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Biomedical subjects

R Giacomelli

Publications and source records attributed to R Giacomelli.

At least 19 recordsLinked to original sources
PubMed2005

Raloxifene reduces urokinase-type plasminogen activator-dependent proliferation of synoviocytes from patients with rheumatoid arthritis.

Extracellular fibrinolysis, controlled by the membrane-bound fibrinolytic system, is involved in cartilage damage and rheumatoid arthritis (RA) synovitis. Estrogen status and metabolism seem to be impaired in RA, and synoviocytes show receptors for estrogens. Our aims in this study were to evaluate in healthy and RA synoviocytes the effects of Raloxifene (RAL), a selective estrogen receptor modulator (SERM), on: proliferation; the components of the fibrinolytic system; and chemoinvasion. The effects of RAL were studied in vitro on synoviocytes from four RA patients and four controls. Proliferation was evaluated as cell number increase, and synoviocytes were treated with 0.5 microM and 1 microM RAL with and without urokinase-plasminogen activator (u-PA) and anti-u-PA/anti-u-PA receptor (u-PAR) antibodies. Fibrinolytic system components (u-PA, u-PAR and plasminogen activator inhibitor (PAI)-1) were assayed by ELISA with cells treated with 0.5 microM and 1 microM RAL for 48 h. u-PA activity was evaluated by zymography and a direct fibrinolytic assay. U-PAR/cell and its saturation were studied by radioiodination of u-PA and a u-PA binding assay. Chemoinvasion was measured using the Boyden chamber invasion assay. u-PA induced proliferation of RA synoviocytes was blocked by RAL (p < 0.05) and antagonized by antibodies alone. The inhibitory effect of RAL was not additive with u-PA/u-PAR antagonism. RA synoviocytes treated with RAL showed, compared to basal, higher levels of PAI-1 (10.75 +/- 0.26 versus 5.5 +/- 0.1 microg/10(6) cells, respectively; p < 0.01), lower levels of u-PA (1.04 +/- 0.05 versus 3.1 +/- 0.4 ng/10(6) cells, respectively; p < 0.001), and lower levels of u-PAR (11.28 +/- 0.22 versus 23.6 +/- 0.1 ng/10(6) cells, respectively; p < 0.001). RAL also significantly inhibited u-PA-induced migration. Similar effects were also shown, at least partially, in controls. RAL exerts anti-proliferative and anti-invasive effects on synoviocytes, mainly modulating u-PAR and, to a lesser extent, u-PA and PAI-1 levels, and inhibiting cell migration and proliferation.

Arthritis, Rheumatoid↗
PubMed2005

Deflazacort modulates the fibrinolytic pattern and reduces uPA-dependent chemioinvasion and proliferation in rheumatoid arthritis synoviocytes.

OBJECTIVE: Extracellular fibrinolysis, controlled by the cell-associated fibrinolytic system (urokinase plasminogen activator, uPA; uPA receptor, uPAR; plasminogen activator inhibitor type-1, PAI-1), is involved in cartilage damage generation and in rheumatoid arthritis (RA) synovitis. Since steroids reduce the rate of radiological progression of RA, we planned to evaluate in healthy and RA synoviocytes the effects of the steroid deflazacort on uPA, uPAR and PAI-1 expression, and subsequent phenotypic modifications in terms of uPA/uPAR-dependent invasion and proliferation. METHODS: uPA, uPAR and PAI-1 levels were studied by ELISA, RT-PCR (uPAR) and zymography (uPA) in synoviocytes from four RA patients and four healthy controls. Chemoinvasion was assessed by the Boyden chamber invasion assay, using Matrigel as the invasion substrate. Proliferation was evaluated by cell counting. Both invasion and proliferation were measured upon treatment with deflazacort 5 muM with or without parallel stimulation with uPA 500 ng/ml or in the presence of monoclonal anti-uPA and anti-uPAR antibodies. RESULTS: Invasion and proliferation of RA synoviocytes require a proper functional balance of the fibrinolytic system. Both deflazacort and monoclonal antibodies against uPA and uPAR reduced expression and activity of the system, thus inhibiting invasion and proliferation. In RA synoviocytes, deflazacort induced higher PAI-1 and lower uPA and uPAR levels, as well as a decrease in uPA enzymatic activity. The levels of uPAR mRNA were concomitantly reduced, as was uPA-induced chemoinvasion. All these effects were also shown in controls, though to a lesser extent. CONCLUSIONS: Deflazacort might control RA synovial proliferation and invasion by differential modulation of single members of the fibrinolytic system.

