A novel peptide-IgG conjugate, CAP18(106-138)-IgG, that binds and neutralizes endotoxin and kills gram-negative bacteria

Although type-specific IgG directed to the O-polysaccharide antigen of bacterial lipopolysaccharide (LPS) is protective in most models of LPS or bacterial challenge, no currently available IgG binds to LPS from all gram-negative bacteria. The ability of a peptide-IgG conjugate, CAP18(106-138)-IgG, to bind and neutralize LPS, to kill gram-negative bacteria, and to protect in a sensitized mouse model of LPS toxicity was studied. CAP18(106-138)-IgG bound LPS from multiple gram-negative bacteria in four different binding assays. In a fluid-phase RIA, half-maximal binding of 5 microg/mL 3H-labeled LPS occurred at 5-10 microg/mL CAP18(106-138)-IgG, similar to binding with monoclonal type-specific IgG. CAP18(106-138)-IgG neutralized LPS, as assessed by LPS-induced coagulation of limulus amebocyte lysate and production of tumor necrosis factor in vitro, was bactericidal for a wide range of gram-negative bacteria, and decreased LPS-induced lethality in sensitized mice. Antibacterial peptide-IgG conjugates merit further study as a novel adjunctive therapy for gram-negative sepsis.

Posttraumatic stress symptoms, intrusive thoughts, loss, and immune function after Hurricane Andrew

OBJECTIVE

To examine the impact of and relationship between exposure to Hurricane Andrew, a severe stressor, posttraumatic stress symptoms and immune measures.

METHODS

Blood draws and questionnaires were taken from community volunteer subjects living in the damaged neighborhoods between 1 and 4 months after the Hurricane.

RESULTS

The sample exhibited high levels of posttraumatic stress symptoms by questionnaire (33% overall; 76% with at least one symptom cluster), and 44% scored in the high impact range on the Impact of Events (IES) scale. A substantial proportion of variance in posttraumatic stress symptoms could be accounted for by four hurricane experience variables (damage, loss, life threat, and injury), with perceived loss being the highest correlate. Of the five immune measures studied Natural Killer Cell Cytotoxicity (NKCC) was the only measure that was meaningfully related (negatively) to both damage and psychological variables (loss, intrusive thoughts, and posttraumatic stress disorder (PTSD). White blood cell counts (WBCs) were significantly positively related with the degree of loss and PTSD experienced. Both NKCC (lower) and WBC were significantly related to retrospective self-reported increase of somatic symptoms after the hurricane. Overall, the community sample was significantly lower in NKCC, CD4 and CD8 number, and higher in NK cell number compared to laboratory controls. Finally, evidence was found for new onset of sleep problems as a mediator of the posttraumatic symptom-NKCC relationship.

CONCLUSIONS

Several immune measures differed from controls after Hurricane Andrew. Negative (intrusive) thoughts and PTSD were related to lower NKCC. Loss was a key correlate of both posttraumatic symptoms and immune (NKCC, WBC) measures.

Cognitive-behavioral stress management decreases dysphoric mood and herpes simplex virus-type 2 antibody titers in symptomatic HIV-seropositive gay men

This study tested the effects of a 10-week group cognitive-behavioral stress management (CBSM) intervention on mood and immunologic parameters in HIV-seropositive gay men whose disease had progressed to a symptomatic stage. Men were randomized to either CBSM or a modified waiting-list control group. The CBSM intervention significantly decreased self-reported dysphoria, anxiety, and total distress. Individuals who practiced relaxation more consistently had significantly greater drops in dysphoria. The intervention also decreased herpes simplex virus-Type 2 (HSV-2) immunoglobulin G antibody titers. The control group showed no significant changes in either mood or antibody titers. Individual difference analyses revealed that decreases in dysphoria significantly predicted lower HSV-2 antibody titers by the end of the 10-week period. Neither group displayed changes in HSV-Type 1 antibody titers or in CD4+ or CD8+ cell numbers.

