Hormonal regulation of complement biosynthesis in human cell lines--II. Upregulation of the biosynthesis of complement components C3, factor B and C1 inhibitor by interleukin-6 and interleukin-1 in human hepatoma cell line

Curcuma longa extract improves serum inflammatory markers and mental health in healthy participants who are overweight: a randomized, double-blind, placebo-controlled trial

Background

The dietary spice Curcuma longa, also known as turmeric, has various biological effects. Both a water extract and a supercritical carbon dioxide extract of C. longa showed anti-inflammatory activities in animal studies. However, the anti-inflammatory effect in humans of a mixture of these two C. longa extracts (CLE) is poorly understood. Therefore, we investigated the effect of CLE containing anti-inflammatory turmeronols on chronic inflammation and general health.

Methods

We performed a randomized, double-blind, placebo-controlled study in healthy subjects aged 50 to 69 years with overweight. Participants took two capsules containing CLE (CLE group, n = 45) or two placebo capsules (placebo group, n = 45) daily for 12 weeks, and serum inflammatory markers were measured. Participants also completed two questionnaires: the Medical Outcomes Study (MOS) 36-Item Short-Form Health Survey (SF-36) and the Profile of Mood States (POMS) scale. Treatment effects were analyzed by two way analysis of variance followed by a t test (significance level, p <  0.05).

Results

After the intervention, the CLE group had a significantly lower body weight (p <  0.05) and body mass index (p < 0.05) than the placebo group and significantly lower serum levels of C-reactive protein (p < 0.05) and complement component 3 (p < 0.05). In addition, the CLE group showed significant improvement of the MOS SF-36 mental health score (p < 0.05) and POMS anger-hostility score (p < 0.05).

Conclusion

CLE may ameliorate chronic low-grade inflammation and thus help to improve mental health and mood disturbance.

Trial registration

UMIN-CTR, UMIN000037370. Registered 14 July 2019, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000042607

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00748-8.

Scientific memory from the early nineties; a common project with professors late János Gergely and Anna Erdei

Based on the findings of common project 29 years ago, the Scandinavian J. of Immunology accepted and published our paper entitled by "FcγR-Dependent Regulation of the Biosynthesis of Complement C3 by Murine Macrophages: the Modulatory Effect of IL-6" (Bajtay et al. in SJI 35:195-201, 1992). In this report we attempt to review the previous results and evaluate them with our current concepts on the interaction between the actors of adaptive and innate immunity. Let us first to summarize the basic results and consequences from the paper from 1992. Abstract from 1991-1992: The effect of murine IgG isotypes (myeloma proteins) on the gene expression and secretion of the third component of complement (C3) has been studied using the in monocytoid cell line P388D1 and oil-elicited mouse peritoneal macrophages. It is demonstrated that the binding of lgG2a and lgG2b but not IgGl and IgG3 isotypes augments the biosynthesis of C3 both in the presence and in the absence of the phorbol myristate acetate in the case of both cell types. The multifunctional cytokine inlerleukin-6 (IL-6) alone reveals no effect on the gene expression of C3, but facilitates the effectiveness of mouse IgG2a and IgG2b. Confirming the role of FcgRll, a strong up-regulation of gene expression and secretion of C3 was found when macrophages were co-cultured with the F(ab')2 fragment of the FcγRII-specific monoclonal antibody 2.4 G2.

Diabetes Induced Alterations in Murine Vitreous Proteome Are Mitigated by IL-6 Trans-Signaling Inhibition

Purpose

Diabetic retinopathy (DR) is a microvascular complication caused by prolonged hyperglycemia and characterized by leaky retinal vasculature and ischemia-induced angiogenesis. Vitreous humor is a gel-like biofluid in the posterior segment of the eye between the lens and the retina. Disease-related changes are observed in the biochemical constituents of the vitreous, including proteins and macromolecules. Recently, we found that IL-6 trans-signaling plays a significant role in the vascular leakage and retinal pathology associated with DR. Therefore, in this study, comprehensive proteomic profiling of the murine vitreous was performed to identify diabetes-induced alterations and to determine effects of IL-6 trans-signaling inhibition on these changes.

