Amino acid position 11 of HLA-DRß1 is a major determinant of chromosome 6p association with ulcerative colitis.

The major histocompatibility complex (MHC) on chromosome 6p is an established risk locus for ulcerative colitis (UC) and Crohn's disease (CD). We aimed to better define MHC association signals in UC and CD by combining data from dense single-nucleotide polymorphism (SNP) genotyping and from imputation of classical human leukocyte antigen (HLA) types, their constituent SNPs and corresponding amino acids in 562 UC, 611 CD and 1428 control subjects. Univariate and multivariate association analyses were performed, controlling for ancestry. In univariate analyses, absence of the rs9269955 C allele was strongly associated with risk for UC (P = 2.67 × 10(-13)). rs9269955 is a SNP in the codon for amino acid position 11 of HLA-DRß1, located in the P6 pocket of the HLA-DR antigen binding cleft. This amino acid position was also the most significantly UC-associated amino acid in omnibus tests (P = 2.68 × 10(-13)). Multivariate modeling identified rs9269955-C and 13 other variants in best predicting UC vs control status. In contrast, there was only suggestive association evidence between the MHC and CD. Taken together, these data demonstrate that variation at HLA-DRß1, amino acid 11 in the P6 pocket of the HLA-DR complex antigen binding cleft is a major determinant of chromosome 6p association with UC.

Interleukin-18 system plays an important role in keloid pathogenesis via epithelial-mesenchymal interactions.

BACKGROUND: Keloid scarring is a dermal fibroproliferative disorder characterized by increased fibroblast proliferation and excessive production of collagen and extracellular matrix (ECM) components. To date, the role of cytokines in keloid pathogenesis has not been completely unravelled. Interleukin (IL)-18 is a pro-inflammatory cytokine that plays important roles in wound healing, fibrogenesis and carcinogenesis. OBJECTIVES: Our aim was to study the role of the IL-18 system in keloid pathogenesis. MATERIALS AND METHODS: Expression and localization of IL-18 and its receptor (IL-18R) were investigated in normal skin and keloid tissues using Western blot and immunohistochemistry. We further studied the expression of the IL-18 system in normal and keloid-derived cell lines in a coculture model. RESULTS: Results from Western blot and immunohistochemistry revealed that IL-18, IL-18Rα and IL-18Rß expression was elevated in keloid tissue compared with normal skin tissue. Studies on the expression of IL-18 and its antagonist, IL-18 binding protein (IL-18BP), using a coculture model demonstrated severe IL-18/IL-18BP imbalance in keloid keratinocyte/keloid fibroblast (KK/KF) cocultures with significant elevation of bioactive IL-18 whereas IL-18BP levels remained the same. This overproduction of bioactive IL-18 in keloid cocultures could be due to increased caspase-1 and decreased caspase-3 expression in keloid tissue, as well as decreased soluble IL-10 levels observed in keloid cocultures. The important inductive effects of IL-18 on KFs were further underscored by the observation that exposure of KF to IL-18 resulted in increased collagen and ECM component synthesis, and increased secretion of profibrotic cytokines such as IL-6 and IL-8. Finally, the addition of phosphatidylinositol 3-kinase (PI3K), mitogen activation protein kinase (MAPK), specificity protein 1 (Sp1) and mammalian target of rapamycin (mTOR) inhibitors inhibited IL-18 secretion in keloid cocultures. CONCLUSIONS: The present study has proven that the IL-18 system plays an important role in keloid pathogenesis via epithelial-mesenchymal interactions. It also suggests a therapeutic potential of PI3K, MAPK, Sp1 and mTOR inhibitors in the treatment of keloid scarring.

The expression of TSLP receptor in chronic rhinosinusitis with and without nasal polyps.