Immunological correlates of disease severity in pediatric slow progressors with human immunodeficiency virus type 1 infection

Pediatric slow progressors are a group of HIV-1-infected individuals who are homogeneous for route and length of infection and standard of care and are therefore amenable to cross-sectional population studies on the immunological correlates of disease progression. We report here that both clinical and immunological categorizations of pediatric slow progressors based on the 1994 CDC criteria for symptom and immunosupression severity levels yield similar immunological findings: declining proportions of CD4 T cells are associated with increasing proportions of CD8 and CD4-CD8- T cells and with declining IL-2, -5, and -10 production levels by peripheral blood cells in response to the T cell-dependent mitogen, phytohemagglutinin, but not to the T and B cell-dependent mitogen from pokeweed. The latter cross-sectional results point to potential prognostic and nosologic markers and therapeutic targets among HIV-infected pediatric slow progressors. Longitudinal studies will help to assess further the relevance of these findings.

Intrathecal synthesis of anti-sulfatide IgG is associated with peripheral nerve disease in acquired immunodeficiency syndrome

Peripheral nervous system involvement in the acquired immunodeficiency syndrome (AIDS) can take the form of an acute or chronic inflammatory demyelinating polyneuropathy, polyradiculopathy, mononeuropathy multiplex, or autonomic neuropathy. There is no widely held consensus on the etiology of PNS or other neurological complications associated with HIV infection. We report here that PNS disease in HIV-infected individuals is associated with intrathecal synthesis of an antibody directed against sulfatide, a major component of myelin. The anti-sulfatide antibody is also present nonspecifically in serum. The antibody requires the presence of the 3-O-sulfogalactosyl residue for binding and recognizes preferentially the hydroxy fatty acid-containing form of sulfatide. Anti-sulfatide antibodies are therefore one of the humoral factors responsible for demyelinating diseases in AIDS patients.

Massage therapy is associated with enhancement of the immune system's cytotoxic capacity

Twenty-nine gay men (20 HIV+, 9 HIV-) received daily massages for one month. A subset of 11 of the HIV+ subjects served as a within subject control group (one month with and without massages). Major immune findings for the effects of the month of massage included a significant increase in Natural Killer Cell number, Natural Killer Cell Cytotoxicity, soluble CD8, and the cytotoxic subset of CD8 cells. There were no changes in HIV disease progression markers (CD4, CD4/CD8 ratio, Beta-2 microglobulin, neopterin). Major neuroendocrine findings, measured via 24 hour urines included a significant decrease in cortisol, and nonsignificant trends toward decrease of catecholamines. There were also significant decreases in anxiety and increases in relaxation which were significantly correlated with increases in NK cell number. Thus, there appears to be an increase in cytotoxic capacity associated with massage. Implications for HIV+ men as those with other illnesses, particularly cancer, are discussed.

Predictors of survival in human immunodeficiency virus type 1-seropositive intravenous drug users

In an ongoing prospective study of street-recruited intravenous drug users (IDUs) in Miami, Fla., 116 human immunodeficiency virus type 1 (HIV-1)-infected IDUs were monitored for up to 7 years. This provided an opportunity to evaluate baseline immunological parameters as potential predictors of survival among HIV-1-infected IDUs. As expected, HIV-1-infected IDUs who had an advanced stage of the disease (Centers for Disease Control and Prevention classification III or IV); p24 antigenemia; human T-cell leukemia virus type 1/2 seropositivity; low CD4 counts (< or = 200); low hemoglobin (< or = 14), high serum immunoglobulin A (IgA) (> 500 mg/dl), or high serum IgG (> or = 3,500 mg/dl) levels; or low proliferative responses to pokeweed mitogen (< or = 1,500 cpm) and to phytohemagglutinin (< or = 80,000 cpm) at baseline had worse survival rates. Results from multivariate Cox's models of survival showed that the baseline serum IgG level, serum IgA level, and CD4 count independently predict survival in HIV-1-infected IDUs. Cross-validation procedures verified the above-mentioned findings. These findings support the routine consideration of serum immunoglobulin levels in addition to CD4 count, especially in early evaluation of disease stage, as these evaluations may modify application of prophylaxis and treatment for HIV-1-infected IDUs. We recommend consideration of use of serum IgG and IgA as immunological markers for long-range prediction of survival in HIV-1-infected IDUs. These determinations are less onerous and more appropriate for use in field studies and financially less favored settings.

