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OBJECTIVE: To investigate the potential role of circulating autoantibodies specific to neuronal cell surface antigens in the pathophysiology of neuropsychiatric disorders. METHODS: We performed two different kinds of immunoscreening approaches using sera from patients with schizophrenia to identify autoantigens associated with neuropsychiatric disorders. Then, we tested the presence of autoantibodies specific to the identified autoantigen in patients with various psychiatric disorders and systemic lupus erythematosus (SLE) with neuropsychiatric manifestations. Furthermore, we evaluated the potential pathogenic role of these autoantibodies both in vitro and in vivo. RESULTS: We identified glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a novel autoantigen associated with neuropsychiatric disorders. We detected serum anti-GAPDH IgG in 51% patients with schizophrenia and 50% patients with major depression. Moreover, patients suffering by SLE with comorbid psychiatric manifestations presented significantly higher serum level of anti-GAPDH antibodies than SLE patients without psychiatric manifestations (P= 0.004 by square Chi test). To note, a significant positive correlation (R = 0.48, P= 0.0049 by Spearman rank correlation test) was found between levels of serum anti-GAPDH antibodies and cognitive dysfunctions in patients with SLE. In vitro analysis of purified human anti-GAPDH autoantibodies effects on SH-SY5Y cells showed an immediate neurite retraction. Finally, in vivo administration of the anti-GAPDH autoantibodies in the right cerebral ventricle of C57BL6/J mice resulted in specific behavioral changes associated to a detrimental cognitive and emotional profile. CONCLUSION: Overall, these data suggest that anti-GAPDH autoantibodies play a role in the etiopathogenesis of neuropsychiatric disorders possibly representing a promising tool for the screening of individual vulnerability. This article is protected by copyright. All rights reserved.

Cystic and alveolar echinococcosis are severe chronic helminthic diseases caused by the cystic growth or the intrahepatic tumour-like growth of the metacestode of Echinococcus granulosus or Echinococcus multilocularis, respectively. Both parasites have evolved sophisticated strategies to escape host immune responses, mainly by manipulating and directing this immune response towards anergy and/or tolerance. Recent research studies have revealed a number of respective immunoregulatory mechanisms related to macrophages and dendritic cell as well as T cell activities (regulatory T cells, Tregs). A better understanding of this complex parasite-host relationship, and the elucidation of specific crucial events that lead to disease, represents targets towards the development of novel treatment strategies and options.

β2-glycoprotein I (β2GPI) is the major antigenic target for antiphospholipid Abs. Anti-β2GPI Abs are a heterogeneous population of Igs targeting all domains of the molecule. Abs specific to β2GPI domain I are strongly associated with thrombosis and obstetric complications. In the present study, we sought to understand the possible pathogenic mechanism for this subset of anti-β2GPI Abs, investigating their potential cross-reactivity with other self-proteins involved in inflammatory or coagulant events. We compared the amino acid sequence of the β2GPI domain I with human proteins in a protein databank and identified a peptide sharing 88% identity with an epitope of human TLR4. A high percentage of patients with antiphospholipid syndrome (41%) and systemic lupus erythematosus (50%) presented serum IgG specific to this peptide. Anti-β2GPI peptide Abs binding the TLR4 were able to induce NF-κB activation in HEK293 cells that were stably transfected with the TLR4 gene. Anti-β2GPI peptide Abs induced activation of TLR4 and triggered interleukin-1 receptor-associated kinase phosphorylation and NF-κB translocation, promoting VCAM expression on endothelial cells and TNF-α release by monocytes. In conclusion, our observations suggest a novel pathogenic mechanism in the TLR4 stimulation by anti-β2GPI peptide Abs that links adaptive immune responses with innate immunity in antiphospholipid syndrome and systemic lupus erythematosus.

SUMMARY Seeking biomarkers reflecting disease development in cystic echinococcosis (CE), we used a proteomic approach linked to immunological characterisation for the identification of respective antigens. Two-dimensional gel electrophoresis (2-DE) of sheep hydatid fluid, followed by immunoblot analysis (IB) with sera from patients with distinct phases of disease, enabled us to identify by mass spectrometry heat shock protein 20 (HSP20) as a potential marker of active CE. Using IB, antibodies specific to the 34 kDa band of HSP20 were detected in sera from 61 ⁄ 95 (64%) patients with CE, but not in sera from healthy subjects. IB revealed anti-HSP20 antibodies in a higher percentage of sera from patients with active disease than in sera from patients with inactive disease (81 vs. 24%; P = 10 )4 ). These primary results were confirmed in a long-term follow-up study after pharmacological and surgical treatment. Herewith antiHSP20 antibody levels significantly decreased over the course of treatment in sera from patients with cured disease, relative to sera from patients with progressive disease (P = 0AE017). Thus, during CE, a comprehensive strategy of proteomic identification combined with immunological validation represents a promising approach for the identification of biomarkers useful for the prognostic assessment of treatment of CE patients.

The pathologic events that ensue after humans ingest the eggs of Echinococcus granulosus and continue while cystic echinococcosis develops, provide an excellent example illustrating the evasive strategies helminth parasites use to develop, progress and cause chronic disease. The hydatid cyst secretes and exposes numerous immunomodulatory molecules to the host's immune system. By characterizing these molecules we can understand the mechanisms that E. granulosus uses for increasing the efficiency and persistency of infection in the host. These molecules modulate both the innate and adaptive arms of the immune response and appear to target cellular and humoral responses. In this review, we discuss recent advances in the immunobiology of host-E. granulosus interactions that provide intriguing insights into the complex interplay between host and parasite that ultimately facilitates parasite survival.