Chronic Rhinosinusitis with or without Nasal Polyps (CRSwNP and CRSsNP) may be characterized by different cytokine profiles. Generally, Th2 cytokines and eosinophilic infiltration have been reported to be more specific of CRSwNP compared to CRSsNP, where neutrophils seem to play a major role. The epithelial cell-derived thymic stromal lymphopoietin (TSLP) has been recently identified as a key factor in Th2-inflammatory response. The aim of this study is to investigate the expression of TSLP Receptor (TSLP R) in surgical specimens obtained from patients affected by CRSwNP (n=10) and CRSsNP (n=5) by immunohistochemical techniques (immunostaining score, IS). TSLP R expression was significantly higher in the inflammatory infiltrate and in the epithelial cells of CRSwNP, CRSsNP patients compared to the control group (IS 4.5±0.68, 4.4±1.44 and 0.43±0.3 respectively, p=0.0024 for inflammatory infiltrate and IS 5.8±0.92, 7.8±2.06 and 0.86±0.55 respectively, p=0.0018 for epithelial cells). No significant difference was observed in IS of inflammatory infiltrate and epithelial cells in CRSwNP compared to CRSsNP. Very low IS for TSLP R was found in connective tissue of all the samples, with no difference among the groups. TSLP receptor is highly expressed in CRS compared to controls and independently from the polyps suggesting an early common inflammatory pathway in the two CRS phenotypes.

Regulation of hematopoiesis in vitro by alloreactive natural killer cell clones.

Natural killer (NK) cells lyse autologous and allogeneic target cells even in the absence of major histocompatibility complex (MHC) class I antigens on the target cells. Recently, however, human allospecific NK cell clones have been generated that recognize at least five distinct specificities inherited recessively and controlled by genes linked to the MHC. Because the genetic specificity of these alloreactive NK cells in vitro appears analogous to that of in vivo NK cell-mediated murine hybrid resistance, i.e., the rejection of parental bone marrow in irradiated F1 animals, we tested the ability of human alloreactive NK clones to recognize allogeneic hematopoietic progenitor cells. NK cells from two specificity 1 alloreactive NK clones, ES9 and ES10, significantly and often completely suppressed colony formation by purified peripheral blood hematopoietic progenitor cells from specificity 1-susceptible donors, but had no significant effect on the cells of specificity 1-resistant donors. Activated polyclonal NK cells were less efficient than the NK clones in inhibiting colony formation and had a similar effect on cells from both specificity 1-susceptible and -resistant donors. The alloreactive NK clones produced cytokines with a suppressive effect on in vitro hematopoiesis, such as interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha), when exposed to phytohemagglutinin blasts from specificity 1-susceptible, but not -resistant donors. However, the mechanism by which alloreactive NK cells inhibit colony formation is more consistent with a direct cytotoxic effect than with the production of inhibitory cytokines because antibodies (anti-IFN-gamma, alpha-TNF-alpha, and -lymphotoxin) that completely blocked the inhibition by polyclonal NK cells had only a minimal effect on the inhibition by the alloreactive clones. Moreover, the alloreactive clones were directly cytolytic in a 51Cr release assay against enriched preparations of peripheral blood progenitor cells from specificity 1-susceptible donors. These data indicate that the alloreactive NK cells are likely the human counterpart of the cells mediating murine hybrid resistance and that these cells might play clinically important roles in rejection or in graft-versus-leukemia reactions after allogeneic bone marrow transplantation.

Exhaled nitric oxide and nitric oxide synthase expression in Hodgkin's disease.

Hodgkin's disease (HD) is a malignant lymphoma with frequent mediastinal involvement, characterized by a significant inflammatory infiltration. Exhaled nitric oxide (FENO), is present in healthy humans, and has been proven to be increased in eosinophilic diseases such as allergic asthma. We investigated whether FENO is increased in mediastinal HD and whether NO is produced by lymphoma tissue. To this aim FENO was measured in 56 HD patients, 17 with and 39 without bulky mediastinal involvement, in the period from January 2007 to December 2008. Thirty-seven patients were reassessed after remission. Lymph node biopsies of 10 patients were evaluated for inducible (iNOS) and constitutive (eNOS) nitric oxide synthase expression by immunohistochemistry. FENO resulted significantly related to the mediastinal mass maximum diameter (p=0.009) and was significantly higher in patients with as compared to those without bulky mediastinal disease (38.7 ppb, CI 95% 19.3-58.0, versus 20.7 ppb, CI 95% 16.6-24.7; p=0.009). iNOS and eNOS immunoreactivity was observed in tumour and inflammatory cells (eosinophils and histiocytes). Only in patients with bulky mediastinal HD there was a significant decrease in FENO (from 50.4 ppb CI 95% 18.0-82.8 to 11.1 ppb CI 95% 4.4-17.8, p=0.011). In conclusion, high FENO and NOS expression in lymph-nodes indicate that NO is a component of the inflammatory network of HD. FENO may be proposed for the assessment and follow up of bulky mediastinal HD patients.

