Defective production of both leukemia inhibitory factor and type 2 T-helper cytokines by decidual T cells in unexplained recurrent abortions

Leukemia inhibitory factor is essential for embryo implantation, and a shift from type 1 T-helper to type 2 T-helper response at the fetal-maternal interface may contribute to successful pregnancy. We show that LIF production is associated with type 2 T-helper cells, is upregulated by IL-4 and progesterone and is downregulated by IL-12, IFN-gamma and IFN-alpha. We also show a decreased production of LIF, IL-4 and IL-10 by decidual T cells of women with unexplained recurrent abortions in comparison with that of women with normal gestation. The defective production of LIF and/or type 2 T-helper cytokines may contribute to the development of unexplained recurrent abortions.

High CD30 ligand expression by epithelial cells and Hassal's corpuscles in the medulla of human thymus

CD30 is a member of tumor necrosis factor (TNF) receptor superfamily that is expressed by activated T cells in the presence of interleukin-4 (IL-4). Although CD30 can mediate a variety of signals, CD30-deficient mice have impaired negative selection of T cells, suggesting that at least in the context of murine thymus, CD30 is a cell death-mediating molecule. The ligand for CD30 (CD30L) is a membrane-associated glycoprotein related to TNF, which is known to be expressed mainly by activated T cells and other leukocytes. However, the nature of CD30L-expressing cells involved in the interaction with CD30+ thymocytes is unclear. We report here that in postnatal human thymus the great majority of CD30+ cells are double positive (CD4+CD8+), activated, IL-4 receptor-expressing T cells which selectively localize in the medullary areas. Moreover, many medullary epithelial cells and Hassal's corpuscles in the same thymus specimens showed unusually high expression of CD30L in comparison with other lymphoid or nonlymphoid tissues. These findings provide additional information on the nature and localization of CD30+ thymocytes and show that epithelial cells are the major holder of CD30L in the thymic medulla.

Decrease of allergen-specific T-cell response induced by local nasal immunotherapy

BACKGROUND

The clinical efficacy and safety of local nasal immunotherapy (LNIT) with lyophilized 'macronized' powder has been demonstrated. However, the immunological changes possibly induced by LNIT which may account for the clinical improvement are still unclear.

OBJECTIVE

To investigate the effects of a successful LNIT-treatment on the allergen-driven T cell response, cytokine secretion and IgE and IgG antibody production.

METHODS

Three groups (untreated, subcutaneous immunotherapy- SIT- and LNIT-treated) of grass-sensitive patients suffering from seasonal rhinitic symptoms were ramdomized for the 2-year study. The proliferative response of PBMC to purified Rye-1 allergen and serum levels of grass-specific IgE and IgG were evaluated before treatment and during the 2-year subsequent pollination periods. The proliferative response of allergen-specific short-term T-cell lines, as well as production of allergen-driven cytokine by PBMC, were also assessed.

RESULTS

Both SIT and LNIT induced a significant reduction of symptom scores during the pollination season. SIT, but not LNIT, induced a significant change in serum levels of allergen-specific IgE and IgG antibody. By contrast, both SIT and LNIT reduced the increase of the proliferative response of allergen-specific T cells driven by natural allergen exposure and significantly decreased T cell proliferation to low doses of allergen, as shown also by the mitogenic index of allergen-specific T-cell lines. A reduced IL-4 and IFNgamma production by PBMC of LNIT- and SIT-treated patients was also observed in the absence of a clearcut TH2-TH1 switch.

CONCLUSIONS

These data suggest that a common mechanism of both LNIT and SIT is the induction of T-cell tolerance, thus providing a rational basis to explain why LNIT may be clinically successful in allergic patients with rhinits.