Adult↗
PubMed2005

Damage of cutaneous peripheral nervous system evolves differently according to the disease phase and subset of systemic sclerosis.

OBJECTIVE: Evidence shows that peripheral nervous system (PNS) is involved in systemic sclerosis (SSc), but few morphological studies have assessed the ultrastructural pathological modifications. The aim was to study ultrastructural modifications of skin PNS fibres in SSc according to subsets [limited SSc (lSSc) and diffuse SSc (dSSc)] and phases (early and advanced) of the disease. METHODS: Skin biopsies were taken from the forearms of 23 SSc patients (11 lSSc and 12 dSSc) and 10 controls. Each biopsy was processed for transmission electron microscopy (TEM). RESULTS: At TEM, observation in skin from early lSSc, signs of inflammation were evident, while PNS fibres were not damaged. The microvascular wall showed hypertrophic endothelial cells bulging into the lumen. In advanced lSSc, fibrosis prevailed on inflammation and slight ultrastructural alterations of PNS fibres were evident in the papillary derma. In early dSSc, ultrastructural alterations of PNS fibres, similar to those observed in the advanced phase of lSSc, were found together with signs of inflammation and fibrosis. In advanced dSSc, in the papillary and reticular dermis PNS fibres were reduced and showed relevant ultrastructural alterations. CONCLUSIONS: In SSc, PNS ultrastructure damage is linked to the progression and severity of skin involvement. The alterations evolve from the early to the advanced phase mainly in the diffuse subset. In particular, the severe PNS lesions found in advanced lSSc are already present and widely diffuse in early dSSc and the microvascular involvement in early lSSc seems to precede the modification of the PNS in the skin. Thus, an early therapeutic approach can be useful to reduce the progression of PNS and skin damage in SSc patients.

Adult↗
PubMed2005

Differential expression of tissue kallikrein in the skin of systemic sclerosis.

Systemic sclerosis (SSc) is characterised by ischemic damage, impaired angiogenesis and skin fibrosis. Tissue kallikrein (t-kallikrein) is involved through kinins in inflammation, vasorelaxation and angiogenesis. T-kallikrein is synthetised by endothelial, smooth muscle, and inflammatory cells and, in skin, also by dark cells of the sweat glands, where it is involved in sweat formation. Our aim was to analyse, by immunohistochemistry and RT-PCR, the expression of t-kallikrein in the skin of patients with different SSc subsets, limited (lSSc) and diffuse (dSSc), and phases, early and advanced. Skin biopsies were taken from 18 SSc patients and 10 controls. Immunohistochemistry was performed on paraffin sections with an antibody against human urinary t-kallikrein. For RT-PCR, cDNA from skin biopsies was amplified using primers specific for human t-kallikrein. In the control skin, dark cells of the secretory units of sweat glands showed immunopositivity for t-kallikrein as well as blood vessels. In the lSSc skin, immunoreactivity was observed only in some glands, with weak staining in the advanced phase. In early lSSc skin, immunoreactivity was observed in microvessel walls and in the inflammatory infiltrate. In dSSc skin, dark cells of the glandular fundus units, and the few remaining vessels showed scarcity (early phase) or lack (advanced phase) of immunoreactivity for t-kallikrein. RT-PCR confirmed a decrease of t-kallikrein mRNA levels from early to advanced phase in SSc subsets, reaching its lowest level in advanced dSSc. In conclusion, immunohistochemical and biomolecular results indicate that t-kallikrein is decreased in the skin of SSc patients and decreases progressively from the early to advanced phase of lSSc and dSSc. The decreased expression of t-kallikrein may be involved in the impairment of the sweating process, vessel functionality and angiogenesis.

Adult↗
PubMed2004

Infliximab in spondyloarthropathy associated with Crohn's disease: an open study on the efficacy of inducing and maintaining remission of musculoskeletal and gut manifestations.