Methods

Vitreous samples from mice were collected by evisceration, and proteomic analyses were performed using liquid chromatography–tandem mass spectrometry (LC-MS/MS).

Results

A total of 154 proteins were identified with high confidence in control mice and were considered to be characteristic of healthy murine vitreous fluid. The levels of 72 vitreous proteins were significantly altered in diabetic mice, including several members of heat shock proteins, 14-3-3 proteins, and tubulins. Alterations in 52 out of 72 proteins in diabetic mice were mitigated by IL-6 trans-signaling inhibition.

Conclusions

Proteomic analysis of murine vitreous fluid performed in this study provides important information about the changes caused by diabetes in the ocular microenvironment. These diabetes-induced alterations in the murine vitreous proteome were mitigated by IL-6 trans-signaling inhibition. These findings further support that IL-6 trans-signaling may be an important therapeutic target for the treatment of DR.

Complement Activation in Liver Transplantation: Role of Donor Macrosteatosis and Implications in Delayed Graft Function

The complement system anchors the innate inflammatory response by triggering both cell-mediated and antibody-mediated immune responses against pathogens. The complement system also plays a critical role in sterile tissue injury by responding to damage-associated molecular patterns. The degree and duration of complement activation may be a critical variable controlling the balance between regenerative and destructive inflammation following sterile injury. Recent studies in kidney transplantation suggest that aberrant complement activation may play a significant role in delayed graft function following transplantation, confirming results obtained from rodent models of renal ischemia/reperfusion (I/R) injury. Deactivating the complement cascade through targeting anaphylatoxins (C3a/C5a) might be an effective clinical strategy to dampen reperfusion injury and reduce delayed graft function in liver transplantation. Targeting the complement cascade may be critical in donor livers with mild to moderate steatosis, where elevated lipid burden amplifies stress responses and increases hepatocyte turnover. Steatosis-driven complement activation in the donor liver may also have implications in rejection and thrombolytic complications following transplantation. This review focuses on the roles of complement activation in liver I/R injury, strategies to target complement activation in liver I/R, and potential opportunities to translate these strategies to transplanting donor livers with mild to moderate steatosis.

Hepatitis C virus infection upregulates CD55 expression on the hepatocyte surface and promotes association with virus particles

CD55 limits excessive complement activation on the host cell surface by accelerating the decay of C3 convertases. In this study, we observed that hepatitis C virus (HCV) infection of hepatocytes or HCV core protein expression in transfected hepatocytes upregulated CD55 expression at the mRNA and protein levels. Further analysis suggested that the HCV core protein or full-length (FL) genome enhanced CD55 promoter activity in a luciferase-based assay, which was further augmented in the presence of interleukin-6. Mutation of the CREB or SP-1 binding site on the CD55 promoter impaired HCV core protein-mediated upregulation of CD55. HCV-infected or core protein-transfected Huh7.5 cells displayed greater viability in the presence of CD81 and CD55 antibodies and complement. Biochemical analysis revealed that CD55 was associated with cell culture-grown HCV after purification by sucrose density gradient ultracentrifugation. Consistent with this, a polyclonal antibody to CD55 captured cell culture-grown HCV. Blocking antibodies against CD55 or virus envelope glycoproteins in the presence of normal human serum as a source of complement inhibited HCV infection. The inhibition was enhanced in the presence of both the antibodies and serum complement. Collectively, these results suggest that HCV induces and associates with a negative regulator of the complement pathway, a likely mechanism for immune evasion.