Prenatal diagnosis: evolution in craniofacial surgery

Prenatal diagnosis of craniomaxillofacial malformations permits early surgery, before 6 months of life and possibly, in the near future, in utero, thereby obtaining the best aesthetic and functional results. Increased knowledge of embryology has largely improved the diagnosis of craniomaxillofacial anomalies, their classification, and therapeutic protocols. We analyzed nine pregnancies (one twin) in which cleft lip and palate (CLP)--isolated or associated with, for example, holoprosencephaly, hypertelorism, and micrognathia--was diagnosed by ultrasonography. Only one fetus of these pregnancies was later operated on in our unit. This patient, with 7 years follow-up, represents our clinical case. For these cases, early diagnosis of CLP allowed informed parental choice regarding the continuation or termination of the affected pregnancy and planning of surgical procedures to correct the malformation. This is demonstrated by the presented clinical case involving an infant operated on within 6 months with success.

Influence of both TCR repertoire and severity of the atopic status on the cytokine secretion profile of Parietaria officinalis-specific T cells

Peripheral blood mononuclear cells (PBMC) from both nonatopic and Parietaria officinalis-sensitive donors proliferated in response to the allergen Par o 1 and developed into Par o 1-specific T cell lines and clones, which also showed reactivity for Par o 1-derived peptides. Virtually all Par o 1-specific T cell lines and large numbers of Par o 1-specific T cell clones proliferated in response to two Par o 1 nonapeptides (p92 and p96), which probably contain immunodominant epitopes of the Par o 1 allergen. Both p92- and p96-specific T cell clones showed the ability to produce IFN-gamma, but p92-specific T cell clones produced significantly lower amounts of IL-4 and IL-5 than p96-specific T cell clones, indicating that distinct epitopes, able to elicit functionally different T helper cell responses, may coexist in Par o 1. However, p92-specific T cell clones derived from atopic subjects with high IgE serum levels (high IgE producers) secreted significantly higher amounts of IL-4 and IL-5 than corresponding T cell clones generated from nonatopic subjects or patients with low IgE serum levels (low IgE producers), whereas p96-specific T cell clones secreted high IL-4 and IL-5 concentrations irrespective of whether they derived from high or low IgE producers. The addition of IL-4 and anti-IL-12 mAb to bulk culture significantly up-regulated the development of p92-specific T cells into IL-4-producing cells, whereas the addition of IL-12 and anti-IL-4 mAb shifted the differentiation of p96-specific T cells towards IFN-gamma-producing cells. Taken together, these results suggest that the cytokine profile of allergen-specific T cells is influenced by both the T cell receptor repertoire and the severity of atopic status and can be modulated, at least in vitro, by stimulation with the specific peptide in the presence, or after removal, of appropriate cytokines.

In search of biological markers of high-risk carotid artery atherosclerotic plaque: enhanced LDL oxidation

The oxidation of low density lipoprotein (LDL) is a key event in the development and progression of atherosclerosis because it generates molecular epitopes that are more atherogenic than parent LDL. We found previously that patients with carotid atherosclerosis have a significantly higher titer of autoantibodies against oxidatively modified LDL than normal subjects. The aim of this study is to correlate biological markers of in vivo LDL oxidation with the degree of carotid stenosis and of plaque ulceration (PU) in a series of patients undergoing carotid endoarteriectomy (CEA). Ninety-four consecutive patients (68M and 26F, aged 67.3 +/- 8.2 years) who underwent CEA at our institution between June 1993 and January 1994 were included in the study. The degree of carotid stenosis and the presence and extent of PU were correlated with the level of autoantibodies (IgG) against oxidatively modified LDL (Cu++-oxidized [oxLDL] or malondialdehyde derivatized LDL [MDA-LDL]), that consistently mirrors the occurrence of oxidative modifications in vivo. A statistically significant correlation (r = 0.23, p = 0.039) was found between the degree of carotid stenosis and antiMDA-LDL specific ratio (a parameter that describes the specificity of LDL towards other proteins as target for oxidative modification). A statistically significant correlation was also found between the PU score and antioxLDL IgG (r = 0.32, p = 0.011), antiMDA-LDL IgG (r = 0.25, p = 0.045) and antiMDA-LDL IgG specific ratio (r = 0.38, p = 0.002). None of the classical biochemical parameters (total, LDL and HDL cholesterol and triglycerides) correlated with the above-mentioned plaque characteristics. The results shown, support the use of biological markers of in vivo LDL oxidation (antioxidatively modified LDL autoantibody titers) to evaluate the clinical setting of high-risk carotid atherosclerosis both in screening and in follow-up studies.