Bereavement is associated with time-dependent decrements in cellular immune function in asymptomatic human immunodeficiency virus type 1-seropositive homosexual men

Seventy-nine human immunodeficiency virus type 1 (HIV-1)-seropositive homosexual men participating in a longitudinal study of HIV-1 infection were assessed twice, 6 months apart, to investigate associations between bereavement and cellular immune function. Subjects were assessed by using a theory-driven model comprising life stressors, social support and coping style, and control variables. Natural killer cell cytotoxicity was decreased among the bereaved at both times. Lymphocyte proliferative response to phytohemagglutinin was decreased among the bereaved at the second time point but not at the first. These functional immune decrements are associated with increased neuroendocrine responses of the sympathetic adrenomeduallary system as well as the limbic-hypothalamic-pituitary-adrenal axis. Implications for differential neuroendocrine responses over time are discussed. Active coping style was independently and positively related to both immune measures. The results imply that a bereavement support group intervention merits investigation for an effect on immunological measures and clinical progression of HIV-1 infection as well as grief resolution.

Micronutrients and HIV-1 disease progression

OBJECTIVE

To determine whether nutritional status affects immunological markers of HIV-1 disease progression.

DESIGN

A longitudinal study, to evaluate the relationship between plasma levels of nutrients and CD4 cell counts, along and in combination with beta 2-microglobulin (beta 2M; AIDS index) over an 18-month follow-up.

METHODS

Biochemical measurements of nutritional status including plasma proteins, zinc, iron and vitamins B1, B2, B6, B12 (cobalamin), A, E, C and folate and immunological markers [lymphocyte subpopulations (CD4) and beta 2M] were obtained in 108 HIV-1-seropositive homosexual men at baseline and over three 6-month time periods. Changes in nutrient status (e.g., normal to deficient, deficient to normal), were compared with immunological parameters in the same time periods using an autoregressive model.

RESULTS

Development of deficiency of vitamin A or vitamin B12 was associated with a decline in CD4 cell count (P = 0.0255 and 0.0377, respectively), while normalization of vitamin A, vitamin B12 and zinc was associated with higher CD4 cell counts (P = 0.0492, 0.0061 and 0.0112, respectively). These findings were largely unaffected by zidovudine use. For vitamin B12, low baseline status significantly predicted accelerated HIV-1 disease progression determined by CD4 cell count (P = 0.041) and the AIDS index (P = 0.005).

CONCLUSIONS

These data suggest that micronutrient deficiencies are associated with HIV-1 disease progression and raise the possibility that normalization might increase symptom-free survival.

Physical symptoms of chronic fatigue syndrome are exacerbated by the stress of Hurricane Andrew

