Polyamine metabolism impacts T cell dysfunction in the oral mucosa of people living with HIV.

Metabolic changes in immune cells contribute to both physiological and pathophysiological outcomes of immune reactions. Here, by comparing protein expression, transcriptome, and salivary metabolome profiles of uninfected and HIV+ individuals, we found perturbations of polyamine metabolism in the oral mucosa of HIV+ patients. Mechanistic studies using an in vitro human tonsil organoid infection model revealed that HIV infection of T cells also resulted in increased polyamine synthesis, which was dependent on the activities of caspase-1, IL-1ß, and ornithine decarboxylase-1. HIV-1 also led to a heightened expression of polyamine synthesis intermediates including ornithine decarboxylase-1 as well as an elevated dysfunctional regulatory T cell (TregDys)/T helper 17 (Th17) cell ratios. Blockade of caspase-1 and polyamine synthesis intermediates reversed the TregDys phenotype showing the direct role of polyamine pathway in altering T cell functions during HIV-1 infection. Lastly, oral mucosal TregDys/Th17 ratios and CD4 hyperactivation positively correlated with salivary putrescine levels, which were found to be elevated in the saliva of HIV+ patients. Thus, by revealing the role of aberrantly increased polyamine synthesis during HIV infection, our study unveils a mechanism by which chronic viral infections could drive distinct T cell effector programs and Treg dysfunction.

Oral immune dysfunction is associated with the expansion of FOXP3+PD-1+Amphiregulin+ T cells during HIV infection.

Residual systemic inflammation and mucosal immune dysfunction persist in people living with HIV, despite treatment with combined anti-retroviral therapy, but the underlying immune mechanisms are poorly understood. Here we report that the altered immune landscape of the oral mucosa of HIV-positive patients on therapy involves increased TLR and inflammasome signaling, localized CD4+ T cell hyperactivation, and, counterintuitively, enrichment of FOXP3+ T cells. HIV infection of oral tonsil cultures in vitro causes an increase in FOXP3+ T cells expressing PD-1, IFN-γ, Amphiregulin and IL-10. These cells persist even in the presence of anti-retroviral drugs, and further expand when stimulated by TLR2 ligands and IL-1ß. Mechanistically, IL-1ß upregulates PD-1 expression via AKT signaling, and PD-1 stabilizes FOXP3 and Amphiregulin through a mechanism involving asparaginyl endopeptidase, resulting in FOXP3+ cells that are incapable of suppressing CD4+ T cells in vitro. The FOXP3+ T cells that are abundant in HIV-positive patients are phenotypically similar to the in vitro cultured, HIV-responsive FOXP3+ T cells, and their presence strongly correlates with CD4+ T cell hyper-activation. This suggests that FOXP3+ T cell dysregulation might play a role in the mucosal immune dysfunction of HIV patients on therapy.

Systemic inflammation and liver damage in HIV/hepatitis C virus coinfection.

OBJECTIVES: Chronic hepatitis C virus (HCV) and HIV viral infections are characterized by systemic inflammation. Yet the relative levels, drivers and correlates of inflammation in these settings are not well defined. METHODS: Seventy-nine HIV-infected patients who had been receiving antiretroviral therapy (ART) for more than 2 years and who had suppressed plasma HIV levels (< 50 HIV-1 RNA copies/mL) were included in the study. Two patient groups, HCV-positive/HIV-positive and HCV-negative/HIV-positive, and a control group comprised of healthy volunteers (n = 20) were examined. Markers of systemic inflammation [interleukin (IL)-6, interferon gamma-induced protein (IP)-10, soluble tumour necrosis factor receptor-I (sTNF-RI) and sTNF-RII], monocyte/macrophage activation [soluble CD163 (sCD163), soluble CD14 and neopterin], intestinal epithelial barrier loss [intestinal fatty acid binding protein (I-FABP) and lipopolysaccharide (LPS)] and coagulation (d-dimers) were analysed. CD4 naïve T cells and CD4 recent thymic emigrants (RTEs) were enumerated. RESULTS: Plasma levels of IP-10, neopterin and sCD163 were higher in HCV/HIV coinfection than in HIV monoinfection and were positively correlated with indices of hepatic damage [aspartate aminotransferase (AST), alanine aminotransferase (ALT) and the AST to platelet ratio index (APRI)]. Levels of I-FABP were comparably increased in HIV monoinfection and HIV/HCV coinfection but LPS concentrations were highest in HCV/HIV coinfection, suggesting impaired hepatic clearance of LPS. Plasma HCV levels were not related to any inflammatory indices except sCD163. In coinfected subjects, a previously recognized relationship of CD4 naïve T-cell and RTE counts to hepatocellular injury was defined more mechanistically by an inverse relationship to sCD163. CONCLUSIONS: Hepatocellular injury in HCV/HIV coinfection is linked to elevated levels of certain inflammatory cytokines and an apparent failure to clear systemically translocated microbial products. A related decrease in CD4 naïve T cells and RTEs also merits further exploration.