The TH1/TH2 paradigm in allergy

Recent evidence has been accumulated to suggest that allergen-reactive type 2 helper T cells (Th2) play a triggering role in the activation and/or recruitment of IgE antibody-producing B cells, mast cells and eosinophils, i.e. the cellular triad involved in the allergic inflammation. Interleukin (IL)-4 production by a still unknown cell type (T cell subset, mast cell/basophil?) at the time of antigen presentation to the Th cell is critical for the development of Th2 cells. Other cytokines, such as IL-1 and IL-10, and hormones, such as calcitriol and progesterone, also play a favoring role. In contrast, cytokines such as interferon (IFN-alpha, IFN-gamma, IL-12 and transforming growth factor (TGF)-beta, and hormones, play a negative regulatory role on the development of Th2 cells. However, the mechanisms underlying the preferential activation by environmental allergens of Th2 cells in atopic individuals still remain obscure. Some gene products selectively expressed in Th2 cells or selectively controlling the expression of IL-4 have recently been described. Moreover, cytokines and other gene products that dampen the production of IL-4, as well as the development and/or the function of Th2 cells, have been identified. These findings allow us to suggest that the up-regulation of genes controlling IL-4 expression and/or abnormalities of regulatory mechanisms of Th2 development and/or function may be responsible for Th2 responses against common environmental allergens in atopic people. The new insights in the pathophysiology of T cell responses in atopic diseases provide exciting opportunities for the development of novel immunotherapeutic strategies. They include the induction of nonresponsiveness in allergen-specific Th2 cells by allergen peptides or redirection of allergen-specific Th2 responses by Th1-inducing cytokines, altered peptide ligands, allergens incorporated into recombinant microorganisms or bound to appropriate adjuvants, and plasmid DNA vaccination. In severe atopic patients, the possibility of nonallergen-specific immunotherapeutic regimens designed to target Th2 cells or Th2-dependent effector molecules, such as specific IL-4 transcription factors, IL-4, IL-5 and IgE, may also be suggested.

Type 2 helper T-cell predominance and high CD30 expression in systemic sclerosis

The pattern of cytokine production of skin-infiltrating T cells from patients with progressive systemic sclerosis was investigated. Most CD4+ T-cell clones generated from skin biopsy specimens showed a type 2 helper (Th2) cytokine profile (production of interleukin-4, but no interferon (IFN)-gamma). High interleukin-4 but little or no IFN-gamma mRNA expression was found by in situ hybridization in skin perivascular mononuclear cell infiltrates. The immunohistochemical analysis revealed CD30 expression by high numbers of CD4+ T cells in the same specimens. Finally, the great majority of patients with diffuse disease had elevated levels of soluble CD30 in their sera. These data suggest the existence in patients with progressive systemic sclerosis of a predominant activation of Th2-like T cells, which may account for the major alterations (endothelial cell injury, fibrosis, and autoantibody production) occurring in this disease.

Opposite role for interleukin-4 and interferon-gamma on CD30 and lymphocyte activation gene-3 (LAG-3) expression by activated naive T cells

Polarized human type 1 and type 2 T helper cells not only produce different sets of cytokines, but they also preferentially express certain activation markers, such as lymphocyte activation gene-3 (LAG-3) and CD30, respectively. In this study we have examined the LAG-3 and CD30 expression in relation to the lineage commitment of human naive CD4+ T cells, as assessed at the single-cell level of committed T cells. Purified CD45RA+ umbilical cord blood T lymphocytes were activated with phytohemagglutinin and interleukin (IL)-2 in the absence or presence of interleukin IL-4 or IL-12 and assessed for CD30 and LAG-3 expression, as well as for intracellular cytokine synthesis. Significant numbers of CD30+ cells were only found in CD4+ and CD8+ T lymphocytes of cultures primed with IL-4, which developed into cells able to produce IL-4 and IL-13 in addition to interferon (IFN)-gamma. By contrast, LAG-3 expression was strongly up-regulated in CD4+ and CD8+ T cells from cultures primed with IL-12, which developed into high numbers of IFN-gamma producers. The addition of a neutralizing anti-IFN-gamma antibody to IL-12-primed CD4+ T cell cultures virtually abolished the development of LAG-3-expressing CD4+ T cells. Taken together, these data suggest that CD30 expression is dependent on the presence of IL-4, whereas LAG-3 expression is dependent on the production of IFN-gamma during the lineage commitment of human naive T cells.

