Measurement of cytokine secretion, intracellular protein expression, and mRNA in resting and stimulated peripheral blood mononuclear cells

Quantitation of cytokine production is a valuable adjunct to standard immunologic assays in defining several pathologic processes. Nevertheless, there is little agreement about which tissues should be assayed, which type of assay should be performed, and which stimulation protocol should be used. As these types of assays enter the clinical arena, there is need for standardization. There is also a need to maximize the amount of information which may be derived from a single sample. We compared secreted interleukin 4 (IL-4), IL-2, IL-6, tumor necrosis factor alpha (TNF-alpha), and gamma interferon proteins as measured by enzyme-linked immunosorbent assay with intracellular cytokine production (IL-2 and gamma interferon) as detected by flow cytometry and quantitative competitive PCR for IL-2, IL-4, TNF-alpha, and gamma interferon mRNA and cDNA. Results from unstimulated cells and cells stimulated with phorbol myristate acetate, phytohemagglutinin, and phorbol myristate acetate plus phytohemagglutin were compared. All three methodologies detected significant stimulation of cytokine production. The combination of phytohemagglutinin and phorbol myristate acetate was overall the most-potent stimulus.

Effect of neonatal test environment on recording transient-evoked otoacoustic emissions

OBJECTIVE

To examine the effect of test environment on recording transient-evoked otoacoustic emissions (TEOAE) in neonates.

METHODS

Thirty-two infants from the newborn nursery (NBN) who passed a screening auditory brainstem response (SABR) test and were at least 34 weeks' postconceptional age were studied. One ear of each newborn was tested using TEOAE in 5 different test environments: open bassinet in the NBN (E1), working isolet located in the NBN (E2), nonfunctioning isolet in the NBN (E3), nonfunctioning isolet in a quiet room off the NBN (E4), and open bassinet in a quiet room (E5). The number of high noise samples (HNS), the test duration (in seconds), the signal-to-noise ratio (SNR; in dB) measured at bandwidths centered at 1.6, 2.4, 3.2, and 4.0 kHz, and the percentage of neonates with a fail screening outcome based on a common pass-fail screening criteria were compared in the 5 test environments.

RESULTS

There were statistically significant differences in the number of HNS accumulated in the 5 test environments (F = 6.79). The use of a nonfunctioning isolet in both the NBN and within a room off the NBN (E3 and E4, respectively) resulted in significantly fewer HNS than when TEOAEs were recorded in the other 3 test environments (E1, E2, and E5). Mean test duration was significantly different among the 5 locations (F = 6. 53). Posthoc analyses revealed that test time in E3 and E4 was significantly shorter than in E1 and E2. The percentage of newborns with a fail (</=3 dB SNR at 2.4, 3.2, and 4.0 kHz) outcome was lowest in E3 (6.3%) and the same in E1 and E4 (12.5%). A high percentage of infants received a fail outcome when tested in both the working isolet and in the open bassinet in a room off the nursery (21.8% and 25%, respectively). SNR (in dB) for bandwidths centered at 1.6, 2.4, and 3.2 kHz was negatively correlated with the HNS in the working isolet. SNR (in dB) at 4.0 kHz was negatively correlated with the HNS when TEOAEs were recorded in the open bassinet in a room adjacent to the NBN. The number of HNS was correlated with overall test time in each environment.

CONCLUSIONS

Test environments typically used for newborn hearing screening can influence the recording of TEOAEs. Performing the TEOAE test with the neonate placed in a nonfunctioning isolet located in either the NBN or in a room off of the NBN resulted in the most desirable outcomes (shortest test times, fewest HNS, highest SNR (in dB), and fewest fail outcomes).

Multisite comparison of CD4 and CD8 T-lymphocyte counting by single- versus multiple-platform methodologies: evaluation of Beckman Coulter flow-count fluorospheres and the tetraONE system. The NIAID DAIDS New Technologies Evaluation Group

