CD4 T cell expansions are associated with increased apoptosis rates of T lymphocytes during IL-2 cycles in HIV infected patients.

OBJECTIVE AND DESIGN: In an attempt to determine the mechanisms underlying the CD4 T cell expansions in patients receiving intermittent interleukin (IL)-2, a cohort of 10 HIV infected patients were studied during a 5-day cycle of IL-2 to measure rates of apoptosis, the expression of activation markers in CD4 and CD8 T cell subsets and the serum levels of proinflammatory cytokines. All patients were receiving highly active antiretroviral therapy. METHODS: Peripheral blood mononuclear cells were tested pre- and at the completion of IL-2 treatment with annexin V/7-AAD for the measurement of apoptosis. Phenotypic analyses of T lymphocytes were performed in parallel. Serum levels of interferon (IFN)gamma, granulocyte-macrophage colony stimulating factor, IL-6 and tumor necrosis factor (TNF)alpha were tested by enzyme-linked immunosorbent assay. RESULTS: IL-2 increased the spontaneous apoptosis rates of CD4 and CD8 T lymphocytes (P = 0.003). Expression of HLA-DR, CD38 and CD95 increased on both CD4 and CD8 T lymphocytes whereas CD25 induction was observed exclusively on CD4 T cells. Significant increases of serum IL-6 and TNFalpha levels were noted in all patients whereas viral loads remained unchanged. CONCLUSION: Administration of IL-2 for 5 days in HIV infected patients leads to enhanced apoptosis of both CD4 and CD8 T cells despite an eventual increase of the CD4 T cell count. A profound activation state with induction of activation markers on T cells and high levels of TNFalpha and IL-6 accompanies the increased apoptosis during the IL-2 cycle. These data suggest that the CD4 expansions seen in the context of intermittent IL-2 therapy are the net result of increases in both cell proliferation and cell death.

Interleukin-2 induced immune effects in human immunodeficiency virus-infected patients receiving intermittent interleukin-2 immunotherapy.

To characterize the immunological effects of intermittent IL-2 therapy, which leads to selective increases in CD4+ T lymphocytes in HIV-infected patients, 11 patients underwent extensive immunological evaluation. While IL-2 induced changes in both CD4+ and CD8+ cell number acutely, only CD4+ cells showed sustained increases following discontinuation of IL-2. Transient increases in expression of the activation markers CD38 and HLA-DR were seen on both CD4+ and CD8+ cells, but CD25 (a chain of the IL-2 receptor) increased exclusively on CD4+ cells. This increase in CD25 expression was sustained for months following discontinuation of IL-2, and was seen in naive as well as memory cells. IL-2 induced cell proliferation, but tachyphylaxis to these proliferative effects developed after 1 week despite continued IL-2 administration. It thus appears that sustained CD25 expression selectively on CD4+ cells is a critical component of the immunological response to IL-2, and that intermittent administration of IL-2 is necessary to overcome the tachyphylaxis to IL-2-induced proliferation.

Impact of HIV-1 infection and highly active antiretroviral therapy on the kinetics of CD4+ and CD8+ T cell turnover in HIV-infected patients.

To evaluate the effects of HIV infection on T cell turnover, we examined levels of DNA synthesis in lymph node and peripheral blood mononuclear cell subsets by using ex vivo labeling with BrdUrd. Compared with healthy controls (n = 67), HIV-infected patients (n = 57) had significant increases in the number and fraction of dividing CD4(+) and CD8(+) T cells. Higher percentages of dividing CD4(+) and CD8(+) T cells were noted in patients with the higher viral burdens. No direct correlation was noted between rates of T cell turnover and CD4(+) T cell counts. Marked reductions in CD4(+) and CD8(+) T cell proliferation were seen in 11/11 patients 1-12 weeks after initiation of highly active antiretroviral therapy (HAART). These reductions persisted for the length of the study (16-72 weeks). Decreases in naive T cell proliferation correlated with increases in the levels of T cell receptor rearrangement excision circles. Division of CD4(+) and CD8(+) T cells increased dramatically in association with rapid increases in HIV-1 viral loads in 9/9 patients 5 weeks after termination of HAART and declined to pre-HAART-termination levels 8 weeks after reinitiation of therapy. These data are consistent with the hypothesis that HIV-1 infection induces a viral burden-related, global activation of the immune system, leading to increases in lymphocyte proliferation.