Prevention of SHIV transmission by topical IFN-ß treatment.

Understanding vaginal and rectal HIV transmission and protective cellular and molecular mechanisms is critical for designing new prevention strategies, including those required for an effective vaccine. The determinants of protection against HIV infection are, however, poorly understood. Increasing evidence suggest that innate immune defenses may help protect mucosal surfaces from HIV transmission in highly exposed, uninfected subjects. More recent studies suggest that systemically administered type 1 interferon protects against simian immunodeficiency virus infection of macaques. Here we hypothesized that topically applied type 1 interferons might stimulate vaginal innate responses that could protect against HIV transmission. We therefore applied a recombinant human type 1 interferon (IFN-ß) to the vagina of rhesus macaques and vaginally challenged them with pathogenic simian/human immunodeficiency virus (SHIV). Vaginal administration of IFN-ß resulted in marked local changes in immune cell phenotype, increasing immune activation and HIV co-receptor expression, yet provided significant protection from SHIV acquisition as interferon response genes were also upregulated. These data suggest that protection from vaginal HIV acquisition may be achieved by activating innate mucosal defenses.

Markers of inflammation and CD8 T-cell activation, but not monocyte activation, are associated with subclinical carotid artery disease in HIV-infected individuals.

OBJECTIVES: The aim of the study was to explore the relationships between lymphocyte and monocyte activation, inflammation, and subclinical vascular disease among HIV-1-infected patients on antiretroviral therapy (ART). METHODS: Baseline mean common carotid artery (CCA) intima-media thickness (IMT) and carotid plaque (IMT > 1.5 cm) were evaluated in the first 60 subjects enrolled in the Stopping Atherosclerosis and Treating Unhealthy Bone with Rosuvastatin in HIV (SATURN-HIV) trial. All subjects were adults on stable ART with evidence of heightened T-cell activation (CD8(+)CD38(+)HLA-DR(+) ≥ 19%) or increased inflammation (high-sensitivity C-reactive protein ≥ 2 mg/L). All had fasting low-density lipoprotein (LDL) cholesterol ≤ 130 mg/dL. RESULTS: Seventy-eight per cent of patients were men and 65% were African-American. Median (interquartile range) age and CD4 count were 47 (43, 52) years and 648 (511, 857) cells/µL, respectively. All had HIV-1 RNA < 400 HIV-1 RNA copies/mL. Mean CCA-IMT was correlated with log-transformed CD8(+)CD38(+)HLA-DR(+) percentage (r = 0.326; P = 0.043), and concentrations of interleukin-6 (r = 0.283; P = 0.028), soluble vascular cell adhesion molecule (sVCAM; r = 0.434; P = 0.004), tumour necrosis factor-α receptor-I (TNFR-I; r = 0.591; P < 0.0001) and fibrinogen (r = 0.257; P = 0.047). After adjustment for traditional cardiovascular disease (CVD) risk factors, the association with TNFR-I (P = 0.007) and fibrinogen (P = 0.033) remained significant. Subjects with plaque (n = 22; 37%) were older [mean (standard deviation) 51 (7.7) vs. 43 (9.4) years, respectively; P = 0.002], and had a higher CD8(+)CD38(+)HLA-DR(+) percentage [median (interquartile range) 31% (24, 41%) vs. 23% (20, 29%), respectively; P = 0.046] and a higher sVCAM concentration [mean (standard deviation) 737 (159) vs. 592 (160) ng/mL, respectively; P = 0.008] compared with those without plaque. Pro-inflammatory monocyte subsets and serum markers of monocyte activation (soluble CD163 and soluble CD14) were not associated with CCA-IMT or plaque. CONCLUSIONS: Participants in SATURN-HIV have a high level of inflammation and immune activation that is associated with subclinical vascular disease despite low serum LDL cholesterol.