New analytic methods that permit absolute CD4 and CD8 T-cell determinations to be performed entirely on the flow cytometer have the potential for improving assay precision and accuracy. In a multisite trial, we compared two different single-platform assay methods with a predicate two-color assay in which the absolute lymphocyte count was derived by conventional hematology. A two-color method employing lymphocyte light scatter gating and Beckman Coulter Flow-Count fluorospheres for absolute counting produced within-laboratory precision equivalent to that of the two-color predicate method, as measured by coefficient of variation of replicate measurements. The fully automated Beckman Coulter tetraONE System four-color assay employing CD45 lymphocyte gating, automated analysis, and absolute counting by fluorospheres resulted in a small but significant improvement in the within-laboratory precision of CD4 and CD8 cell counts and percentages suggesting that the CD45 lymphocyte gating and automated analysis might have contributed to the improved performance. Both the two-color method employing Flow-Count fluorospheres and the four-color tetraONE System provided significant and substantial improvements in between-laboratory precision of absolute counts. In some laboratories, absolute counts obtained by the single-platform methods showed small but consistent differences relative to the predicate method. Comparison of each laboratory's absolute counts with the five-laboratory median value suggested that these differences resulted from a bias in the absolute lymphocyte count obtained from the hematology instrument in some laboratories. These results demonstrate the potential for single-platform assay methods to improve within-laboratory and between-laboratory precision of CD4 and CD8 T-cell determinations compared with conventional assay methods.

T-lymphocyte subsets in HIV-infected and high-risk HIV-uninfected adolescents: retention of naive T lymphocytes in HIV-infected adolescents. The Adolescent Medicine HIV/AIDS Research Network

BACKGROUND

The capacity of the immune system of adolescents to generate and repopulate naive and memory cell populations under conditions of normal homeostasis and human immunodeficiency virus (HIV) infection is largely unknown.

OBJECTIVE

To assess lymphocyte subsets in HIV-infected and high-risk HIV-negative adolescents.

DESIGN

The Reaching for Excellence in Adolescent Care and Health Project of the Adolescent Medicine HIV/AIDS Research Network recruits a cohort of HIV-infected and high-risk HIV-uninfected adolescents, aged 13 to 18 years 364 days, into a study of biomedical and behavioral features of HIV infection as seen in the context of full availability of primary care and HIV-related consultative services. Lymphocyte phenotypes were determined using standard 3-color flow cytometry.

SETTING

The Reaching for Excellence in Adolescent Care and Health Project is carried out at 16 clinical sites in 14 urban areas.

PARTICIPANTS

T-lymphocyte subsets are reported in 192 HIV-positive and 78 HIV-negative youths.

RESULTS

For HIV-positive subjects, the total CD4+ cell count and the percentage of CD4+ cells are decreased when compared with those of the HIV-negative controls (P<.001). The reduction in total CD4+ cells reflects a loss of naive, and memory, CD4+ cells compared with HIV-negative youths. Human immunodeficiency virus-infected adolescents, many of whom have been infected recently (ie, those with CD4+ cell counts > or =0.500 x 10(9)/L [500/microL]), have a significant increase in naive CD8+ cells compared with HIV-negative youths (P<.01). There also is a significant increase in memory CD8+ cells at all strata of total CD4+ cells compared with HIV-negative youths (P<.01). The increase in naive CD8+ cells in those subjects with CD4+ cell counts of 0.500 x 10(9)/L or greater is a unique finding in this cohort.

CONCLUSIONS

This study demonstrates high levels of naive CD8+ cells in response to HIV infection in adolescents with CD4+ cell counts of 0.500 X 10(9)/L or greater. The presence of high levels of naive CD8+ cells suggests functioning thymic tissue in some adolescents infected with HIV. Furthermore, the normal level of naive CD4+ cells in adolescents with CD4+ levels of 0.500 x 10(9)/L or greater provides additional support for the concept of a more robust immune system in HIV-infected adolescents compared with HIV-infected adults. These observations suggest that the immune system of HIV-infected adolescents may be capable of better responses to neoantigens and cytotoxic T-lymphocyte responses to HIV than the immune system of infected children or adults. Human immunodeficiency virus-infected adolescents may have an immune system that is capable of reconstitution following highly active antiretroviral therapy.

Rapid method for determining the rate of DNA synthesis and cellular proliferation

A new method has been developed for determination of DNA synthesis during cell proliferation. The method is based on the metabolism of [U-(13)C(6)]glucose to deoxyribose (DR) and then incorporation of [U-(13)C(5)]DR into newly synthesized DNA. Extracted cellular DNA is subjected to HCl hydrolysis (2 h at 100 degrees C), which converts DR into levulinic acid. The (13)C enrichment in DR is determined in the trimethylsilyl derivative of levulinate using gas chromatography-mass spectrometry. The method is rapid and sensitive. It can precisely determine (13)C enrichment below 1 at.% excess in as little as 4 ng DNA. We have used this method to determine the rate of cell proliferation in vitro and the level of DR in a given amount of DNA. The current approach has significant advantages over previously described methods and overcomes several difficulties related to the determination of DNA synthesis both in vivo and in vitro.

