Relatively high levels of anti-HLA antibodies (measured by Luminex Single-Antigen bead assay) are required to mediate inhibition of lymphocyte proliferation induced by sera from alloimmunized renal patients.

BACKGROUND: Rejection of transplanted organs is caused by alloimmune responses, primarily against HLA molecules. Anti-donor HLA antibodies are associated with antibody-mediated rejection (AMR) and poor graft outcome. Because of clinical interest in detecting these antibodies, new technologies have recently been introduced to increase the sensitivity of detection. The Luminex Single-Antigen (LSA) bead assay may yield new information, but it must be validated against biological and clinical data. MATERIAL AND METHODS: Based on previously published data regarding the in vitro effects of anti-HLA antibodies on lymphocytes, we measured the effect on lymphocytes of sera from patients on the transplant waiting list who had high titers of anti-HLA antibodies. Anti-CD3-mediated lymphocyte activation was studied in the presence of whole serum from these patients. Changes in lymphocyte proliferation, measured by carboxyfluorescein succinimidyl ester (CFSE) labeling, were detected, and these changes correlated with the level of anti-HLA antibodies. RESULTS: Whole serum containing anti-HLA antibodies inhibited lymphocyte proliferation; this effect correlated with the level of antibodies, as measured by LSA. This inhibitory effect was HLA-specific, as shown by adsorption experiments. We also found that relatively high levels of anti-HLA antibodies were necessary to induce changes in an in vitro model of lymphocyte proliferation. CONCLUSIONS: Our results demonstrate the clinical utility of detecting anti-HLA antibodies by LSA.

Predictive value of the Luminex single antigen panel for detecting flow cytometry cross-match positivity.

Anti-human leukocyte antigen (HLA) antibodies are a major cause of allograft loss. Solid-phase immunoassays, notably Luminex technology, have lately begun to replace traditional techniques for detecting these antibodies. This platform, however, carries some restrictions in the type of antibodies it detects. For this reason, results using these new technologies must be correlated with results using traditional techniques that have proven clinical significance. We have correlated flow cytometry cross-match (FCXM) outcomes with results from Luminex assays. Serum samples from patients awaiting transplantation who had known anti-HLA antibodies as detected by Luminex were incubated with lymphocytes expressing (a) 1 of the HLA antigens detected by the sera or (b) several of them. Of the 169 T-cell FCXMs we performed, in 92 cases the target cell expressed only 1 of the HLA antigens detected by the serum. The results obtained correlated well with Luminex data (r = 0.84). A cutoff mean fluorescence intensity value of 6,500 for the Luminex single antigen assay yielded a sensitivity of 85% and specificity of 82% for detecting a positive FCXM. In the other 77 cases, the target cell expressed 2 or more of the HLA antigens detected by the serum. In this situation, the same cutoff proved a useful tool for differentiating negative from positive FCXMs.

Randomized clinical trial on acute effects of i.v. iron sucrose during haemodialysis.

AIM: Haemodialysis induces endothelial dysfunction by oxidation and inflammation. Intravenous iron administration during haemodialysis could worsen endothelial dysfunction. The aim of this study was to ascertain if iron produces endothelial dysfunction and the possible neutralizing effect of N-acetylcysteine when infused before iron. The oxidative and inflammatory effects of iron during haemodialysis were also assessed. METHODS: Forty patients undergoing haemodialysis were studied in a randomized and cross-over design with and without N-acetylcysteine infused before iron sucrose (50 or 100 mg). Plasma Von Willebrand factor (vWF), soluble intercellular adhesion molecule-1 (sICAM-1) levels, malondialdehyde, total antioxidant capacity, CD11b/CD18 expression in monocytes, interleukin (IL)-8 in monocytes and plasma IL-8 were studied at baseline and during haemodialysis. RESULTS: Haemodialysis produced significant (P < 0.001) increase in plasma vWF, sICAM-1, malondialdehyde, IL-8 and CD11b/CD18 expression in monocytes, as well as decrease in total antioxidant capacity. Iron induced significant increase in plasma malondialdehyde and IL-8 in monocytes, but had no effect on total antioxidant capacity, CD11b/CD18 expression, plasma IL-8, vWF and sICAM-1. The addition of N-acetylcysteine to 50 mg of iron produced a significant (P = 0.040) decrease in malondialdehyde. CONCLUSION: Standard (100 mg) and low (50 mg) doses of iron during haemodialysis had no effects on endothelium. Iron only had minor effects on inflammation and produced an increase in oxidative stress, which was neutralized by N-acetylcysteine at low iron dose. Haemodialysis caused a significant increase in oxidative stress, inflammation and endothelial dysfunction markers.