Effects of recombinant human interleukin 7 on T-cell recovery and thymic output in HIV-infected patients receiving antiretroviral therapy: results of a phase I/IIa randomized, placebo-controlled, multicenter study.

BACKGROUND: The immune deficiency of human immunodeficiency virus (HIV) infection is not fully corrected with ARV therapy. Interleukin-7 (IL-7) can boost CD4 T-cell counts, but optimal dosing and mechanisms of cellular increases need to be defined. METHODS: We performed a randomized placebo-controlled dose escalation (10, 20 and 30 µg/kg) trial of 3 weekly doses of recombinant human IL-7 (rhIL-7) in ARV-treated HIV-infected persons with CD4 T-cell counts between 101 and 400 cells/µL and plasma HIV levels <50 copies/mL. Toxicity, activity and the impact of rhIL-7 on immune reconstitution were monitored. RESULTS: Doses of rhIL-7 up to 20 µg/kg were well tolerated. CD4 increases of predominantly naive and central memory T cells were brisk (averaging 323 cells/µL at 12 weeks) and durable (up to 1 year). Increased cell cycling and transient increased bcl-2 expression were noted. Expanded cells did not have the characteristics of regulatory or activated T cells. Transient low-level HIV viremia was seen in 6 of 26 treated patients; modest increases in total levels of intracellular HIV DNA were proportional to CD4 T-cell expansions. IL-7 seemed to increase thymic output and tended to improve the T-cell receptor (TCR) repertoire in persons with low TCR diversity. CONCLUSIONS: Three weekly doses of rhIL-7 at 20 µg/kg are well tolerated and lead to a dose-dependent CD4 T-cell increase and the broadening of TCR diversity in some subjects. These data suggest that this rhIL-7 dose could be advanced in future rhIL-7 clinical studies. CLINICAL TRIALS REGISTRATION: NCT0047732.

Genetic variations in loci relevant to natural killer cell function are affected by ethnicity but are generally not correlated with susceptibility to HIV-1.

Polymorphisms in cell surface receptors of natural killer cells and their ligands on target cells can affect susceptibility to viral infections including human immunodeficiency virus (HIV)-1. We found that the carriage of the human leukocyte antigen (HLA)-G minus 14-bp polymorphism, LILRB1 single nucleotide polymorphism rs1061680, and activating and inhibitory killer immunoglobulin-like receptors (KIRs) were different when data were compared between Caucasian, African Americans and Asian populations. However, carriage was similar when HIV-1 patients were compared with control donors, with the exception of the African American cohort.

Lower peripheral blood CD14+ monocyte frequency and higher CD34+ progenitor cell frequency are associated with HBV vaccine induced response in HIV infected individuals.

We evaluated immunologic predictors of response to HBV vaccine administered in the presence or absence of GM-CSF in HIV infected individuals. We measured peripheral blood hematopoietic progenitor, monocyte and myeloid-derived suppressor cell (MDSC) frequencies, and expression of GMCSF receptor on monocytes and MDSCs, at baseline and 4weeks after immunization in relation to antibody response. We observed higher baseline progenitor and lower monocyte frequencies among week 16 antibody responders. Week 4 decline in MDSC frequency was associated with week 16 antibody response, while administration of GM-CSF was associated with preservation of these cells. No significant differences in GM-CSF receptor expression were observed in the presence vs. absence of GM-CSF. These findings are consistent with a positive role of progenitor cells and a potential negative role of monocytes in vaccine response. Additionally, GM-CSF augmented the preservation of peripheral blood MDSC, which may contribute to the lack of improved vaccine responses.

Role of human beta-defensins in HIV infection.