An IL6 promoter polymorphism is associated with a lifetime risk of development of Kaposi sarcoma in men infected with human immunodeficiency virus.

Kaposi sarcoma (KS) is an angioproliferative inflammatory condition that occurs commonly in patients infected with human immunodeficiency virus (HIV). Inflammatory cytokines and growth factors promote the development of KS. Because physiologically important cytokine polymorphisms modulate host inflammatory responses, we investigated the association between KS and common regulatory polymorphisms in 5 proinflammatory cytokine genes encoding interleukin (IL) IL-1alpha, IL-1beta, tumor necrosis factor (TNF) alpha, TNF-beta, and IL-6 and in the IL-1 receptor antagonist (IL1RN). We also examined the contribution of stromal-derived factor 1 and chemokine receptor 5 (Delta32) polymorphisms to KS development. The population consisted of 115 HIV-infected men with KS and 126 deceased HIV-infected men without KS. The only strong association was observed between an IL6 promoter polymorphism (G-174C) and susceptibility to KS in HIV-infected men (P =.0035). Homozygotes for IL6 allele G, associated with increased IL6 production, were overrepresented among patients with KS (P =.0046), whereas allele C homozygotes were underrepresented (P =.0062). Substantial in vitro evidence indicates that IL-6 contributes to the pathogenesis of KS. Our results show that IL6 promoter genotypes associated with altered gene expression are risk factors for development of KS. Identification of a genetic risk factor for development of KS has important clinical implications for prevention and therapy.

Rapid activation of lymph nodes and mononuclear cell HIV expression upon interrupting highly active antiretroviral therapy in patients after prolonged viral suppression.

OBJECTIVE: To compare the architecture and HIV-1 RNA and Gag p24 protein expression in lymph nodes (LN) excised from individuals during chronic highly active antiretroviral therapy (HAART) with LN removed from the same patient after plasma virus rebound following the interruption of HAART. MATERIALS AND METHODS: Six HIV-1-infected patients on HAART, with CD4 cell counts greater than 350 cells/microl, and plasma HIV-1 RNA less than 50 copies/ml, underwent inguinal LN excision upon discontinuation of HAART, and again after rebound of plasma virus. Lymph nodes were evaluated by immunohistochemical staining for Gag p24 antigen and Ki67, in-situ hybridization for HIV-1 RNA and H3-histone, and transmission electron microscopy (TEM). RESULTS: LN at baseline were quiescent to mildly hyperplastic and generally contained more primary than secondary follicles. Only one LN had detectable follicular dendritic cell (FDC)-associated p24 antigen, none had HIV RNA. Few mononuclear cells (MNC) expressed RNA or p24 antigen. Plasma virus at the second biopsy ranged from 329 to 3.2 x 10(6) copies/ml. CD4 cell count decline ranged from 5 to 51% during drug hiatus, and was greatest in patients with highest viral rebound. Four of six of the second LN were more hyperplastic than the initial LN, two showed paracortical hyperplasia. MNC expression of HIV RNA in the second LN paralleled the level of plasma viremia. Increased Ki67 and H3-histone signal occurred in the second LN. CONCLUSION: Quiescent LN from individuals on HAART rapidly become hyperplastic and activated within 1-2 months after treatment interruption. As in acute HIV infection, virus expression by LN MNC parallels the rebound in plasma viremia and fall in CD4 cell count.

Effects of intermittent interleukin-2 therapy on plasma and tissue human immunodeficiency virus levels and quasi-species expression.