Functional characterization and modulation of cytokine production by CD8+ T cells from human immunodeficiency virus-infected individuals

CD8+ T-cell clones were generated from peripheral blood mononuclear cells (PBMC) of three human immunodeficiency virus (HIV)-seronegative individuals and six HIV-seropositive individuals and assessed for their cytokine secretion profile, cytolytic potential, and chemokine production. While the great majority of CD8+ T-cell clones generated from HIV-seronegative individuals produced interferon (IFN)-gamma, but not interleukin-4 (IL-4), that is a type 1 cytotoxic (Tc1) profile, high numbers of CD8+ T-cell clones generated from HIV-seropositive individuals produced IL-4 in addition to IFN-gamma or IL-4 alone, thus showing a type 0 cytotoxic (Tc0)- or a type 2 cytotoxic (Tc2) profile, respectively. Tc0/Tc2 cells displayed lower cytolytic activity than Tc1 cells, including a reduced ability to lyse autologous targets pulsed with HIV or HIV peptides. By contrast, the production of chemokines RANTES and macrophage inflammatory protein-1alpha was comparable in Tc1, Tc0, and Tc2 clones irrespective of whether they were derived from HIV-seronegative or HIV-seropositive individuals. When CD8+ T-cell clones were generated from PBMC cultures of HIV-seronegative individuals conditioned with IL-4 plus an anti-IL-12 antibody (Ab), a shift towards the Tc0/Tc2-like profile was observed. Conversely, the addition to PBMC cultures of IL-12 plus an anti-IL-4 Ab shifted the differentiation of CD8+ T cells from HIV-infected individuals towards the Tc1-like profile, whereas IL-12 or anti-IL-4 Ab alone had a lower Tc1-promoting effect. Irradiated PBMC from HIV-infected individuals, used as feeder cells, shifted the differentiation of CD8+ T cells from a healthy HIV-seronegative individual towards the Tc0/Tc2-like profile. On the other hand, a shift towards the Tcl-like profile was noted in CD8+ T-cell clones generated from the skin specimens of two HIV-seropositive patients with Kaposi's sarcoma, successfully treated with IFN-alpha, in comparison to CD8+ clones generated from the same skin areas before treatment. The IFN-alpha-induced Tc1 shift could be prevented by the incubation of skin-infiltrating CD8+ T cells with IL-4 before cloning. Taken together, these data indicate that both defective production of IL-12 and abnormal IL-4 production in bulk PBMC populations of HIV-infected individuals may contribute to the development of high numbers of CD8+ T-cell clones showing a Tc0/Tc2-like phenotype and reduced cytolytic potential against HIV itself. They also suggest that the cytokine profile of CD8+ T-cell clones can be modulated by cytokines (or anticytokine Ab) both in vitro and in vivo.

An update on human Th1 and Th2 cells

The existence of functionally polarized human T cell responses based on their profile of cytokine secretion in both the CD4+ T helper (Th) and the CD8+ T cytotoxic cell subset has been established. Human Th1 and Th2 cells not only produce a different set of cytokines but also exhibit distinct functional properties and preferential expression of some activation markers, such as LAG-3 and CD30, respectively. Several factors are involved in the Th cell differentiation into the polarized Th1 or Th2 pathway. They include the cytokine profile of 'natural immunity' evoked by different offending agents, the nature of the peptide ligand, as well as the activity of some costimulatory molecules and microenvironmentally secreted hormones, in the context of different host genetic backgrounds. Polarized Th1-type and Th2-type responses play different roles in protection, Th1 being effective in the defense against intracellular pathogens and Th2 against intestinal nematodes. Moreover, they are responsible for different types of immunopathological reactions. Th1 responses predominate in organ-specific autoimmune disorders, acute allograft rejection, unexplained recurrent abortions, and in some chronic inflammatory disorders of unknown etiology. In contrast, Th2 responses predominate in Omenn's syndrome, transplantation tolerance, chronic graft versus host disease, systemic sclerosis; moreover allergen-reactive Th2 cells are involved in the triggering of atopic disorders.

