the survival of HIV-1 transgenic mice

A strain of mouse transgenic for the env gene of the HIV-1 virus was used to study the immunogenicity of a gp160-derived vaccine (the protein encoded by the HIV env gene) and its effect on disease progression. Untreated transgenic mice frequently developed a rapidly progressive renal disease similar to that affecting approximately 10% of HIV-infected humans. When transgenic mice were immunized with recombinant purified gp160, their edema, proteinuria, and serum BUN levels were substantially reduced and their survival prolonged (p < 0.01). The increased longevity of immunized transgenic mice correlated with the production of IgG antibodies reactive with gp160.

Affinity of anti-GP41 antibody in patients infected with human immunodeficiency virus type 1

Anti-gp41 antibody affinity was investigated prospectively in 25 patients with asymptomatic and symptomatic HIV-1 infection for a period of 9-42 months. Major differences in the processes of immune response maturation towards gp41 were observed among individual subjects, however, antibody affinity increased with time in all examined persons including patients with AIDS. Anti-gp41 affinity values were found to reflect both the duration and the clinical stage of HIV infection.

Possible roles for nitric oxide in AIDS and associated pathology

The endogenous free radical, nitric oxide (NO), plays a neurotransmitter-like role in vascular endothelium, a second-messenger role in N-methyl-D-aspartate (NMDA)-responsive neurons in the central nervous system (CNS), a neurotoxic role after its release from these neurons, and a cytotoxic role after its release by macrophages. NO also derives from exogenous sources, such as the nitrite inhalants, amyl, butyl and isobutyl nitrite. There is evidence that abuse of nitrite inhalants can affect immunomodulation, and epidemiological studies suggest that such abuse may be a cofactor in the pathogenesis of acquired immunodeficiency syndrome (AIDS). Hitherto, however, the potential role of NO in such pathogenesis has not been examined. This paper presents some current evidence that implicates both endogenous and exogenous sources of NO in AIDS and associated pathology.

Human immunodeficiency virus infection induces both polyclonal and virus-specific B cell activation

Peripheral blood lymphocytes (PBL) were obtained from HIV-1-infected patients at different stages of disease. The absolute number of IgM-, IgG-, and IgA-producing lymphocytes per 10(6) PBL was increased 2.8-, 3.4-, and 1.9-fold, respectively, compared with normal controls. 2-17% of IgG-secreting patient cells reacted with the gp160 envelope glycoprotein of HIV-1 (a 737-fold increase over background), while 1-9% reacted with p24 (140-fold over background). In addition to this HIV-specific B cell activation, the number of lymphocytes reactive with nonviral antigens such as DNA, myosin, actin, trinitrophenylated keyhole limpet hemocyanin, and ovalbumin was increased by a mean of 17.9-fold. Evidence suggests that the latter changes reflect an HIV-induced polyclonal B cell activation unrelated to the production of anti-HIV antibodies. For example, the proportion of IgG anti-gp160- and anti-p24-secreting lymphocytes declined in patients with advanced disease, whereas the number of B cells producing antibodies to non-HIV antigens rose. Moreover, CD4 cell count and T4/T8 ratio showed a significant inverse correlation with the degree of polyclonal activation but not with anti-HIV responsiveness. These observations demonstrate that both quantitative and qualitative changes in B cell activation accompany (and may be predictive of) disease progression in HIV-infected individuals.