Mechanisms of resistance to HIV-1 infection in the human oral cavity are incompletely understood. While salivary components have been implicated in protection, there is growing evidence that human beta-defensins (hBDs), originating in oral epithelial cells, may be playing an important role in the prevention of HIV infection. New antiviral, chemotactic, and immunosurveillance properties are being attributed to hBDs, which are small cationic antimicrobial innate response molecules expressed in mucosal epithelium. Inducible hBDs are always expressed in normal oral epithelium, a property not shared by other mucosal barriers. Data reviewed in this paper demonstrate that: (1) HIV-1 X4 and R5 phenotypes induce hBD-2 and -3 mRNA in normal human oral epithelial cells; (2) hBD-2 and -3 inhibit HIV-1 infection by both viral strains, with greater activity against X4 viruses; and (3) this inhibition is due to a direct interaction with virions and through modulation of the CXCR4 co-receptor. These properties may be exploited as strategies for mucosal protection against HIV-1 transmission.

Gender differences in human immunodeficiency virus (HIV) RNA and CD4 cell counts among new entrants to HIV care.

Clinic database extraction identified 806 new entrants to human immunodeficiency virus (HIV) care in Cleveland, OH, USA. At entry, women had higher CD4 counts and lower HIV RNA levels than men (mean, 388 vs. 310 cells/microL, and 8.94 x 10(4) vs. 1.27 x 10(5) copies/mL, respectively), but the proportion of entrants with category C illnesses, category B conditions, sexually transmitted diseases and CD4 counts < 200 microL did not differ between genders. Hepatitis B seroprevalence was higher in men (8.7% vs. 0.6%), but there was no difference in hepatitis C prevalence. Whether women in Cleveland seek HIV care earlier, or whether early markers of HIV disease differ between the genders, remains to be determined.

HIV nephropathy and the Duffy antigen/receptor for Chemokines in African Americans.

BACKGROUND AND OBJECTIVES: HIV nephropathy (HIVAN) is markedly racially biased in its distribution, occurring in about 10% of HIV infected African Americans according to some studies. Based upon previous laboratory and epidemiological studies, the Duffy promoter polymorphism, which occurs almost exclusively in individuals of African descent, has been postulated to be the predisposing factor. We aimed to explore that relationship by directly genotyping individuals with HIV nephropathy to determine the proportion homozygous for this mutation to test the hypothesis it was responsible for the genetic component of this disease. We anticipated that if the polymorphism was associated with HIV nephropathy all individuals would be homozygous for this mutation. METHOD: Individuals with HIVAN proven on biopsy were identified from previous studies and a pre-existing clinical database. This diagnosis was confirmed by an experienced pathologist examining the biopsies in a blinded fashion. PCR and RFLP strategies were used on the biopsy samples to genotype for the Duffy promoter polymorphism. The cases were compared to a control population of HIV seronegative African Americans. RESULTS: Twenty African American individuals with HIV nephropathy were successfully genotyped. Only nine were homozygous for the promoter mutation. Nine were heterozygous and two homozygous wild type. Furthermore, the frequency of the polymorphism did not differ from the background rate in the African American population (OR = 0.788 95% confidence intervals 0.378-1.64). CONCLUSION: The Duffy promoter polymorphism was not disproportionately represented in persons with HIVAN calling into question any significant role in the pathogenesis of HIVAN.

Genotypic drug resistance and cause of death in HIV-infected persons who died in 1999.

We analyzed the relationship between viral drug resistance and causes of death in 29 HIV-1-infected patients who had been followed in an HIV-outpatient clinic and died in 1999. Six patients (21%) died with plasma HIV-RNA levels <1000 copies/ml. Seven (24%) died with wild-type (WT) virus in plasma, 6 (21%) had reverse transcriptase (RT) mutations only, 10 (34%) had multidrug-resistant (MDR) virus. The causes of death were not differently distributed among these groups; however, 8 of 16 patients (50%) with resistant viruses died of end-organ failure versus 2 of 7 patients (29%) with WT virus. Seventeen of 32 patients (53%) were thought by their physicians to be noncompliant with prescribed therapy. Major resistance mutations to antiretroviral drugs were present in viruses from at least 55% of our HIV-1-infected patients who died in 1999. Nonetheless, deaths also occurred among patients with well-controlled HIV infection and among patients with WT virus in plasma. Infections related to incomplete immune restoration, inability to maintain suppressive antiretroviral drug levels, and end-organ failures all contribute to mortalities in the era of highly active antiretroviral therapy.

Poor CD4 T cell restoration after suppression of HIV-1 replication may reflect lower thymic function.