Osteo-promoting activity of OSTEOPLANT ANGIOSTAD in vitro.

AIM: There is an increasing need for an appropriate and readily-available material to reconstruct large bone defects, one of the most significant problems in the dental and maxillo-facial fields. The in vitro study examines the effects of OSTEOPLANT ANGIOSTAD, a product developed to increase osteoinductivity. METHODS: The product's biological properties were assessed by examining: the viability of cultured bone-marrow mesenchymal stem cells (MSC) through the methylthiazol tetrazolium assay; transforming growth factor (TGF)-b release by these cells through the enzyme-linked immunosorbent assay (ELISA) and the migration capacity of MSC and endothelial cells, by the in vitro wound closure test and transwell-migration assay, respectively. RESULTS: OSTEOPLANT ANGIOSTAD preserved MSC's viability and improved their capacity to release TGF-b1. It also increased in vitro wound healing by MSC and migration of endothelial cells. CONCLUSION: The results show that, since it increases the production by MSC of proangiogenic factors such as TGF-beta and promotes endothelial cell migration, OSTEOPLANT ANGIOSTAD may be an appropriate adjunct to accelerate the osteointegration of bone substitutes.

Aberrant activation of c-kit protects colon carcinoma cells against apoptosis and enhances their invasive potential.

Multiple genetic aberrations contribute to the development of biologically aggressive, clinically malignant colorectal carcinomas (CRCs). Some of these have been linked to inappropriate signaling through the tyrosine kinase moieties of growth factor receptors. We have described previously (G. Bellone et al., J. Cell. Physiol., 172: 1-11, 1997) that human CRCs overexpress both the receptor tyrosine kinase c-kit and its ligand, stem cell factor (SCF), relative to normal mucosa cells, thus establishing an autocrine c-kit-mediated loop. In addition, we noted that exogenous SCF contributes to anchorage-independent growth of HT-29 colon carcinoma cells in semisolid medium. Here, we investigated possible roles of the c-kit/SCF autocrine/paracrine system in survival and invasive capacity of DLD-1 colon carcinoma cells. We report that SCF was required for migration and invasion of DLD-1 cells through reconstituted basement membranes (Matrigel) and up-regulated gelatinase (matrix metalloproteinase-9) activity in DLD-1 cells. Furthermore, we describe that SCF supported survival of DLD-1 cells in growth factor-deprived conditions. These results suggest multiple roles of c-kit activation in support of the malignant phenotype of DLD-1 cells related to growth, survival, migration, and invasive potential.

Constitutive production of tumor necrosis factor-alpha in hairy cell leukemia: possible role in the pathogenesis of the cytopenia(s) and effect of treatment with interferon-alpha.