IL-6, but not TNF-α, increases plasma YKL-40 in human subjects

Plasma levels of YKL-40 are elevated in patients with systemic infection, inflammatory disorders and cancer. Both monocytes/macrophages, neutrophils, and cancer cells have the capacity to produce YKL-40, but the regulation during the inflammatory response is unknown. To study the possible role of interleukin-6 (IL-6) and tumor necrosis factor (TNF)-α in the regulation of YKL-40 plasma levels, we included healthy men, who received either recombinant human (rh)IL-6 (n=6), rhTNF-α (n=8) or vehicle (n=7) for 3h. The plasma levels of IL-6 and TNF-α reached ∼ 150 and ∼ 18 pg/ml, respectively, during the infusions. Following the IL-6 infusion, the plasma level of YKL-40 increased from ∼ 30 to ∼ 57 ng/ml (p<0.05) at 24h, and returned to normal values after 48 h. The plasma level of YKL-40 did not change during TNF-α infusion or infusion of vehicle. These data demonstrate that IL-6, but not TNF-α, has a key-role in the regulation of plasma YKL-40 levels during inflammation.

Long-term efficacy of danazol treatment in hereditary angioedema

BACKGROUND

No systematic study has been published yet on the long-term efficacy of attenuated androgens in hereditary angioedema (HAE). Our aim was to conduct a follow-up study in two (German and Hungarian) cohorts of HAE patients (45 and 39 patients, respectively) undergoing uninterrupted treatment for 6 years with similar (starting dose 128 ± 78 mg per day and 136 ± 70 mg per day, respectively) and constant doses of danazol.

DESIGN

The frequencies of subcutaneous, abdominal and laryngeal attacks were recorded each year.

RESULTS

The annual frequency of all the three types of attacks was significantly lower during the first year of danazol treatment, compared to the last year before baseline. During subsequent years in Hungarian patients, the frequency of both subcutaneous and abdominal attacks - but not that of laryngeal attacks - increased significantly. In the case of abdominal attacks, a significant increase in the attack frequency was observed only in female patients. In the German cohort, by contrast, no change in the frequency of either type of attack was found during the 6-year study period.

CONCLUSIONS

The differences observed between these cohorts cannot be related to drug dose, the age or gender distribution of subjects or the age at the onset of symptoms or the length of diagnostic delay in the patients. There were, however, marked differences in the baseline pattern of attacks: significantly - 3 times - more abdominal attacks were recorded in German patients. Further studies are necessary to clarify the mechanism of these findings.

Local renal complement C3 induction by donor brain death is associated with reduced renal allograft function after transplantation

BACKGROUND

Kidneys derived from brain-dead donors have inferior outcomes after transplantation compared to kidneys from living donors. Strikingly, early and profound serum levels of IL-6 in brain-dead donors are observed. IL-6 is the main regulator of the acute phase response (APR). The aim of this translational study was to investigate the expression of renal acute phase proteins (APPs) following brain death (BD) and to assess the association with renal allograft outcome after transplantation.

METHODS

BD was induced in rats by inflating a subdurally placed balloon catheter. Kidney biopsies were obtained from human living and brain-dead donors at donation, after cold preservation and reperfusion. In vitro, renal proximal tubular epithelial cells (HK-2 cells) were stimulated with IL-6.

RESULTS

Both in human and rat brain-dead donors, C3 and FBG expression was enhanced at donation compared to living donors and sham-operated animals. In human donors, no additional expression was found after cold ischaemia or reperfusion. C3 expression after reperfusion was independently associated with decreased short-term function after transplantation in grafts from brain-dead donors. In cultured HK-2 cells, C3 production was induced in the presence of IL-6.

CONCLUSIONS

In conclusion, BD induces renal C3 and FBG expression. Moreover, C3 expression is associated with a worse allograft function early after transplantation. Therefore, targeting renal APPs in brain-dead donors, especially complement C3, may improve transplant outcome.