To characterize the effects of intermittent interleukin (IL)-2 therapy on human immunodeficiency virus (HIV), 11 patients underwent detailed virological evaluation during a year of IL-2 therapy. Six patients showed a >0.5 log increase in plasma HIV during at least 1 IL-2 cycle, with 2 experiencing an increase in >50% of cycles. Three of the remaining 5 patients had a >0.5 log decrease during at least 1 IL-2 cycle, and the remaining patients exhibited <0.5 log changes. No changes in lymphoid (tonsil) levels of HIV were seen during the year. Quasi-species analysis in a separate cohort demonstrated that the virus induced by IL-2 most commonly resembled pre-IL-2 plasma quasi species. Thus, intermittent IL-2 does not result in sustained increases in either plasma or tissue levels of HIV and does not result in sustained expression of a previously silent quasi species.

CD40 ligand trimer and IL-12 enhance peripheral blood mononuclear cells and CD4+ T cell proliferation and production of IFN-gamma in response to p24 antigen in HIV-infected individuals: potential contribution of anergy to HIV-specific unresponsiveness.

It has been suggested that CD4+ T cell proliferative responses to HIV p24 Ag may be important in the control of HIV infection. However, these responses are minimal or absent in many HIV-infected individuals. Furthermore, while in vitro and in vivo responses to non-HIV recall Ags improve upon administration of highly active antiretroviral therapy, there does not appear to be a commensurate enhancement of HIV-specific immune responses. It is possible that CD4+ p24-specific T cells are deleted early in the course of infection. However, it is also possible that a discrete unresponsiveness, or anergy, contributes to the lack of proliferation to p24. To evaluate the possible contribution of unresponsiveness to the lack of CD4+ T cell proliferation to p24 in HIV-infected individuals, we attempted to overcome unresponsiveness. CD40 ligand trimer (CD40LT) and IL-12 significantly increased PBMC and CD4+ T cell proliferative responses to p24 Ag in HIV-infected, but not uninfected, individuals. No increase in proliferative response to CMV Ag was observed. CD40LT exerted its effect through B7-CD28-dependent and IL-12- and IL-15-independent mechanisms. Finally, the increase in proliferation with CD40LT and IL-12 was associated with an augmented production of IFN-gamma in most, but not all, individuals. These data suggest the possible contribution of HIV-specific unresponsiveness to the lack of CD4+ T cell proliferation to p24 Ag in HIV-infected individuals and that clonal deletion alone does not explain this phenomenon. They also indicate the potential for CD40LT and IL-12 as immune-based therapies for HIV infection.

Long-term in vivo survival of receptor-modified syngeneic T cells in patients with human immunodeficiency virus infection.

To study human immunodeficiency virus (HIV)-specific cellular immunity in vivo, we transferred syngeneic lymphocytes after ex vivo expansion and transduction with a chimeric receptor gene (CD4/CD3-zeta) between identical twins discordant for HIV infection. Single and multiple infusions of 10(10) genetically modified CD8(+) T cells resulted in peak fractions in the circulation of approximately 10(4) to 10(5) modified cells/10(6) mononuclear cells at 24 to 48 hours, followed by 2- to 3-log declines by 8 weeks. In an effort to provide longer high-level persistence of the transferred cells and possibly enhance anti-HIV activity, we administered a second series of infusions in which both CD4(+ )and CD8(+) T cells were engineered to express the chimeric receptor and were costimulated ex vivo with beads coated with anti-CD3 and anti-CD28. Sustained fractions of approximately 10(3) to 10(4) modified cells/10(6) total CD4(+) or CD8(+) cells persisted for at least 1 year. Assessment of in vivo trafficking of the transferred cells by lymphoid tissue biopsies revealed the presence of modified cells in proportions equivalent to or below those in the circulation. The cell infusions were well tolerated and were not associated with substantive immunologic or virologic changes. Thus, adoptive transfer of genetically modified HIV-antigen-specific T cells was safe. Sustained survival in the circulation was achieved when modified CD4(+ )and CD8(+) T cells were infused together after ex vivo costimulation, indicating the important role played by antigen-specific CD4(+) T cells in providing "help" to cytotoxic effectors. (Blood. 2000;96:467-474)

Variant genotypes of FcgammaRIIIA influence the development of Kaposi's sarcoma in HIV-infected men.