C-C chemokine profile of cord blood mononuclear cells: selective defect in RANTES production

Three C-C chemokines inhibit human immunodeficiency virus (HIV) entry into macrophages: macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, and regulated-upon activation, normal T-cell expressed and secreted (RANTES). We studied the ability of placental cord blood mononuclear cells (CBMC) to secrete these C-C chemokines in comparison to adult blood mononuclear cells (ABMC). CBMC had diminished ability to secrete RANTES, as determined by enzyme-linked immunosorbent assay. Secretion of MIP-1alpha and MIP-1beta were similar in CBMC and ABMC. Whereas MIP-1alpha and MIP-1beta secretion were comparable in monocytes and lymphocytes, RANTES was secreted primarily by lymphocytes. Flow cytometric analysis of RANTES expression showed diminished intracellular RANTES expression in cord blood lymphocytes (CBL) compared to adult (peripheral) blood lymphocytes (ABL). A subset analysis of RANTES-producing CBL and ABL demonstrated that RANTES was produced predominantly by CD8+/CD45RO+ cells. CBL had a reduced proportion of CD8+/CD45RO+ cells compared with ABL, which may account for the diminished RANTES secretion by CBMC. These results may be relevant to the pathogenesis of perinatal HIV infection. (Blood. 2000;95:715-718)

Furosemide for symptomatic patent ductus arteriosus in indomethacin-treated infants

BACKGROUND

Inhibition of prostaglandin synthesis mediates closure of the ductus arteriosus and renal side effects after indomethacin administration. Because furosemide increases prostaglandin production, it could potentially help prevent indomethacin-related toxicity but also decrease ductal response to indomethacin.

OBJECTIVES

The primary objectives of this review were to assess (1) whether furosemide affects the incidence of failure of ductal closure after indomethacin and that of indomethacin-related toxicity and (2) the effect of furosemide on mid-term and long-term outcome. The secondary objective was to determine whether the effect of furosemide on renal function and water balance depends on prior extracellular volume (assessed by blood urea nitrogen [BUN]/creatinine ratio).

SEARCH STRATEGY

We searched electronic databases (Medline, Embase and Cochrane) and selected abstract books, without language restriction.

SELECTION CRITERIA

We selected studies with (1) random allocation to either indomethacin alone or indomethacin and furosemide and (2) analysis of either short-term risk-benefit ratio of furosemide, mid- or long-term outcome, or the relationship between extracellular volume at study entry and changes in renal function.

DATA COLLECTION AND ANALYSIS

We assessed studies for possible bias and for quality of assessment of ductal patency. We assessed categorical variables using relative risk and absolute risk reduction. We assessed the effects of furosemide on renal function and fluid balance by comparing changes from baseline in the treatment group with those in controls. Subsets were determined a priori based on BUN/creatinine ratio at study entry.

MAIN RESULTS

All 3 studies fulfilling the entry criteria had limitations, including possible or definite bias. There was substantial heterogeneity among studies. Furosemide administration did not significantly increase the risk of failure of ductal closure; however, sample size was insufficient to rule out even a 31% increase. In the subset with initial BUN/creatinine ratio > 20 mg/mg, 2 of 18 patients receiving furosemide could not complete a 3-dose course of indomethacin because of toxicity. Minimal or no information was available about any of the other main outcome variables. Furosemide increased urine output regardless of the initial BUN/creatinine ratio, leading to a 5% weight loss during a 3-dose course, an undesired effect in patients with initial BUN/creatinine ratio > 20 mg/mg. Furosemide increased creatinine clearance only in patients with initial BUN/creatinine ratio <20 mg/mg.

REVIEWER'S CONCLUSIONS

There is not enough evidence to support the administration of furosemide to premature infants treated with indomethacin for symptomatic patent ductus arteriosus. Furosemide appears to be contraindicated in the presence of dehydration in those infants.