PURPOSE: In view of the pleomorphic role cytokines play in human lymphoproliferative disorders, we investigated the possible involvement of tumor necrosis factor-alpha (TNF) in hairy cell leukemia (HCL). PATIENTS AND METHODS: The levels of TNF were measured in the serum of untreated patients, and in the culture supernatants of unstimulated and stimulated enriched hairy cells (HC). Furthermore, the presence of TNF mRNA transcripts in HC was analyzed. The possibility that HC could inhibit the in vitro growth of normal erythroid progenitors via the release of TNF was also investigated. Finally, in an attempt to correlate the circulating levels of TNF with the course of the disease, these were retested during and after treatment with interferon-alpha (IFN). RESULTS: Significantly increased levels of TNF were found in the sera of untreated HCL patients compared with normal control sera were seen from patients with other diseases (P less than .001), with values greater than 10 pg/mL in 21 of 42 samples tested. A significant decrease (P less than .01) of TNF levels was recorded following IFN-2a administration in 16 cases with detectable pretreatment serum levels of TNF. In two cases, an increase in TNF values was associated with persistence or progression of disease. The likelihood that the circulating levels of TNF were caused by the pathologic cells is supported by the evidence that purified HC may release TNF spontaneously. The values can be markedly increased following in vitro activation with the phorbol ester 12-0-tetradecanoylphorbol-13 acetate (PMA), with B-cell growth factor (BCGF), and, to a further extent, with the combination of PMA and BCGF. Furthermore, the constitutive mRNA for TNF was found in seven of eight HC samples analyzed. Although supernatants of enriched HC, were capable of reducing the growth of normal bone marrow erythroid progenitors by 50%, duplicate experiments using an anti-TNF antibody produced an almost complete disappearance of the inhibitory effect. CONCLUSION: The results of this study suggest that TNF plays an important role in the pathogenesis of the cytopenia(s) characteristically associated with HCL.

Interstitial cells of Cajal, enteric nerves, and glial cells in colonic diverticular disease.

BACKGROUND: Colonic diverticular disease (diverticulosis) is a common disorder in Western countries. Although its pathogenesis is probably multifactorial, motor abnormalities of the large bowel are thought to play an important role. However, little is known about the basic mechanism that may underlie abnormal colon motility in diverticulosis. AIMS: To investigate the interstitial cells of Cajal (the gut pacemaker cells), together with myenteric and submucosal ganglion and glial cells, in patients with diverticulosis. PATIENTS: Full thickness colonic samples were obtained from 39 patients undergoing surgery for diverticulosis. Specimens from tumour free areas of the colon in 10 age matched subjects undergoing surgery for colorectal cancer served as controls. METHODS: Interstitial cells of Cajal were assessed using anti-Kit antibodies; submucosal and myenteric plexus neurones and glial cells were assessed by means of anti-PGP 9.5 and anti-S-100 monoclonal antibodies, respectively. RESULTS: Patients with diverticulosis had normal numbers of myenteric and submucosal plexus neurones compared with controls (p = 0.103 and p = 0.516, respectively). All subtypes of interstitial cells of Cajal were significantly (p = 0.0003) reduced compared with controls, as were glial cells (p = 0.0041). CONCLUSIONS: Interstitial cells of Cajal and glial cells are decreased in colonic diverticular disease, whereas enteric neurones appear to be normally represented. This finding might explain some of the large bowel motor abnormalities reported to occur in this condition.

Effect of human interleukin 3 on the susceptibility of fresh leukemia cells to interleukin-2-induced lymphokine activated killing activity.

Pretreatment of acute myeloblastic leukemia cells with the hemopoietic growth factor interleukin 3 (IL3) increased their susceptibility to lymphokine activated killing (LAK) but did not affect their constitutive resistance to native natural killer activity. In addition, IL3 treatment did not alter the LAK cell-mediated killing of CD34+ hemopoietic progenitors present in normal bone marrow. Increased 3H-thymidine uptake was generally observed after IL3 treatment. However, failure to proliferate in response to IL3, observed in some cases, did not prevent changes in LAK susceptibility. Enhanced lysis of IL3-treated leukemic cells was accompanied by a moderate increase of the effector-target binding. Increased LAK susceptibility was already observed at 18 h, while optimal cytolysis and expression of the cell adhesion molecule (CAM) LFA-3 (CD58) by IL3-treated AML cells were concomitantly observed at later culture times. In contrast, the CAM ICAM-1 (CD54) was not modulated by IL3, nor were significant changes in the expression of either CAMs observed in normal hemopoietic cells. Blocking experiments with the anti-CD58 monoclonal antibody demonstrated a variable neutralizing effect on the IL3-induced increase of LAK activity, depending on the leukemia cell studied. The effect described here, together with the known role of IL3 in normal hemopoiesis makes it a factor of potential therapeutic value for the treatment of leukemic patients.

