Increased number of non-invariant NKT cells and low number of circulating CD1-expressing leukocytes in patients infected with hepatitis C virus.

Natural killer T (NKT) cells represent an heterogeneous T cell population involved in host immunity against several microorganisms. They also have important immunoregulatory functions. Studies on circulating levels of NKT cells during HCV infection have been focused on the invariant NKT (iNKT) subset which recognizes the non-classical Ag-presenting molecule CD1d, with little information about the non-invariant NKT (non-iNKT) cell subset. In the present study, we assessed the number of both NKT cells subsets and the surface expression of CD1a, b, c and d isoforms in peripheral blood of 31 HCV-infected patients and 31 ages matched healthy individuals. A significant increase of circulating non-iNKT cells was observed in HCV-infected patients as compared to controls (74 ± 57 cells/µL vs 42 ± 16 cells/µL respectively, p<0.0042) with no differences in the iNKT subset. In addition, the percentage of CD1a, CD1c and CD1d-expressing leukocytes was significantly low in patients as compared to controls. These findings suggest that both components, non-iNKT cells and CD1 molecules expression are involved in the control of natural immunity against HCV.

CD16 cross-linking induces increased expression of CD56 and production of IL-12 in peripheral NK cells.

Human NK cells are classified into two populations according to the intensity of CD56 surface expression, as well as possession of CD16, FcRIII. CD56(dim)CD16(bright) make up 90% circulating NK cells, whereas CD56(bright)CD16(-/dim) comprises the remaining 10%. Here we report that peripheral NK cells upon CD16 cross-linking up-regulates the expression of activating markers and receptors such as CD25, CD69, NKp44, NKp30, CD40L and the intensity of CD56 expression. Additionally, co-culturing immature DCs with CD16 activated NK cells was found to significantly increase the expression of maturation markers on DCs. These results suggest that CD16 cross-linking on resting peripheral blood NK cells triggers the activation of these cells and induces the appearance of CD56(bright) NK cells. The latter were found capable of producing pro-inflammatory cytokines, IFN-gamma and TNF-alpha and notably IL-12.

[Expression of Fc receptors for IgG in peripheral blood leucocytes from hepatitis C virus infected individuals]. / Expresión de los receptores para el Fc de la IgG en leucocitos de sangre periférica de pacientes con hepatitis C crónica.

The immune response represents a fundamental element in the control of Hepatitis C virus (HCV) infection. Viral and cellular host factors may modulate this response. In the present study, we characterized immune complexes (cryoprecipitates) isolated form HCV-infected patients and evaluated the expression of Fc receptors for IgG (FcgammaR) in peripheral blood leucocytes of these patients. Twelve HCV (+) patients and 12 healthy control individuals were selected for this study. For each group, sera samples were collected for cryoglobulins isolation and characterization and EDTA-anticoagulated venous blood samples were collected for flow cytometry analysis of FcgammaR, CD64 (FcgammaRI), CD32 (FcgammaRII) and CD16 (FcgammaRIII) expression. Presence of HCV RNA in serum and cryoprecipitates was analysed by RT-PCR. Results show that 50% of HCV-infected patients present high levels of cryoglobulins mainly constituted by IgG. Three out of 5 cryoglobulins analyzed by RT-PCR were positive for HCV-RNA. Expression of CD64 was observed mainly in monocytes (80%), CD32 in monocytes, B lymphocytes and neutrophils (> 90%) and CD16 in NK cells and neutrophils (85% and 95% respectively). No differences were observed in the percentage of FcgammaR expression when comparing HCV-infected patients with healthy controls. On the contrary, density of expression of CD32 in monocytes and neutrophils cell populations of HCV patients was significantly lower than that observed in healthy controls (p < 0.05). We concluded that low density expression of FcgammaRII in HCV-infected patients may have implications in the physiopatholgy of HCV infection.