Human immunodeficiency virus infection of human placental cord blood CD34+AC133+ stem cells and their progeny

The AC133 is a novel antigen selectively expressed on primitive CD34bright stem cells and is a valuable marker for the selection of long-term culture-initiating cells (LTC-ICs) and severe combined immunodeficiency (SCID)-repopulating cells. Human placental cord blood (HPCB) is a rich source of CD34+AC133+ cells. Since AC133 antibody is likely to be used as an alternative to CD34 for the selection of stem cells in transplant and gene therapy situations, we examined the susceptibility of HPCB-isolated CD34+AC133+ stem cells to infection with free and cell-associated HIV-1 in vitro. Freshly isolated HPCB CD34+AC133+ stem cells were not susceptible to HIV-1 infection as determined by PCR and reverse transcriptase assays. Inoculation with HIV-1 did not affect the viability and clonogenic ability of HPCB CD34+AC133+ cells. Although the highly purified HPCB CD34+AC133+ stem cells contained mRNA for CD4 and CXCR4 receptors, CD4 and CXCR4 proteins were not expressed on these cells. Similarly, CCR5 protein, the major macrophage-tropic HIV-1 coreceptor, was not expressed in freshly isolated HPCB CD34+AC133+ stem cells, although the transcript for CCR5 was identified in these cells. Expression of CD4, CXCR4, and CCR5 receptor proteins on the progeny derived from HPCB CD34+AC133+ stem cells was detected and correlated with susceptibility to HIV-1 infection in vitro. These findings suggest that freshly isolated HPCB CD34+AC133+ stem cells are not susceptible to HIV-1 infection and may not be a viral reservoir. These data have important implications for the use of AC133 antibody as a means of enriching for primitive hematopoietic stem cells from placental cord blood and in the design of stem cell or progenitor cell-based gene therapeutic strategies for perinatal HIV-1 infection.

Cutaneous lymphocyte-associated antigen expression in children with atopic dermatitis and non-atopic healthy children

Cutaneous lymphocyte-associated antigen (CLA) is a cell surface glycoprotein which has been implicated in the homing of lymphocytes to cutaneous sites. It is postulated to play an important role in T-cell migration to skin in atopic dermatitis; however, the expression of CLA in both normal children and children with atopic dermatitis has not been extensively studied. If CLA expression on T cells were important in the traffic of lymphocytes to atopic dermatitis skin lesions, it might be expected that the proportion of CLA+ T cells in unstimulated peripheral blood from children with atopic dermatitis would be elevated. We have examined the proportion of CLA+ T cells in children with atopic dermatitis and non-atopic age-matched controls. The proportion of CLA+ T cells in non-atopic children was highly associated with and increased with increasing age (r = 0.88, p < 0.001). There was no difference between the proportion of T cells expressing CLA in the unstimulated peripheral blood mononuclear cells from children with severe (p = 0.18) or with mild/moderate (p = 0.3) atopic dermatitis and age-matched non-atopic controls. Despite this, children with atopic dermatitis did show evidence of perturbation of CLA expression, as unlike the non-atopic children the proportion of CLA+ T cells in the atopic children did not correlate with age. These findings suggest that while CLA expression may play a role in atopic dermatitis, other as yet undefined surface markers are likely to principally determine the migration of T cells to skin in atopic dermatitis.

Decreased superoxide production, degranulation, tumor necrosis factor alpha secretion, and CD11b/CD18 receptor expression by adherent monocytes from preterm infants

Preterm infants have an increased incidence of infection, which is principally due to deficiencies in neonatal host defense mechanisms. Monocyte adherence is important in localizing cells at sites of infection and is associated with enhanced antimicrobial functions. We isolated cord blood monocytes from preterm and full-term infants to study their adhesion and immune functions, including superoxide (O2-) generation, degranulation, and cytokine secretion and their adhesion receptors. O2- production and degranulation were significantly diminished, by 28 and 37%, respectively, in adherent monocytes from preterm infants compared to full-term infants (P < 0. 05); however, these differences were not seen in freshly isolated cells. We also observed a significant decrease of 35% in tumor necrosis factor alpha secretion by lipopolysaccharide-stimulated adherent monocytes from preterm infants compared to full-term infants (P < 0.05); however, this difference was not observed in interleukin-1beta or interleukin-6 production by the monocytes. The cell surface expression of the CD11b/CD18 adhesion receptor subunits was significantly decreased (by 60 and 52%, respectively) in monocytes from preterm infants compared to full-term infants (P < 0. 01). The cascade of the immune response to infection involves monocyte upregulation and adherence via CD11b/CD18 receptors followed by cell activation and the release of cytokines and bactericidal products. We speculate that monocyte adherence factors may be important in the modulation of immune responses in preterm infants.