A human leukemic T cell line (PF-382) inhibits the growth of myeloid and erythroid progenitor cells.

We have recently described a human T cell line, named PF-382, obtained from the pleural effusion of a child with T-acute lymphoblastic leukemia (T-ALL), which expresses phenotypic and functional features of suppression. In this study we report that PF-382 spontaneously releases a factor which inhibits the in vitro growth of myeloid (CFU-GM) and erythroid (BFU-E) progenitor cells. The same effect is obtained when irradiated PF-382 cells are co-cultured with the hemopoietic precursors. In both instances, maximal inhibitory activity is exerted on day 14 CFU-GM and BFU-E obtained from the light density nonadherent fraction of normal human bone marrow and peripheral blood; this finding suggests that the target of the inhibition is represented by the more immature elements within the progenitor cell compartment. Progressive depletion of monocytes, T, B lymphocytes, and NK cells as well as recloning experiments indicate that the inhibitory effect is directly exerted on the target cell and not via an intermediate population of accessory cells. Partial purification by gel filtration and by subsequent high performance liquid chromatography demonstrates that this factor is a protein with a molecular weight of 47 kd. The physicochemical characterization and the specific functional properties suggest that the PF-382 inhibitory factor represents a lymphokine which differs from those so far reported. The PF-382 cell line provides a useful model toward a better understanding of the interrelations between T cell subsets and other hemopoietic compartments.

Production and pro-apoptotic activity of soluble CD95 ligand in pancreatic carcinoma.

We report here that the progression of pancreatic carcinomas in tumor patients is associated with increased serum levels of both the soluble forms of CD95 ligand (CD95L/FasL) and its receptor, CD95 (Fas). Shedding of proteolytically processed soluble CD95L was also observed in pancreatic carcinoma cells in vitro, thus identifying one possible source of CD95L in patients' sera. Because the secreted forms of both CD95 and CD95L have been implicated previously in protection of cells from CD95-mediated cell death, we assessed the effect of soluble CD95L in supernatants of pancreatic carcinoma cells on viability of Jurkat T lymphocytes. We describe that (a) supernatants derived from cultured pancreatic carcinoma cells caused apoptosis of Jurkat cells; (b) soluble tumor-derived CD95L contributed significantly to this effect; and (c) in comparison to Jurkat cells, pancreatic carcinoma cells themselves revealed increased resistance to apoptosis induction by autocrine soluble CD95L. These results are consistent with the notion that in the microenvironment of pancreatic tumors, tumor-derived shed CD95L exerts paracrine pro-apoptotic effects. In addition, because it is released at high levels into the bloodstream, soluble CD95L may have systemic effects in tumor patients that reach beyond the microenvironment of the tumor site.

[Biological aspects of pancreatic cancer]. / Aspetti bbiologici del carcinoma pancreatico.

Pancreatic ductal carcinoma still is an aggressive disease with a fatal prognosis due to late diagnosis and resistance to pharmacological and surgical treatments. Molecular investigations of pancreatic cancer are complicated by the restricted accessibility of the organ for biopsies. However, recent studies have indicated that pancreatic cancer is a multi-stage process resulting from the accumulation of genetic changes in the somatic DNA of normal cells. These molecular alterations, including overexpression of receptor-ligand systems, oncogene activation and loss of tumour suppressor genes, leads to a profound disturbance in cell cycle regulation and continuous growth. The molecular findings are now integrated in a pancreatic tumour progression model, with genetically and morphological defined precursor lesions. However, it remains unclear whether the initial target cells of this cancer develop from ductal or acinar cells. This review will present recent emerging questions on the biology of pancreatic cancer with particular emphasis on the cell origin and tumour microenvironment.

Differential expression of transforming growth factors-beta1, -beta2 and -beta3 in human colon carcinoma.