OBJECTIVE: To characterize immune phenotype and thymic function in HIV-1-infected adults with excellent virologic and poor immunologic responses to highly active antiretroviral therapy (HAART). METHODS: Cross-sectional study of patients with CD4 T cell rises of > or = 200 x 10(6) cells/l (CD4 responders; n = 10) or < 100 x 10(6) cells/l (poor responders; n = 12) in the first year of therapy. RESULTS: Poor responders were older than CD4 responders (46 versus 38 years; P < 0.01) and, before HAART, had higher CD4 cell counts (170 versus 35 x 106 cells/l; P = 0.11) and CD8 cell counts (780 versus 536 x 10(6) cells/l; P = 0.02). After a median of 160 weeks of therapy, CD4 responders had more circulating naive phenotype (CD45+CD62L+) CD4 cells (227 versus 44 x 10(6) cells/l; P = 0.001) and naive phenotype CD8 cells (487 versus 174 x 10(6) cells/l; P = 0.004) than did poor responders (after 130 weeks). Computed tomographic scans showed minimal thymic tissue in 11/12 poor responders and abundant tissue in 7/10 responders (P = 0.006). Poor responders had fewer CD4 cells containing T cell receptor excision circles (TREC) compared with CD4 responders (2.12 versus 27.5 x 10(6) cells/l; P = 0.004) and had shorter telomeres in CD4 cells (3.8 versus 5.3 kb; P = 0.05). Metabolic labeling studies with deuterated glucose indicated that the lower frequency of TREC-containing lymphocytes in poor responders was not caused by accelerated proliferation kinetics. CONCLUSION: Poor CD4 T cell increases observed in some patients with good virologic response to HAART may be caused by failure of thymic T cell production.

HIV-1 infection impairs cell cycle progression of CD4(+) T cells without affecting early activation responses.

Failure of CD4(+) T cells to proliferate in response to antigenic stimulation is a characteristic of HIV infection. Analysis of the proliferation defect has been hampered by an inability to identify CD4(+) cells with T cell receptor specificity for antigen. To focus only on cells that had been stimulated through the T cell receptor, CD4(+) T cells were stimulated with an anti-Vbeta3 Ab that activates approximately 3-5% of peripheral blood T cells. This approach revealed proliferation defects in cells from HIV-infected patients that were not appreciated using anti-CD3 Ab stimulation and provided the capacity to examine responses on a single cell basis. After anti-Vbeta3 Ab stimulation, CD4(+)Vbeta3(+) cells from HIV-infected patients demonstrated defects in expression of cell cycle-associated proteins, D-type cyclins, and cyclin A. However, the expression of early activation markers, CD69 and CD25, was not significantly impaired in cells from most patients. Thus, CD4(+) T cell proliferation failure in HIV disease is characterized by dysregulated activation that precludes cell cycle progression. This proliferation defect was most apparent in patients with diminished CD4(+) T cell numbers and higher plasma HIV RNA levels. CD4(+) T cell proliferation failure may be a key determinant of immune impairment in HIV disease.

Differential expression of interleukin-2 and gamma interferon in human immunodeficiency virus disease.

Subnormal T-cell production of interleukin-2 (IL-2) in human immunodeficiency virus (HIV) disease has been described; however, it is not clear whether failure to synthesize IL-2 represents a selective or global defect in T-cell cytokine production. We evaluated the intracellular production of gamma interferon (IFN-gamma) and IL-2 in CD4(+) cells that were stimulated with staphylococcal enterotoxin B or cytomegalovirus antigen. Strikingly, IFN-gamma and IL-2 are differentially regulated in T cells of HIV-infected patients such that the numbers of CD69(+) cells or IFN-gamma-positive cells that make IL-2 are proportionally decreased in CD4(+) T cells from HIV-infected patients. These findings demonstrate a selective defect in IL-2 production and suggest that enumeration of IFN-gamma-producing cells in response to T-cell receptor stimulation, while providing some estimate of antigen-reactive cell frequency, may not reflect or predict "normal" T-cell function in HIV-infected patients.

Multiple CD4+ cell kinetic patterns and their relationships with baseline factors and virological responses in HIV type 1 patients receiving highly active antiretroviral therapy.