Although detection of autoantibodies in the peripheral blood from patients with immune-mediated endothelial dysfunctions has so far failed to provide tools of diagnostic or pathogenetic value, putative bioindicators include anti-endothelial cell antibodies, a heterogeneous family of antibodies that react with autoantigens expressed by endothelial cells. In this study, to identify endothelial autoantigens involved in the autoimmune processes causing endothelial damage, we screened a human microvascular endothelial cell cDNA library with sera from patients with Behçet's disease. We identified antibodies to the C-terminus of Ral binding protein1 (RLIP76), a protein that catalyzes the ATP-dependent transport of glutathione (GSH) conjugates including GSH-4-hydroxy-t-2,3-nonenal, in the serum of a significant percentage of patients with various diseases characterized by immune-mediated endothelial dysfunction, including Behçet disease, systemic sclerosis, systemic lupus erythematosus and carotid atherosclerosis. These autoantibodies increased intracellular levels of 4-hydroxy-t-2,3-nonenal, decreased levels of GSH and activated C-Jun NH2 Kinase signaling (JNK), thus inducing oxidative stress-mediated endothelial cell apoptosis. The dietary antioxidant alpha-tocopherol counteracted endothelial cell demise. These findings suggest that autoantibodies to RLIP76 play a pathogenetic role in immune-mediated vascular diseases and represent a valuable peripheral blood bioindicator of atherosclerosis and immune-mediated vascular diseases.

Summary Early non-invasive diagnostic information would be useful in identifying patients at risk of progressive carotid atherosclerosis, despite an apparently harmless plaque on ultrasound imaging. In this study, we assessed the possible association of intracellular cytokines in peripheral blood with the ultrasound (stenosis ≥ 70%) and clinical indications (transient ischaemic attack, amaurosis fugax or stroke) for carotid endarterectomy (CEA) in patients. Intracellular cytokine expression was determined in 106 patients (67 undergoing and 39 not undergoing CEA). Cells primed for the proinflammatory cytokines tumour necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-1β, IL-6, IL-8 and the anti-inflammatory cytokines IL-4 and IL-10 were found in significantly higher percentages in patients undergoing CEA than in patients who were not (P

The pathogenesis of Alzheimer's disease (AD) includes the participation of the immune system. To identify antigenic targets in AD, we screened a human microvascular endothelial cell cDNA library with sera from patients with AD, and we identified rabaptin 5 (RABPT5). We detected serum IgG specific to RABPT5 in 65% of patients with AD and in 35% of patients with systemic lupus erythematosus, but in no healthy controls. Our results demonstrated a massive redistribution of this protein in the cytoplasm of endothelial and neuronal cells in apoptosis. In conclusion, we identified RABPT5 as a novel autoantigen in AD.

Atherosclerosis is a chronic inflammatory multifactorial disease in which immune responses are key pathogenetic factors. T cell-mediated immunity contributes to the initiation and progression of atherosclerotic disease, but the nature of antigens responsible for immune cell activation is still not completely elucidated. Convincing evidence supports a determinant role of autoimmune responses to self-structures in shaping the progression of the disease. Autoimmune responses may be directed against altered self-structures, such as oxidized low-density lipoproteins (LDL). Oxidative stress, increasingly reported in patients with atherosclerosis, is the major event causing protein structural modification, thus inducing the appearance of neo/cryptic epitopes on the molecule. Intraplaque hemorrhage, a common event in advanced lesions, causes the deposition of large amounts of hemoglobin (Hb). The pro-oxidative intraplaque microenvironment may induce structural changes in extra-erythrocytic free Hb, thus generating novel/cryptic autoantigenic epitopes. We demonstrated that an oxidized Hb preparation enriched in hemichromes expands IFN-gamma-secreting T lymphocytes in patients with advanced carotid atherosclerosis and enhances the phenotypical and functional maturation of human monocyte-derived dendritic cells induced by lipopolysaccharide (LPS). Overall, our findings suggest that oxidized forms of Hb could act as a dangerous signal for the immune system, thus contributing to the inflammatory process that takes place within the atherosclerotic plaque.

Despite inducing a strong host cellular and humoral immune response, the helminth Echinococcus granulosus is a highly successful parasite that develops, progresses, and ultimately causes chronic disease. Although surgery remains the preferred therapeutic option, pharmacological research now envisages antihelminthic strategies. To understand the mechanisms that E. granulosus uses to escape host immunosurveillance and promote chronic infection, we investigated how two hydatid cyst components, purified antigen B (AgB) and sheep hydatid fluid (SHF), act on host dendritic cell (DC) differentiation from monocyte precursors and how they influence maturation of DC that have already differentiated. We evaluated the immunomodulatory potential of these antigens by performing immunochemical and cytofluorimetric analyses of monocyte-derived DCs from healthy human donors. During monocyte differentiation, AgB and SHF downmodulated CD1a expression and upregulated CD86 expression. Compared with immature DCs differentiated in medium alone (iDCs), AgB- and SHF-differentiated cells stimulated with lipopolysaccharide included a significantly lower percentage of CD83 + cells ( P < 10 −4 ) and had weaker costimulatory molecule expression. When stimulated with AgB and SHF, iDCs matured and primed lymphocytes towards the Th2 response typical of E. granulosus infection. SHF and particularly AgB reduced the production of interleukin-12p70 (IL-12p70) and tumor necrosis factor alpha in lipopolysaccharide-stimulated iDCs. Anti-IL-10 antibodies increased the levels of IL-12p70 secretion in AgB- and SHF-matured DCs. AgB and SHF induced interleukin-1 receptor-associated kinase phosphorylation and activated nuclear factor-κB, suggesting that Toll-like receptors could participate in E. granulosus -stimulated DC maturation. These results suggest that E. granulosus escapes host immunosurveillance in two ways: by interfering with monocyte differentiation and by modulating DC maturation.