OBJECTIVE: To evaluate the efficacy and tolerability of anti-tumour necrosis factor alpha (TNFalpha) monoclonal antibody (infliximab) in the treatment of spondyloarthropathy (SpA) associated with active and inactive Crohn's disease (CD). METHODS: Twenty four patients with SpA associated with active or inactive CD (16 active, 8 quiescent) were treated with anti-TNFalpha monoclonal antibody (infliximab) with repeated infusions for a period of 12-18 months. The treatment aimed at ameliorating the general musculoskeletal and spinal pain, controlling peripheral arthritis and enthesitis, decreasing the BASDAI score, modifying acute phase reactants, and reducing CD activity. RESULTS: Infliximab improved both gastrointestinal (p<0.01) and overall articular symptoms (BASDAI, p<0.01; general musculoskeletal and spinal pain, p<0.01; peripheral arthritis, p<0.01) in patients with active CD. Additionally, infliximab effectively controlled not only axial involvement and peripheral arthritis but also enthesitis (p<0.01) and prevented inflammatory bowel disease reactivation in patients with inactive CD and low inflammatory markers. Amelioration of gut and musculoskeletal involvement persisted for up to 12 months. CONCLUSION: Infliximab may act on the inflammation of entheses and of periarticular structures, which usually does not cause a change in the haematological markers that are the main indicators of pain and joint ankylosis in SpA. Infliximab induces and maintains remission of CD while at the same time treating active and severe SpA, suggesting that it should be the preferred drug for the treatment of active and severe SpA associated with active or quiescent CD.

Adult↗
PubMed2003

Familial autoimmunity as a risk factor for systemic lupus erythematosus and vice versa: a case-control study.

The objective of this multicentric case-control study was to investigate if a history of autoimmune disease (AD) in first-degree relatives (FDR) is a risk factor for systemic lupus erythematosus (SLE) and to evaluate the risk of AD among FDR of SLE patients. Cases were Italian SLE patients consecutively enrolled. Controls were orthopaedic inpatients without any autoimmune diseases. The strength of the association between family history of AD and SLE was measured as an odds ratio (OR) calculated from the coefficient of an unconditional regression model. To calculate the risk of AD among FDR of SLE patients, the extended generalized estimating equation technique was used. In total, 154 SLE cases and 140 controls were enrolled. A family history of AD was reported by 22.7% of SLE patients and by 5.7% of the controls. The risk of SLE increased with the number of FDR with AD (one FDR affected, OR = 4.1; two or more, OR = 11.3). The probability of having AD was higher among FDR of SLE cases in comparison to FDR of controls (RR = 4.6; 95%CI 1.9-11.1). A female SLE patient conferred an increased risk of AD to her FDR; this risk is doubled in females (OR 10.3; 95% CI 3.1-34.4).

Adult↗
PubMed2003

Non organ based laboratory markers in systemic sclerosis.

Candidate markers for endothelial cell, lymphocyte and fibroblast function in systemic sclerosis have been reviewed. Autoantibody measurement and general inflammatory markers were considered the minimum requirements, with other markers needing further evaluation.

Autoantibodies↗
PubMed2001

Circulating gamma/delta T lymphocytes from systemic sclerosis (SSc) patients display a T helper (Th) 1 polarization.

Systemic sclerosis (SSc) is a connective tissue disease in which immune system activation is evidenced by high levels of different cytokines in the sera and/or in the supernatants of cultured peripheral blood mononuclear cells (PBMC) and by the presence of specific autoantibodies. gamma/delta T cells accumulate in the lung and the skin of SSc patients suggesting their potential role in the development and maintenance of the disease. The aim of this study was to assess cytokine production and cytotoxic activity of circulating gamma/delta T lymphocytes obtained from SSc patients and to evaluate their potential role during this disorder. Our results showed that both the proportion and the absolute number of IFN-gamma gamma/delta-producing cells (i.e. displaying a Th1 polarization) in SSc was significantly higher than either the proportion and the absolute number of IL-4 gamma/delta-producing cells in SSc or the proportion and the absolute number of IFN-gamma gamma/delta-producing cells in healthy controls (P < 0.05 for both groups). Furthermore, the cytotoxic activity of enriched gamma/delta T cells was significantly increased in SSc patients compared with controls. The results concerning the Vdelta1+ T cell subset paralleled those of total gamma/delta T lymphocytes. In contrast, alpha/beta T cells from SSc and control subjects displayed Th2 cytokine production. All these findings were independent of both disease subset and clinical status. Our data demonstrate that, although SSc is generally considered a Th2 autoimmune disease, Th1 polarization of gamma/delta T cells and an increase in their cytotoxic activity is observed in SSc, suggesting that gamma/delta T cells could have a relatively autonomous role in the pathogenesis in this disease.

Adult↗
PubMed2001

Nerve growth factor and neuropeptides circulating levels in systemic sclerosis (scleroderma).

