Immune development in HIV-exposed uninfected children born to HIV-infected women

ABSTRACT Immunological and clinical findings suggestive of some immune dysfunction have been reported among HIV-exposed uninfected (HEU) children and adolescents. Whether these defects are persistent or transitory is still unknown. HEU pediatric population at birth, 12 months, 6-12 years were evaluated in comparison to healthy age-matched HIV-unexposed controls. Plasma levels of LPS, sCD14, cytokines, lymphocyte immunophenotyping and T-cell receptor excision circles (TREC) were assessed. HEU and controls had similar LPS levels, which remained low from birth to 6-12 years; for plasma sCD14, IL-2, IL-6, IL-7, IL-10, IL-12p70, IL-13, IL-17, IFN-γ, TNF-α, G-CSF, GM-CSF and MCP-1, which increased from birth to 12 months and then decreased at 6-12 years; and for TREC/106 PBMC at birth in HEU and controls. By contrast, plasma MIP-1β levels were lower in HEU than in controls (p=0.009) at 12 months, and IL-4 levels were higher in HEU than controls (p=0.04) at 6-12 years. Immune activation was higher in HEU at 12 months and at 6-12 years than controls based on frequencies of CD38+HLA-DR+CD8+T cells (p=0.05) and of CD38+HLA-DR+CD4+T cells (p=0.006). Resting memory and activated mature B cells increased from birth to 6-12 years in both groups. The development of the immune system in vertically HEU individuals is comparable to the general population in most parameters, but subtle or transient differences exist. Their role in influencing clinical incidences in HEU is unknown.

Inhibition of transglutaminase 2 reduces efferocytosis in human macrophages: Role of CD14 and SR-AI receptors.

BACKGROUND AND AIMS: Transglutaminase 2 (TGM2), a member of the transglutaminase family of enzymes, is a multifunctional protein involved in numerous events spanning from cell differentiation, to signal transduction, apoptosis, and wound healing. It is expressed in a variety of cells, macrophages included. Macrophage TGM2 promotes the clearance of apoptotic cells (efferocytosis) and emerging evidence suggests that defective efferocytosis contributes to the consequences of inflammation-associated diseases, including atherosclerotic lesion progression and its sequelae. Of interest, active TGM2 identified in human atherosclerotic lesions plays critical roles in plaque stability through effects on matrix cross-linking and TGFß activity. This study explores the mechanisms by which TGM2 controls efferocytosis in human macrophages. METHODS AND RESULTS: Herein we show that TGM2 increases progressively during monocyte differentiation towards macrophages and controls their efferocytic potential as well as morphology and viability. Two experimental approaches that took advantage of the inhibition of TGM2 activity and protein silencing give proof that TGM2 reduction significantly impairs macrophage efferocytosis. Among the mechanisms involved we highlighted a role of the receptors CD14 and SR-AI whose levels were markedly reduced by TGM2 inhibition. Conversely, CD36 receptor and αvß3 integrin levels were not influenced. Of note, lipid accumulation and IL-10 secretion were reduced in macrophages displaying defective efferocytosis. CONCLUSION: Overall, our data define a crucial role of TGM2 activity during macrophage differentiation via mechanisms involving CD14 and SR-AI receptors and show that TGM2 inhibition triggers a pro-inflammatory phenotype.

Determination of reference interval for presepsin, an early marker for sepsis.

INTRODUCTION: Presepsin, the circulating soluble form of CD14 subtype (sCD14-ST) is a new emerging early marker for sepsis. Various cutoff levels of presepsin have been proposed, to discriminate between systemic bacterial and nonbacterial infectious diseases. The aim of this work was to define the reference interval for presepsin according to the CLSI C28-A3c approved guideline. MATERIALS AND METHODS: Reference individuals (N=200; 120 females) aged 18-75 years (median 39 years), free from inflammatory diseases, were selected for the study. Presepsin concentrations were measured by a commercially available chemiluminescent enzyme immunoassay (PATHFASTTM, Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany). Reference limits were calculated using the non-parametric percentile method. RESULTS: Overall, the reference limits for the presepsin were 55-184 pg/mL (90% confidence intervals, CI, were 45 to 58 and 161 to 214, respectively). There were no significant differences between males and females and the presepsin concentrations were not even particularly influenced by age. The upper reference limit for the presepsin is much lower than every cut-off limit so far proposed, both for sepsis and also for systemic inflammatory response syndrome. CONCLUSION: Specific decision levels are required to define the diagnostic and prognostic roles of presepsin in different settings of inflammatory and infectious diseases. Reference values can help to distinguish and quickly rule out healthy subjects or patients with other pathologies.

Evaluation of salivary biomarker profiles following non-surgical management of chronic periodontitis.