SummaryThe worldwide problem of chronic Echinococcus granulosus disease calls for new parasite-derived immunomodulatory molecules. By screening an E. granulosus cDNA library with IgG4 from patients with active cystic echinococcosis, we identified a cDNA that encodes a predicted partial protein that immunofluorescence studies localized in the protoscolex tegument and on the germinal layer of cyst wall. We named this protein EgTeg because the 105 amino acid sequence scored highest against a family of Schistosoma tegumental proteins. Evaluating the role of EgTeg in the human early inflammatory response we found that EgTeg significantly inhibited polymorphonuclear cell (PMN) chemotaxis. Cytometric analysis of intracellular cytokines disclosed a significantly higher percentage of cells producing IL-4 than IFN-γ (P = 0·001, Student's t-test) in T lymphocytes from patients with cystic echinococcosis stimulated with EgTeg. EgTeg induced weak Th1-dependent proliferation in 42% of patients’ peripheral blood mononuclear cells. In immunoblotting (IB) analysis of total IgG and IgG subclass responses to EgTeg in patients with cystic echinococcosis, patients with other parasitoses, patients with cystic lesions and healthy controls, total IgG specific to EgTeg yielded high sensitivity (73%) but low specificity (44%) precluding its use in immunodiagnosis. Conversely, IgG4 specific to EgTeg gave acceptable sensitivity (65%) and high specificity (89%) suggesting its use in immunodiagnosis to confirm ultrasound documented cysts suggestive of E. granulosus. Because the new tegumental antigen EgTeg inhibits chemotaxis, induces IL-4-positive T lymphocytes and noncomplement fixing antibodies (IgG4) it is an immunomodulatory molecule associated with chronic infection.

To investigate the role of T lymphocytes in the immune response to Echinococcus granulosus, using sheep hydatid fluid (SHF) and antigen B (AgB), we generated T-cell lines from patients with active, transitional and inactive hydatid cysts. We established 16 T-cell lines, eight specific to SHF and eight specific to AgB. At surface phenotyping 88-98% of cells displayed the helper/inducer CD4 antigen. In all patients, at all clinical stages of hydatid cyst disease, T-cell stimulation with SHF and AgB invariably amplified a large number of almost identical Vbeta subfamily fragments. Irrespective of antigen-specificity, the two cell lines from the patient with an inactive cyst had a Th1 profile, because they exclusively expressed and produced IFN-gamma. Conversely, the T-cell lines derived from the seven patients with active and transitional hydatid cysts had mixed Th1/Th2 and Th0 clones. The functional characteristics of the 16 T-cell lines differed markedly in the various clinical stages of cystic echinococcosis, thus providing new in vitro evidence that Th1 lymphocytes contribute decisively to the inactive stage of hydatid disease, Th2 lymphocytes in the active and transitional stages. The parasite-specific T-cell lines, especially the two Th1 lines from the patient with an inactive cyst, may help identify Th1 protective epitopes on SHF and AgB.

By screening an expression library of Echinococcus granulosus with IgE from sera of patients with cystic echinococcosis (CE) and allergic reactions, we isolated the C-terminal region of a new heat shock protein (HSP)70 of E. granulosus. The protein, named Eg2HSP70, has close homology with the C-terminal region of Dermatophagoides farinae and human HSP70. We investigated the humoral and cell-mediated immune responses to this antigen in patients with CE grouped according to the presence of allergic reactions. Immunoblotting detected total IgG, IgG4 and IgE specific to Eg2HSP70 (83% of sera contained IgG, 31% IgG4 and 57% IgE). No significant difference was found in immunoglobulin percentages according to the presence of allergic reactions. Immunoblotting inhibition showed that no IgG or IgE specific to Eg2HSP70 cross-reacted with D. farinae or human HSP70. Eg2HSP70-stimulated PBMC from 26 patients produced significantly greater amounts of TNF-alpha, IFN-gamma, and IL-10 than unstimulated cultures in all patients, irrespective of the presence of allergic reactions (P < 0.05). They also produced significantly greater amounts of IL-4 than unstimulated cultures exclusively in patients with allergic reactions (P < 0.05). These findings show that Eg2HSP70 is a new antigenic molecule inducing both B and T cell responses.

Summary Allergic reactions, such as urticaria, itching and anaphylactic shock, often complicate the course of cystic echinococcosis (CE). To investigate the role of the IgE-immunoreactive recombinant Echinococcus granulosus elongation factor-1 β/δ (EgEF-1 β/δ) in the allergic disorders during CE we determined humoral and cell-mediated responses to this antigen in patients with CE grouped according to the clinical presence or absence of allergic reactions. Immunoblotting analysis showed that serum IgE-binding reactivity to EgEF-1 β/δ differed significantly in patients with and without allergic reactions (38 of 42, 90% vs. 31 of 56, 56%; P

SUMMARYThe influence of pharmacological treatment on the immune response of patients with Echinococcus granulosus infection was evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) to determine mRNA expression for IL-12 p35, IL-12 p40, interferon-gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α) and IL-4 in PBMC from 12 patients before and after chemotherapy and from seven uninfected controls. Most patients’ PBMC showed measurable amounts of IL-12 p35, IL-4, IFN-γ and TNF-α mRNA in parasite antigen-stimulated and unstimulated cultures. Conversely, IL-12 p40 mRNA was detected almost exclusively in successfully treated patients (86%) after therapy. In these patients semiquantitative analysis of RT-PCR products showed a significant difference between IL-12 p40 mRNA mean levels before and after therapy (P = 0.03 in parasite antigen-stimulated cultures; P = 0.001 in unstimulated cultures). IL-4 mRNA was weakly expressed before therapy and more highly so after treatment in both groups of patients and under both culture conditions; IL-4 mRNA reached its highest level in post-therapy PBMC from patients in whom therapy failed (stimulated cultures). IFN-γ and TNF-α mRNA expression increased in patients who responded to therapy and decreased in patients who did not. In contrast to IL-12 p35, IFN-γ and TNF-α mRNAs, IL-12 p40 and IL-4 mRNAs were detected exclusively in patients, suggesting a close relationship between these two cytokines and cystic echinococcosis. Our findings indicate that chemotherapy influences the immune response, thus determining changes in Th1/Th2 cytokine mRNA patterns, predominantly in IL-12 p40 and IL-4 mRNA expression.