Disturbances in inflammatory cytokine production and immune regulation coupled with human herpesvirus-8 (HHV-8) infection underlie the current understanding of the pathogenesis of Kaposi's sarcoma (KS), the most common HIV-associated malignancy. The low affinity Fc gamma receptors (FcgammaR) for IgG link humoral and cellular immunity by mediating interaction between antibodies and effector cells, such as phagocytes and natural killer cells. We examined the frequency of polymorphic forms of the low affinity FcgammaRs, FcgammaRIIA, FcgammaRIIIA, and FcgammaRIIIB in 2 cohorts of HIV-infected men with KS and found that the FcgammaRIIIA genotype exerts a significant influence on susceptibility to or protection from KS. The FF genotype was underrepresented in patients with KS, whereas the VF genotype was associated with development of KS. A similar association was observed between FcgammaRIIIA genotypes and HHV-8 seropositivity. These observations suggest a possible role for FcgammaRIIIA in the development of KS during HIV infection.

HIV-1 and T cell dynamics after interruption of highly active antiretroviral therapy (HAART) in patients with a history of sustained viral suppression.

Identifying the immunologic and virologic consequences of discontinuing antiretroviral therapy in HIV-infected patients is of major importance in developing long-term treatment strategies for patients with HIV-1 infection. We designed a trial to characterize these parameters after interruption of highly active antiretroviral therapy (HAART) in patients who had maintained prolonged viral suppression on antiretroviral drugs. Eighteen patients with CD4(+) T cell counts >/= 350 cells/microliter and viral load below the limits of detection for >/=1 year while on HAART were enrolled prospectively in a trial in which HAART was discontinued. Twelve of these patients had received prior IL-2 therapy and had low frequencies of resting, latently infected CD4 cells. Viral load relapse to >50 copies/ml occurred in all 18 patients independent of prior IL-2 treatment, beginning most commonly during weeks 2-3 after cessation of HAART. The mean relapse rate constant was 0.45 (0.20 log(10) copies) day(-1), which was very similar to the mean viral clearance rate constant after drug resumption of 0.35 (0.15 log(10) copies) day(-1) (P = 0.28). One patient experienced a relapse delay to week 7. All patients except one experienced a relapse burden to >5,000 RNA copies/ml. Ex vivo labeling with BrdUrd showed that CD4 and CD8 cell turnover increased after withdrawal of HAART and correlated with viral load whereas lymphocyte turnover decreased after reinitiation of drug treatment. Virologic relapse occurs rapidly in patients who discontinue suppressive drug therapy, even in patients with a markedly diminished pool of resting, latently infected CD4(+) T cells.

Discontinuation of anticytomegalovirus therapy in patients with HIV infection and cytomegalovirus retinitis.

CONTEXT: Persons with cytomegalovirus (CMV) retinitis and acquired immunodeficiency syndrome (AIDS) have required lifelong anti-CMV therapy to prevent the progression of retinal disease and subsequent loss of vision. OBJECTIVE: To determine whether patients who were taking highly active antiretroviral therapy (HAART) and who had stable CMV retinitis could safely discontinue anti-CMV therapy without reactivation of their retinitis or increase in human immunodeficiency virus (HIV) viral load. DESIGN: Prospective nonrandomized interventional trial performed from July 1997 to August 1999. SETTING: Clinical Center of the National Institutes of Health, Bethesda, Md. PATIENTS: Fourteen patients with stable CMV retinitis and HIV infection and CD4+ cell counts higher than 0.1 5 x 10(9)/L and being treated with systemic anti-CMV medications and HAART. INTERVENTIONS: Discontinuation of specific anti-CMV therapy. MAIN OUTCOME MEASURES: Reactivation of CMV retinitis, development of extraocular CMV infection, detection of CMV in blood and urine, HIV burden, immunologic function, quality of life, morbidity, and mortality. RESULTS: Twelve (89.7%) of 14 patients had evidence of immune recovery uveitis before anti-CMV drugs were discontinued. No patient had reactivation of CMV retinitis or development of extraocular CMV disease during mean follow-up of 16.4 months (range, 8.3-22.0 months) without anti-CMV therapy. Human immunodeficiency viral load remained stable following cessation of anti-CMV medications. Blood and urine assays for CMV were briefly positive in 9 patients but did not predict reactivation of CMV disease. Worsening immune recovery uveitis was associated with a substantial (>3 lines) vision loss in 3 patients. CONCLUSIONS: Maintenance anti-CMV medications were safely stopped in those patients who had stable CMV retinitis and elevated CD4+ cell counts and who were taking HAART. The study demonstrates that immune recovery following potent antiretroviral therapy is effective in controlling a major opportunistic infection, even in patients with a history of severe immunosuppression.

