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Biomedical subjects

D Novick

Publications and source records attributed to D Novick.

At least 37 records · Page 2Linked to original sources

IL-18 regulates IL-1beta-dependent hepatic melanoma metastasis via vascular cell adhesion molecule-1.

Proinflammatory cytokines, including IL-1beta and tumor necrosis factor-alpha (TNF-alpha), promote cancer cell adhesion and liver metastases by up-regulating the expression of vascular cell adhesion molecule-1 (VCAM-1) on hepatic sinusoidal endothelium (HSE). In this study, hepatic metastasis after intrasplenically injected mouse B16 melanoma (B16M) cells was reduced 84-95% in mice with null mutations for either IL-1beta or the IL-1beta-converting enzyme (ICE, caspase-1) compared with wild-type mice. On day 12, 47% of wild-type mice were dead compared with 19% of either IL-1beta or ICE-deficient mice. In vitro, conditioned medium from B16M cells (B16M-CM) induced the release of TNF-alpha and IL-1beta from cultures of primary murine HSE. The effect of B16M-CM on HSE resulted in increased numbers of B16M cells adhering to HSE, which was completely abrogated by a specific inhibitor of ICE, anti-IL-18 or IL-18-binding protein. Exogenous IL-18 added to HSE also increased the number of adhering melanoma cells; however, this was not affected by IL-1 receptor blockade or TNF neutralization but rather by anti-VCAM-1. These results demonstrate a role for IL-1beta and IL-18 in the development of hepatic metastases of B16M in vivo. In vitro, soluble products from B16M cells stimulate HSE to sequentially release TNF-alpha, IL-1beta, and IL-18. The IL-18 cytokine increases expression of VCAM-1 and the adherence of melanoma cells.

Animals↗

Subcutaneous administration of recombinant glycosylated interleukin 6 in patients with cancer: pharmacokinetics, pharmacodynamics and immunomodulatory effects.

This is the first report of the serum profile of a glycosylated recombinant form of human IL-6 (rhIL-6) administered subcutaneously (1-10 microg/kg/day) in a phase I/II trial as a thrombopoietic agent in patients with advanced cancer. The pharmacodynamic effects of IL-6 were also examined. Detailed pharmacokinetic measurements were made in four patients. Peak concentrations at 5-8 h and a median t0.5 of ca. 5 h were similar to those previously reported for non-glycosylated IL-6. However, higher peak concentrations and apparent differences in effective dose levels to those previously reported with the non-glycosylated form were seen. Indications of an apparent attenuation in circulating IL-6 concentrations with continuing injections were seen in eight of 10 patients examined but anti-IL-6 antibody generation was seen in only two patients. Soluble interleukin 6 receptor concentrations generally decreased. No major changes in T cell subsets were seen but expression of CD25 and CD54 by T lymphocytes significantly increased, accompanied by marked increases in soluble CD25 (sIL-2R) and CD54 (sICAM-1). No consistent change in B cells, monocytes or NK cells were seen. No evidence for induction of TNF-alpha was found. This study demonstrates similar biological effects of glycosylated rhIL-6 to those reported for the non-glycosylated form but illustrates several apparent differences which are discussed further.

Adjuvants, Immunologic↗

Production of a biologically active human interleukin 18 requires its prior synthesis as PRO-IL-18.

Interleukin (IL-)18 is an activator of NK cells and a co-inducer of Th(1)cytokines, sharing structural features with the IL-1 family of proteins. Unlike most other cytokines, IL-18 and IL-1beta lack a signal peptide, have an all beta-pleated sheet structure and are synthesized as biologically inactive precursors (pro-IL-18 and pro-IL-1beta). These precursors are cleaved by caspase-1 (IL-1beta-converting enzyme, ICE) to form the biologically active mature cytokines. Direct expression of mature recombinant human IL-18 in E. coli resulted in a partially active cytokine. We tested the possibility that correct folding of huIL-18 requires its prior synthesis as pro-IL-18. Because caspase-1 is not readily available, we constructed an expression vector encoding human pro-IL-18 in which the caspase-1 cleavage site was mutated into a factor Xa site. To facilitate purification, the mutated pro-IL-18 cDNA was fused in frame to a glutathione-S-transferase (GST) coding sequence. The GST-pro-IL-18 fusion protein was expressed in E. coli, captured on glutathione agarose and mature human IL-18, exhibiting high biological activity was released upon cleavage with factor Xa. This result indicates that correct folding of huIL-18 occurs at the level of pro-IL-18 and provides a practical way to produce biologically active huIL-18.