In vivo CD30 expression in human diseases with predominant activation of Th2-like T cells

CD30 is a member of the tumor necrosis factor (TNF) receptor family, originally described as a marker for Hodgkin and Reed-Sternberg cells in Hodgkin's disease, which has been found to be preferentially expressed by T cells producing Th2-type cytokines. The presence of CD30 expression was assessed by both immunohistochemistry and reverse transcriptase-polymerase chain reaction in the target organs of patients with Th1- or Th2-dominated disorders. CD30 expression was found in neither the gut of patients with Crohn's disease nor in the gastric antrum of Helicobacter pylori-infected patients, where there was high interferon-gamma (IFN-gamma) expression. In contrast, high CD30 expression in the apparent absence of IFN-gamma expression was observed in the skin of patients with systemic sclerosis or chronic graft versus host disease (GVHD), which can be considered Th2-dominated disorders. Moreover, high levels of soluble CD30 were found in the serum of both systemic sclerosis and GVHD patients but not in the serum of patients suffering from multiple sclerosis, a Th1-dominated disorder. Thus, CD30 expression appears to be preferentially associated with Th2-type responses not only in vitro but also in vivo.

Type 1 T-helper cell predominance and interleukin-12 expression in the gut of patients with Crohn's disease

Crohn's disease (CD) is a chronic bowel inflammatory disorder in which the pathogenic role of immune alterations has been suggested, but the immunologic mechanisms responsible for the inflammatory reaction are still poorly understood. We investigated the profile of cytokine secretion by T-cell clones generated from gut tissue specimens of four patients with active CD, five patients with ulcerative colitis, and four patients with noninflammatory gut disorders (NIGDs). The great majority of CD4+ T-cell clones generated from the gut of patients with CD produced high levels of interferon-gamma (IFN-gamma) but low or undetectable amounts of interleukin-4 (IL-4), whereas substantial proportions of CD4+ T-cell clones derived from the gut of patients with either ulcerative colitis or NIGDs produced IL-4 in addition to IFN-gamma. The immunohistochemical analysis revealed high numbers of activated CD4+ T cells showing IFN-gamma but not IL-4 reactivity, as well as substantial proportions of IL-12-containing macrophages, in the intestinal lamina propria and muscularis propria of patients with CD, whereas these cells were very rare or undetectable in patients with NIGDs. Culturing T cells from gut biopsy specimens of a patient with CD in the presence of a neutralizing anti-IL-12 antibody down-regulated the development of IFN-gamma-producing CD4+ T cells. These findings suggest that a critical event in the initiation of bowel inflammatory lesions in CD may involve up-regulation of IL-12 production, resulting in conditions that maximally promote type 1 T-helper immune responses.

Circulating autoantibodies recognizing peroxidase-oxidized low density lipoprotein. Evidence for new antigenic epitopes formed in vivo independently from lipid peroxidation