Large Evaluation of Anti-Cardiolipin and anti-Beta2Glycoprotein I Assays: Results from the AutoimmunityWorkshop of the Spanish Society of Immunology

Despite their clinical utility and the importance that laboratory testshave in APS diagnosis, probably the most important drawback of suchtests is the elevated intra- and inter-laboratory variation. The aim of thepresent work was to assess the multilaboratory performance of aCL (..) (AU)

A pesar de la indudable utilidad clínica y de la importancia de laspruebas de laboratorio en el diagnóstico del síndrome antifosfolípido(APS), probablemente el mayor defecto de dichas pruebas es su elevadavariabilidad intra- e inter-laboratorio. El objetivo del presente trabajo fueevaluar el comportamiento de los ensayos (..) (AU)

[Neurohormones and cytokines in heart failure. Correlation with coronary flow reserve]. / Neurohormonas y citocinas en la insuficiencia cardíaca. Correlación con la reserva de flujo coronario.

INTRODUCTION AND OBJECTIVES: In heart failure, the coronary flow reserve (CFR) measured by positron-emission tomography (PET) is reduced. As neurohormone and cytokine levels are also altered in patients with the condition, our aim was to determine whether there is a correlation between CFR and neurohormone and cytokine levels. PATIENTS AND METHOD: The study included 40 patients with heart failure but without ischemic heart disease. Myocardial blood flow was measured by PET using nitrogen-13 ammonia at baseline and during ATP infusion. The CFR was calculated for each patient. In addition, levels of the following were determined: norepinephrine, endothelin-1, angiotensin-II, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), tumor necrosis factor-alpha, interleukin (IL)-1beta, soluble IL-2 receptor, and IL-6. RESULTS: All neurohormone levels were elevated above reference values. The levels of all cytokines, except IL-1beta, were also elevated. There was a significant negative correlation between CFR and the levels of several neurohormones: ANP (r=-0.476), BNP (r=-0.442), and IL-6 (r=-0.509). CONCLUSIONS: In heart failure, the decrease in CFR is correlated with increases in the levels of certain neurohormones (i.e., ANP and BNP) and cytokines (i.e., IL-6), with vasodilatory effect. These increases are probably are related to compensatory mechanisms that are unable to correct for the endothelial dysfunction present in these patients.

Neurohormonas y citocinas en la insuficiencia cardíaca. Correlación con la reserva de flujo coronario / Neurohormones and cytokines in heart failure. Correlation with coronary flow reserve

Introducción y objetivos. La reserva del flujo coronario (RFC) medida con tomografía por emisión de positrones (PET) está disminuida en la insuficiencia cardíaca. Puesto que las neurohormonas y las citocinas también presentan modificaciones en estos pacientes, pretendemos comprobar si hay correlación entre la RFC y los valores de neurohormonas y citocinas.Pacientes y método. Se estudió a 40 pacientes diagnosticados de cardiopatía no isquémica e insuficiencia cardíaca. El flujo miocárdico (FM) se midió mediante PET y N-13 amonio: en condiciones basales y durante la infusión de trifosfato de adenosina (ATP). En cada uno se calculó la RFC. En todos se determinaron la noradrenalina, la endotelina-1, angiotensina II, el péptido natriurético auricular (ANP) y cerebral (BNP), el factor de necrosis tumoral alfa, la interleucina (IL)-1β y el receptor soluble de IL-2 e IL-6.Resultados. Todas las neurohormonas medidas tuvieron valores superiores a los de referencia. Las citocinas medidas también estuvieron elevadas, excepto la IL-1β. Se encontró una correlación negativa significativa entre la RFC y los siguientes factores: ANP (r = ­-0,476), BNP (r = ­-0,442) e IL-6 (r = ­0,509).Conclusiones. En la insuficiencia cardíaca, la disminución de la RFC se correlaciona con el aumento de determinadas neurohormonas (ANP, BNP) y citocinas (IL-6), de efecto vasodilatador. Se trata, probablemente, de mecanismos de compensación insuficientes ante la disfunción endotelial que presentan estos enfermos

Introduction and objectives. In heart failure, the coronary flow reserve (CFR) measured by positron-emission tomography (PET) is reduced. As neurohormone and cytokine levels are also altered in patients with the condition, our aim was to determine whether there is a correlation between CFR and neurohormone and cytokine levels.Patients and method. The study included 40 patients with heart failure but without ischemic heart disease. Myocardial blood flow was measured by PET using nitrogen-13 ammonia at baseline and during ATP infusion. The CFR was calculated for each patient. In addition, levels of the following were determined: norepinephrine, endothelin-1, angiotensin-II, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), tumor necrosis factor-alpha, interleukin (IL)-1β, soluble IL-2 receptor, and IL-6.Results. All neurohormone levels were elevated above reference values. The levels of all cytokines, except IL-1β, were also elevated. There was a significant negative correlation between CFR and the levels of several neurohormones: ANP (r=­0.476), BNP (r=­-0.442), and IL-6 (r=-­0.509).Conclusions. In heart failure, the decrease in CFR is correlated with increases in the levels of certain neurohormones (i.e., ANP and BNP) and cytokines (i.e., IL-6), with vasodilatory effect. These increases are probably are related to compensatory mechanisms that are unable to correct for the endothelial dysfunction present in these patients

Association between peripheral IFN-gamma producing CD8+ T-cells and disability score in relapsing-remitting multiple sclerosis.