Pooled human immunoglobulin inhibits IL-4 but not IFN-gamma or TNF-alpha secretion following in vitro stimulation of mononuclear cells with Staphylococcal superantigen

Intravenous immunoglobulin preparations have been successfully used in many disorders, where immunomodulation rather than immunoglobulin replacement has been the goal of therapy. The exact mechanisms by which immunoglobulin exerts its immunomodulatory effects are unclear. Proposed mechanisms include modification of T cell activation and alteration to cytokine production. As intravenous immunoglobulin therapy has been used in a number of disorders where superantigens are proposed to play a role in the disease pathogenesis, we have examined the effect of in vitro human pooled immunoglobulin on cytokine production from peripheral blood mononuclear cells in response to activation with the Staphylococcal superantigen Staphylococcal enterotoxin B. The authors found inhibition of secretion of interleukin 4 (IL-4) (P<0.001) but not interferon gamma (IFN-gamma) (P=0.13) or tumour necrosis factor alpha (TNF-alpha) (P=0.66) by pooled immunoglobulin at concentrations (6 g/l) which approximate the rise in serum immunoglobulin following in vivo IVIG therapy. Mononuclear cell proliferation was also inhibited by addition of pooled immunoglobulin to superantigen stimulated cultures. These effects do not relate to specific anti-staphylococcal enterotoxin B antibodies in the immunoglobulin preparation. The authors show that pooled human immunoglobulin can differentially modulate the secretion of IL-4 and IFN-gamma in response to superantigen stimulation.

Furosemide in indomethacin-treated infants--systematic review and meta-analysis

This study was designed to assess: (1) whether furosemide modifies the incidence of failure to close a symptomatic patent ductus arteriosus (PDA) in response to indomethacin in premature infants, (2) whether furosemide decreases renal and hydromineral side effects of indomethacin, and (3) whether the effects of furosemide on renal function depend on initial extracellular volume [assessed by blood urea nitrogen (BUN)/creatinine ratio]. We did a systematic review and meta-analysis of all published controlled trials assessing either ductal closure or renal function after randomized allocation to treatment with indomethacin and furosemide versus indomethacin alone. All of the three studies meeting entry criteria were small and had methodological limitations. The number of patients was too small to rule out a 10% risk increase in failure of ductal closure. After the first dose of indomethacin, patients receiving furosemide had higher urine output, fractional excretion of sodium, and osmolar clearance than controls. Among patients with initial BUN/creatinine ratio <20, those on furosemide had a higher glomerular filtration rate (GFR) than controls. Among patients with initial BUN/creatinine of 20-30, those on furosemide had a lower GFR than controls. Thus, dehydration appears to be a contraindication for furosemide administration in premature infants treated with indomethacin for symptomatic PDA. The risk-benefit ratio of administering furosemide in well-hydrated patients treated with indomethacin for symptomatic PDA could only be assessed by a large randomized clinical trial.

Intracellular interferon-gamma (IFN-gamma) production in normal children and children with atopic dermatitis

A reduction in the in vitro production of IFN-gamma has been consistently described in atopic dermatitis (AD). Whether this reduction is due to a decrease in the population of peripheral blood mononuclear cells (PBMC) producing IFN-gamma or reduced IFN-gamma production per cell, or a combination of both is not clear. We have examined the intracellular production of IFN-gamma in children with AD and in healthy non-atopic controls. As Staphylococcus aureus colonization is a feature of childhood AD, and is postulated to contribute to the cutaneous inflammation in atopic dermatitis, S. aureus and Staphylococcal enterotoxin B (SEB) were used to activate PBMC. Stimulated PBMC from subjects with AD had significantly fewer IFN-gamma-containing cells in response to SEB (P < 0.001) and S. aureus (P < 0.01) than normal non-atopic children. In addition, SEB-stimulated PBMC from children with AD had less IFN-gamma per cell than normal non-atopic children (P < 0.01). Reduction in the proportion of cells containing IFN-gamma was seen in CD4+, CD8+ and natural killer (NK) cells in PBMC from children with AD. Our findings indicate that reduced production of IFN-gamma observed in childhood AD is due to both a decrease in the number of IFN-gamma-producing cells and a reduced amount of IFN-gamma production per cell. Furthermore, we found that this defect was not confined to CD4+ T cells, suggesting a more generalized defect in IFN-gamma production in childhood AD.