Alteration in indinavir clearance during interleukin-2 infusions in patients infected with the human immunodeficiency virus.

STUDY OBJECTIVE: To evaluate the effect of interleukin-2 (IL-2) infusions on the pharmacokinetics of indinavir in patients infected with the human immunodeficiency virus. DESIGN: Observational, noncontrolled trial and prospective, open-label, nonrandomized, pharmacokinetic study. SETTING: Government research hospital. PATIENTS: Seventeen patients receiving indinavir 800 mg every 8 hours and a 5-day continuous infusion of recombinant IL-2. INTERVENTIONS: Observational study: trough indinavir concentrations were measured on day 1 and day 5 of IL-2 as part of a clinical trial. Prospective study: serial plasma samples were collected on days 1 and 5 of IL-2 to determine indinavir concentrations. Samples were also collected over the study period to determine IL-6 concentrations. The data were fit by a one-compartment model that allowed clearance to change based on IL-6 production and by standard noncompartmental equations. MEASUREMENTS AND MAIN RESULTS: The area under the curve of indinavir increased in eight of nine patients by a mean of 88% (range -29-215%) between days 1 and 5 of IL-2 infusion. Over this period, IL-6 concentrations also increased in all patients and indinavir clearance significantly decreased. Observational data in eight patients from the clinical trial showed significantly increased indinavir trough concentrations from 264+/-493 to 670+/-677 ng/ml in the presence of IL-2. CONCLUSION: Indinavir concentrations were altered during IL-2 infusions, possibly by induction of IL-6. Investigation into the effects of other proinflammatory cytokines is warranted.

Controlled trial of interleukin-2 infusions in patients infected with the human immunodeficiency virus.

BACKGROUND: Interleukin-2 is a cytokine that regulates the proliferation and differentiation of lymphocytes. In preliminary studies, intermittent infusions of interleukin-2 led to increases in CD4 counts in patients with human immunodeficiency virus (HIV) infection and more than 200 CD4 cells per cubic millimeter. We conducted a controlled study to evaluate the long-term effects of such therapy on both CD4 counts and the viral burden. METHODS: Sixty HIV-infected patients with base-line CD4 counts above 200 cells per cubic millimeter were randomly assigned to receive either interleukin-2 plus antiretroviral therapy (31 patients, 1 of whom was lost to follow-up) or antiretroviral therapy alone (29 patients). Interleukin-2 was administered every two months for six cycles of five days each, starting at a dosage of 18 million i.u. per day. Safety and immunologic and virologic measures were monitored monthly until four months after the last treatment cycle. RESULTS: In patients treated with interleukin-2, the mean (+/-SE) CD4 count increased from 428 +/- 25 cells per cubic millimeter at base line to 916 +/- 128 at month 12, whereas in the control group, the mean CD4 count decreased from 406 +/- 29 cells per cubic millimeter to 349 +/- 41 (P < 0.001). There were no significant differences between the groups in serial measurements of the plasma HIV RNA or p24 antigen concentration during the 12 months of treatment. Constitutional symptoms (fever, malaise, and fatigue) and asymptomatic hyperbilirubinemia were the chief dose-limiting toxic effects of interleukin-2 therapy. CONCLUSIONS: In patients with HIV infection and base-line CD4 counts above 200 cells per cubic millimeter, intermittent infusions of interleukin-2 produced substantial and sustained increases in CD4 counts with no associated increase in plasma HIV RNA levels.

Evidence for the utilization of peptides for milk protein synthesis in the lactating dairy goat in vivo.