Transforming growth factor (TGF)-beta is a protein family which affects multiple cellular functions including survival, proliferation, differentiation and adhesion. Among the three known isoforms, TGF-beta1 is commonly overexpressed in solid malignancies. Recent studies in knock-out mice demonstrated non-redundant roles of different TGF-beta isoforms in development. The present study was performed to assess tumour-associated expression of the three TGF-beta isoforms in colon carcinoma. We report that colon carcinoma progression is associated with gradual and significant increases in expression of TGF-beta1 and TGF-beta2 mRNA and proteins. By contrast, TGF-beta3 expression was detected in normal colonic mucosa and, at slightly higher levels, in tumour tissues. In addition, plasma levels of both TGF-beta1 and TGF-beta2 were significantly higher in cancer patients when compared with unaffected individuals. Taken together, our results indicate distinct expression patterns of the three TGF-beta isoforms in colon carcinoma cells and possible systemic effects of TGF-beta1 and TGF-beta2 in tumour patients.

An immunoenzyme technique for the identification of granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors using digoxigenated-GM-CSF.

A method for detecting granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors has been devised using human macrophages and a GM-CSF/IL-3-dependent human megakaryoblastic leukemia cell line (M-07e). Recognition of the factor-binding site was accomplished by linking recombinant human (rh) unglycosylated GM-CSF previously labeled with digoxigenated compounds. Digoxigenates were able to link amino and sulphydryl groups of the soluble factor and an immunoperoxidase technique using monoclonal anti-digoxigenin antibody was employed to demonstrate the interaction. To support morphological data cross-linking analysis was performed with M-07e cells using digoxigenated-rh-GM-CSF. Macrophages and M-07e cells incubated with digoxigenated-rh-GM-CSF showed intense positivity by the immunoperoxidase technique. In cross-linking, M07e cells showed a 96 kDa band corresponding to receptor plus bound factor. This technique permits a high degree of specificity in the detection of GM-CSF receptors with good morphological preservation of cellular detail.

Microplate selection technique (MPST). A new method for selecting mouse transfectants expressing human gene products.

This paper examines the analytical power of fluorescence activated cell sorting and immunorosetting technique as compared with the newly devised microplate selection technique in identifying transfected murine L cells expressing human surface molecules. The microplate selection technique relies on the mechanical transfer of transfected cells to a terasaki microplate, where an indirect immunofluorescence assay is carried out. It is a simple procedure not requiring costly equipment and with a detection capacity equivalent to that of the fluorescence activated cell sorter. The microplate selection technique proved to be sensitive enough to detect all the transfectants produced during the present study.

Murine monoclonal antibodies as probes for the phenotypical, functional, and molecular analysis of a discrete peripheral blood lymphocyte population exerting natural killer activity in vitro.

Two monoclonal antibodies (AB8.28 and A10) reacting with large granular lymphocytes were extensively studied and characterized. The two peripheral blood lymphocyte subsets positive for the expression of AB8.28 and A10 determinants were isolated by cell sorting and the phenotype analyzed using a panel of anti-lymphocyte reagents. Both subsets displayed the characteristics of "null cells." Moreover, these subsets encompassed a significant amount of the natural killer activity, since preparations of peripheral blood lymphocytes deprived of AB8.28+ and A10+ cells showed a remarkable reduction of such activity. The analysis of the distribution of the AB8.28 and A10 epitopes has been carried out using a variety of cells, i.e., normal tissues, tumor cells, established cell lines, and preparations obtained from patients with different leukemic disorders. The structure bearing the epitopes recognized by the two monoclonal antibodies was characterized immunologically (immunoprecipitation, SDS-PAGE analysis, immunomodulation, and competition with other antibodies) and by various functional assays. On the basis of inhibition tests, the AB8.28 molecule seems to be related functionally and/or structurally with the IgG Fc receptor. By contrast, the A10 structure does not share this activity and so far has eluded any precise biological characterization.

Lymphokine Activated Killer (LAK) Cells Inhibit the in vitro Growth of Myeloid and Erythroid Progenitor Cells Via the Release of Tumor Necrosis Factor-Alphadagger.