This study examined the effects of Hurricane Andrew on physical symptoms and functional impairments in a sample of chronic fatigue syndrome (CFS) patients residing in South Florida. In the months after Hurricane Andrew (September 15-December 31, 1992), 49 CFS patients were assessed for psychosocial and physical functioning with questionnaires, interviews, and physical examinations. This sample was made up of 25 CFS patients living in Dade county, a high impact area, and 24 patients in Broward and Palm Beach counties, areas less affected by the hurricane. Based on our model for stress-related effects on CFS, we tested the hypothesis that the patients who had the greatest exposure to this natural disaster would show the greatest exacerbation in CFS symptoms and related impairments in activities of daily living (illness burden). In support of this hypothesis, we found that the Dade county patients showed significant increases in physician-rated clinical relapses and exacerbations in frequency of several categories of self-reported CFS physical symptoms as compared to the Broward/Palm Beach county patients. Illness burden, as measured on the Sickness Impact Profile, also showed a significant increase in the Dade county patients. Although extent of disruption due to the storm was a significant factor in predicting relapse, the patient's posthurricane distress response was the single strongest predictor of the likelihood and severity of relapse and functional impairment. Additionally, optimism and social support were significantly associated with lower illness burden after the hurricane, above and beyond storm-related disruption and distress responses. These findings provide information on the impact of environmental stressors and psychosocial factors in the exacerbation of CFS symptoms.

Immunoglobulin E levels in relationship to HIV-1 disease, route of infection, and vitamin E status

Our recent studies have demonstrated that in early HIV-1 infection, elevation of plasma immunoglobulin E (IgE) levels precedes the decline of CD4 cell count and is influenced by vitamin E status. In order to further investigate the role of IgE elevation in HIV-1 infection, we determined IgE levels in HIV-1-seropositive and -seronegative intravenous drug users (IDUs) (n = 38), in relationship to cellular and humoral immune function, liver enzymes, and vitamin E status. To examine the possible impact of the route of HIV-1 infection on IgE levels, comparisons between the cohorts of the HIV-1-seropositive and -seronegative IDUs and homosexual men (n = 45) were also conducted. All HIV-1-seropositive participants had significantly higher (P = 0.003) IgE levels than the HIV-1-seronegative subjects. The HIV-1-seropositive IDUs, moreover, demonstrated significantly higher (P = 0.01) IgE levels than HIV-1-seropositive homosexual men, despite similar CD4 cell counts. Stepwise regression analysis was used to evaluate the possible variables contributing to the IgE variation. HIV-1 status (P = 0.0009), intravenous drug use (P = 0.014), CD8 cell counts (P = 0.0001), plasma level of vitamin E (P = 0.006), and alcohol intake (P = 0.047) were significant, accounting for 71% of the IgE elevation. These findings suggest that IgE may serve as a sensitive marker to reflect the evolution of HIV-1 disease in individuals from different risk groups.

Effects of benzalkonium salts on eukaryotic and microbial G-protein-mediated processes and surface membranes

Benzalkonium salts comprise a group of positively charged surface-active alkylamine biocides with the general formula alkyldimethylbenzylammonium chloride or bromide. They interact with guanine nucleotide triphosphate-binding proteins (G proteins), thereby affecting signal transduction in a variety of cell types and processes. The present report reviews the known and potential basic science research and clinical applications and manifestations of benzalkonium salts. Benzalkonium salts have antiproliferative effects on a variety of cells through G-protein-dependent pathways, affect cytokine gene expression, and are also effective bactericidal, fungicidal, and virucidal agents with multisite (direct and immunologically-mediated) inhibitory activity against many pathogens, including the human immunodeficiency virus (HIV), papillomavirus, and herpesviruses. Therefore, benzalkonium salts not only appear to be effective as disinfectants and spermicides but may also prove useful in the prevention and treatment of neoplasias and other disease, particularly those linked to viruses and originating at the skin or mucosal surface.