Interferon-gamma upregulates CCR5 expression in cord and adult blood mononuclear phagocytes

The C-C chemokine receptors CCR5 and CCR3 are fusion coreceptors for human immunodeficiency virus (HIV) entry into macrophages. The regulation of their expression influences infectivity by HIV. We report here that interferon-gamma (IFN-gamma) a cytokine that has bidirectional effects on HIV infection of macrophages, significantly upregulated CCR5 and CCR3 cell surface expression in human mononuclear phagocytes isolated from placental cord blood and adult peripheral blood. Monocytes treated with IFN-gamma showed increased chemotaxis to the CCR5 ligands macrophage inflammatory protein-1alpha (MIP-1alpha) and MIP-1beta, confirming the functional relevance of IFN-gamma-induced CCR5 expression. However, IFN-gamma suppressed HIV entry into macrophages. Interestingly, we demonstrated that IFN-gamma inhibited cell surface expression of CD4, the major receptor for HIV. This finding may explain the suppressive effect of IFN-gamma on HIV entry into macrophages, despite its enhancing effect on the expression of CCR5 and CCR3 by these cells. In addition, IFN-gamma-induced secretion of C-C chemokines (RANTES, MIP-1alpha, and MIP-1beta) by mononuclear phagocytes may also suppress HIV entry into macrophages. These data provide further evidence for cytokine-mediated regulation of CCR5 expression and are consistent with a novel paradigm in which cytokines regulate HIV infection and leukocyte migration by reciprocal and opposing effects on the expression of CD4 and chemokine receptors.

Production of antibodies to staphylococcal superantigens in atopic dermatitis

Staphylococcal superantigens (SAG) are implicated in the inflammation of atopic dermatitis. As SAG mediated diseases may be modified by specific antibodies, the antibody response to SAG in atopic dermatitis was investigated. Immunoglobulin (Ig) G to staphylococcal enterotoxin A (SEA), staphylococcal enterotoxin B (SEB), and toxic shock syndrome toxin 1 (TSST-1) were measured by sandwich enzyme linked immunosorbent assay (ELISA) in 74 children with atopic dermatitis and 111 controls. Controls had detectable IgG to SEA, SEB, and TSST-1, which increased with age. Atopic dermatitis subjects had an increased response to SEB at 6 months to 2 years (76% v 42%) and 2 to 7 years (79% v 57%), and equivalent responses to SEA and TSST-1, compared to controls. It is suggested that increased responses to SEB relate to increased colonisation and hence exposure to superantigen producing staphylococcus in atopic dermatitis, and that inflammation of atopic dermatitis is not caused by an inability to make antibody to SAG.

Enhanced IL-4 but normal interferon-gamma production in children with isolated IgE mediated food hypersensitivity

Atopic disorders such as atopic dermatitis and asthma have been characterised by an imbalance in interferon-gamma (INF-gamma) and IL-4. Whether similar imbalances are found in atopic disorders with different clinical manifestations, such as IgE mediated immediate food hypersensitivity, is not clear. We have examined the in vitro production of INF-gamma and IL-4 in peripheral blood mononuclear cells (PBMC) following phytohaemagglutinin stimulation from children with isolated immediate IgE mediated food hypersensitivity (egg, milk, "nut"), children with moderate and severe atopic dermatitis, and normal children. Children with immediate food reactions were excluded if they had a history or evidence of atopic dermatitis or asthma. PBMC from children with IgE mediated food hypersensitivity produced significantly more IL-4 (p = 0.013) but equivalent INF-gamma (p = 0.26) compared to PBMC from control children. In contrast, PBMC from children with atopic dermatitis produced significantly less INF-gamma (p < 0.001) and more IL-4 (p < 0.008) than PBMC from normal children. In addition, there was no difference in IL-4 (p = 0.74) but significantly less INF-gamma (p < 0.001) produced by PBMC from the children with atopic dermatitis than food hypersensitivity. We demonstrate that children with IgE mediated food hypersensitivity and no other manifestation of atopic disease have enhanced IL-4 production without the defect in INF-gamma production observed in childhood AD and asthma. We postulate that isolated IL-4 enhancement promotes the development of IgE mediated hypersensitivity disorders such as food allergy, whilst the combination of defective INF-gamma and enhanced IL-4 production promotes inflammatory atopic disorders such as AD and asthma.