Proliferative response of mononuclear cells from HIV-infected patients to B-cell mitogens: effects of lymphocyte subset frequency, T-cell defects and prostaglandins

Proliferative responses of mononuclear cells from patients seropositive for human immunodeficiency virus to B-cell mitogens are severely depressed compared with those of controls. The role of several immunoregulatory phenomena was analyzed. Experimental results show that addition of exogenous lymphokines to cultures increases responses to anti-mu and SAC. Addition of indomethacin to cultures greatly increases the SAC response and causes a smaller increase in the pokeweed mitogen (PWM) response. When both exogenous lymphokines and indomethacin are present in cultures, responses of patients' cells to all three mitogens are positively correlated with the percentage of CD4+ T cells and negatively correlated with the percentage of CD8+ T cells. Responses to anti-mu and SAC are also positively correlated with the percentage of B cells in these cultures. On the basis of these correlations between B-cell responses and lymphocyte subset frequency, patients' B-cell responses can be mathematically corrected to estimate the responsiveness of the B cells in the presence of normal numbers of CD4+ and CD8+ cells. These corrected responses for all three mitogens are virtually identical to control responses. Furthermore, responses of enriched B-cell populations from HIV+ subjects and normal controls to SAC were not significantly different when assays were performed in the presence of indomethacin and exogenous lymphokines. These results suggest that B cells from HIV+ patients are inherently normal in their responsiveness to B-cell mitogens. The depressed function is imposed upon them as a result of the abnormal frequency of lymphocyte subsets in the blood, by increased prostaglandin production, and deficient lymphokine production.

Lymphoproliferative responses to mitogen and antigen in HIV-infected children

We endeavored to study lymphoproliferative responses in children with human immunodeficiency virus (HIV) infection and to compare them with normal control children. Children were grouped according to age; 6-18 months and greater than 18 months, and according to CDC classification: asymptomatic (P1), mildly symptomatic (P2A), and advanced symptoms (P2D). Absolute CD4 and CD8 numbers were compared and found to be higher in the younger age groups. The children in P1 and P2A classes demonstrated an increase in CD8+ cells; only the children with AIDS showed a significant decrease in CD4+ cells. Lymphoproliferative responses to phytohemagglutinin A (PHA) were compared to tetanus toxoid. Only the children with acquired immunodeficiency syndrome (AIDS) (P2D) in the older group and only the symptomatic children (P2A and P2D) in the younger group showed a significant decrease in proliferative responses to PHA. All classes of infected children demonstrated a significant decrease in response to tetanus toxoid. We have been able to demonstrate a loss of antigen responsiveness which precedes the loss of mitogenic responsiveness. Furthermore, we have been able to demonstrate an age related increase in lymphoproliferative responses to both PHA and tetanus in HIV-infected and control children. Therefore, we conclude that children are particularly susceptible to the immunologic effects of HIV infection. Loss of lymphoproliferative responses to antigen occurs early in infected children and precedes the loss of CD4+ helper cells and of PHA responsiveness. This increased susceptibility to the immunopathogenesis of HIV infection is due, at least in part, to the relative immunodeficiency of infancy.

Biological and biochemical characterization of a factor produced spontaneously by adherent cells of human immunodeficiency virus-infected patients inhibiting interleukin-2 receptor alpha chain (Tac) expression on normal T cells

Adherent cells from human immunodeficiency virus (HIV)-infected subjects but not from normal blood donors, patients with Gram-positive or -negative bacteremia, active tuberculosis, toxoplasmosis, pulmonary aspergillosis, and cytomegalovirus infection produce spontaneously an activity which inhibits alpha chain of interleukin-2 (Tac) expression and interleukin 2 (IL-2) production by normal activated T cells and IL-2 production by these cells. A similar biologic activity was detected in culture supernatants of in vitro HIV-I-infected normal adherent and leukemic U937 cells. Tac-inhibitory activity is not cytotoxic and it could be detected in serum-free conditioned media. Recombinant granulocyte/macrophage colony-stimulating factor and phorbol myristate acetate stimulation of patients' and normal adherent cells did not enhance specifically the production of the Tac inhibitor. Biologically active conditioned media did not contain infectious virus as well as secreted p24, gp120 viral proteins; the biologic activity could not be abolished by anti-p24, anti-gp120, and anti-nef monoclonal antibodies or human purified polyclonal anti-HIV IgG. Gel filtration of conditioned media followed by anion exchange chromatography resulted in a 1,200-fold degree of purification and revealed that the biologically active molecule was cationic. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of this fraction and gel elution of the proteins showed that the biologic activity was associated with a 29-kD protein which was distinct from alpha- or gamma-interferon, tumor necrosis factor-alpha, and prostaglandin E2. The above findings demonstrate the production of inhibitory factor(s) during HIV infection, which might be involved in the pathogenesis of the patients' immune defect.