Adoptive CD8+ T-cell immunotherapy of AIDS patients with Kaposi's sarcoma

This article reviews published and original findings from two clinical trials of adoptive CD8+ T-cell immunotherapy of patients with acquired immunodeficiency syndrome (AIDS) and Kaposi's sarcoma (KS). In the first trial, AIDS patients with either KS or oral hairy leukoplakia (OHL) received five rounds of reinfusions of 10(8)-10(10) ex vivo expanded and activated autologous CD8+ T cells. Recombinant interleukin-2 (rIL-2) was coadministered only with the fifth and final infusion. Improvement, and in some cases, resolution of OHL, KS, and candidiasis was observed with no side effects. The observation that clinical improvement of KS was more pronounced when reinfusion of CD8+ T cells was followed by rIL-2 infusion led to a second clinical trial designed to examine the effect of repeated infusions of autologous CD8+ T cells with concomitant rIL-2 administration in the treatment of AIDS-related KS. Improvement of KS status was observed in four out of the eight patients studied (three partial and one complete response). The CD8+ T-cell immunotherapy protocol also provided the opportunity to comparatively study CD8+ T-cell-associated genetic programs. Baseline expression patterns of soluble and surface immune markers by CD8+ T cells from AIDS patients and uninfected controls were predominantly of the type 1 type and differed mainly at a quantitative or kinetic level. Deficiencies in immune mediator expression by CD8+ T cells from AIDS patients tended to dissipate with progression through the protocol. Findings are discussed in the context of current knowledge and therapeutic implications of CD8+ T-cell function in AIDS and neoplasia.

Structure and pathophysiology of the erythrocyte membrane-associated Paul-Bunnell heterophile antibody determinant in Epstein-Barr virus-associated disease

Epstein-Barr virus (EBV), which was first isolated by Epstein, Barr, and Achong (1964) from a cultured Burkitt's lymphoma lymphoblast cell line, is the etiological agent for infections mononucleosis (IM), polyclonal oligoclonal lymphomas associated with primary and acquired immunodeficiencies, and the complications of X-linked lymphoproliferative syndrome (XLP) (Cantani and Mastrantoni, 1989; Englund, 1988; Ernberg et al., 1990; Jones and Straus, 1987; Okano et al., 1988; Purtilo et al., 1981; Shearer et al., 1985; Wilmes and Wolf, 1989). EBV also contributes to the pathogenesis of Burkitt's lymphoma (Frizzera, 1987; Harrington et al., 1988; Henle et al., 1968; Purtilo et al., 1981; Rowe et al., 1986; Saemundsen et al., 1981) and nasopharyngeal cancer (Pearson et al., 1984). Furthermore, people who have had IM have higher rates of subsequent development of malignant lymphoproliferative disorders (Abo et at., 1982; Snydman et al., 1982) and Hodgkin's disease (Green et al., 1979; Mueller, 1987; Poppema et al., 1985; Weiss et al., 1989), while patents with XLP have a higher incidence of non-Hodgkin's malignant lymphoma (Harrington et at., 1987). The precise role of EBV in these diseases is not well understood. Nonetheless, it is known that EBV infection triggers the formation of heterophile antibodies that, for many decades, have formed the basis for serologic diagnosis of IM. In this review, we discuss the discovery, species variation, and structure of the erythrocyte membrane-associated Paul-Bunnell (PB) heterophile antibody determinant, its implications to IM diagnosis, and its potential contribution to defective immune surveillance and associated uncontrolled proliferation of EBV-infected cells.

Psychosocial counseling to improve quality of life in HIV infection

Psychosocial interventions such as cognitive behavioral stress management (CBSM), may enhance coping and social support which contribute to an improvement of quality of life factors such as emotional functioning, social functioning, and sense of well-being, for HIV-infected men during several phases of HIV spectrum disease. These phases include the acutely stressful period immediately following notification of HIV+ status, the adjustment period following this news, and the process of dealing with chronic symptomatic HIV infection. Normalization of some aspects of immunological status were found to accompany some of these psychosocial changes in the short-run. Longer-term follow-up indicated relationships between psychosocial factors and improved immunological status and physical functioning up to 2 years later. Factors such as an increased use of active coping strategies, including relaxation exercises, use of more functional appraisals and elicitation of social support, and decreased use of denial/avoidance coping strategies, may be key predictors of longer-term emotional well-being, social functioning, and physical functioning in HIV-infected populations. Special issues need to be addressed in emerging models of quality of life assessment in HIV populations. For example, the way resurgence of stigmatization and self-doubt affects sense of identity and well-being need to be addressed in quality of life research as well as in psychosocial interventions. Loss of employment and its financial and existential consequences are also factors which impact sense of self and well-being, and need to be addressed both in research as well as in interventions. The effect of repeated HIV-related bereavements upon an individual's social network and the emotional, social, and physical sequelae of bereavement have implications for HIV quality of life research as well. Quality of survival time has become a paramount issue in the context of HIV spectrum disease. Examining the relationships among coping strategies, social support, emotional well-being, realistic appraisals of one's functioning in comparison to their aspirations, and the influence of psychosocial functioning on disease course are central missions of our research program.