Development and evaluation of a chromatographic procedure for partial purification of substance P with quantitation by an enzyme immunoassay

We have developed a simple chromatographic procedure for the partial purification of substance P (SP) from acidified plasma and serum samples. We have evaluated a sensitive antigen competition enzyme immunoassay (EIA) for the quantitation of SP. The chromatographic procedure has recovery efficiencies ranging from 94.8 to 125%. The immunoreactivity of unknown amounts of purified SP subjected to the preparative procedure yielded a coefficient of variance of 9.4%. The EIA yielded reproducible standard curves having an interassay (n = 8) correlation coefficient of 0.984. The evaluation of normal adult control serum yielded a mean value of 51 pg/ml (range, 35 to 61 pg/ml). The evaluation of 3.33 x concentrates of serum-derived partially purified SP provided uncorrected SP values of 117 to 201 pg/ml, which fell within the midpoint of the three-decalog standard curve. These studies indicate that both the preparative and quantitative procedures are required for the detection of SP in plasma or serum samples collected from patients with several clinical disorders.

Immune responses in mothers of term and preterm very-low-birth-weight infants

Differences in the levels of immune cell subsets present in peripheral blood have been demonstrated based on sociodemographic factors such as age and race. Postpartal women, who are recovering from the immune changes that are concomitant with pregnancy, have lymphocyte and monocyte values that differ from other populations. A subgroup of postpartal women, mothers who deliver preterm very-low-birth-weight (VLBW) (< or = 1,500 g) infants, may have further differences in values of immune cell subsets and in immune functioning either because of hormonal factors or lifestyle changes or because of the stress they experience after their infant's birth and for the first few months of infant caretaking. This study examined anxiety, depression, and immune cell phenotypes in 30 mothers of VLBW infants and in 30 mothers of healthy term infants over the first 4 postpartal months to determine if mothers of preterm VLBW infants differed from mothers of healthy term infants in psychological and immunologic parameters. Additionally, lymphocyte proliferation and natural killer cell functional assays were performed in a subset of mothers. Mothers of VLBW infants had increased anxiety and decreased lymphocyte proliferation compared to mothers of term infants. When lymphocyte and monocyte subsets were compared over time between the two groups of mothers differences were found in CD8, CD20, CD3-/CD56+, CD14, and HLA class II Ia on monocytes. Mothers with high-fat diets had lower percentages of some monocytes (CD14), lymphocytes (CD4+/CD45RA+), and natural killer cells (CD3-/CD57+) during the first 4 postpartal months.

Caregiving to very low birthweight infants: a model of stress and immune response

Mothers of preterm, very low birthweight (< or = 1500 g; VLBW) infants experience the stress of caring for small, fragile infants at the same time that they are recovering from the relative immunosuppression of pregnancy and when many health behaviour changes (e.g., nutrition) occur which also may influence immune status. The purpose of this study was to examine changes in anxiety and depression and in health behaviors, as well as lymphocyte proliferation and natural killer cell activity in mothers of preterm, VLBW infants compared to mothers of healthy term infants. Mothers of preterm VLBW infants have decreased in vitro lymphocyte response to mitogens compared to mothers of healthy term infants over time, and this difference could not be explained by anxiety, depression, or health behaviors. However, among mothers of VLBW infants, anxiety was related to decreased lymphocyte proliferation response at 1 month postpartum. There was no relationship between maternal depression and lymphocyte proliferative response in mothers of term infants. Natural killer cell activity did not differ between the two groups of mothers, nor was there a relationship between natural killer cell activity and maternal anxiety, depression, or health behaviors. Thus, lymphocyte proliferative response to mitogens may be an important biologic market of increased stress in mothers of VLBW infants in the first couple of months postpartum.

Lymphocyte, monocyte, and natural killer cell reference ranges in postpartal women

Normative values for immune-cell subsets in postpartal women, who are recovering from the relative immunosuppression of pregnancy, have not been established. Considerable differences in normative values for subsets of immune cells have been demonstrated based on sociodemographic factors, such as age and race. In order to make accurate clinical decisions about postpartal women, comparisons with normal reference ranges are necessary. Therefore, flow cytometric data for 51 healthy women at 4 months postpartum are presented and changes over the first 4 postpartal months are documented. The levels of some lymphocyte cell subsets, such as CD4+/CD45RA+ and Ia on lymphocytes, remained stable over time. The levels of other lymphocyte cell subsets, such as CD4+/CD29+, increased over the first 4 postpartal months, while those of other cell subsets, such as CD8 and CD11b, increased between delivery and 2 months postpartum and then dropped again by the fourth postpartal month. The levels of two natural killer cell subsets (CD3-/CD16+ and CD3-/CD57+) rose from delivery until 1 month postpartum and then plateaued. Comparisons were made with reference ranges of nonpostpartal groups provided in the literature and in a study of healthy women being conducted in the same laboratory, and postpartal women were found to have lower values of CD8, CD3-/CD16+, CD4+/CD45RA+, CD20, and CD11b than those reported in the literature.