Kaposi sarcoma associated with human immunodeficiency virus infection

In the present study, 11 patients with epidemic Kaposi sarcoma were evaluated; 55% were in stage IV and 45% in stage II; in addition, 75% had systemic symptoms, 89% had low total and T-lymphocyte counts, and all of them had not only low T-helper lymphocyte counts but also T-helper/T-suppressor ratios. The majority of patients (89%) had low proliferative responses with phytohemagglutinin (PHA). Nine patients were treated with: alpha-2 interferon (five patients), zidovudine (two patients), doxorubicin and zidovudine (one patient), and radiotherapy (one patient). There were only five patients with stable disease, three treated with alpha-2 interferon, one with doxorubicin, and one with doxorubicin plus azidothymidine. Two patients (one with doxorubicin and one with doxorubicin plus zidovudine) needed lithium to increase leukocyte and platelet counts. In May 1989, 73% of patients were dead (median survival 8 +/- 2 months). It is concluded that: (1) it is important to select the patients who have the best chance to improve with treatment; (2) the response with alpha-2 interferon or monochemotherapy is low and there is no change in overall survival; (3) a low helper cell count, low T-helper/T-suppressor ratio, and low proliferative response with mitogens are features of poor prognosis; (4) toxicity with treatment was acceptable; and (5) lithium increased neutrophil and platelet counts.

Long-term combined rIFN-alpha-2a and zidovudine therapy for HIV-associated Kaposi's sarcoma: clinical consequences and side effects

Interferon alpha (IFN-alpha) has been shown to be effective in treating HIV-associated KS in at least 30% of patients, and Zidovudine has proved beneficial for AIDS patients. Moreover, both drugs have demonstrated an inhibitory effect on HIV replication. Based on the above, we combined IFN-alpha and zidovudine for treatment of HIV-associated KS in order to evaluate tolerance and clinical efficacy. Twenty-one homosexual men with histologically proved HIV-associated KS were treated in an open trial with rIFN-alpha-2a 18 X 10(6) IU every second day and zidovudine 800-1200 mg/d. Treatment was discontinued within the first month in six patients: three of them developed subjective intolerance, and three others contracted severe opportunistic infections or HIV-cachexia. Fifteen evaluable patients received combination treatment over a period of 2-20 months (average 10 months). The dosage was reduced as required based on drug-induced cytotoxicity. Complete remission was observed in four patients, partial remission in three, stable disease in two, and progression in six, resulting in an overall response rate of 46%. Negative p24 expression prior to treatment was a positive predictor. Although extracutaneous involvement had a negative influence on tumor remission, even patients with a mean initial T-helper cell count below 100 mm3 responded positively. In conclusion, combination therapy of rIFN-alpha-2a with AZT may effectively control HIV-related Kaposi's sarcoma in more than 40% of patients. In contrast to monotherapy with IFN-alpha, patients with severely reduced immune systems will also benefit from combined treatment.