Expresión de los receptores para el Fc de la IgG en leucocitos de sangre periférica de pacientes con hepatitis C crónica / Expression of Fc receptors for IgG in peripheral blood leucocytes from hepatitis C virus infected individuals

La respuesta inmunitaria representa un elemento fundamental en el control de la infección por el Virus del Hepatitis C (VHC). Factores de origen viral y del hospedero modulan dicha respuesta. El presente trabajo tuvo como objetivo caracterizar complejos inmunitarios, bajo la forma de crioglobulinas, de pacientes infectados con el VHC y evaluar la expresión de superficie de los receptores para el Fc de la IgG (FcyR)COLOCARSIGNO en subpoblaciones leucocitarias de sangre periférica de estos pacientes. Se seleccionaron 12 individuos VHC (+) y 12 sujetos sanos. De ambos grupos se tomaron muestras de suero para aislar crioglobulinas y sangre venosa con EDTA para evaluar la expresión e los FcyR CD64 (FcyRI), CD32 (FcyRII) y CD16 (FcyRIII) mediante citometr¡a de flujo. La presencia de ARN del VHC en suero y crioglobulinas fue analizada mediante RT-PCR. Los resultados muestran que el 50 por ciento de los pacientes VHC (+) presentaron niveles elevados de crioglobulinas constituidas fundamentalmente por IgG. En 3 de 5 pacientes con crioglobulinas elevadas se identificó ARN del VHC. La expresión de CD64 se observó principalmente en monocitos (80 por ciento), CD32 en monocitos, linfocitos B y neutrófilos (>90 por ciento) y CD16 en células NK y neutrófilos (85 por ciento y 95 por ciento respectivamente) no encontrándose diferencias significativas entre pacientes y controles. La densidad de expresión de CD32 resultó significativamente menor en poblaciones de monocitos y neutrófilos de pacientes en comparación con controles (p<0,05). Se concluye que esta disminución en la densidad del receptor FcyRII podría tener implicaciones en la fisiopatología de la infección por el VHC.

Respiratory allergies in Venezuela: are fungi responsible?

Exposure to fungi in the indoor environment may trigger hypersensitivity to a variety of fungi and is known to be an influencing factor in allergic rhinitis and asthma. A wide list of airborne fungal spores and dust containing fungi have been described for different environments; however, their clinical relevance is seldom clear. In this survey we measure levels of fungi indoor and outdoor of domestic dwellings of 10 patients with known chronic allergic respiratory disease to fungi. To measure hypersensitivity to fungi, Prick (sensitivity to fungi), RAST (specific serum IgE levels) and PAR (persistent allergic rhinitis) severity are assessed in relation to fungal load in the environment. Only association of PAR and indoor fungal load were found to be significant (P = 0.1648). No direct causality with sensitivity to the amount of exposure, or a hypersensitivity to a specific fungal genus could be established. There is still no consensus on the most relevant methods for measuring personal exposure and 'no safe levels' have been established yet.

Expresión de receptores leucocitarios similares a las inmunoglobulinas (lirs) en eosinofilos humanos / Expresion leukocyte receptors similar the ammunoglobulins (lirs) in eosinophils human

Los eosinófilos son células efectoras de la respuesta inmune, implicadas principalmente en las enfermedades alérgicas y en las infecciones parasitarias. Los eosinófilos pueden ser activados in vitro por diversas clases de agonistas, como las inmunoglobulinas, los mediadores lipídicos y las citocinas. Los receptores leucocitarios tipo Ig (leukocyte Ig-like receptors, LIRs) constituyen una familia de receptores de superficie celular con funciones activadoras e inhibitorias. Los LIRs inhibitors regulan en forma negativa las respuestas celulares a través de secuencias de tirosina inmunoreguladoras de inhibición (ITIM) citoplasmáticas. Hay muy poca data sobre el mecanismo de acción de los LIRs, aunque se piensa que actúan a través de la cadena de receptor Fc, que contiene una secuencia de tirosina inmunoreguladora de activación. En este trabajo demostramos la espresión de los LIRs en eosinófilos hipo y normodensos de donantes sanos y pacientes con enfermedades alérgicas

Interleukin-2 induces peroxide production by primed normodense eosinophils of patients with asthma.