A cDNA clone (Eg EF-1beta/delta) of Echinococcus granulosus has been isolated by an expression library screened with immunoglobulin (Ig)E of sera from patients with cystic echinococcosis (CE). The Eg EF-1beta/delta was identified on the basis of sequence homology to the subunits beta or delta of the elongation factor-1. The amino acid sequence deduced from this open reading frame is 244 residues long with a predicted molecular mass of 31 kDa. In Southern blot under high stringent condition, Eg EF-1beta/delta hybridized to genomic DNA of E.granulosus at two bands of 4 and 2.5 Kb. In immunoblotting analysis, the Eg EF-1beta/delta protein shows immunological reactivity with sera from CE patients: 51.7% of sera contained IgE, 41.7% IgG and 18.3% IgG4 specific to the recombinant protein. We identify the Eg EF-1beta/delta by immunoblotting with specific monoclonal antibody both in protoscoleces and in sheep hydatid fluid. The higher percentage of humoral immune response against Eg EF-1beta/delta observed in CE patients with calcified cysts than in patients with active cysts indicates the possible release of the protein in the hydatid fluid after protoscoleces degeneration suggesting the possible use of this antigen in the immunosurveillance of CE. Overall, these findings seem to assign to Eg EF-1beta/delta a key role in the allergic disorders and in the complex host-parasite relationship in CE.

To investigate the involvement of immunological variables, including the Th1/Th2 balance, in the mechanisms underlying seronegativity in cystic echinococcosis (CE), Th1 and Th2 cytokines were evaluated in ELISA determining IFN-γ, IL-4, -5 and -10 production in peripheral blood mononuclear cell (PBMC) cultures from 16 patients (six seronegative and ten seropositive) with CE and from six healthy donors. Patients who had undetectable antibody levels in their sera invariably produced no IL-5 and scarce IL-4 and -10 (Th2 response); both groups of patients produced similar amounts of IFN-γ (Th1 response). The analysis of host clinical features and cyst characteristics shows that these variables do not explain the lack of detectable serum antibody levels. These findings suggest that seronegativity arises because unknown host or parasite factors, or both, cause inadequate Th2 cell activation thus reducing production of Th2 cytokines, including IL-5, the cytokine primarily implicated in immunoglobulin expression in CE.

Resume Pour obtenir plus d'informations sur l'epidemiologie de l'infection par Pneumocystis carinii sp. f. hominis, nous avons analyse les regions intercalaires internes transcrites du noyau de l'operon de l'ARNr du microorganisme, a partir d'echantillons respiratoires obtenus de cinq patients sideens italiens ayant eu deux atteintes de pneumocystose. Le procede nous a permis d'identifier 8 types de P. carinii, et parmi ceux-ci trois types nouveaux: A4a1 , B1b5 et B1c2. Le type B1a3 apparait comme le genotype italien le plus representatif de cette etude. Nos resultats suggerent que les reinfections sont exogenes de facon predominante plutot que dues a la reactivation d'une infection prealable.

DNA amplification using dihydrofolate reductase (DHFR) primers in bronchoalveolar lavage fluids (BALFs) from patients with Pneumocystis carinii (PC) pneumonia yielded low sensitivity and specificity. Amplified products of BALFs from an AIDS patient without PC pneumonia and five patients with PC pneumonia were cloned and sequenced. All samples showed the same sequence without any homology with DHFR cDNA of rat PC, or with any DHFR sequences in databases at the DNA or amino acid level. The data demonstrate that these DHFR primers amplify a non-specific region of DNA with a sequence unrelated to the human PC DHFR gene both in PC positive and in PC negative samples. This finding precludes the use of these DHFR primers for the diagnosis of PC pneumonia in respiratory specimens.

Cystic echinococcosis (CE) is a neglected infectious disease caused by the larval stage of Echinococcus granulosus. It constitutes a major public health problem in developing countries. During CE, the distinguishing feature of the host-parasite relationship is that chronic infection coexists with detectable humoral and cellular responses against the parasite. In order to establish successfully an infection, E. granulosus releases molecules that directly modulate the host immune responses favoring a strong anti-inflammatory response and perpetuating parasite survival in the host. In vitro and in vivo immunological approaches, together with molecular biology and immunoproteomic technologies provided us exciting insights into the mechanisms involved in the initiation of E. granulosus infection and the consequent induction and regulation of the immune response. Here, we review some of the recent developments and discuss how these observations helped to understand the immunology of E. granulosus infection in man. Although the last decade has clarified many aspects of host-relationship in human CE, establishing the full mechanisms that cause the disease require more studies. We need to define more clearly the events that manipulate the host immune response to protect the E. granulosus from elimination and minimizing severe pathology in the host.

Cystic echinococcosis (CE) is a widespread chronic endemic helminthic disease caused by infection with metacestodes of the tapewormEchinococcus granulosus. CE affects humans and has a worldwide prevalence of approximately six million. In this review, we discuss current findings in diagnosis and clinical management of CE and new concepts relating toE. granulosusmolecules that directly modulate the host immune responses favouring a strong anti-inflammatory response and perpetuating parasite survival in the host. New insights into the molecular biology ofE. granulosuswill improve considerably our knowledge of the disease and will provide new potential therapeutic applications to treat or prevent inflammatory immune-mediated disease.

The ability of Pneumocystis carinii to induce tumor necrosis factor (TNF)-alpha release by monocytes/macrophages from immunocompetent humans was investigated. Monocytes and monocyte-derived macrophages from healthy individuals produced an increased amount of TNF-alpha when exposed to P. carinii cysts obtained from rats with steroid-induced pneumocystosis. The cysts induced increased TNF-alpha production in a dose-dependent manner; baseline TNF-alpha production was restored after addition of an anti-P. carinii hyperimmune serum. Kinetics experiments showed that the secretion of TNF-alpha occurs early and reaches a maximal peak after 8 h. Since TNF-alpha is directly lethal to P. carinii in vitro, it is suggested that the production of this cytokine in response to the cysts may be one of the mechanisms for the control of this parasitic infection.