Amino Acid Sequence↗

Cytokines and soluble cytokine receptor induction after IL-12 administration in cancer patients.

This study shows that subcutaneous administration of increasing doses of IL-12, once a week, in 21 cancer patients increased the expression of cytokine genes (interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), IP-10, MIG, IL-10, IL-4) in peripheral blood mononuclear cells even at very low doses (30 ng/kg). Surprisingly, no circulating TNF-alpha or IL-4 could be detected in the plasma of patients treated with IL-12. However, a marked increase of soluble IL-4 receptor was demonstrated in the plasma of five of the six patients studied, which may represent an additional mechanism by which IL-12 inhibits the development of the Th2 response in vivo. A marked decline of IFN-gamma and IP10 induction was recorded after repeated cycles of IL-12. In contrast, in most patients IL-12 increased IL-10 expression with no subsequent decrease during the course of therapy, and even an earlier peak of IL-10 induction at the 6th cycle. In addition, a constant up-regulation of serum soluble IFN-gamma receptor levels was observed after each cycle of IL-12 treatment with a delayed peak compared with the IFN-gamma peak. The constant rise of IL-10 and soluble IFN-gamma receptor during IL-12 therapy may therefore contribute to the inhibition of IFN-gamma activity detected after repeated cycles of IL-12. Lastly, a marked heterogeneity of cytokine induction was observed from one patient to another, which appeared to be independent of the dose of IL-12 administered. These data may lead to a better understanding of the biological activity of IL-12 and the in vivo mechanisms of its regulation.

Antineoplastic Agents↗

The neutralization of type I IFN biologic actions by anti-IFNAR-2 monoclonal antibodies is not entirely due to inhibition of Jak-Stat tyrosine phosphorylation.

A panel of monoclonal antibodies (mAb) derived against human interferon-alpha/beta receptor-2 (IFNAR-2) was evaluated for their ability to antagonize the biologic effects of type 1 interferons (IFN-alpha1, IFN-alpha2a, and IFN-beta). Anti-IFNAR-2 mAb 117.7, 35.9, 53.2, and 51.44 neutralized type I IFN-mediated antiviral, antiproliferative, and major histocompatibility complex (MHC) class I upregulation functions. However, only mAb 51.44 neutralized IFN-alpha2a and IFN-beta-mediated natural killer (NK) cell cytotoxicity. In BIAcore and cell binding studies, only mAb 51.44 and 234.28 inhibited IFN-alpha2a and IFN-beta binding to its receptor. The receptor blockade by mAb 51.44 and 234.28 resulted in the inhibition of IFN-alpha2a and IFN-beta-induced tyrosine phosphorylation of Jak1, Tyk2, Stat1/2/3, and IFNAR-1/2 and inhibition of IFN-stimulated gene factor 3 (ISGF3) formation. mAb 117.7, 35.9, and 53.2, although antagonists of IFN's biologic activities, did not block the binding of IFN-alpha/beta to its receptor. The 117.7 mAb, representative of this class of receptor nonblocking mAb, induced hyper-tyrosine phosphorylation of IFNAR-2 in the presence of IFN-alpha/beta but did not inhibit IFN-alpha/beta-induced Jak-Stat tyrosine phosphorylation and ISGF3 complex formation. These results show that the neutralization of type I IFN biologic actions by anti-IFNAR-2 mAb cannot be entirely explained by inhibition of Jak-Stat tyrosine phosphorylation.

Antibodies, Monoclonal↗

C-reactive protein: a physiological activator of interleukin 6 receptor shedding.

The soluble interleukin 6 receptor (sIL-6R) circulates at elevated levels in various diseases. This suggests that inflammatory mediators control sIL-6R release. Through examination of human neutrophils, it was found that the acute phase reactant C-reactive protein (CRP) activates a threefold increase in sIL-6R production. Maximal release occurred after 30-60 min exposure to CRP (50 micrograms/ml), and was mimicked by peptides corresponding to amino acid residues 174- 185 and 201-206 of native CRP. A third peptide fragment (77-82) had no effect. Differential mRNA splicing did not account for the CRP-mediated release of sIL-6R, since this isoform was not detected in conditioned media. Furthermore, stimulation of neutrophils with CRP or with peptides 174-185 or 201-206 promoted a loss of membrane-bound IL-6R, suggesting release by proteolytic shedding. The metalloprotease inhibitor TAPI had only a marginal effect on CRP-mediated sIL-6R release, suggesting that shedding occurs via a mechanism distinct from that previously reported. It well established that IL-6 stimulates the acute phase expression of CRP. Our current findings demonstrate a novel relationship between these two mediators, since CRP may affect IL-6-mediated inflammatory events by enabling formation of the sIL-6R/IL-6 complex.