Effects of aerobic exercise training on lymphocyte subpopulations

This study was conducted to determine the effects of an aerobic exercise training program on subpopulations of lymphocyte phenotypes. Fourteen healthy but sedentary males, 18-40 years of age, were randomly assigned to either an aerobic exercise training or control condition. Aerobic exercise training consisted of three 45-minute sessions of cycle ergometry exercise per week at 70-80% of age-predicted maximum heart rate for ten weeks. The aerobic exercise training resulted in a significant decrease in submaximal heart rate from 176 to 150 beats per minute to a fixed work rate of 150 watts (p < .01). This training effect was accompanied by increases in the resting level of the following lymphocyte subpopulations: CD2 (1717 vs 2183 mm3; p < .01), CD4 (942 vs 1280 mm3; p < .01), CD45RA+CD4+ (312 vs 595 mm3; p < .01), CD8 (655 vs 816 mm3; p < .05), and CD20 (162 vs 244 mm3; p < .01) cell counts. These findings indicate that several lymphocyte subpopulations are increased following a 10-week program of aerobic exercise training.

Effect of low- and intermediate-purity clotting factor therapy on progression of human immunodeficiency virus infection in congenital clotting disorders. Transfusion Safety Study Group

Low- and intermediate-purity clotting-factor therapies are believed to accelerate human immunodeficiency virus (HIV) progression in hemophiliacs through adverse immune effects of the other plasma proteins in the preparations. To investigate this postulate, we evaluated data from six clinical centers that observed persons with congenital factor deficiencies at 6-month intervals. The present analysis is based on HIV-infected subjects who received intermediate purity factor VIII or factor IX concentrates, or cryoprecipitate. For long-term outcome, we classified 374 subjects by the type and amount of treatment during our first year of observation, and determined the subsequent rate of progression to a CD4 count less than 200 cells/microL. A second analysis of this group used a repeated-measures, random-effect model that allowed for individual differences in CD4 decline. Finally, we compared short-term rates of change in CD4 count in each treatment interval of 525 subjects with the type and amount of factor therapy received in the same interval. There was no overall or dose-related deleterious effect of any form of treatment on CD4 trend. The CD4 decrease was less when cryoprecipitate was administered alone or combined with concentrate, but not significantly so. Our results counter the assertion that low- and intermediate-purity products accelerate the rate of CD4 decrease in HIV-1-infected hemophiliacs.

Emotional disclosure through writing or speaking modulates latent Epstein-Barr virus antibody titers

Healthy Epstein-Barr virus (EBV) seropositive undergraduates (N = 57) completed a personality inventory, provided blood samples, and were randomly assigned to write or talk about stressful events, or to write about trivial events, during three weekly 20-min sessions, after which they provided a final blood sample. Individuals assigned to the verbal/stressful condition had significantly lower EBV antibody titers (suggesting better cellular immune control over the latent virus) after the intervention than those in the written/stressful group, who had significantly lower values than those in the written/trivial control group. Subjects assigned to the written/stressful condition expressed more negative emotional words than the verbal/stressful and control groups and more positive emotional words than the verbal/stressful group at each time point. The verbal/stressful group expressed more negative emotional words compared with the control group at baseline. Content analysis indicated that the verbal/stressful group achieved the greatest improvements in cognitive change, self-esteem, and adaptive coping strategies.

