Massimo Ghio

Soluble HLA-A,-B,-C and -G molecules induce apoptosis in T and NK CD8+ cells and inhibit cytotoxic T cell activity through CD8 ligation.

There is convincing evidence that soluble HLA‐A,‐B,‐C (sHLA‐A,‐B,‐C) and soluble HLA‐G (sHLA‐G) antigens can induce apoptosis in CD8+ activated T cells although there is scanty and conflicting information about the mechanism(s) by which sHLA‐A,‐B,‐C antigens and sHLA‐G antigens induce apoptosis. In this study we have compared the apoptosis‐inducing ability of sHLA‐A,‐B,‐C antigens with that of sHLA‐G1 antigens in CD8+ T lymphocytes and CD8+ NK cells. Furthermore we have compared the inhibitory effect of sHLA‐A,‐B,‐C antigens and of sHLA‐G1 antigens on theactivity of EBV‐specific CD8+ cytotoxic T lymphocytes (CTL). sHLA molecules were purified from serum and from the supernatant of HLA class I‐negative cells transfected with one gene encoding either classical or non‐classical HLA class I antigens. Both classical and non‐classical sHLA class I molecules trigger apoptosis in CD8+ T lymphocytes and in CD8+ NK cells, which lack the T cell receptor, and their apoptotic potency is comparable. The binding of sHLA‐A,‐B,‐C and sHLA‐G1 molecules to CD8 leads to Fas ligand (FasL) up‐regulation, soluble FasL (sFasL) secretion and CD8+ cell apoptosis by Fas/sFasL interaction. Moreover, classical and non‐classical sHLA class I molecules inhibit the cytotoxic activity of EBV‐specific CD8+ CTL. As the amount ofsHLA‐G molecules detectable in normal serum is significantly lower than that of sHLA‐A,‐B,‐C molecules, the immunomodulatory effects of sHLA class I molecules purified from serum are likely to be mainly attributable to classical HLA class I antigens. As far as the potential in vivo relevance of these findings is concerned, we suggest that classical sHLA class I molecules may play a major immunoregulatory role in clinical situations characterized by activation of the immune system and elevated sHLA‐A,‐B,‐C serum levels. In contrast, non‐classical HLA class I molecules may exert immunomodulatory effects in particular conditions characterized by elevated sHLA‐G levels such as pregnancy and some neoplastic diseases.

Gastroesophageal reflux and pulmonary fibrosis in scleroderma: a study using pH-impedance monitoring.

RATIONALE Interstitial lung disease (ILD) in patients with systemic sclerosis (SSc) is associated with increased morbidity and mortality. Gastroesophageal reflux (GER) is considered a contributing factor in the pathogenesis of ILD. OBJECTIVES To characterize GER (acid and nonacid) in patients with SSc with and without ILD. METHODS Patients with SSc underwent pulmonary high-resolution computer tomography (HRCT) scan and 24-hour impedance-pH monitoring off-proton pump inhibitor therapy. The presence of pulmonary fibrosis was assessed using validated HRCT-scores. Reflux monitoring parameters included number of acid and nonacid reflux episodes, proximal migration of the refluxate, and distal esophageal acid exposure. Unless otherwise specified, data are presented as median (25th-75th percentile). MEASUREMENTS AND MAIN RESULTS Forty consecutive patients with SSc (35 female; mean age, 53 yr; range, 24-71; 15 patients with diffuse and 25 with limited SSc) were investigated; 18 (45%) patients with SSc had pulmonary fibrosis (HRCT score >or= 7). Patients with SSc with ILD had higher (P < 0.01) esophageal acid exposure (10.3 [7.5-15] vs. 5.2 [1.5-11]), higher (P < 0.01) number of acid (41 [31-58] vs. 19 [10-23]) and nonacid (25 [20-35] vs. 17 [11-19]) reflux episodes, and higher (P < 0.01) number of reflux episodes reaching the proximal esophagus (42.5 [31-54] vs. 15 [8-22]) compared with patients with SSc with normal HRCT scores. Pulmonary fibrosis scores (HRCT score) correlated well with the number of reflux episodes in the distal (r(2) = 0.637) and proximal (r(2) = 0.644) esophagus. CONCLUSIONS Patients with SSc with ILD have more severe reflux (i.e., more reflux episodes and more reflux reaching the proximal esophagus). Whether or not the development of ILD in patients with SSc can be prevented by reflux-reducing treatments needs to be investigated.