A large body of evidence supports the involvement of the immune system in the pathogenesis of multiple sclerosis (MS). Nevertheless, how the peripheral T-cells phenotypes are associated with factors such as the disability score, the effects of immunomodulatory treatments, or the activation period is poorly understood. In this study, we have centered our attention on the presence of IFN-gamma and IL-4 producing CD4+ and CD8+ T-cells in the peripheral blood of 58 relapsing-remitting MS (RRMS) patients, 48 that were stable and 10 who were in relapse period, and 30 healthy controls (HC). Our results support the existence of an independent association between the percentage of IFN-gamma producing CD8+ lymphocytes and the increased levels of disability score. Furthermore, the number of IFN-gamma producing CD8+ lymphocytes and the disability score were not correlated in patients treated with interferon-beta, evidence of its possible benefits in combating a pro-inflammatory profile. Finally, we compared the T-cell populations in RRMS patients in the stable or active period, and we found a significant decrease of IFN-gamma producing CD4+ lymphocytes in active patients. In conclusion our study supports the hypothesis that different peripheral blood T-cell phenotypes are associated with disability score or active period of the disease.

Lipopolysaccharide needs soluble CD14 to interact with TLR4 in human monocytes depleted of membrane CD14.

Toll-like receptors recognize specific patterns of microbial components and regulate the activation of both innate and adaptive immunity. TLR4 recognizes lipopolysaccharide (LPS) in monocytes/macrophages with the help of other molecules like CD14 and MD-2, which indicates that the functional LPS receptor forms a large complex. The functional relationship between the components has been the subject of debate, as have the modifications induced by the ligand in the expression of some of these components. Moreover, as for other members of this family of receptors, the possible direct interaction of receptors and their ligands is a matter of discussion. In this paper we address the question of whether the expression of some of the components influences the expression of the rest. Human monocytes in which CD14 has been downregulated through interference in the turnover of the molecule at the Golgi level, show normal membrane TLR4 expression, when compared with control cells. On the other hand, LPS alters membrane TLR4 expression by monocytes devoid of membrane CD14 only in the presence of human serum. The effect of serum is blocked by anti-CD14 monoclonal antibodies, which strongly suggests a functional role for soluble CD14/LPS complexes in the interaction with TLR4. Our data add information on the relationship between the components of the LPS receptor and the characteristics of the interaction of LPS and TLR4 in cells devoid of membrane CD14.

Secretion of cytokines, histamine and leukotrienes in chronic urticaria.

BACKGROUND: Approximately 35-40% of patients with chronic urticaria have an IgG autoantibody to the IgE receptor which can activate basophils and mast cells so that they release histamine. In this study we assessed the cytokine profile present in chronic urticaria sera, and then measured cytokine and leukotriene release from basophils and mast cells upon incubation with chronic urticaria sera. Finally we assessed cytokine expression at the single-cell level and characterized the T cell subpopulations involved in their production. We chose IL-4 as representative of Th2 lymphocytes and IFN-gamma for Th1 lymphocytes. METHODS: We analyzed IL-4, IL-5 and IFN-gamma in 60 chronic urticaria sera versus 51 controls. Sera were incubated with purified human basophils and cutaneous mast cells and the release of histamine, IL-4 and leukotrienes (C(4), D(4), E(4)) was quantitated. Immunoblotting was performed to identify IgG antibody to FcepsilonRIalpha, alpha subunit. We measured intracellular cytokine production in peripheral blood mononuclear cells of 17 chronic urticaria patients compared to 50 healthy controls. RESULTS: We found higher IL-4 levels (p = 0.028) in the sera of chronic urticaria patients (1.03 pg/ml) versus healthy donors (0.20 pg/ml) but no difference between urticaria sera and atopic control sera (0.52 pg/ml). We did not detect IFN-gamma or IL-5 in any serum. However, sera that activated basophils so that they released histamine also produced leukotriene and IL-4, and leukotriene production by cutaneous mast cells and basophils was closely correlated. However, there was no correlation between immunoblotting and the functional ability to induce either histamine or IL-4. After stimulating with PMA-ionomycin we found significant differences in CD4+ lymphocyte production of IL-4 and IFN-gamma with no differences in CD8+ lymphocyte production of either cytokine. CONCLUSION: Our data support the presence of basophil and mast cell activators in the sera of patients with chronic urticaria which can lead to the production of leukotrienes and IL-4 in addition to the histamine. IL-4 levels are similar to those seen in atopic subjects. We found that CD4+ T cells from patients with chronic urticaria are activated and tend to produce higher cytokine levels than CD4+ T cells from healthy controls. There were no differences when cytokine production by CD8+ lymphocytes was similarly assessed. These results are consistent with the histology found in biopsies of chronic urticaria lesions, where a CD4+-predominant infiltrate is found with cytokine production suggesting either a Th0 response or a mixture of Th1 and Th2 lymphocytes.