Cystic echinococcosis (CE), a zoonosis caused by the development of Echinococcus granulosus tapeworm larvae in the internal organs of ungulates and humans, continues to pose a major public health burden in underdeveloped and industrialised areas worldwide. Research designed to improve parasitic disease control and find out more about parasite biology has already identified a number of E. granulosus antigenic molecules. The major E. granulosus immunomodulant antigen isolated from hydatid fluid is antigen B, a 120 kDa polymeric lipoprotein consisting of various 8 kDa subunits. By inhibiting elastase activity and neutrophil chemotaxis and eliciting a non-protective Th2 cell response, antigen B helps the parasite evade the human response. In this review, we briefly discuss current information on the molecular characteristics and immunomodulatory properties of E. granulosus antigen B. Besides focusing on findings that provide intriguing insights into the complex interplay between host and parasite, we suggest how this information could extend the current therapeutic options in inflammatory diseases.

Screening a cDNA expression library is a powerful technique that allows identification of previously uncharacterized antigens. Proteins recognized by antibodies from patients with autoimmune diseases have been intensively studied over the past two decades since cDNAs encoding autoantigens have become available. Identity of many of them has been defined, and specific structural motifs or post-translational modifications, which may be important to explain the generation of such antibodies during the autoimmune process, have been pointed out. The screening of human umbilical artery or microvascular endothelial cell expression libraries appears to be a useful tool for the characterization of endothelial autoantigens allowing us to identify several molecules recognized from serum anti-endothelial cell antibodies of patients with diseases characterized by immune-mediated endothelial dysfunctions.

The currently available tests for the diagnosis of cystic echinococcosis (CE), enzyme-linked immunosorbent assay (ELISA), and immunoblotting (IB) lack sensitivity and specificity, and antigen panels need standardizing. By screening an Echinococcus granulosus cDNA library with IgG1 from patients with CE, we identified E. granulosus thioredoxin peroxidase (EgTPx). Although IB and ELISA achieved the same specificity (92%), ELISA showed higher sensitivity than IB (83% versus 42%) in determining total immunoglobulin G (IgG) specific to EgTPx in CE sera. The percentage of total IgG- and IgG1-positive sera in ELISA was equally distributed in patients with active, transitional, and inactive disease. Conversely, the percentages of IgG4-positive sera were significantly higher in sera from patients with active than inactive disease (P = 0.03). Our data suggest that adding this highly specific recombinant antigen to the standard diagnostic panel of antigens used in ELISA would increase diagnostic sensitivity. Antibodies specific to EgTPx are of potential interest in the host-parasite relationship.

Objective We investigated the possible association of intracellular cytokine profiles in peripheral mononuclear cells in whole blood from patients with carotid atherosclerosis in whom follow-up after carotid endarterectomy (CEA) showed the onset or progression of contralateral disease. Methods and results Intracellular expression of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-1β, IL-6, IL-8, IL-4 and IL-10 was determined in 43 patients with carotid atherosclerosis, at baseline and at 1, 3, 6 and 12 months after CEA, and in 16 healthy subjects. When follow-up ended patients were divided into two groups, those with cured or stable disease (no onset of disease or unchanged stenosis in the contralateral vessel) and those with progressive disease (onset of disease or increased stenosis in the contralateral vessel). In patients with cured or stable disease, cytokine-positive cells significantly decreased or remained unchanged (IL-8 and IL-10) during follow-up, whereas in patients with progressive disease they increased or remained unchanged (TNF-α). Multivariate ANOVA confirmed that the trend of cytokine expression between baseline and 12 months differed significantly in the two groups. Conclusions Intracellular expression of TNF-α, IFN-γ, IL-1β, IL-6, IL-8, IL-4 and IL-10 in peripheral mononuclear cells is associated with the outcome of contralateral disease after CEA.

By using a recently developed PCR-solution hybridization enzyme-linked assay (PCR-SHELA), we investigated Pneumocystis carinii in bronchoalveolar lavage fluid samples and induced sputa of patients with pneumocystosis. In detecting P. carinii, PCR-SHELA proved more sensitive than immunofluorescence staining or a single PCR and significantly more diagnostically specific than a nested PCR. Our data suggest that PCR-SHELA could be used to detect P. carinii organisms in respiratory samples, particularly in patients with uncertain diagnoses.

The human plasma protein beta2-glycoprotein I (beta2-GPI) is the most common target for antiphospholipid antibodies associated with thrombotic events in chronic disorders related to endothelial cell dysfunction. Crucial information is needed to clarify why this self-abundant protein is targeted by autoimmune responses. In this study, we investigated whether oxidative modification of beta2-GPI, either spontaneous in culture wells or induced by treatment with H2O2, renders this self-protein able to activate immature monocyte-derived dendritic cells (DCs) from healthy human donors. Oxidized beta2-GPI caused DCs to mature so that CD83 appeared and CD80, CD86, human leukocyte antigen-D region related (HLA-DR), and CD40 increased. The interaction between oxidized beta2-GPI and DCs specifically stimulated these cells to secrete interleukin 12 (IL-12), IL-1beta, IL-6, IL-8, tumor necrosis factor alpha (TNF-alpha), and IL-10. Oxidized beta2-GPI-stimulated DCs had increased allostimulatory ability and primed naive T lymphocytes, thus inducing T helper 1 (Th1) polarization. The interaction between oxidized beta2-GPI and DCs involved interleukin-1 receptor associated kinase (IRAK) phosphorylation and nuclear factor kappaB (NFkappaB) activation. Pretreatment of beta2-GPI with the antioxidant alpha-tocopherol prevented DC maturation. These findings show that human oxidized beta2-GPI, probably by interacting with a member of the Toll-like receptor (TLR) family, causes DCs to mature. Because this key beta2-GPI function requires oxidative modification, in several chronic disorders related to endothelial cell dysfunction oxidative stress might trigger the "autoimmune spiral."