Impairment of CD8+ T Suppressor Cell Function in Patients with Active Systemic Lupus Erythematosus

Alteration of T cell suppression function has been recognized in patients with systemic lupus erythematosus (SLE). Recently, CD8+ T suppressor lymphocytes (CD8+ Ts) have been generated in vitro by incubating purified CD8+ T cells with IL-2 and GM-CSF. Using this method, we generated CD8+ Ts from patients affected by SLE. No major differences were found in the CD8+ Ts phenotype between SLE patients and healthy subjects. CD8+ Ts from SLE patients with active disease did not inhibit the anti-CD3 mAb-induced proliferation of autologous PBMC, whereas CD8+ Ts from SLE patients in remission exerted an inhibitory activity comparable to normal subjects. The inhibitory effect of CD8+ Ts cells was neither mediated by cytotoxic activity nor by apoptosis induction. Two cytokines, IFN-γ and IL-6, were found to be responsible for the function of CD8+ Ts. In fact, counteraction of CD8+ Ts suppression activity was obtained by blocking IFN-γ with a specific Ab or by inhibiting CD8+ Ts-mediated IL-6 secretion by an antisense oligonucleotide. Interestingly, CD8+ Ts from SLE patients showed a peculiar cytokine pattern characterized by an impaired secretion of IL-6 and an increased secretion of IL-12. Thus, it appears that an altered balance between inhibitory (IL-6) and stimulatory (IL-12) cytokines might be responsible for the functional impairment of CD8+ Ts in SLE patients.

CD8+CD28− T Regulatory Lymphocytes Inhibiting T Cell Proliferative and Cytotoxic Functions Infiltrate Human Cancers

Tumor growth is allowed by its ability to escape immune system surveillance. An important role in determining tumor evasion from immune control might be played by tumor-infiltrating regulatory lymphocytes. This study was aimed at characterizing phenotype and function of CD8+CD28− T regulatory cells infiltrating human cancer. Lymphocytes infiltrating primitive tumor lesion and/or satellite lymph node from a series of 42 human cancers were phenotypically studied and functionally analyzed by suppressor assays. The unprecedented observation was made that CD8+CD28− T regulatory lymphocytes are almost constantly present and functional in human tumors, being able to inhibit both T cell proliferation and cytotoxicity. CD4+CD25+ T regulatory lymphocytes associate with CD8+CD28− T regulatory cells so that the immunosuppressive activity of tumor-infiltrating regulatory T cell subsets, altogether considered, may become predominant. The infiltration of regulatory T cells seems tumor related, being present in metastatic but not in metastasis-free satellite lymph nodes; it likely depends on both in situ generation (via cytokine production) and recruitment from the periphery (via chemokine secretion). Collectively, these results have pathogenic relevance and implication for immunotherapy of cancer.

Gastro-oesophageal reflux and gastric aspiration in idiopathic pulmonary fibrosis patients

The aim of the study was to characterise gastro-oesophageal reflux (GOR) in idiopathic pulmonary fibrosis (IPF). 40 consecutive IPF patients underwent pulmonary high-resolution computed tomography (HRCT) scan and impedance-pH monitoring while off antisecretory therapy. The presence of pulmonary fibrosis was assessed using validated HRCT scores. Reflux features included distal oesophageal acid exposure, number of acid/weakly acidic reflux episodes and their proximal migration. 40 consecutive patients with interstitial lung disease other than IPF (non-IPF patients) and 50 healthy volunteers were also enrolled. IPF patients had significantly higher (p<0.01) oesophageal acid exposure (median (interquartile range (IQR)) 9.25 (4.7–15.4)% versus 3.3 (1.4–7.4)% versus 0.7 (0.2–4.2)%, number of acid (median (IQR) 45 (23–55) versus 32 (19–44) versus 18 (10–31)), weakly acidic (median (IQR) 34 (19–43) versus 21 (11–33) versus 18 (15–28)) and proximal reflux (median (IQR) 51 (26.5–65.5) versus 20 (9.5–34.5) versus 9 (5–20)) events compared to non-IPF patients and healthy volunteers, respectively. Pulmonary fibrosis HRCT scores correlated well with reflux episodes in both the distal (r2=0.567) and proximal (r2=0.6323) oesophagus. Patients with IPF had more bile acids and pepsin (p<0.03) in bronchoalveolar lavage fluid (BALF) (62% and 67%, respectively) and saliva (61% and 68%, respectively) than non-IPF patients (25% and 25% in BALF, and 33% and 36%, respectively, in saliva) and controls (0% and 0% in BALF and saliva, respectively). Acid GOR is common in IPF, but weakly acidic GOR may also occur. Patients with IPF had a risk of pulmonary aspiration of gastric contents. Outcome studies with intense antireflux therapy are needed. Frequent acid/weakly acidic gastro-oesophageal reflux and high risk of pulmonary aspiration of gastric contents in IPF http://ow.ly/nSNv8

Small intestinal bacterial overgrowth in patients suffering from scleroderma: clinical effectiveness of its eradication.