In this study we assessed, by flow cytometry, the effect of interleukin 2 (IL-2) on the oxidative burst of normodense eosinophils (Eos's) isolated from 15 patients with moderately severe extrinsic asthma and 17 controls. We found that IL-2 significantly induced peroxide (H2O2) production in normodense Eos's from patients with asthma on a time kinetics study. This rise was higher in patients with immunoglobulin E levels > 180 IU/mL versus normal immunoglobulin E values. The effect of IL-2 was partially blocked by using anti-Tac antibody. In contrast, IL-2 decreased H2O2 production in normodense Eos's from controls. Cell surface expression of CD25, CD122, CD132, and CD69 were also determined and no statistical differences were found between both groups. In conclusion, IL-2 is able to increase H2O2 production by normodense Eos's isolated from patients with asthma and it may contribute to bronchial epithelium damage and chronic inflammation.

Niveles séricos de proteína cationica del eosinofilo en pacientes con asma bronquial y rinitis alérgica perenne: relación con el número absoluto de eosinofilos en sangre periférica e IGE sérica total / Level seric protein cationic of the eosinofile in patients with bronchial asthma and allergy rhinitis: relations with the absolute number of eosinofiles in periphenal blood and IGE total serum

La proteína cationica del eosinófilo (ECP)es considerada un reflejo del grado de activación del pool de eosinófilos. Nosotros analizamos la importancia de la determinación de ECP en pacientes con diagnóstico de asma bronquial (AB) y rinitis alérgica perenne (RAP). Los resultados muestran una tendencia a niveles elevados de ECP en los pacientes, con diferencias estadísticamente significativas (P=0,027) en los pacientes con RAP. Encontramos una correlación significativa en ECP con el número absoluto de eosinófilos y los niveles de IgE total (r=0,6765; P=0,0079 y r=0,6273; P=0,009 respectivamente). Podemos concluir que la determinación de los niveles séricos de ECP constituye un marcador útil de la inflamación alérgica

Hypodense eosinophils: characterization of surface molecule expression.

Distinct eosinophil populations have been characterized on the basis of discontinuous Percoll density gradients. In peripheral blood, normal individuals show a low number of normodense and hypodense eosinophils, contrasting with the high amount of hypodense cells in patients who have allergies. To characterize these two eosinophil populations, we analyzed membrane expression of several antigens and cytokine receptors in normodense and hypodense eosinophils from patients who have allergies and controls. Hypodense eosinophils expressed higher levels of CD122, CD69, and CD4 in both patients with allergies and control individuals when compared to normodense eosinophils. The expression of CD125, CD124, CD25, CD132, and CD23 were similar in both cell types.

Expresión diferencial de moleculas de superficie en eosinofilos normodensos e hipodensos de pacientes alérgicos / The diferencial expression of surface molecules in normodense eosinophils and hypodense of allergic patients

Se han descrito poblaciones heterógeneas de eosinófilos, basado en gradientes de densidad. En sangre periférica de sujetos sanos se observan principalmente eosinófilos normodensos (fenotipo de reposo) mientras que un número aumentado de eosinófilos hipodensos (fenotipo activado) está presente en pacientes alérgicos. En el presente trabajo analizamos, por citometría de flujo, la expresión de moléculas de superficie en eosinófilos normodensos e hipodensos de sujetos sanos y pacientes alérgicos. Nuestros resultados mostraron que los eosinófilos hipodensos expresan altos niveles de CD122, CD69 y CD4 en ambos grupos de estudio respecto de los eosinófilos normodensos, mientras que la expresión de CD125, CD124, CD25, CD132 y CD23 fueron similares en ambos tipos celulares