Cutaneous response to recombinant interleukin 2 in human immunodeficiency virus 1-seropositive individuals

We report that 11 human immunodeficiency virus 1 (HIV-1)-seropositive patients, including three AIDS patients, were able to generate a cellular immune response to the intradermal injection of low doses (2-10 micrograms) of recombinant interleukin 2 (rIL-2). A dose-dependent zone of induration appeared at the site of injection, peaked at 24 hr, and was accompanied by the local accumulation of T cells, monocytes, and Langerhans cells. Despite the reductions in the CD4+ T-cell counts in the peripheral blood of most patients, CD4+ T-cells could still be mobilized with rIL-2 injections into the skin. The total number of immigrant cells was equivalent to those in HIV-1-seronegative patients, although the CD4+/CD8+ ratio of the dermal population was reduced. In response to rIL-2, major histocompatibility complex (MHC) class II antigen was expressed on the surface of keratinocytes, Langerhans cells, lymphocytes, and macrophages. In addition, the gamma interferon (IFN-gamma)-induced protein IP-10 rapidly appeared in dermal inflammatory cells and keratinocytes. A majority of HIV-1-seropositive patients demonstrated low or absent responses to common skin-test antigens. Those with positive zones of induration were often defective in the cellular expression of the IFN-gamma-induced MHC class II antigen. The simultaneous administration of rIL-2 and soluble antigen at widely separated cutaneous sites led to an enhancement of skin-test antigen reactivity in seropositive patients. The results suggest that local administration of rIL-2 to seropositive patients may act systemically, stimulating cellular immunity to recall antigens, and thus may be of potential benefit in the defense against opportunistic pathogens encountered in HIV-1 infection.

The spectrum of syphilis in patients with human immunodeficiency virus infection

Five patients infected with the human immunodeficiency virus (HIV) with unusual manifestations of syphilis are reported. The high prevalence of HIV seropositivity among our patients with syphilis, the rapid progression to tertiary disease, the increased severity of the clinical manifestations, inappropriate antibody responses to infection, relapse without reexposure despite "adequate" treatment, and lack of response to penicillin therapy have been observed in these and in other patients. Data are presented to explain these unusual observations.

The changing incidence of Kaposi's sarcoma among patients with AIDS

Kaposi's sarcoma (KS), the most common cancer in patients with acquired immunodeficiency syndrome (AIDS), occurs predominantly in homosexual men. However, the percentage of homosexual AIDS patients with KS has declined during the past 6 years. This and other findings suggest that one or more cofactors associated with the homosexual lifestyle, rather than a special viral strain, probably influence the development of KS in patients infected with the human immunodeficiency virus (HIV). Possible reasons for the decline include changes in homosexual behaviors, leading to the practice of safer sexual techniques, and a decrease in use of nitrite inhalants. Identification of the KS-AIDS cofactor(s) could be invaluable to developing prevention and treatment strategies.

Lymphocyte phenotype does not predict immune function in pediatric patients infected with human immunodeficiency virus type 1

To determine whether assays of lymphocyte phenotype were predictive of antigen-specific immunologic function in children infected with human immunodeficiency virus type 1 (HIV-1), we compared the antigen-specific cellular and humoral functions (tetanus toxoid-induced T lymphocyte blastogenesis and anti-tetanus toxoid antibody) with the patients' T lymphocyte phenotype, determined at the same time. Although both HIV-1-infected patient populations studied (pediatric hemophilia patients and other pediatric patients) had decreases in the values determined by their functional and phenotypic assays, no association between the functional and phenotypic assays was demonstrated. Thus some HIV-1-infected patients with a normal phenotype had no antigen-specific function, whereas other patients with a markedly abnormal T lymphocyte phenotype had normal antigen specific T lymphocyte function. These results indicate that the assessment of HIV-1-infected patients should include assays of antigen-specific immune function in addition to assays of T lymphocyte phenotype.