Acute-Phase Reaction↗

Interleukin-18 binding protein: a novel modulator of the Th1 cytokine response.

An interleukin-18 binding protein (IL-18BP) was purified from urine by chromatography on IL-18 beads, sequenced, cloned, and expressed in COS7 cells. IL-18BP abolished IL-18 induction of interferon-gamma (IFNgamma), IL-8, and activation of NF-kappaB in vitro. Administration of IL-18BP to mice abrogated circulating IFNgamma following LPS. Thus, IL-18BP functions as an inhibitor of the early Th1 cytokine response. IL-18BP is constitutively expressed in the spleen, belongs to the immunoglobulin superfamily, and has limited homology to the IL-1 type II receptor. Its gene was localized on human chromosome 11q13, and no exon coding for a transmembrane domain was found in an 8.3 kb genomic sequence. Several Poxviruses encode putative proteins highly homologous to IL-18BP, suggesting that viral products may attenuate IL-18 and interfere with the cytotoxic T cell response.

Amino Acid Sequence↗

Interleukin 18 stimulates HIV type 1 in monocytic cells.

The cytokine interleukin (IL) 18 (formerly interferon gamma-inducing factor) induces the T helper type 1 response. In the present studies, IL-18 increased HIV type 1 (HIV-1) production from 5- to 30-fold in the chronically infected U1 monocytic cell line. Inhibition of tumor necrosis factor (TNF) activity by the addition of TNF-binding protein reduced IL-18-stimulated HIV-1 production by 48%. In the same cultures, IL-18-induced IL-8 was inhibited by 96%. Also, a neutralizing anti-IL-6 mAb reduced IL-18-induced HIV-1 by 63%. Stimulation of U1 cells with IL-18 resulted in increased production of IL-6, and exogenous IL-6 added to U1 cells increased HIV-1 production 4-fold over control. A specific inhibitor of the p38 mitogen-activated protein kinase reduced IL-18-induced HIV-1 by 73%, and a 50% inhibition was observed at 0.05 microM. In the same cultures, IL-8 was inhibited by 87%. By gel-shift and supershift analyses, increased binding activity of the transcription factor NF-kappaB was measured in nuclear extracts from U1 cells 1 h after exposure to IL-18. These results demonstrate induction of HIV-1 by IL-18 in a monocyte target associated with an intermediate role for TNF and IL-6, activation of p38 mitogen-activated protein kinase, and nuclear translocation of NF-kappaB.

Base Sequence↗

Shedding of the soluble IL-6 receptor is triggered by Ca2+ mobilization, while basal release is predominantly the product of differential mRNA splicing in THP-1 cells.

The soluble IL-6 receptor (sIL-6R) is generated through either proteolytic shedding of the cognate receptor (PC-sIL-6R), or released as the product of differential mRNA splicing (DS-sIL-6R). Using monocytic THP-1 cells, we demonstrate that both mechanisms are independently regulated, and that each process contributes to sIL-6R production. Shedding of the IL-6R was activated by the Ca2+ ionophore, ionomycin, and inhibited by the TNF-alpha protease inhibitor (TAPI). In contrast, basal sIL-6R release was unaffected by Ca2+ depletion and largely insensitive to TAPI. Moreover, although IL-6R shedding was inactivated by serum starvation, non-stimulated production remained intact. Basal sIL-6R production via differential mRNA splicing was shown through the inhibitory action of brefeldin A and an enzyme-linked immunosorbent assay specific for DS-sIL-6R. Release of this isoform was unaffected by ionomycin or TAPI, indicating that Ca2+ mobilization activates PC-sIL-6R generation, but not DS-sIL-6R. The divergent control of these sIL-6R isoforms indicates that they may independently influence the inflammatory response.

Animals↗

Overview of interleukin-18: more than an interferon-gamma inducing factor.