SUMMARY The humoral immune response to endothelium has a pivotal role in the development of atherosclerosis. Using a molecular method, we sought to identify endothelial autoantigens in carotid atherosclerosis. Immunoscreening of a HUAEC expression library with IgG from a pool of two sera from patients with carotid atherosclerosis identified a clone specific to actin. We evaluated actin-specific IgG reactivity in patients with carotid atherosclerosis and compared responses with those in patients with systemic lupus erythematosus and type 1 diabetes mellitus and in healthy subjects. Enzyme-linked immunoassay detected actin-specific IgG in a significantly higher percentage of sera from patients with atherosclerosis and systemic lupus erythematosus than from healthy subjects (16/61, 26% and 13/33, 39%versus 2/41, 5%, P = 0·012 and P

Immunological parameters are increasingly investigated as possible markers for the development of cystic echinococcosis. Among the newer immunologic tests for assessing the host-parasite relationship, assay of immunoglobulin isotypes with the use of distinct parasite antigens and detection of Th1/Th2 cytokine expression are an interesting new approach. The findings upon which we have constructed our immunological hypothesis of the host-parasite relationship are: (1) immunoglobulin isotype profiles differ in patients with distinct clinical outcomes of the disease; in particular, antigen B is the antigen of choice to detect specific IgG4, which is the immunoglobulin isotype most clearly associated with the progression of the disease; (2) the isolation and characterisation of recombinant parasite proteins that behave as molecular markers of allergic reactions associated with cystic echinococcosis; (3) Th1/Th2 cell activation is involved in the clinical outcome of Echinococcus granulosus infection and, in particular Th2 response, is associated with susceptibility to the disease, whereas a Th1 response is associated with protective immunity.

The latest developments in the molecular and cellular mechanisms that underlie Echinococcus infection have renewed interest in the immunodiagnosis of this disease and have helped in understanding the host-parasite relationship. This review discusses current concepts on the immune response to Echinococcus granulosus in humans, and relates these findings to diagnosis and clinical management. The two most promising molecular tools developed for the immunodiagnosis of cystic echinococcosis involve isolating native or recombinant parasite antigens to detect specific serum antibodies in patients with suspected echinococcosis and producing monoclonal antibodies to detect parasite antigens in clinical samples. Novel drugs should be designed to strengthen host immune responses thus combating parasitic survival. Currently, attention has been focused on understanding T-helper lymphocyte activity; in particular the role of Th1 and Th2 subsets in orchestrating immune responses. The Th1/Th2 model explaining how selective immune responses--including cell-mediated or humoral immunity--develop, seems promising as the rationale for molecular tools that could lead to new therapeutic strategies.

SUMMARY By immunological screening of a cDNA library derived from protoscoleces of Echinococcus granulosus with IgE from patients with cystic echinococcosis (CE) and allergic manifestations, we isolated a protein identical to E. granulosus cyclophilin. The protein, named EA21, has close homology with Malassezia furfur cyclophilin allergen (Mal f 6) and with human cyclophilin. Using immunoblotting (IB) with a polyclonal antibody specific to EA21, we identified E. granulosus cyclophilin both in protoscoleces and in sheep hydatid fluid. Of the 58 sera from patients with CE, 29 (50%) were IgE positive to EA21, whereas, despite the high sequence homology, none were IgE positive to Mal f 6 or human cyclophilin. Only 26 of the 58 patients (45%) had IgG specific to EA21, whereas all patients (100%) had IgG specific to Mal f 6 and human cyclophilin. IB analysis showed that serum IgE-binding reactivity to EA21 differed significantly in patients with and without allergic reactions (20 of 25, 80%versus nine of 33, 27%; P < 10–4). Conversely, five of the 25 patients who had CE-related allergic manifestations (20%) and 21 of the 33 who did not (63%) had specific IgG4 (P = 10–3) and total IgG to EA21. EA21 induced a proliferative response in 15 of 19 (79%) patients’ PBMC regardless of the allergic manifestations, but it induced no IL-4 production. Overall, these findings suggest that E. granulosus cyclophilin is a conserved, constitutive, parasite protein that does not cross-react with cyclophilins from other organisms and is involved in the allergic symptoms related to CE.

SUMMARY Seeking better immunological markers indicating the long-term outcome of cystic echinococcosis (CE) after chemotherapy we studied 23 patients receiving albendazole, clinically followed for 8 years, and grouped ultrasonographically according to therapeutic outcome. Antibody responses against a partially purified fraction of hydatid fluid (HFF) and antigen B (AgB) were evaluated by indirect haemagglutination (IHA), ELISA and immunoblotting (IB). Although IHA titres varied over the course of treatment, differences in mean antibody titres to HFF between groups were significant only at 4 years (P = 0·031). IgG isotype expression remained unchanged during follow-up whereas IgE expression decreased in patients with cured or stable disease. AgB disclosed higher IgG4 expression (P < 10–4; P = 0·025) and lower IgG1 expression than HFF (P < 10–4; P = 0·022). IHA antibody titres were higher in patients with progressive than in those with cured or stable disease, even in those with the same cyst type. ELISA isotype profiles differed between groups, particularly for type CE 3, 4 and 5 cysts: higher serum IgG1 and IgG3, lower IgG4 and IgE in patients with cured or stable disease. Although combined serological testing provides scarce information on the long-term outcome of CE after chemotherapy it may be useful for reviewing in a retrospective study the outcome of a cyst and for assessing the host-parasite relationship.

The purpose of this study was to determine whether dihydropteroate synthase gene (DHPS) mutations were associated with the failure of sulpha/sulphone drugs used as prophylaxis agents in HIV infected patients. Results suggested that DHPS mutations were significantly associated with failure of anti-Pneumocystis carinii sulphone prophylaxis (P=0.031). An increasing number of mutant P. carinii strains have been isolated from patients no longer having prophylaxis. There was no statistically significant difference in severity or outcome of the pneumonia caused by wild-type or mutant DHPS. Moreover, two of the three patients with mutant P. carinii pneumonia (PCP) were successfully treated with sulpha drugs. We think that P. carinii drug-resistance could be an emerging problem for immunocompromised patients including those with HIV infection.