Interferon-alpha but not AZT suppresses HIV expression in chronically infected cell lines

Promonocytic (U1) and T lymphocytic (ACH-2) cell lines chronically infected with human immunodeficiency virus type 1 (HIV-1) constitutively express low levels of virus, but expression can be induced by phorbol esters and cytokines. Whereas ACH-2 cells produce infectious virions, U1 cells produce defective, noninfectious particles. Although 3'-azido-3'-deoxythimidine (AZT) prevented acute HIV infection of susceptible cells, it did not prevent the induction of HIV expression in the infected cell lines. In contrast, interferon alpha (IFN-alpha) inhibited the release of reverse transcriptase and viral antigens into the culture supernatant after phorbol ester stimulation of both cell lines. Further, IFN-alpha suppressed the production or release (or both) of whole HIV virions, but had no effect on the amount of cell-associated viral proteins. Also, after phorbol ester stimulation of ACH-2 cells, IFN-alpha reduced the number of infectious viral particles secreted into the culture supernatant, but had no effect on the infectivity of cell-associated virus. These findings lend support to the combined use of antiviral agents that have action at both the early (AZT) and the late (IFN-alpha) stages of HIV replication.

A prospective study of immunoglobulin changes in relation to human immunodeficiency virus infection in a cohort of homosexual men

Changes in IgG levels and patterns in association with human immunodeficiency virus, (HIV) infection were characterized in a prospective investigation by studying serum electrophoresis and antibodies to HIV at least once a year in 144 homo/bisexual (HS) men during a 4-year period. Initially, 25 men (17.4%) were HIV-positive, and this increased to 44 at the end of the study period. HIV-negative men had IgG levels of 11.2 +/- 2.2 g/l. In the 19 HIV seroconverters the mean IgG level rose with time according to the equation IgG = 0.054x + 12.56 (x = months after the last HIV-negative test). Oligoclonal IgG bands were found in three of the 19 seroconverters (16%) prior to conversion and in 2/16 (13%), 5/13 (38%), 7/11 (64%), and 3/8 (38%) 1, 2, 3, and 4 years after conversion, respectively. Of the 25 initially HIV-positive men, five have developed acquired immunodeficiency syndrome (AIDS) during the 4.5 year follow-up. At the first investigation these five men had higher mean IgG levels (16.0 +/- 2.7 g/l) than the 20 men who have remained healthy (14.6 +/- 2.8 g/l), and all five had oligoclonal bands as compared to 9/20 of those who did not develop AIDS. Oligoclonal IgG bands reflect the IgG increase and seem to indicate long-standing HIV infection and a poor prognosis.

Monitoring human immunodeficiency virus type 1-infected patients by ratio of antibodies to gp41 and p24

Antibody responses of 85 patients to human immunodeficiency virus type 1 antigens were quantitated by densitometric analysis of Western blot (immunoblot) assays. All patients had been classified into the following three clinical categories: asymptomatic (ASY), acquired immunodeficiency syndrome (AIDS)-related complex (ARC), or AIDS. Fifty of the patients were monitored for 6 to 29 months. The gp41/p24 antibody ratio was examined in three studies. In the first study, initial specimens from each patient were analyzed. The mean gp41/p24 antibody ratios were 1.5 (ASY), 3.2 (ARC), and 5.4 (AIDS). Of ASY patients, 79% had antibody ratios of less than 2.0. In contrast, 72% of patients with AIDS had ratios of greater than or equal to 2.0. In the second study, serially obtained specimens from ASY, ARC, and AIDS patients were analyzed. These patients were further grouped according to progression of their clinical condition. Of ASY patients whose clinical condition progressed to ARC, 80% consistently had ratios of greater than or equal to 2.0. Of ARC patients whose clinical condition progressed to AIDS, 71% consistently had ratios of greater than or equal to 2.0. Of AIDS patients who died during the study, 100% consistently had ratios of greater than or equal to 2.0. No patients were treated with azidothymidine during the first two studies. In the third study, AIDS patients were monitored before and during treatment with azidothymidine. During treatment, ratios stabilized or improved transiently in five of seven patients. In these three studies, a gp41/p24 antibody ratio of less than 2.0 correlated with a benign clinical state and a ratio of greater than or equal to 2.0 correlated with AIDS or progression to AIDS.