Initially described in 1989 as interferon-gamma (IFN-gamma) inducing factor (IGIF), interleukin-18 (IL-18) is a novel pro-inflammatory cytokine that is clearly more than an inducer of IFN-gamma. The cytokine possesses several biological properties such as activation of nuclear factor-kappaB (NF-kappaB), Fas ligand expression, the induction of both CC and CXC chemokines, and increased production of competent human immunodeficiency virus. Most activities are due to a receptor complex that recruits the IL-1 receptor-activating kinase (IRAK), leading to translocation of NF-kappaB. This property and others support the concept that IL-18 is related to the IL-1 family. Indeed, one of the IL-18 receptor chains is the IL-1 receptor-related protein, a member of the IL-1R family. In addition, IL-18 is structurally similar to IL-1beta and like IL-1beta is first synthesized as a leaderless precursor requiring the IL-1beta converting enzyme for cleavage into an active molecule. The biology of IL-18 is reviewed in the overview and the implication for a role for this cytokine in disease is presented.

Animals↗

Mammalian type I interferon receptors consists of two subunits: IFNaR1 and IFNaR2.

The human type I interferon (IFN) receptor consists of two essential subunits, huIFNaR1 and huIFNaR2; however, so far only IFNaR1 has been identified in other species. Furthermore, it has been suggested that in some species the type I IFN receptor may consist of a single subunit, since expression of murine IFNaR1 in human cells rendered them responsive to several type I murine IFNs. To resolve this issue, we screened a mouse cDNA library with a probe derived from huIFNaR2 cDNA. A cDNA clone, coding for a transmembrane protein which has 49% identity with huIFNaR2 was isolated. This level of identity suggests that this cDNA codes for a muIFNaR2. In addition, several cDNA clones, coding for two distinct soluble variants of muIFNaR2 were identified. To test whether muIFNaR2 is a functional component of the receptor, we co-expressed it with muIFNaR1 in human cells and with an IFN-responsive luciferase reporter vector. Treatment of these cells with muIFN-beta induced high levels of luciferase, whereas no induction was obtained in cells expressing only one of the two subunits. We therefore conclude that the murine type I IFN receptor consists of two different subunits--a configuration shared by humans, and probably all other mammals.

Amino Acid Sequence↗

Mechanism(S) of interferon inhibitory activity in blood from patients with AIDS and patients with lupus erythematosus with vasculitis.

We have earlier reported that patients suffering from acquired immuno-deficiency syndrome (AIDS), systemic lupus erythematosus (SLE) with vasculitis, Wegner granulomatosis and certain types of late stage cancer have interferon inhibitory activity in their serum. The purpose of this study was to identify the factor(s) involved in this interferon inhibitory activity. Twenty patients with advanced AIDS, twenty patients with SLE and vasculitis and twenty normal healthy controls between ages 25-40 years were studied. In contrast to normal, healthy controls, significant interferon inhibitory activity was found in AIDS and SLE patients. This appears to be largely due to: (a) increased soluble circulating interferon alpha/beta receptors, (b) increased prostaglandin E2 levels which inhibits interferon and (c) a interferon inhibitory protein. Further understaging of the nature of interferon inhibitory activity in the patient's sera and development of anti-interferon inhibitory agents would greatly enhance interferons potential as a treatment modality.

3',5'-Cyclic-AMP Phosphodiesterases↗

Concentrations and origins of soluble interleukin 6 receptor-alpha in serum and synovial fluid.

OBJECTIVE: To determine levels of soluble interleukin 6 receptor-alpha (sIL-6R alpha) in synovial fluid (SF) and serum from patients with different rheumatic diseases, and to analyze its cellular origin compared to IL-6. METHODS: IL-6 and sIL-6R alpha concentrations were measured in sera, SF, and culture supernatants of different cells types using specific sandwich ELISA. RESULTS: IL-6 levels were significantly higher (30 to 1000-fold) in SF than in sera, and higher in inflammatory arthropathies such as rheumatoid arthritis (RA), chondrocalcinosis, and gout than in osteoarthritis (OA). sIL-6R alpha levels in SF from patients with RA, gout, and chondrocalcinosis were also higher (24.7 +/- 7.5, 23.2 +/- 9.1, and 19.5 +/- 7.4 ng/ml, respectively) than in patients with OA (10.1 +/- 5 ng/ml), although the difference was distinctly smaller. In contrast, sIL-6R alpha concentrations did not differ significantly between the sera of healthy donors and patients. sIL-6R alpha levels were similar in SF and sera from inflammatory arthropathies, but lower in all osteoarthritic SF, compared to their corresponding serum. In contrast to IL-6, sIL-6R alpha was produced in high amounts by hepatocytes but not by structural cells of the joint (chondrocytes, synoviocytes, fibroblasts, and endothelial cells). Polymorphonuclear cells and mononuclear cells released intermediate levels. A significant correlation between sIL-6R alpha concentration and total number of leukocytes was observed in SF. CONCLUSION: Elevated levels of sIL-6R alpha were found in serum, likely to result from a marked release by hepatocytes in vitro. That levels are higher in inflammatory SF may be due in part to release by inflammatory cells in situ.