OBJECTIVE: To determine the circulating levels of nerve growth factor (NGF), neuropeptide Y (NPY), and vasoactive intestinal peptide (VIP) in systemic sclerosis (SSc), and to correlate these levels with clinical and laboratory features. METHODS: Forty four patients with SSc were evaluated for circulating NGF (immunoenzymatic assay), NPY and VIP (radioimmunoassay), anticentromere and antitopoisomerase I autoantibodies, lung disease (pulmonary function tests with carbon monoxide transfer factor (TLCO), ventilation scintiscan with 99mTc DTPA radioaerosol, high resolution computed tomography (HRCT), pulmonary pressure (echo colour Doppler)), heart disease (standard and 24 ECG, echocardiography), cutaneous involvement (skin score), joint involvement (evidence of tender or swollen joints, or both), peripheral nervous system (PNS) involvement (electromyography), rheumatoid factor, angiotensin converting enzyme (fluorimetric method), von Willebrand factor (ELISA), and erythrocyte sedimentation rate (ESR) (Westergren). RESULTS: Circulating NGF levels in SSc were significantly increased compared with controls (p<0.00001) and significantly higher in the diffuse than in the limited subset of patients (p<0.01). Patients with articular disease had significantly higher levels of NGF. A significant indirect correlation between NGF levels and TLCO was detected (p<0.01), but no correlation was found between NGF and HRCT, DTPA, skin score, PNS involvement and angiotensin converting enzyme and von Willebrand factor levels, antitopoisomerase or anticentromere antibodies, and ESR. NGF levels increased progressively as the disease worsened. Similarly, VIP circulating levels were significantly increased in patients with SSc (p<0.001), whereas the increase of NPY levels did not reach statistical significance. However, both neuropeptides, following the same trend as NGF, increased as the disease worsened (skin score and lung disease). CONCLUSIONS: The increase of NGF and VIP in patients with SSc, the former in the diffuse subset of the disease, and in patients with prominent articular disease, may suggest a link between neurotransmitters and the disease pathogenesis. Neuropeptide circulating levels seem to increase only in patients with the most severe disease.

Biomarkers↗
PubMed2001

European multicentre study to define disease activity criteria for systemic sclerosis. I. Clinical and epidemiological features of 290 patients from 19 centres.

OBJECTIVE: To investigate the existence of differences among European referral centres for systemic sclerosis (SSc) in the pattern of attendance and referral and in the clinical and therapeutical approaches. METHODS: In 1995 the European Scleroderma Study Group initiated a multicentre prospective one year study whose aim was to define the disease activity criteria in SSc. During the study period each participating European centre was asked to enroll consecutive patients satisfying American College of Rheumatology criteria for SSc and to fill out for each of them a standardised clinical chart. Patients from various centres were compared and differences in epidemiological, clinical, and therapeutical aspects were analysed. RESULTS: Nineteen different medical research centres consecutively recruited 290 patients. The patients could be divided into two subgroups: 173 with the limited (lSSc) and 117 with the diffuse (dSSc) form of the disease. The clinical and serological findings for the series of 290 patients seemed to be similar to data previously reported. However, when the data were analysed to elicit any differences between the participating centres, a high degree of variability emerged, in both epidemiological and clinical features and in the diagnostic and therapeutic approaches to the disease. CONCLUSIONS: The clinical approach to SSc, not only in different countries but also in different centres within the same country, is not yet standardised. To overcome this problem, it will be necessary for the scientific community to draw up a standardised procedure for the management of patients with SSc. This would provide a common research tool for different centres engaged in research on this complex disease.

Adolescent↗
PubMed2001

European multicentre study to define disease activity criteria for systemic sclerosis. II. Identification of disease activity variables and development of preliminary activity indexes.