By directly suppressing the function of certain immune cell subsets and by stimulating other cell populations related to immunopathology, parasite-derived substances play an important role in the chronic establishment of parasitic disease. Our objective was twofold: (i) to investigate further the role ofEchinococcus granulosusantigen B (AgB) in the human early inflammatory response by determining its effect on polymorphonuclear cell (PMN) random migration, chemotaxis, and oxidative metabolism and (ii) to determine its action in acquired immunity by evaluating AgB and sheep hydatid fluid (SHF)-driven Th1 (gamma interferon [IFN-γ] and interleukin 12 [IL-12]) and Th2 (IL-4 and IL-13) cytokine production by peripheral blood mononuclear cells (PBMC) from 40 patients who had cured or stable or progressive cystic echinococcosis. AgB significantly inhibited PMN recruitment but left their random migration and oxidative metabolism unchanged. Patients' PBMC stimulated with AgB produced IL-4 and IL-13 but did not produce IL-12. They also produced significantly lower IFN-γ concentrations than did PBMC stimulated with SHF (P= 10−5). AgB skewed the Th1/Th2 cytokine ratios towards a preferentially immunopathology-associated Th2 polarization, predominantly in patients with progressive disease. AgB-stimulated patients' PBMC also proliferated less than SHF-stimulated PBMC (P= 9 × 10−3). In vitro Th2 cytokine production was reflected in vivo by elevated specific immunoglobulin E (IgE) and IgG4 antibodies binding to AgB. These findings confirm that AgB plays a role in the escape from early immunity by inhibiting PMN chemotaxis. They also add new information on the host-parasite relationship, suggesting that AgB exploits the activation of T helper cells by eliciting a nonprotective Th2 cell response.

To evaluate the diagnostic sensitivity and specificity of immunoelectrophoresis (IEP), indirect haemagglutination (IHA), enzyme-linked immunosorbent assay (ELISA) and immunoblotting (IB), we compared their ability in detecting IgG antibodies to a hydatid fluid fraction (HFF) and to native and recombinant antigen B of Echinococcus granulosus. We tested sera from patients who had cystic echinococcosis (CE) grouped according to their type of cysts (n = 204), from patients with other parasitic diseases (n = 21), lung or liver carcinomas (n = 6) or serous cysts (n = 26) and from healthy controls (n = 90). HFF-IB gave the highest sensitivity (80%) followed by ELISA (72%), IHA (54%) and IEP (31%), respectively. The diagnostic sensitivity significantly (P < 0.01) decreased as cysts matured from type I-II to type VII. Recombinant and native antigen B-IB yielded similar sensitivity (74%). A large number of clinically or surgically confirmed CE patients (20%) resulted negative. In these patients' sera, IB to assess the usefulness of the recombinant E. granulosus elongation factor-1 beta/delta in detecting IgE antibodies yielded 33% of positivity. Our findings underline the need to standardize techniques and antigenic preparations and to improve the performance of immunodiagnosis by characterizing new antigens and detecting distinct immunoglobulin classes.

The aim of this study was to determine the kinetics, the dissemination of the infection and the immunological response to Pneumocystis carinii primary infection in a non-immunosuppressed rabbit model. For this purpose, we developed a nested PCR that amplified a portion of the mitochondrial large-subunit rRNA gene of rabbit-derived P. carinii. The PCR detected P. carinii DNA in lung and bronchoalveolar lavage fluids from 14- to 45-day-old rabbits but not in their serum. No P. carinii DNA was detected in extrapulmonary organs from 28-day-old rabbits with P. carinii pneumonia. ELISA and immunoblotting analysis showed that 5-day-old pups had elevated specific IgG. The IgG concentration sharply decreased, reaching a trough on day 21, and from then onwards progressively increased as the infection cleared. Conversely, the specific IgM concentration increased during the infection and peaked on day 28. IgG mainly recognized a 50-kDa subunit of P. carinii organisms; IgM recognized first a 45-kDa subunit on day 21, whereas from day 28 onwards it also recognized the 50-kDa subunit. A P. carinii-specific splenocyte proliferative response was observed on day 45. These findings suggest that P. carinii primary infection is a time-limited and a lung-limited event and contribute new information on the relationship between the kinetics of primary P. carinii infection and the immunological response in a model that mimics the primary infections in humans.

SUMMARY The relation of serum cytokine levels and outcome of chemotherapy was evaluated in 15 patients with cystic echinococcosis. Serum IL-4, IL-10 and interferon-gamma (IFN-γ) concentrations were determined by ELISA before and after a 3-month course of albendazole treatment: at least one serum sample per patient from 13 patients (87%) contained measurable amounts of IL-4; samples from five patients (33%) measurable amounts of IL-10 and samples from only two patients (13%) measurable amounts of IFN-γ. Clinical assessment at 1 year after the end of therapy showed that 11 of the 15 patients had responded clinically. Seven of these patients had lower IL-4 serum concentrations, two had unchanged and two undetectable amounts (pre- versus post-therapy, n = 11, P = 0.008). Conversely, of the patients who did not respond, three had higher and one patient unchanged serum IL-4 concentrations. Serum IL-10 levels also decreased in all patients who responded (3/5) and increased in all patients who did not (2/5). No association was found between cytokine concentrations and cyst characteristics or antibody levels. Overall these data suggest that serum IL-4 detection may be useful in the follow up of patients with cystic echinococcosis.

Our aim was to evaluate if genetic diversity of Pneumocystis carinii could influence the detection by molecular techniques in bronchoalveolar lavage (BAL) fluids and in non-invasive specimens (induced sputum, oropharyngeal washing and serum/blood). P. carinii is morphologically similar in different hosts although several strains have been identified by biomolecular techniques. Variations of mt-LSU and ITSs sequences could determine a lack of hybridization of some clinical samples and could have diagnostic consequences with loss in sensitivity and specificity of available molecular tests, but at the moment no data support a significant impact of genetic diversity in these sequences on molecular detection of P. carinii for clinical purposes.