Antigens, CD↗

Soluble interferon-gamma receptor and interferon-gamma in patients undergoing allogeneic bone marrow transplantation for hematological malignancies.

Interferon-gamma (IFN-gamma) is known to be involved in graft rejection of solid organs and acute graft-versus-host disease (GVHD). Its role, and especially that of soluble IFN-gamma receptor (sIFN-gamma R), in bone marrow transplantation (BMT) has not been established. We evaluated the sera of 27 patients following BMT. Fourteen of them underwent uneventful BMT, whereas 13 developed transplant-related complications, including acute GVHD (n = 5), early rejection (n = 4), or relapse of basic disease (n = 4). Soluble IFN-gamma R and IFN levels were evaluated at day -10 (preconditioning), day 0 (day of BMT), day of engraftment, and during BMT-related complications using sIFN-gamma R-specific monoclonal antibodies (McAB) followed by double-sandwich ELISA, and a sensitive radioimmunoassay respectively. In normal controls (n = 80) sIFN-gamma R and IFN-gamma levels in the sera were 0.5 +/- 0.05 and 0.3 +/- 0.04 ng/ml respectively. Soluble IFN-gamma R levels increased in direct correlation with engraftment (0.63 +/- 0.11 ng/ml at the day of BMT to 1.43 +/- 0.16 ng/ml at the day of engraftment; n = 14; P < 0.001). IFN-gamma levels increased in direct correlation with engraftment (0.37 +/- 0.03 ng/ml at the day of BMT to 5.69 +/- 1.64 ng/ml at the day of engraftment; n = 14; P < 0.001). In five patients with GVHD sIFN-gamma R levels increased from 0.43 +/- 0.19 ng/ml at the day of BMT to 1.73 +/- 0.17 ng/ml (P < 0.004) at the time of GVHD. Similarly, IFN-gamma levels increased from 0.43 +/- 0.08 ng/ml at the day of BMT to 3.03 +/- 0.5 ng/ml at the time of GVHD (P < 0.05). Both graft rejection and early relapse were associated with an elevation of IFN-gamma levels. In short, both s-IFN-gamma R and IFN-gamma were found to be significantly elevated during engraftment and GVHD. Hence these cytokines may be used as a tool for assessing engraftment and AGVHD.

Adolescent↗

Modulation of insulin activities by leptin.

Leptin mediates its effects on food intake through the hypothalamic form of its receptor OB-R. Variants of OB-R are found in other tissues, but their function is unknown. Here, an OB-R variant was found in human hepatic cells. Exposure of these cells to leptin, at concentrations comparable with those present in obese individuals, caused attenuation of several insulin-induced activities, including tyrosine phosphorylation of the insulin receptor substrate-1 (IRS-1), association of the adapter molecule growth factor receptor-bound protein 2 with IRS-1, and down-regulation of gluconeogenesis. In contrast, leptin increased the activity of IRS-1-associated phosphatidylinositol 3-kinase. These in vitro studies raise the possibility that leptin modulates insulin activities in obese individuals.

Adaptor Proteins, Signal Transducing↗

Soluble interleukin-6 receptors in hematology patients undergoing bone marrow transplantation.