Clinical and immunological changes in AIDS patients following adoptive therapy with activated autologous CD8 T cells and interleukin-2 infusion

OBJECTIVES

(1) To determine the safety and feasibility of repetitive reinfusions of activated autologous CD8 cells followed by low-dose continuous interleukin (IL)-2 infusion in patients with AIDS. (2) To study the relationships between clinical responses, surface marker phenotypic distributions and cytokine expression patterns of both cultured CD8 cells and lymphocytes in the peripheral blood compartment.

DESIGN

Six adult patients with Centers for Disease Control and Prevention group IV HIV-1 disease ranging from mild to severe, were studied. All patients were receiving zidovudine prior to and during the study period, and had initial CD4 and CD8 cell counts > 50 and 200 x 10(6)/l, respectively.

METHODS

Autologous CD8 T cells (10(8)-10(10)) were reinfused five times after ex vivo culture and stimulation with phytohemagglutinin and recombinant (r) IL-2. The fifth such infusion was followed by 5 days of rIL-2 infusion. Phenotypes and cytokine expression patterns of the expanded cells were determined as well as serum levels of immune mediators throughout the study.

RESULTS

Patients showed stable CD4 and CD8 cell counts, p24 antigenemia, and minimal toxicity over the 24-week protocol study. Clinical improvement was observed in lymphadenopathy (six out of six), oral hairy leukoplakia (three out of four), and Kaposi's sarcoma (KS; two out of two) in the patients studied. In vivo induction of detectable levels of bioactive acid-stable interferon (IFN)-alpha, but not of other cytokines studied, upon activated CD8 cell reinfusion was associated consistently with improvement of oral hairy leukoplakia. However, partial regression of KS was observed after the CD8 cell infusion cycles and without IFN-alpha induction. In one of the two patients studied, KS regression was associated with decreased IL-1 alpha serum levels. In the other patient, who had failed previous IFN-alpha therapy, KS regression was observed after a decline in reinfused CD8 cell-associated gene expression of tumor necrosis factor (TNF)-beta. Both IL-1 alpha and TNF-beta are growth factors for KS cells.

CONCLUSIONS

These observations demonstrate the feasibility and safety of ex vivo CD8 cell activation, expansion, and reinfusion, and rIL-2 infusion in AIDS patients. The findings in this Phase I trial suggest potential clinical efficacy and encourage Phase II trials. The correlations obtained between clinical and immunological states could contribute to an understanding of the relationship between CD8 T-cell function and HIV-1-associated disease progression.

Umbilical arterial catheter use: report of an audit conducted by the Study Group for Complications of Perinatal Care

The Study Group for Complications of Perinatal Care through 13 of its participating neonatal intensive care units conducted an audit of umbilical artery catheter (UAC) use over 3 months. Of 1941 patient admissions, 582 (30%) had a UAC inserted and left in place for a mean of 4.9 days. The mean supplemental oxygen concentration (FIO2) at removal was 0.35 with over 55% of UACs remaining in place until FIO2 was less than 0.26. Institutional practices varied widely for positioning the catheter tip, use of heparin, and types of infusates, as did the frequency of adverse events that prompted removal of the UAC. Most institutions with multiple physicians found less consistency in practice patterns within their own units than presumed prior to the audit. Just two institutions preferred catheter placement in the abdominal aorta (low) with the others selecting a low site only after detecting a malposition below the initially sought thoracic level. All but one group routinely used heparin, although in varying concentrations and total doses. Patient weight and catheter duration were inversely correlated, with smaller patients having catheters left in place for significantly longer periods (P < 0.01). Similarly, smaller patients had a higher likelihood of catheter removal because of an adverse event; the adverse events were not necessarily related to longer duration. A significant relationship existed between positioning a catheter tip in the abdominal aorta and removal for adverse events (P < 0.05).