OBJECTIVE: To develop criteria for disease activity in systemic sclerosis (SSc) that are valid, reliable, and easy to use. METHODS: Investigators from 19 European centres completed a standardised clinical chart for a consecutive number of patients with SSc. Three protocol management members blindly evaluated each chart and assigned a disease activity score on a semiquantitative scale of 0-10. Two of them, in addition, gave a blinded, qualitative evaluation of disease activity ("inactive to moderately active" or "active to very active" disease). Both these evaluations were found to be reliable. A final disease activity score and qualitative evaluation of disease activity were arrived at by consensus for each patient; the former represented the gold standard for subsequent analyses. The correlations between individual items in the chart and this gold standard were then analysed. RESULTS: A total of 290 patients with SSc (117 with diffuse SSc (dSSc) and 173 with limited SSc (lSSc)) were enrolled in the study. The items (including Delta-factors-that is, worsening according to the patient report) that were found to correlate with the gold standard on multiple regression were used to construct three separate 10-point indices of disease activity: (a) Delta-cardiopulmonary (4.0), Delta-skin (3.0), Delta-vascular (2.0), and Delta-articular/muscular (1.0) for patients with dSSc; (b) Delta-skin (2.5), erythrocyte sedimentation rate (ESR) >30 mm/1st h (2.5), Delta-cardiopulmonary (1.5), Delta-vascular (1.0), arthritis (1.0), hypocomplementaemia (1.0), and scleredema (0.5) for lSSc; (c) Delta-cardiopulmonary (2.0), Delta-skin (2.0), ESR >30 mm/1st h (1.5), total skin score >20 (1.0), hypocomplementaemia (1.0), scleredema (0.5), digital necrosis (0.5), Delta-vascular (0.5), arthritis (0.5), TLCO <80% (0.5) for all patients with SSc. The three indexes were validated by the jackknife technique. Finally, receiver operating characteristic curves were constructed in order to define the value of the index with the best discriminant capacity for "active to very active" patients. CONCLUSIONS: Three feasible, reliable, and valid preliminary indices to define disease activity in SSc were constructed.

Adolescent↗
PubMed2001

Intravenous N-acetylcysteine for treatment of Raynaud's phenomenon secondary to systemic sclerosis: a pilot study.

OBJECTIVE: To assess the efficacy and tolerability of N-acetylcysteine (NAC) in patients with Raynaud's phenomenon (RP) secondary to systemic sclerosis (scleroderma; SSc). METHODS: Twenty-two patients with RP secondary to SSc were enrolled in a multicenter, open clinical trial lasting 11 weeks and conducted in winter. Primary outcome measures were frequency and severity of RP attacks, and number of digital ulcers. Secondary outcome measure was improvement in digital cold challenge test assessed by photoelectric plethysmography. Patients received a continuous 5 day intravenous infusion of NAC starting with a 2 h loading dose of 150 mg/kg subsequently adjusted to 15 mg/kg/h. RESULTS: All 22 patients completed the 5 day infusion and 20 of them the posttreatment followup. Both frequency and severity of RP attacks decreased significantly compared to pretreatment values. Active ulcers were significantly less numerous at all followup visits (25.18% of baseline count on Day 33 from the beginning of infusion). In the cold challenge test mean recovery time fell by 69.56%, 67.70%, 71.42%, and 71.05% on Days 12, 19. 33, and 61 from the beginning of treatment. Side effects were minor, easily controlled, and reversible. CONCLUSION: N-acetylcysteine appears to be safe for the treatment of RP secondary to SSc. These preliminary data warrant further controlled studies.

Acetylcysteine↗
PubMed2000

Impaired human ovarian follicular fluid complement function in hereditary angioedema.

We sought and detected functionally active complement in human ovarian follicular fluid obtained during the peri-ovulatory period. All the functional complement activities tested, including total haemolytic complement, classical pathway activity, alternative pathway activity and C1 inhibitor function were present with values within the normal serum range. Active complement in follicular fluid is relevant for the function of the enzymatic multifactorial mechanism of ovulation. The presence in hereditary angioedema patients of both complement (C1 inhibitor deficiency and chronically consumed complement) and ovarian abnormalities (cystic ovaries), led us to study complement function in the follicular fluid of women of reproductive age affected with hereditary angioedema. In contrast to healthy women, hereditary angioedema patients showed dramatically reduced classical pathway activity and undetectable functional and antigenic C1 inhibitor. C4 was very low, while C3 and B were slightly reduced or within the normal serum range. This complement profile was also detected in patients' sera. Since hereditary angioedema patients often show cystic ovaries (polycystic or multifollicular), the presence of multifollicular ovaries in the two patients studied, along with complement dysfunction, may be relevant. These findings, as well as the normalisation of the ovaries found by us in hereditary angioedema patients and in the patients reported here who were undergoing danazol treatment, and the increase in C1 inhibitor and the improvement of clinical symptoms, suggest a further link between complement and ovarian function.

Adult↗
PubMed2000

Use of scanning electron microscopy to investigate the prophylactic efficacy of rifampin-impregnated CSF shunt catheters.