Detection and quantification of different Pneumocystis carinii (PC) life cycle forms were performed by polymerase chain reaction (PCR) and by morphological stains on bronchoalveolar lavage fluids (BALF) from HIV-infected patients with P. carinii pneumonia (PCP). The number of PC trophozoites was higher in patients with PCP who were receiving prophylaxis than in those not receiving prophylaxis. Also the cyst: trophozoite ratio was lower in the first group. No difference was observed between patients receiving different prophylactic medications. The imbalance between PC forms in BALF from patients with PCP receiving anti-PC prophylaxis may hamper the sensitivity of cyst stains. Multiple stains or PCR examination should be performed on BALF from patients with clinically suspected PCP who are receiving prophylaxis.

The efficiency of three different primer pairs, complementary to different Pneumocystis carinii DNA regions, was compared in the polymerase chain reaction (PCR) for the diagnosis of Pneumocystis carinii pneumonia (PCP) on bronchoalveolar fluid (BALF) from patients with AIDS. PCR coupled with dot-blot hybridization (BLOT) using primers and probe from the mitochondrial 23SrDNA region showed the highest sensitivity, with a lower detection limit of 0·5–1 organisms μl −1 . When testing 47 BALF, PCR plus BLOT if the mitochondrial 23SrDNA region showed also the best diagnostic efficiency (97% sensitivity, 100% specificity). Sensitivity was significantly higher than with PCR and BLOT of the 5SrDNA region (81·5% sensitivity; P = 0.025 , McNemar test); and of the dehydrofolate reductase (DHFR) gene region (75·6% sensitivity; P = 0·019 ). Sensitivity was also significantly higher than indirect immunofluorescence (75·8% sensitivity; P = 0·008 ). Using DHFR primers and probe, specificity was also reduced. The diagnostic sensitivity in clinical specimens paralleled the detection limit in the standard dilutions. The use of repeated DNA sequences of proven specificity as target of PCR amplification favourably influences sensitivity and specificity. This comparative study demonstrates that primer selection plays a significant role in the diagnosis of PCP by PCR.

SUMMARY The role of cytokines in human hydatidosJs (Echinococcus granulosus infection) was evaluated in immunoassays determining production of IL-4, IL-10 and interferon-gamma (IFN-γ) in peripheral blood mononuclear cell (PBMC) cultures from 30 hydatid patients and 14 uninfected controls. In ceil cultures from hydatid patients parasite and non-parasite antigen stimulation significantly increased IL-4 production (P·0·005). Spontaneous and milogen-driven IL-4 production was similar in patients and controls. IL-10 and IFN-γ production did not differ statistically in the two groups, even though some hydatid patients produced these cytokines in large amounts. Notably, antigen-driven IFN-γ concentrations were invariably higher in patients than in uninfected controls. Data analysis showed a relationship between IgE and IgG4 responses and parasite-driven cytokine production. High IgE and IgG4 responders produced high IL-4 and IL-10 concentrations. High IgE responders showed decreased IFN-γ production, but high IgG4 responders had IFN-γ levels slightly higher than those of low responders. Cytokine response patterns did not relate to the clinical stage of disease. The significantly increased IL-4 and the high IL-10 concentrations found in PBMC from many hydatid patients in this study are consistent with Th2 cell activation in human hydatidosis. The presence of antigen-driven IFN-γ production in patients with E. granulosus infection implies concurrent intervention of the Th1 or Th0 cell subset.

The hydatid fluid antigenic subunits which stimulate the proliferative response of T cells in PBMC isolated by hydatid patients were identified. In the same subjects, the serum IgG antibody profiles were determined by immunoblotting to compare T cell activation and IgG production. The study was carried out on 18 patients with clinically and serologically diagnosed hydatidosis and on ten healthy blood donors. To assess the proliferative response to the different antigenic subunits, sheep hydatid fluid was separated by the SDS-PAGE and the fractions were blotted onto nitrocellulose and solubilized. The comparison between immunoblotting and PBMC proliferation assay shows that the 55 and 65 kDa subunits of antigen 5 and the 12 kDa subunit of antigen B are the most reactive subunits in the two techniques. The 16 and 20 kDa subunits of antigen B are more reactive in PBMC proliferation assay than in immunoblotting, thus assigning a specific role to antigen B in cellular response.

We evaluated the peripheral autoreactive response in patients with Echinococcus granulosus who showed a negative humoral response as compared to seropositive patients and healthy controls. For this purpose, a limiting dilution analysis (LDA) of autologous mixed lymphocyte cultures was established to both estimate frequency of autoreactive T cells and, by analysing the shape of the curves, to clarify the mechanisms that underlie the autoreactive response. Different LDA curves were observed between healthy controls and patients, suggesting that different cell interactions are involved in the two populations. More interestingly, all hydatid patients, independent of their humoral response, showed a higher number of autoreactive T cells than controls. Precisely, subjects with a negative humoral response showed a range of values for autoreactive T cells exactly between the value ranges observed in seropositive and normal subjects. The present data also show that the increase of autoreactive T cells in hydatid patients correlates with the production of specific antibodies.

We evaluated the peripheral autoreactive response in patients with Echinococcus granulosus compared with healthy individuals. A limiting dilution analysis (LDA) was performed to estimate frequency of autoreactive T cells and to detect the complex mechanism that often underlies the autoreactive response. Different LDA curves were seen in healthy controls and patients. The control group provided a straight line passing through the origin (‘single hit’ kinetics), indicating that only peripheral autoreactive T cells are limiting. On the other hand, autoreactive T cell titration in hydatid patients did not follow ‘single hit’ kinetics, suggesting that two or more cell types are titrated. More interestingly, we observed a very high frequency of autoreactive T cells in hydatid patients ( 1 1,000 to 1 2,500 ) compared with healthy controls ( 1 5,000 to 1 35,000 ). These data suggest that chronic infection may provide adequate stimuli for the induction of autoimmune disorders and increase in autoreactive T cells.