Soluble interleukin-6 receptor (sIL-6R) has previously been shown to potentiate the activity of interleukin (IL)-6, which may display antitumor activity. We evaluated sIL-6R and IL-6 levels in the sera of 24 patients following transplantation (allogeneic, n=17; autologous, n=7). Five patients developed acute graft-versus-host disease (AGVHD), three had early graft rejection, and three had an early relapse following bone marrow transplantation (BMT). Soluble IL-6R levels were evaluated at day - 10, day 0, day of engraftment, and during BMT-related complications, using IL-6R-specific monoclonal antibodies (mAb) and double-sandwich ELISA. In normal controls, sIL-6R and IL-6 levels were 20+/-3 ng/ml and 0.01+/-0.005 ng/ml, respectively. Soluble IL-6R levels increased in direct correlation with engraftment in the uneventful allogeneic transplants (17.7+/-2.1 ng/ml at day 0 to 49.7+/-2.6 ng/ml at day of engraftment, n=6, P<0.05) as well as in the autologous transplants (26.8+/-2.82 at day 0 to 66.4+/-12.9 at day of engraftment, n=5, P=0.01). In contrast, IL-6 levels declined with time during the conditioning period and showed only a modest elevation following BMT. Increased levels of sIL-6R and IL-6 were found in the patients who developed AGVHD (23.8+/-4.2 and 0+/-0 ng/ml at day 0 to 79+/-6.9 and 0.26+/-0.04 ng/ml, respectively, at time of AGVHD, n=5, P=0.01). No correlation was found between the severity of AGVHD and sIL-6R levels. In the three patients with early relapse, sIL-6R levels increased from 30+/-0 ng/ml at day 0 to 90 ng/ml (P=0.05) and IL-6 levels increased from 0 to 0.16+/-0 ng/ml, respectively. The mean elevation of sIL-6R in the patients with early relapse and AGVHD was significantly higher than the mean elevation in the patients with the relatively smooth engraftment (P<0.05). Contrary to these findings, in the three patients with graft rejection, sIL-6R levels decreased while IL-6 was found to be elevated. Basic disease, conditioning regimen, type of transplant, GVHD propylaxis, and T cell depletion had no effect on sIL-6R or IL-6 levels. In summary, sIL-6R levels positively correlated with engraftment. Both sIL-6R and IL-6 levels were found to be significantly elevated in patients who developed AGVHD or early relapse following BMT. Therefore, the sIL-6R level may be used as a tool for assessing engraftment and transplant-related complications following BMT.

Acute Disease↗

Cutaneous CD56+ large T-cell lymphoma associated with high serum concentration of IL-2.

We report the case of a patient with a clinically aggressive large cell lymphoma (LCL) which expressed several T-lymphocyte markers and, in addition, CD56 and, to a lesser degree, CD68 antigens. A marked increase in serum concentration of interleukin (IL)-2 was found (490 and 167 pg/0.1 mL in two serum samples collected 6 months apart). This increase in IL-2 appeared unique to this lymphoma because serum concentration of IL-2 was not increased in any of the cases of various types of cutaneous lymphoproliferative disorders tested: mycosis fungoides-related cutaneous T-cell lymphoma (CTCL: 28 patients), granulomatous slack-skin syndrome (GS-SS: 1 patient), anaplastic large cell lymphoma (ALCL: 2 patients), subcutaneous gamma/delta T-cell lymphoma (gamma/delta-TCL: 1 patient), adult-type leukemia/lymphoma (ATLL: 1 patient), and lymphomatoid papulosis (LyP: 4 patients). Furthermore, the increase in IL-2 serum concentration appeared selective in this CD56+ large-cell lymphoma-bearing patient, because concentration of none of the five other cytokines tested (IL-4, IL-6, IFNgamma, GM-CSF, and TNFalpha) was increased. In contrast, soluble receptors for IL-2 and two of the other cytokines (IL-6, and TNFalpha) were markedly increased not only in this patient, but also in most patients with the other cutaneous lymphoproliferative disorders that we examined except for lymphomatoid papulosis. These data indicate that increased IL-2 serum concentration may help to diagnose a unique type of cutaneous CD56(+) large (T-) cell lymphoma and suggest that IL-2 way play a role of an autocrine growth factor for this lymphoma.

Aged↗

Immunohistochemical studies of proinflammatory cytokines and their receptors in hair follicles of normal human skin.

Immunoreactivity to interleukin-1 alpha, interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha and their receptors, as well as the endogenous interleukin-1 receptor antagonist, was investigated in hair follicles in paraffin-embedded normal human skin. Interleukin-1 beta- and tumour necrosis factor-alpha-like immunoreactivities were found in the inner root sheath layer of hair follicles, at the suprapapillary level. Interleukin-1 receptor-like immunoreactivity was also found in this layer, while there was a variable immunoreactivity to the interleukin-1 receptor antagonist. In the outer root sheath there was a weak to moderate staining for the four cytokines, in addition to intense staining for their receptors and a weak staining for the antagonist. The fibrous root sheath had a moderate immunoreactivity for interleukin-1 alpha and interleukin-6. The distribution patterns suggest that these cytokines, particularly interleukin-1 beta and tumour necrosis factor-alpha, may have a protective role in hair formation, while all the investigated proinflammatory cytokines may have a role in the differentiation process.

Adult↗