Oxidatively modified LDLs are antigenic and elicit the generation of autoantibodies often detected in plasma and within plaques of atherosclerotic patients. Although Cu(2+)-oxidized LDL and malondialdehyde (MDA)-modified LDL are usually used as antigens in immunoassays, other, still unrecognized epitopes may be formed in vivo during LDL oxidation and may induce antibody production. Antibodies recognizing LDL oxidatively modified by Cu2+, 2,2'-azobis-(2-amidino propane) hydrochloride (AAPH), and the combination of horseradish peroxidase and H2O2 (HRP) were detected in serum of a group of 90 unselected patients. HRP-oxidized LDL was the antigen that revealed the highest IgG titers, although the extent of LDL oxidation (evaluated as conjugated diene formation, loss of tryptophan fluorescence, production of fluorescent aldehydic adducts, and change in electrophoretic mobility) was comparable to that obtained with Cu2+ and AAPH. There was a highly statistically significant correlation between the IgG titers detected using Cu(2+)- and AAPH-oxidized LDLs as antigens, but no correlation was found between the IgG titers revealed by HRP and Cu2+ or AAPH. In addition, the antibody titers against MDA-modified LDL exhibited a significant correlation with those against Cu(2+)- or AAPH-oxidized LDL but did not correlate with those against HRP-oxidized LDL. Finally, immunocompetition experiments revealed that IgG recognizing HRP-oxidized LDL did not cross-react with Cu(2+)-oxidized LDL and vice versa. The possibility that lipid peroxidation-independent modifications could play a role in HRP-induced formation of antigenic epitopes in LDL was supported by two lines of evidence. First, in probucol-enriched LDL, despite the complete inhibition of lipid peroxidation, HRP, but not Cu2+ and AAPH, was still able to generate epitopes that were recognized by the same sera reacting with HRP-oxidized native (not probucol-enriched) LDL. In addition, the presence of autoantibodies against Cu(2+)- and AAPH-oxidized LDLs was negatively correlated with serum alpha-tocopherol concentration, whereas the titers against HRP-oxidized LDL did not exhibit any statistically relevant correlation with alpha-tocopherol levels. Together, these findings indicate that peroxidase(s)-dependent mechanisms can trigger peculiar lipid peroxidation-independent modifications of LDL in vivo.

Immune mechanisms in the pathogenesis of inflammatory gastrointestinal disorders

The cytokine secretion profile of T cells present in the gastric antrum of Helicobacter pylori-infected patients with peptic ulcer and in the gut of patients with Crohn's disease was investigated. A type 1 T helper (Th1)-dominated response was detected in the gastric antrum of Helicobacter pylori-infected subjects with peptic ulcer by both reverse transcriptase-PCR and immunohistochemistry. By using a T-cell cloning technique, it was shown that the majority of Th 1 cells were specific for Hp antigens. A Th1 predominance, which associated with high IL-12 expression, was also found, at both clonal and immunohistochemical level, in the gut of patients with Crohn's disease. These findings suggest that the Th1/Th2 paradigm may be useful to explain the inflammatory reactions involved in the pathogenesis of some gastrointestinal disorders.

Human CD8+ T lymphocyte subsets that express HLA class I-specific inhibitory receptors represent oligoclonally or monoclonally expanded cell populations

A small percentage of human T lymphocytes, predominantly CD8+ T cells, express receptors for HLA class 1 molecules of natural killer type (NK-R) that are inhibitory for T-cell antigen receptor (TCR)-mediated functions. In the present study, it is demonstrated that the various NK-R molecules typically expressed by NK cells are also expressed on periheral blood T lymphocytes. These CD3+ NK-R+ cells have a cell surface phenotype typical of memory cells as indicated by the expression of CD45RO and CD29 and by the lack of CD28 and CD45RA. Furthermore, by the combined use of anti-TCR V beta-specific antibodies and a semiquantitative polymerase chain reaction assay, the TCR repertoire in this CD3+ NK-R+ cell subset was found to be skewed; in fact, one or two V beta families were largely represented, and most of the other V beta s were barely detected. In addition, analysis of recombinant clones of the largely represented V beta families demonstrated that these V beta s were oligoclonally or monoclonally expanded.

Abnormal production of T helper 2 cytokines interleukin-4 and interleukin-5 by T cells from newborns with atopic parents

T cell clones were generated from umbelical cord blood lymphocytes (UCBL) of nine newborns with atopic or nonatopic parents and their cytokine secretion profile was assessed. Both phytohemagglutinin-induced and Dermatophagoides pteronyssinus-specific T cell clones from newborns with atopic parents exhibited an enhanced ability to produce the Th2 cytokines interleukin (IL)-4 and IL-5, compared to T cell clones from newborns with nonatopic parents. In contrast, the ability to produce interferon-gamma by UCBL from the two groups of newborns was not different. Of the five children who could be followed up to 3 years after birth, four with atopic parents developed clinical and/or biological atopic manifestations, whereas one without atopic parents did not. Thus, the pronounced production of IL-4 and IL-5 by UCBL not only appears to be related to the atopic status of parents, but also associates with the subsequent development of atopy in childhood.