Proliferation and production of interferon-gamma (IFN-gamma) and IL-4 in response to Staphylococcus aureus and staphylococcal superantigen in childhood atopic dermatitis

We have examined the cell-mediated immunity (CMI) to Staphylococcus aureus (S. aureus) and Staphylococcal enterotoxin B (SEB) in peripheral blood mononuclear cells (PBMC) from children with atopic dermatitis (AD) and from non-atopic child controls by measurement of proliferative responses and production of the cytokines IFN-gamma and IL-4. PBMC from children with AD showed significantly higher proliferative responses to both S. aureus (P < 0.01) and SEB (P < 0.05). Despite this enhanced proliferation, production of IFN-gamma in response to S. aureus (P < 0.001) and SEB (P < 0.01) from these PBMC was significantly diminished. In contrast, PBMC from children with AD were significantly more likely to produce IL-4 in response to S. aureus (P < 0.01). These findings demonstrate in vitro heightened CMI to S. aureus in children with AD, and implicate S. aureus as a potent inflammatory stimulant. Impaired IFN-gamma production to S. aureus in vivo may result in failure to eradicate S. aureus from skin. The organism's persistence on skin would contribute to inflammation by causing continued T cell activation and release of pro-inflammatory mediators.

Cytokines released by human peripheral blood mononuclear cells inhibit the production of early and late cytomegalovirus proteins

Cytomegalovirus-infected human fibroblasts are susceptible to lysis by natural killer cells and cytotoxic T cells. The purpose of this study was to determine whether non-lytic mechanisms might also contribute to the control of cytomegalovirus infection. The appearance of cytomegalovirus proteins in infected fibroblasts was determined by flow cytometry. Infected fibroblasts incubated with peripheral blood mononuclear cells for 3 days expressed less early and late proteins than fibroblasts incubated without peripheral blood mononuclear cells. Supernatants generated by the cocultivation of peripheral blood mononuclear cells with cytomegalovirus-infected fibroblasts inhibited the production of cytomegalovirus early and late proteins. The soluble factors in supernatants which contributed to the inhibitory effect were identified as interferons alpha, beta and gamma, and tumor necrosis factors alpha and beta. The ability of supernatants to inhibit the production of cytomegalovirus early protein was mimicked by combinations of corresponding recombinant cytokines. The inhibition of cytomegalovirus protein production by cytokines produced by peripheral blood mononuclear cells may contribute to early containment of cytomegalovirus infection.

Production of T-helper cell subsets and cytokines by lymphocytes from patients with chronic mucocutaneous candidiasis

Chronic mucocutaneous candidiasis (CMC) is a heterogeneous group of disorders characterized by recurrent and persistent superficial candidal infections. Cytokine-induced dysregulation of T-helper cell function has been described in other immune-deficient states but has not been studied in CMC patients. We studied T-helper cell subsets by flow cytometry and cytokine production by stimulated lymphocytes in six CMC patients, two healthy pediatric controls, and five healthy adult controls. Peripheral blood lymphocytes were stimulated in vitro with phytohemagglutinin or Candida albicans extract, and the production of interleukin-2R (IL-2R), IL-4, IL-10, and gamma interferon in the supernatants was measured by enzyme-linked immunosorbent assay. CMC patients had a decrease in the CD29+/CD29+ cell population compared with the numbers in controls (P < 0.02). The percentage of CD4+/CD45RA+ cells was greater in patients than in controls, but the difference was not significant. There was no difference in the production of IL-10 or gamma interferon by the patient lymphocytes. CMC patients produced more IL-4 than the controls (P < 0.001), whereas the controls tended to produce more IL-2R than the patients (P = 0.19). These findings support the concept that a decrease in CD4+/CD29+ T-helper inducer cells along with T-helper cell dysregulation may lead to defective memory responses to antigens in CMC patients and a decrease in cell-mediated immunity due to inhibition of TH1 cells by increased levels of IL-4.