This exploratory analyses characterizes patterns of lymphocyte recovery in HIV-1-infected patients treated with highly active antiretroviral therapy (HAART) and investigates their relationship with baseline indices and virologic responses. We modeled kinetics of total CD4+ lymphocytes, as well as naive (CD45RA+ CD62L+), and memory (CD45RA- CD45RO+) subsets in 48 patients treated with AZT/3TC/Ritonavir for 48 weeks in ACTG protocol 315. Cell kinetic indices were estimated by nonlinear regression methods and were correlated with baseline factors and virologic responses. Five different kinetic patterns were identified, including biphasic growth, growth-plateau, growth-depletion, decay-recovery, and biphasic decay. Although overall mean lymphocyte responses showed a biphasic increase in cell number, a careful investigation reveals that only one-third of patients actually followed the biphasic growth pattern in CD4+ cell response, while 44% of 48 patients from this study followed the growth-depletion pattern. CD4+ cell recovery during the first phase and the 48-week study period were negatively correlated with baseline CD4+ cell counts, and positively correlated with baseline viral load. Memory CD4+ cell recovery during the first phase was also negatively correlated with baseline memory CD4+ and total CD4+ cell number, but the recovery rate of memory CD4+ cells during the second phase was positively correlated with baseline CD4+ cell number. Patients with a decay in CD4+ cell count during treatment were more likely to have experienced virological rebound (58%) than patients with nondecay patterns (24%). The rate and magnitude of the absolute increase in total CD4+ and memory CD4+ cell number (but not naive CD4+ cells) during the second phase were lower in patients with viral rebound compared with patients with persistent viral suppression. These results show that the kinetics of lymphocyte reconstitution in response to potent antiretroviral therapy in individual patients vary considerably from the "classic" biphasic increase that characterizes the mean or median response pattern. Pattern analysis of lymphocyte kinetics may be useful for testing relationships among factors that modulate the response to treatment.

Survival of transfused donor white blood cells in HIV-infected recipients.

The appearance and expansion of donor white blood cells in a recipient after transfusion has many potential biologic ramifications. Although patients with HIV infection are ostensibly at high risk for microchimerism, transfusion-associated graft-versus-host disease (TA-GVHD) is rare. The purpose of this study was to search for sustained microchimerism in such patients. Blood samples were collected from 93 HIV-infected women (a subset from the Viral Activation Transfusion Study, an NHLBI multicenter randomized trial comparing leukoreduced versus unmodified red blood cell [RBC] transfusions) before and after transfusions from male donors. Donor lymphocytes were detected in posttransfusion specimens using a quantitative Y-chromosome-specific polymerase chain reaction (PCR) assay, and donor-specific human leukocyte antigen (HLA) alleles were identified with allele-specific PCR primers and probes. Five of 47 subjects randomized to receive nonleukoreduced RBCs had detectable male lymphocytes 1 to 2 weeks after transfusion, but no subject had detectable male cells more than 4 weeks after a transfusion. In 4 subjects studied, donor-specific HLA haplotypes were detected in posttransfusion specimens, consistent with one or more donors' cells. None of 46 subjects randomized to receive leukoreduced RBCs had detectable male lymphocytes in the month after transfusion. Development of sustained microchimerism after transfusion in HIV-infected patients is rare; HIV-infected patients do not appear to be at risk for TA-GVHD.

Immune restoration and CD4+ T-cell function with antiretroviral therapies.

OBJECTIVES: To review the current understanding of the details and mechanisms of immune restoration that follows administration of suppressive antiretroviral therapies to persons with chronic HIV-1 infection. SUMMARY: A first-phase cellular increase often includes increases in multiple circulating lymphocyte populations and is largely attributable to rapid redistribution of cells from lymphoid tissue. A second slower phase is largely comprised of naïve cell increases that may reflect cells newly produced in the thymus. Improvement in CD4+ cell function is demonstrable but functional restoration is incomplete. Immunization can enhance the restoration of CD4+ cell-dependent responses, and the magnitude of restoration is related in part to the degree to which HIV-1 replication and immune activation are controlled. Despite the incomplete nature of immune restoration seen after suppression of HIV-1 replication in chronic infection, clinical benefits of these responses are reflected in decreased HIV-1-related opportunistic infections and mortality. The effects of these therapies on the occurrence of non-Hodgkins lymphoma are less apparent. CONCLUSIONS: Suppression of HIV-1 replication results in both laboratory and clinical evidence of immune restoration. Although incomplete, this immune restoration provides 'breathing room' to develop better-tolerated antiviral therapies and therapies designed to enhance immune function.