Carotid intima-media thickening and in vivo LDL oxidation in patients with essential hypertension

Low density lipoproteins (LDL) from hypertensive patients are more prone to in vitro oxidation and undergo a more pronounced oxidation in vivo. Due to the pro-atherogenic activity of oxidatively modified LDL, the correlation between the carotid intima-media thickening (IMT) and the markers of in vivo LDL oxidation was investigated in hypertensive patients. A cross-sectional study on 101 normocholesterolemic patients with newly diagnosed and untreated essential hypertension was performed. The occurrence of in vivo LDL oxidation was evaluated by measuring the titers of autoantibodies against Cu(2+)-oxidised LDL (oxLDL) and malondialdehyde-derivatised LDL (MDA-LDL). The extent and degree of atherosclerosis and the IMT were measured by means of carotid and femoral ultrasonography with a duplex scanner equipped with a high resolution probe. We did not find significant correlations between in vivo LDL oxidation parameters and the extent of atherosclerotic lesion in the entire group of hypertensive patients. However, a significant direct correlation was detected between the carotid IMT and the titer of autoantibodies against both oxLDL and MDA-LDL in hypertensive patients without advanced atherosclerotic plaques. The results obtained support the hypothesis that enhanced LDL oxidation may be one of the pathophysiological events related to the formation and progression of early atherosclerotic lesions (IMT) in carotid arteries of hypertensive patients.

Role for CD30 in HIV expression

CD30 is a member of the tumor necrosis factor (TNF)-receptor superfamily, whose ligand (CD30L) has been identified on B cells, activated macrophages and a subset of activated T cells. We show here that infection in vitro with human immunodeficiency virus (HIV) of CD4+ T-cell clones generated from HIV-seronegative individuals can enhance the expression of CD30, which often preceeds and is associated with the death of clonal T cells. Furthermore, cross-linking CD30 with an agonistic CD30-specific monoclonal antibody potentiated HIV replication induced by an insolubilized anti-CD3 antibody in T-cell lines generated from HIV-infected individuals. More importantly, paraformaldehyde-fixed CD8+ T-cell clones expressing CD30L enhanced HIV replication in anti-CD3-stimulated allogeneic or autologous HIV-infected CD4+ T-cell lines and such a potentiating effect was inhibited by an anti-CD30L antibody. The anti-CD30L antibody also exerted a suppressive effect on the spontaneous HIV replication occurring in lymph node cells, freshly derived from an HIV-seropositive patient showing CD30 expression in B cells and in a proportion of CD8+ T lymphocytes. Thus, CD30 triggering may play an important role in both HIV replication and the death of HIV-infected CD4+ T cells.

Expression and release of LAG-3-encoded protein by human CD4+ T cells are associated with IFN-gamma production

The lymphocyte activation gene (LAG) -3 is a member of the immunoglobulin super-family that is selectively transcribed in human activated T and NK cells. In this work, the possibility that LAG-3 expression by human CD4+ T cells was preferentially related to one or another phenotype of cytokine secretion was investigated. Surface LAG-3 expression correlated with IFN-gamma, but not IL-4, production in antigen-stimulated T cells and it was up-regulated by IL-12. Most activated CD4+ T cell clones with established Th1 or Th0 profiles of cytokine secretion expressed LAG-3 on their surface, whereas the great majority of Th2 clones showed neither surface LAG-3 nor LAG-3 mRNA expression. After activation, the majority of CD4+ T cell clones also released soluble LAG-3-related peptides, and such a release correlated positively with the production of IFN-gamma and inversely with the production of IL-4. Thus, LAG-3 expression by activated CD4+ human T cells appear to be preferentially associated with the differentiation/activation pathway leading to the production of IFN-gamma.