OBJECTIVES:After the skin, the gastrointestinal tract is the second most common target of systemic sclerosis (SSc).AIM:Our aims were to investigate orocecal transit time (OCTT) and the presence of small intestinal bacterial overgrowth (SIBO) in SSc as a cause of intestinal symptoms.METHODS:Fifty-five SSc patients and 60 healthy controls, sex and age matched, entered the study. Enrolled subjects completed a questionnaire for intestinal symptoms and a global symptomatic score (GSS) was calculated. OCTT and the presence of SIBO were assessed by a lactulose breath test (LBT). Patients with SIBO were treated with rifaximin 1,200 mg/day for 10 days. Finally, a second questionnaire and LBT were performed 1 month after the end of therapy.RESULTS:The prevalence of SIBO was higher in SSc patients compared with controls (30/54 vs 4/60, respectively, P < 0.001). OCTT was significantly slower in SSc patients compared with controls (150 min, 25–75th percentile 142.5–165 vs 105 min, 25–75th percentile 90–135, respectively, P < 0.001). In patients with SIBO, the median GSS score was 8 (25–75th percentile 3.25–10.75). Eradication of SIBO was achieved in 73.3% of patients, with a significant reduction of symptoms in 72.7% of them (GSS score 2, 25–75th percentile 1–3, P < 0.05).CONCLUSIONS: These data suggest that SIBO occurs more frequently in SSc patients than in controls. Intestinal symptoms in these patients may be related to this syndrome and its eradication seems useful to improve clinical features. OCTT is significantly delayed in SSc patients, suggesting an impairment of intestinal motility, a further risk factor for the development of SIBO.

Alteration of Th17 and Treg cell subpopulations co-exist in patients affected with systemic sclerosis.

Aim of the study has been to understand the relationship between TH17 and Treg cell subsets in patients affected with systemic sclerosis (SSc). Phenotypes and functions of Th17 and Treg cell subsets were analyzed in a series of 36 SSc patients. Th17 cell concentration in the peripheral blood was found to be increased in SSc patients with respect to healthy controls independently from type or stage of disease. After PBMC stimulation with a polyclonal stimulus or Candida albicans antigens the frequency of Th17 T cell clones was significantly higher in SSc patients with respect to controls suggesting the skewing of immune response in SSc patients toward Th17 cell generation/expansion. Concerning the Treg compartment, both CD4+CD25+ and CD8+CD28- Treg subsets showed quantitative and qualitative alteration in the peripheral blood of SSc patients. Collectively, these data highlight the existence of an imbalanced ratio between Th17 and Treg cell subsets in SSc patients.

Gastrointestinal motility disorder assessment in systemic sclerosis

OBJECTIVES SSc is a clinically heterogeneous and generalized disease, characterized by thickness of the connective tissue of the skin and internal organs, such as the digestive tract, impairing gastrointestinal (GI) motility. Our aim is to evaluate retrospectively abnormalities of oesophageal motility, gastric emptying, oro-cecal transit time (OCTT) and small intestine bacterial overgrowth (SIBO) in a large cohort of SSc patients. METHODS Ninety-nine SSc patients were included in the study. Forty-two patients underwent oesophageal conventional manometry, 45 performed a [(13)C]octanoic acid breath test to measure gastric emptying time and all 99 patients performed a lactulose breath test in order to evaluate OCTT and SIBO. Data were compared with healthy controls. RESULTS In SSc patients, median lower oesophageal sphincter (LOS) pressure [14 mmHg (25th-75th; 8-19) vs 24 mmHg (19-28); P < 0.01] and median wave amplitude [30 mmHg (16-70) vs 72 mmHg (48-96); P < 0.01] were lower than in controls. Oesophageal involvement, defined as reduced LOS pressure and ineffective oesophageal motility pattern, was encountered in 70% of SSc patients. A delayed gastric emptying time was present in 38% of SSc patients: mean t½ was 141 ± 79 min vs 90 ± 40 min of controls (P < 0.01). Also, OCTT was significantly delayed in SSc: median OCTT was 160 min (25th-75th; 135-180) vs 105 min (25th-75th; 90-135) of controls (P < 0.01). SIBO was observed in 46% of SSc compared with 5% of controls (P < 0.01). CONCLUSION GI involvement is very frequent in SSc patients. Oesophagus and small bowel are more frequently impaired, whereas delayed gastric emptying is less common.