Serial determinations of HIV-1 titers in HIV-infected homosexual men: association of rising titers with CD4 T cell depletion and progression to AIDS

Lymphocyte subset enumerations, antibody titers to specific proteins of human immunodeficiency virus (HIV), and measurement of infectious HIV titers in peripheral blood mononuclear cells were performed on serial blood specimens from 15 HIV-infected homosexual men with chronic lymphadenopathy syndrome (LAS); 6 of these men have subsequently progressed to AIDS (progressors), and 9 have remained clinically stable (nonprogressors). For the earliest samples studied, no test distinguished those who would progress to AIDS from those who have not. The two groups diverged significantly about 1 year before AIDS diagnosis in the progressor group. Virus titers rose in progressors but remained relatively stable in nonprogressors. CD4 T cells and the CD4 T cell subset, 4B4, declined more rapidly in progressors than in nonprogressors. HIV antibody titers tended to decline in progressors, but the differences were significant only for antibody and to the pol-encoded proteins, p51/65, and the gag-encoded polyprotein, p55. Before the onset of clinical AIDS, progressors are distinguished from nonprogressors by markedly different rates of CD4 cell depletion and virus replication, but the elements that control these dynamics remain to be defined.

The relationship of serum IgA concentration to human immunodeficiency virus (HIV) infection: a cross-sectional study of HIV-seropositive individuals detected by screening in the United States Air Force

Serum immunoglobulins were measured in 107 patients with human immunodeficiency virus seropositivity. Each patient was categorized by the Walter Reed staging classification and serum concentrations of immunoglobulins were compared with patient staging. Serum IgM concentrations were normal in all but nine patients. Serum IgG concentrations were elevated in 74 of 107 patients, with no significant differences noted between different stages of disease severity. Serum IgA concentrations were elevated in 38 of 107 patients, with a significant relationship noted between increasing staging category and increasing serum IgA concentration (p = 0.0001). Serum IgA concentrations in patients with human immunodeficiency virus seropositivity may be a useful marker of immunologic progression of disease.

Urinary neopterin and immunological features in patients with Kaposi's sarcoma

We studied neopterin excretion levels and immunological features of 20 patients affected by Kaposi's sarcoma (KS), compared to 30 normal controls. Eighteen patients had the classic form of Kaposi's sarcoma (CKS), while two patients were anti-human immunodeficiency virus (HIV) seropositive and affected by the epidemic form associated with the acquired immunodeficiency syndrome (AIDS). In CKS patients, a trend of an increase of neopterin levels with more advanced stages appeared from our data whereas a significant reduction in CD3+ and CD4+ lymphocytes subsets was observed already at early stages (P less than 0.01). CD8+ cells did not show significant variations. A significant increase in serum IgA immunoglobulins (P less than 0.05) was also observed. Comparative analysis of the two patients affected by AIDS/KS showed the profound deficit in T-cell immunity but also the prognostic value of neopterin monitoring. Furthermore these findings seem to confirm Kaposi's sarcoma as an 'opportunistic neoplasia' and indicate neopterin as a useful prognostic marker.

Candida and AIDS: evidence for protective antibody

Clinical observation and animal models of candidosis suggest that, although T lymphocytes are important in preventing superficial candidosis, defence against systemic candidosis depends upon humoral immunity. An antibody response to the immunodominant 47 kD antigen of Candida albicans is invariably associated with recovery. The presence of this antibody in patients with chronic mucocutaneous candidosis and the acquired immunodeficiency syndrome (AIDS) could account for the rarity of disseminated candidal infection in these conditions. Polyclonal B cell activation may be responsible for the frequency with which this antibody is produced in AIDS. Antibody to the 47 kD antigen could be useful in the treatment and prevention of systemic candidosis, though not in the superficial candidosis of AIDS.