Precursors for milk protein synthesis have been examined in lactating dairy goats using arteriovenous difference and isotope kinetic techniques. Certain amino acids, such as phenylalanine and histidine, are taken up by the mammary gland in quantities that are insufficient to account for their output in milk protein. Some amino acids have been shown to be present in significant quantities (10-30% of total non-protein-bound amino acids) as peptides (< 1,500 Da) in the arterial supply to the mammary gland, although methodological considerations make it difficult to accurately assess the extent of their uptake across the tissue bed. Indirect evidence for the utilization of peptides for milk protein synthesis in vivo has been obtained, however, by examination of the kinetics of milk casein labeling during long-term (24 h) systemic infusion of [1-13C]phenylalanine and [1-13C]leucine. Comparison of plateau enrichments for blood, plasma, and casein indicate that, although, for leucine, the plasma free pool seems to provide all the leucine for milk protein synthesis, sources other than the labeled plasma free amino acids contribute phenylalanine (10-20%) for casein biosynthesis. These findings raise questions relating to the type and source of amino acid precursors used by tissues for protein synthesis.

Pharmacokinetics and pharmacodynamics of subcutaneous interleukin-2 in HIV-infected patients.

STUDY OBJECTIVES: To assess the pharmacokinetics and pharmacodynamics of subcutaneously administered interleukin-2 (IL-2) in patients infected with the human immunodeficiency virus (HIV). DESIGN: Open, dose-escalating phase I clinical trial. SETTING: Government research hospital. PATIENTS: Eighteen patients infected with HIV. INTERVENTIONS: Recombinant IL-2 at dosages of 12, 15, or 18 MIU/day was administered subcutaneously once or twice/day for 5 consecutive days every 2 months. A total of 28 cycles of therapy were included in the analysis. MEASUREMENTS AND MAIN RESULTS: Concentrations of IL-2 in serum were determined by a commercial enzyme-linked immunosorbent assay. Interleukin-2 was well absorbed, with peak concentrations from 21.9-112.9 IU/ml. Absorption was slow, with mean (+/- SD) time to maximum of 4.4 +/- 1.8 hours and a lag time of 26.9 +/- 13.7 minutes. Elimination half-life was 3.3 +/- 0.9 hours. The concentrations had wide variability both within and among patients. Levels of tumor necrosis factor-alpha were increased. Maximum body temperature and systemic side effects were associated with peak serum levels. CONCLUSION: Interleukin-2 is well absorbed after subcutaneous injection in HIV-infected patients, and that route of administration is an alternative to intravenous infusions.

Utilization of dipeptides by the caprine mammary gland for milk protein synthesis.

Specific use by the mammary gland in vivo of amino acids (AA) of peptide origin has been demonstrated in lactating dairy goats using a dual-labeled tracer technique involving close-arterial (external pudic artery, EPA) infusion of 13C-labeled dipeptides. The extent of utilization does not appear to differ for glycyl-L-[1-13C]phenylalanine and glycyl-L-[1-13C]leucine, perhaps indicative of a common mechanism by which AA are incorporated from peptide into milk protein. [1-13C]phenyl-alanine of peptide origin appears to be concentrated within the red blood cell, suggesting a role for the erythrocyte in peptide metabolism in vivo. In conclusion, it appears that the lactating mammary gland of goats has the ability to utilize AA of peptide origin for milk protein synthesis, and while the mechanism by which [1-13C]AA are incorporated into milk protein is not clear, it may involve peptide hydrolysis by either mammary cell surface or red blood cell hydrolases followed by uptake of liberated AA by the mammary gland.

Induction of humoral and cell-mediated anti-human immunodeficiency virus (HIV) responses in HIV sero-negative volunteers by immunization with recombinant gp160.

Development of an effective vaccine for prevention of infection with HIV would provide an important mechanism for controlling the AIDS epidemic. In the current study, the first clinical trial of a candidate HIV-1 vaccine initiated in the United States, the safety and immunogenicity of escalating doses (10-1,280 micrograms) of recombinant gp160 (rgp160), were evaluated in 138 HIV-negative volunteers. Maximal antibody responses, as evaluated by ELISA, were seen after immunization with three doses of 1,280 micrograms rgp160. Responses to some specific epitopes of HIV gp160, including the second conserved domain and the CD4 binding site, were seen more frequently than after natural infection. Neutralizing antibodies to the homologous HIV strain, but not heterologous strains, were induced by this regimen. Blastogenic responses to rgp160 were seen in most volunteers receiving at least two doses of > or = 20 micrograms. These envelope-specific T cell responses were also seen against heterologous strains of HIV. No major adverse reactions were seen after immunization. Thus, rgp160 is a safe and immunogenic candidate HIV vaccine; further studies are needed to determine if it will provide any clinical benefit in preventing HIV infection.