HLA class-I-soluble antigen serum levels in liver transplantation : a predictor marker of acute rejection

The serum levels of sHLA-I have been determined in 16 patients following liver transplantation. sHLA-I levels did not show remarkable variations in six patients without evidence of transplant-related complications. sHLA-I levels strongly increased in 10 patients undergoing acute rejection episodes. In these patients, an average 20% daily increase of sHLA-I levels was detected on the 6 days preceding and on the 2 days following the rejection episode. A fast decrease of sHLA-I levels was observed in seven patients following treatment of acute rejection with anti-CD3 mAb. The serum level of sHLA-I antigens positively correlated with ALT serum level and inversely correlated with PT. The determination of sHLA-I in serum may therefore be proposed as a useful marker in the monitoring of patients following liver transplantation. The increase of sHLA-I antigens may predict the onset of acute rejection whereas their decrease may be related to a good response of acute rejection to immunosuppressive treatment.

Soluble HLA class I molecules/CD8 ligation trigger apoptosis of CD8+ cells by Fas/Fas-ligand interaction.

The human major histocompatibility complex (HLA) encodes two sets of HLA class I molecules, which have been termed class Ia (or classical) and class Ib (or nonclassical) molecules. The class Ia molecules include the gene products of HLA-A, HLA-B, and HLA-C loci and are characterized by broad tissue expression and by a high degree of polymorphism. The class Ib molecules include the gene products of HLA-E, HLA-F, and HLA-G loci and are characterized by a restricted tissue distribution and by limited polymorphism. Besides being expressed on nucleated cells, classical and nonclassical HLA class I molecules are present in serum in soluble form (sHLA-I). The serum level of sHLA-I molecules is significantly increased in a variety of physiological and pathological conditions such as pregnancy, acute rejection episodes following organ allografts, acute graft-versus-host-disease (GVHD) following bone marrow transplantation, autoimmune diseases, viral infections, and malignant melanoma. Because of the statistically significant association with clinical parameters, the level of sHLA-I antigens has been suggested to represent a useful marker to predict the evolution of viral infections and to monitor the clinical course of allografts. Moreover, elevated levels of functional sHLA-I and soluble Fas-ligand molecules have been detected by our group in blood components and might play a role in the immunomodulatory effect of autologous and allogeneic transfusions. Several lines of evidence suggest that sHLA-I molecules are immunologically functional and may play an immunoregulatory role. In fact, they have been shown to elicit antibodies in both allogeneic and xenogeneic combinations, to inhibit the activity of alloreactive cytotoxic T lymphocytes (CTL), and to induce apoptosis in alloreactive and virus-specific CTL, in activated autologous and allogeneic CD8+ T cells, and in CD8+ NK cells. There is general agreement about the mechanism underlying the inhibition of CTL activity by sHLA antigens. This inhibition appears to be mediated by interactions of sHLA-I antigens a1 and a2 domains with T cell receptor (TCR). By contrast, there is conflicting information about the mechanism underlying induction of apoptosis of activated T cells by sHLA-I antigens. Several authors reported that sHLA-I molecules induced apoptosis of alloreactive CD8+ cytotoxic T lymphocytes through interaction with their TCR. However, our own data and those other groups indicate that classical and nonclassical sHLA-I molecules trigger Fas/Fas-ligand mediated apoptosis of phytohemoagglutinin (PHA)-activated and virus-specific CD8+ T lymphocytes as well as of CD8+ NK cells by interacting with CD8 coreceptor. Recently, we performed a series of experiments in our laboratory to clarify the intracellular mechanism(s) leading to Fas-ligand upregulation and secretion. These unpublished data indicate that sHLA-I/CD8 ligation elicits the phosphorylation of p56lck protein thyrosin kinase (PTK) associated with CD8 cytoplasmic domain in the absence of any other TCR-derived signal, the activation of syk-like ZAP-70 PTK and protein kinase C, and extracellular calcium influx. Then, activation and nuclear translocation of NF-kB and NF-AT occurs, leading to Fas-ligand mRNA transcription and soluble Fas-ligand secretion, which delivers the death signal. Interestingly, soluble Fas-ligand secretion and CD8+ cell apoptosis, but not CD8+ cell cytolitic activity, are completely inhibited by Cyclosporin A, which specifically blocks the activation of the calcineurin/calmodulin pathway. Taken together, these data suggest that sHLA-I molecules are involved in a signal-transduction pathway leading to Fas-ligand expression, soluble Fas-ligand secretion, and CD8+ cells apoptosis.