A potential role for interleukin-7 in T-cell homeostasis.

Interleukin (IL)-7 is known to up-regulate thymopoietic pathways of T-cell regeneration. Recent work also has shown it to potently enhance thymic-independent peripheral expansion and to restore immunocompetence in athymic T-cell-depleted hosts. We hypothesized that endogenous IL-7 could contribute to the restoration of T-cell homeostasis following T-cell depletion. To analyze this, we evaluated circulating IL-7 levels and lymphocyte subsets in multiple clinical cohorts with T-cell depletion of varying etiologies. In pediatric (n = 41) and adult (n = 51) human immunodeficiency virus-infected CD4-depleted patients, there were strong inverse correlations between IL-7 levels and CD4 counts (r = -0.77, P <.0001, and r = -0.68, P <.0001). Declines in IL-7 were temporally correlated with recovery of CD4 counts. Similar patterns were observed in CD4-depleted patients receiving cancer chemotherapy (r = -0.65, P =.009). Therefore, in 2 disparate clinical scenarios involving CD4 depletion, IL-7 levels dynamically respond to changes in CD4 T-cell number, making this cytokine uniquely suited as a candidate regulator of T-cell homeostasis. Furthermore, in patients with idiopathic CD4 lymphopenia, a much weaker relationship between IL-7 levels and peripheral blood CD4 counts was observed, suggesting that an impaired IL-7 response to CD4 depletion may contribute to the impaired lymphocyte homeostasis observed in this population. In light of the known effects of IL-7 on T-cell regeneration, we postulate that increased availability of IL-7 could play a critical role in restoring T-cell homeostasis following T-cell depletion.

Leukocyte-reduced red blood cell transfusions in patients with anemia and human immunodeficiency virus infection: the Viral Activation Transfusion Study: a randomized controlled trial.

CONTEXT: Allogeneic blood transfusions have immunomodulatory effects and have been associated with activation of human immunodeficiency virus (HIV) and cytomegalovirus (CMV) in vitro and of HIV in small pilot studies. Retrospective studies suggest that transfusions adversely affect the clinical course of HIV. Data in selected non-HIV-infected patients requiring blood transfusion have suggested clinical benefit with leukocyte-reduced red blood cells (RBCs). OBJECTIVE: To compare the effects of leukoreduced and unmodified RBC transfusions on survival, complications of acquired immunodeficiency syndrome, and relevant laboratory markers in HIV-infected patients. DESIGN AND SETTING: Double-blind randomized controlled trial conducted in 11 US academic medical centers from July 1995 through June 1999, with a median follow-up of 12 months (24 months in survivors). PATIENTS: A total of 531 persons infected with HIV and CMV, aged 14 years or older, who required transfusions for anemia; 259 received leukoreduced transfusions and 262 received unmodified transfusions (10 did not receive the planned transfusion). MAIN OUTCOME MEASURES: Survival and change in plasma HIV RNA level 7 days after transfusion, compared by type of transfusion. RESULTS: At entry, the groups were similar in demographic, clinical, and relevant laboratory characteristics. A total of 3864 RBC units were transfused. Two hundred eighty-nine deaths occurred (151 with leukoreduced transfusion; 138 with unmodified transfusion); median survival was 13.0 and 20.5 months, respectively (relative hazard [RH], 1.20; 95% confidence interval [CI], 0.95-1.51; log-rank P =.12). Analyses adjusted for prognostic factors suggested possible worse survival with leukoreduction (RH, 1.35; 95% CI, 1.06-1.72). There was no difference in time to new opportunistic event/death or frequency of transfusion reactions. No changes in plasma HIV RNA level were seen in either group at days 7, 14, 21, or 28, even in patients not taking antiretroviral drugs. There were no differences in trends between groups in CMV DNA, CD4 cell counts, activated (CD38% or human leukocyte antigen-DR) CD8 cell counts, or plasma cytokine levels. CONCLUSIONS: We found no evidence of HIV, CMV, or cytokine activation following blood transfusion in patients with advanced HIV infection. Leukoreduction provided no clinical benefit in these patients. These data demonstrate the importance of conducting controlled studies of effects of leukoreduction in different patient populations, since smaller studies in other patient populations have suggested leukoreduction may be beneficial.