Infection continues to be one of the major complications of cerebrospinal fluid (CSF) shunting procedures, and is caused mainly by skin-derived bacteria. Production of an extracellular biofilm plays an important role in the pathogenesis of shunt-associated infections by protecting bacteria from immune mechanisms and antibiotics. So far, removal of the original shunt and implantation of a new shunting device has been the only successful treatment for most patients. As an alternative strategy to prevent CSF infections, a rifampin-impregnated silicone catheter was designed to provide high initial and long-lasting (>60 days) release of bactericidal drug. To investigate the pathophysiological mechanism of its function, this new device was investigated both in vitro and in a rodent model of CSF infection by scanning electron microscopy (SEM) and bacterial culture. Staphylococcus epidermidis (10(8) cfu/ml) and S. aureus (10(4) cfu/ml) served as test strains. SEM demonstrated that, in contrast to the unloaded catheters, initial bacterial adherence on the catheter surface could be reduced to a few single cells, which did not show visible signs of proliferation. Bacterial cultures obtained simultaneously were all sterile, showing that adherent bacteria were killed immediately by the rifampin released from the catheter. Although rifampin incorporation into silicone polymers was not able to prevent initial bacterial adhesion completely, subsequent colonisation could be prevented.

Animals↗
PubMed2000

Mucosal 5-aminosalicylic acid concentration inversely correlates with severity of colonic inflammation in patients with ulcerative colitis.

BACKGROUND AND AIM: The treatment of ulcerative colitis (UC) with 5-aminosalicylic acid (5-ASA) does not have the same therapeutic effect in all patients. We tested the hypothesis that the effectiveness of the drug is related to its mucosal concentration. PATIENTS: Twenty one UC patients receiving oral 5-ASA (2.4-3.2 g/day) were enrolled in the study. Four were also receiving topical treatment (2 g/day). METHODS: Six endoscopic biopsies were taken from the rectum for measurement of 5-ASA concentrations (ng/mg) by HPLC; soluble interleukin 2 receptor (sIL-2R) concentrations (U/ml) were measured by ELISA and histology. Endoscopic and histological appearance was graded on a four point scale (0-3). The Wilcoxon's rank test and Pearson's correlation coefficient were used for statistical analysis. RESULTS: Mucosal concentrations of 5-ASA were significantly higher (p=0.03) in patients with endoscopic scores of 0-1 compared with those with scores of 2-3 (16.1 (range 10.2-45) v 5. 5 (3.5-17.4), respectively) and in patients with lower histological inflammation compared with those with more severe scores (17.4 (10. 5-45) v 8.9 (3.5-17.2), respectively) (p<0.01). In contrast, mucosal sIL2-R concentrations were significantly lower in patients with slight endoscopic and histological lesions than in those with more severe disease. A significative inverse correlation (r=-0.85) was found between 5-ASA and sIL-2R mucosal concentrations (p=0.00008). CONCLUSIONS: In patients with UC, in the same area of the intestinal tract, we found that the higher the 5-ASA mucosal concentrations, the lower the IL-2R levels and endoscopic and histological scores. We hypothesise that maintenance of high mucosal 5-ASA concentrations in all colonic segments could contribute to improve clinical outcome in UC patients.

Adult↗
PubMed1999

Circulating soluble factor-inhibiting natural killer (NK) activity of fresh peripheral blood mononuclear cells (PBMC) from inflammatory bowel disease (IBD) patients.

This study was performed in order to assess the cytotoxic activity, both natural (NK) and antibody-dependent (ADCC), of PBMC from 38 IBD patients and correlate it with their clinical features. Cytotoxicity assays were performed using sensitive target cells for NK and ADCC activities. In some experiments, highly purified NK cells, obtained both by Percoll density gradient and by co-culturing non-adherent PBMC with RPMI 8866 feeder cells, were used as effector cells. Furthermore, we evaluated NK cell parameters such as number, surface expression of adhesion molecules (CD11a/CD18, CD49d and CD54) and response to different stimuli. We observed a decreased NK cytotoxicity of PBMC from IBD patients, both in ulcerative colitis (UC) and Crohn's disease (CD), independently of the clinical activity of disease. In contrast, the ADCC lytic activity was within normal range. The lower NK cytotoxic activity observed in our IBD patients cannot be related to a decreased number of NK cells, surface expression of adhesion molecules, defective response to IL-2 and maturative defect. Decreased NK activity was induced in PBMC of controls when serum of patients was added and this was unrelated to monocyte-derived modulating factor(s). Our data show a decreased natural killing by fresh PBMC from IBD patients. This lower activity seems to be unrelated to a primary NK cell defect, since purified NK cells exhibited normal levels of killing. It might be hypothesized that serum factors, possibly derived from lymphocytes, with inhibitory properties on NK activity, might be functionally active in the blood of IBD patients, thus modulating NK activity.

Adolescent↗