Adoptive immunotherapy with lymphokine-activated killer (LAK) cells induced by Interleukin 2 (IL2) has provided a new and promising strategy for the treatment of cancer patients. The clinical observation of variable degrees of cytopenia(s) in patients with solid tumors treated with LAK cells suggests that IL2-activated effector cells may play a role on the normal progenitor cell compartment. We therefore carried out in vitro studies designed to assess the influence of LAK cells on normal hemopoiesis. LAK cells from different individuals were cultured with enriched normal peripheral blood and bone marrow colony-forming cells at effector: target ratios ranging between 1:1 and 10:1. Both LAK effectors generated from peripheral blood mononuclear non-adherent cells (PBL-LAK) and from sheep erythrocyte rosette-forming cells (RFC-LAK) suppressed in a reproducible manner the growth of CFU-GM and CFU-E from both peripheral blood and bone marrow. This inhibitory effect is dose-dependent, appears to be smaller with LAK cells generated from RFC rather than from unfractionated PBL and is less evident on the early erythroid compartment. In general, the effect is more pronounced when LAK cells are pre-incubated for 18 hours with the target cell populations prior to seeding. Both autologous and allogeneic PBL-LAK inhibit colony formation. The mechanism of killing implicates a release of soluble factor(s) after close cell-to-cell interaction, as only cell-free supernatants produced after pre-incubation of PBL-LAK cells with hemopoietic progenitors give rise to inhibitory effects. The evidence that during this incubation time high levels of Tumor Necrosis Factor-alpha (TNF) are released and that the use of an anti-TNF antibody completely abolishes the inhibitory effect suggests that TNF plays a part in the LAK cell-induced inhibitory activity.

Transforming growth factor-beta and interleukin 10 in oral implant sites in humans.

Cross-talk between cells and cytokines in peri-implant tissue is largely unknown. The immune response in the gingival mucosa appears to favor implant integration over rejection, since titanium-implant-retained overdentures show long-term success. This study evaluates pro-inflammatory (interleukin [IL]-2, interferon [IFN]-gamma, IL-12) and anti-inflammatory (IL-4, IL-10, transforming growth factor [TGF]-beta1) cytokine mRNA expression and tissue morphometry in peri-implant soft tissue from patients before and during treatment with Brånemark titanium implants. Immediately after treatment with endosseous implant and overdenture, TGF-beta1 mRNA increased in peri-implant mucosa specimens; transcript accumulation for IL-10 was elevated at 4 months and decreased dramatically thereafter. Transcripts for IL-2, IFN-gamma, IL-12, and IL-4 were absent. Healthy osseointegrated implants showed no histological inflammation in most patients. These findings suggest that newly classified TGF-beta and/or IL-10 secreting T regulatory (r)/T helper (h)-3 cells may populate implant insertion sites.

Cytokine production and bone remodeling in patients wearing overdentures on oral implants.

The stability of titanium dental implants is determined by osseointegration. Bone is a dynamic tissue continuously remodeled through resorption and formation, processes controlled by local cytokine production. This study investigated osseotropic cytokine expression in gingival mucosa, in the intraforamina and inferior first molar zones, during rehabilitation with implant-retained overdentures. Specimens were taken from six patients prior to placement of implants in the intraforamina bone; at connection of healing abutments; and 4, 8, and 12 months after prosthetic anchorage. Through semi-quantitative reverse-transcriptase polymerase chain-reaction, the following constitutively expressed cytokines were found at first surgical stage: interleukin-1, -6, and -8; small amounts of interleukin-11; stem cell factor; and transforming growth factor-beta1, -beta2, and -beta3. From the connection of healing abutments to 12 months after prosthetic anchorage, transforming growth factor-beta1, -beta2, and -beta3 were markedly higher than initial values. Expression of interleukin-6 and -8 decreased 8 months after prosthetic anchorage, while that of interleukin-1 increased at 12 months. In cultured gingival fibroblasts, modulation of cytokine secretion was also time-dependent. Cell culture supernatants influenced osteoclast-like multinucleated cell formation in long-term human marrow culture or osteoblast function, depending on the cytokine profile produced. These results are consistent with functional contributions of cytokines to osseointegration and minimization of posterior edentulous zone bone resorption.