Kaposi's sarcoma in AIDS: basement membrane and endothelial cell markers in late-stage lesions

Early-stage lesions of Kaposi's sarcoma (KS) are composed of single-layered, highly flattened cells lining collagen bundles, whereas late-stage lesions contain densely packed, spindle-shaped cells. We examined the progression of KS lesions in oral mucosa and lymph nodes from patients with AIDS, using antibodies specific for blood vascular endothelial cells (Factor VIII-related antigen) and their basement membrane (Type IV collagen and laminin). In addition, the plant lectin Ulex europaeus, which selectively stains blood vessels, was also used. In early-stage KS lesions, fibronectin, laminin and Type IV collagen were co-distributed at the interface between KS cells and collagen bundles; Factor VIII-related antigen and Ulex europaeus lectin staining was present in vascular channels and in the KS cells. However, in late-stage lesions, few if any KS cells stained with antibody to Factor VIII-associated antigen, although endothelial cells lining blood vessels were positive. Strong staining for laminin and Type IV collagen was present in a pericellular pattern throughout the nodular late-stage lesions. Since lymphatic capillary endothelium does not produce basement-membrane-specific macromolecules, these results support the conclusion that KS cells are related to blood vascular endothelium but eventually lose certain endothelium-specific markers as the cells are transformed into the spindle-shaped cell type.

Spontaneous in vitro production of virus-specific antibody by lymphocytes from HIV-infected subjects

In vitro synthesis of IgG directed against HIV components was detected by ELISA and Western blot assay of lymphocyte culture supernatants. Lymphocytes from HIV-infected individuals spontaneously produced antibody against HIV proteins very early in culture, suggesting in vivo activation of HIV-specific antibody-forming cells. The frequency of circulating B cells spontaneously secreting HIV-specific IgG was very high in some cases, but spontaneous HIV-specific antibody synthesis was not accompanied by polyclonal reactivation of B-cell clones of different specificity. The pattern of specificity of the anti-HIV antibody produced in vitro did not reflect the serum pattern consistently. These findings indicate a new approach potentially useful for the study of the immunobiology of HIV infection. The possible implications of the in vitro production of HIV-specific antibody for the diagnosis, prognosis and clinical management of this infection are also discussed.

Assessing alcoholism as a risk factor for acquired immunodeficiency syndrome (AIDS)

Acquired Immunodeficiency Syndrome (AIDS) is characterized by a range of risk factors that determine susceptibility to HIV and the clinical expression of the disease. These include sexual practices, intravenous drug use, and blood exchange. Appropriate preventive measures have been formulated for these risk factors. This paper reviews alcohol abuse as a prominent feature of the homosexual experience, and suggests that it may merit consideration as a risk factor in relation to AIDS. The presumably high prevalence of alcohol abuse among homosexuals and the damaging effects of alcohol on the immune system are discussed as a basis for linking alcoholism, homosexuality, and AIDS. The implications of the potentiating effects of alcohol misuse as the human immunodeficiency virus infiltrates the heterosexual population are presented in terms of high risk populations and the need for additional preventive measures.

The effects of human immunodeficiency virus recombinant envelope glycoprotein on immune cell functions in vitro

The effect of human immunodeficiency virus (HIV) recombinant envelope glycoprotein 120 (rgp 120) on the functions of peripheral blood mononuclear cells (PBMC) in vitro was investigated. The results demonstrate that rgp 120 used at concentrations less than 1 microgram/ml has no significant effects on PBMC function in vitro. However, the addition of 1-20 micrograms/ml of rgp 120 significantly inhibits the tetanus toxoid-induced PBMC proliferative response in a dose-related manner as determined by [3H]thymidine incorporation. The data also show that rgp 120 (5 micrograms/ml) causes up to 70% reduction in the number of immunoglobulin G-secreting cells in pokeweed mitogen-stimulated PBMC cultures. Further, rgp 120 can selectively interact with the CD4a epitope of the CD4 helper cell membrane receptor. These results indicate that microgram per milliliter levels of rgp 120 can depress certain immune functions in vitro. The significance of these findings to the pathogenesis of immunodeficiency in HIV infection remains to be determined.