Variations in blood flow to and from the bovine mammary gland measured using transit time ultrasound and dye dilution.

Blood flow across the lactating bovine mammary gland was measured by two techniques. The use of transit time flow probes appeared to give flows which correlated well with dye dilution in only one of five cows, although the relative changes in flow were similar between the techniques in four of the cows. Further studies were made on the effect of posture on mammary blood flow using both techniques. The crossover of venous blood from one side of the mammary gland was also studied using the dye dilution technique, and revealed large differences between animals and also with posture. These observations suggest that particular care should be taken when sampling blood from the milk vein of cows, if a representative sample is required. Changes in blood flow with posture may be indicative of a repartitioning of flow within the body, and the physiology of such a mechanism would be of interest in itself. The control of this mechanism may be useful in modifying blood flow to the mammary gland and thus milk yield, since blood flow is related to the level of milk production.

Indeterminate western blot patterns in a cohort of individuals at high risk for human immunodeficiency virus (HIV-1) exposure.

Our objective was to map serial patterns of Western blot reactivity over time of a cohort of initially ELISA-negative, Western blot-indeterminate individuals from a high-risk group and to determine if these individuals were at increased risk of harboring occult HIV-1 infection. A 2-year prospective study used serial ELISA, two types of Western blot, immunologic profiles, HIV-1 culture, and analysis by polymerase chain reaction. Subjects were 20 ELISA-negative, Western blot indeterminate homosexual volunteers and 20 matched seronegative controls. Results showed that 19 of 20 study subjects completed a mean of 17.0 months of clinical and laboratory follow-up. Reactivities with p24 and/or with p55 were the two most commonly observed Western blot patterns, occurring in 70% of individuals. Specific Western blot reactivity was dependent upon the particular immunoblot preparation being used and varied considerably on a longitudinal basis. No individual pattern appeared predictive of an increased likelihood of subsequent seroconversion to HIV-1 relative to controls. By all other criteria including polymerase chain reaction analysis, samples from 17 of 19 individuals remained negative for HIV-1 at each time point. Two individuals evolved from an indeterminate to a positive Western blot and, simultaneously, from a negative to a positive polymerase chain reaction analysis, during follow-up. Our conclusions were as follows. ELISA-negative, Western blot-indeterminate individuals from a high-risk group show marked variability in immunoblot findings over time, and these patterns do not appear predictive of an increased likelihood of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

A phase I/II trial of zidovudine, interferon-alpha, and granulocyte-macrophage colony-stimulating factor in the treatment of human immunodeficiency virus type 1 infection.

Twenty-four patients infected with human immunodeficiency virus type 1 (HIV-1) who had CD4+ counts of 0.2-0.5 x 10(9) cells/l received granulocyte-macrophage colony-stimulating factor (GM-CSF) in combination with zidovudine plus escalating doses of daily subcutaneous interferon-alpha. Mean neutropenia-inducing doses of interferon-alpha were 9.4 x 10(6) and 10.6 x 10(6) IU/day for groups receiving 100 or 200 mg zidovudine every 4 h, respectively. Mean GM-CSF doses used to reverse neutropenia were 0.64 and 0.63 microgram/kg/day for these two groups, respectively, although the mean minimum effective GM-CSF dose for both was only 0.30 microgram/kg/day. Serum p24 antigen declined greater than 70% in all 5 antigenemic patients. Toxicities included a dose-dependent increase in lymphokine-like side effects (100%), anorexia and weight loss (42%), fatigue (42%), and anemia (50%). While toxicities of the combination can be significant, low-dose GM-CSF readily ameliorated neutropenia associated with zidovudine and interferon-alpha therapy without adversely affecting the antiviral properties of the combination.