OBJECTIVES: Soluble toll-like receptor-2 (sTLR-2) and cytokines in saliva were assessed as clinical markers for chronic periodontitis in a longitudinal study. MATERIALS AND METHODS: Unstimulated whole saliva was collected from 20 periodontally healthy individuals and 20 patients with chronic periodontitis at diagnosis and at 1 and 6 weeks following scaling and root planing (SRP). Biomarkers including the cytokines (IL-4, IL-6, IL-10, and IL-17), sTLR-2, and sCD14 in saliva were measured by enzyme-linked immunosorbent assay. Mann-Whitney U-test and Student's t-test were used to determine the significance between healthy and chronic periodontitis groups and that between pre- and post-SRP samples, respectively. RESULTS: Salivary sTLR-2, IL-17, and IL-10 levels were significantly lower and those of sCD14, IL-6, and IL-4 were significantly higher in patients with chronic periodontitis as compared with healthy controls. Furthermore, sTLR-2 and IL-4 in saliva reached levels comparable to those of healthy individuals at 6-week re-evaluation visit, implicating a correlation of the two markers with the disease process. CONCLUSIONS: Our data suggest that salivary sTLR-2 is a potential prognostic or maintenance marker for chronic periodontitis. The observed variability of salivary cytokines is consistent with the role of these cytokines in the progression of chronic periodontitis.

Immunohistochemical Characterization of Human Synovial Bursa Cells by Light and Transmission Electron Microscopy: Where do These Cells Come From? / Caracterización Inmunohistoquímica de las Células de la Bolsa Sinovial Humana Através de Microscopías de Luz y Transmisión: ¿De dónde Provienen esas Células?

In the present study human synovial bursa specimens were examined by light and transmission electron microscopy. For light microscopical investigation the bursa tissue was stained with azan, haematoxylin-eosin and monoclonal antibodies (CD14, CD33, CD36, CD68, laminin). For electron microscopical investigation the bursa specimens were fixated with Karnovsky's solution and 1,5% osmium tetroxide (Os0(4)) in water distilled and contrasted with 5% uranylacetate and embedded in Epon®. For the first time the antigenic phenotype was characterized and conclusions were drawn about the origin of the synovial bursa cells. Histologically the bursa was divided in two distinct layers; the intima, which is formed by a lining layer and a lamina propria, and a subintimal layer. The intima consisted of macrophage like (type I) and fibroblast like cells (type II). According to the immunohistochemical staining and the electron microscopy the type I cell seemed to be a bone marrow derived monocyte and the more frequently seen type II cell was derived from subintimal fibroblasts. The intimal bursa cell frequently interdigitated and usually communicated by their filopodia (indirect cell-cell-communication). Neither tight or gap junctions nor desmosomes could be documented. Although there was no evidence for the existence of a basal lamina, a concentration of extracellular matrix components beyond the bursa cells was observed. In our study there was no accumulation of laminin around the bursal cells, but striking was a vascular bundle of the intima subintima border zone, which was positive for laminin and CD68 and separated the intima from the subintima. In our opinion this histological structure plays an important role in the regeneration of the lining cells and acts like a barrier between bursa and blood.

En el presente estudio se examinaron bolsas sinoviales humanas a través de microscopía de luz y electrónica de transmisión. Para la microscopía de luz, el tejido de las bolsas se tiñó con Azan, H-E y anticuerpos monoclonales (CD14, CD33, CD36, CD68, laminina). Para la microscopía electrónica las bolsas fueron fijadas con solución de Karnovsky y tetróxido de osmio al 1,5% (Os04) en agua destilada y contrastada con acetato de uranilo al 5% y embebido en Epon®. En primera instada, el fenotipo antigénico fue caracterizado, concluyéndose acerca del origen de las células que componen la bolsa sinovial. Histológicamente la bolsa fue dividida en dos capas distintas - la íntima - la cual es formada por una capa lineal y una lámina propia, y, una subintima. La íntima consistió en células parecidas a macrófagos (Tipo I) y células semejantes a fibroblastos (Tipo II). De acuerdo a la tinción inmunohistoquímica y a la microscopía electrónica, las células tipo I parecen provenir de la médula ósea derivada de monocitos y el más frecuente tipo celular II fue derivadado de los fibroblastos de la subintima. Frecuentemente las células de la íntima de la bolsa se interdigitaban y usualmente se comunicaban a través de sus prolongaciones (comunicación célula indirecta-célula). No se observaron ni uniones abiertas, ni cerradas, ni desmosomas. Aunque no hubo evidencia de la existencia de una lámina basal, se observó una concentración de componentes de matriz extracelular más allá de las células de la bolsa. No hubo acumulación de laminina alrededor de estas células, pero destacada era una banda vascular de la zona límite entre íntima y subintima, la cual fue positiva para laminina y CD68 la cual separaba la íntima de la subintima. En nuestra opinión esta estructura histológica juega un importante rol en la regeneración de las células lineales y actúa como una barrera entre la bolsa y la sangre.