C1 inhibitor: just a serine protease inhibitor? New and old considerations on therapeutic applications of C1 inhibitor

C1 inhibitor is a potent anti-inflammatory protein as it is the major inhibitor of proteases of the contact and the complement systems. C1-inhibitor administration is an effective therapy in the treatment of patients with hereditary angioedema (HAE) who are genetically deficient in C1 inhibitor. Owing to its ability to modulate the contact and complement systems and the convincing safety profile, plasma-derived C1 inhibitor is an attractive therapeutic protein to treat inflammatory diseases other than HAE. In the present review we give an overview of the biology of C1 inhibitor and its use in HAE. Furthermore, we discuss C1 inhibitor as an experimental therapy in diseases such as sepsis and myocardial infarction.

Hostility, anger, and depression predict increases in C3 over a 10-year period

We examined the relation of hostility, anger, and depression to 10-year changes in the third (C3), and fourth (C4) complement in 313, apparently healthy male participants enrolled in the Air Force Health Study (AFHS), a 20-year study designed to evaluate the health consequences of dioxin exposure. Hostility, depression, and anger were assessed using subscales from the Minnesota Multiphasic Personality Inventory (MMPI), which was administered in 1985. Given the high intercorrelations among these psychological scales, we used a principal component analysis to generate a composite score representing the linear combination of the hostility, anger, and depression scales. The dependent variables, C3 and C4 levels, were determined from samples collected in 1992, 1997, and 2002. Regression analyses controlling for age, race, alcohol use, body mass index, and cigarette use as well as onset of disease, and use of lipid lowering and blood pressure medications during follow-up revealed a significant timexcomposite score interaction for C3 complement (p<.0003), but not C4. Post-hoc analyses revealed that high composite scores were associated with larger 10-year increases in C3. These observations suggest that men who are hostile and are prone to experience frequent and intense feelings of anger, and depression show activation of the complement system, and specifically increases in C3, that may contribute to the development of coronary heart disease.

The C3 subtypes are differentially regulated after immunostimulation in rainbow trout, but head kidney macrophages do not contribute to C3 transcription

The complement system plays key roles in innate and adaptive immunity through mediating phagocytosis, chemotaxis and cell lysis. Complement component C3 is a central component in the complement cascade and belongs to the acute-phase proteins whose synthesis increase immediately upon inflammatory stimuli. The liver is the main producer of C3 and it is a well-known fact that the mammalian monocyte-macrophage lineage is a major contributor to extrahepatic C3. Immunomodulators, such as LPS and beta-glucan, can stimulate complement, lysozyme, natural killer cells and antibody responses in fish, thus enhancing the resistance to bacterial pathogens and parasitic infections. The aim of this study was to assess the effects of LPS and beta-glucan on the expression of interleukins (IL-1beta1, IL-1beta2 and IL-6) and the modulated expression of C3 subtypes (C3-1, C3-3 and C3-4) in the rainbow trout (Oncorhynchus mykiss) using real-time RT-PCR. From in vitro studies, we demonstrated that head kidney macrophages from rainbow trout and Atlantic salmon showed no basal transcription of C3. After immunostimulation, the cells responded by increased levels of ILs, but transcription of C3 was not induced. In contrast to the in vitro findings, the rainbow trout complement C3 subtypes were differentially regulated 48 h after in vivo stimulation with LPS and beta-glucan. These results support the previous findings of absence of C3 in macrophages of the spotted wolffish (Anarhichas minor) and is the first functional study showing differential regulation of the C3 subtypes in any vertebrate.

Complement levels and activity in the normal and LPS-injured lung

Complement, a complex protein system, plays an essential role in host defense through bacterial lysis, stimulation of phagocytosis, recruitment of immune cells to infected tissue, and promotion of the inflammatory response. Although complement is most well-characterized in serum, complement activity is also present in the lung. Here we further characterize the complement system in the normal and inflamed lung. By Western blot, C5, C6, and factor I were detected in bronchoalveolar lavage (BAL) at lower levels than in serum, whereas C2 was detected at similar levels in BAL and serum. C4 binding protein (C4BP) was not detectable in BAL. Exposure to lipopolysaccharide (LPS) elevated levels of C1q, factor B, C2, C4, C5, C6, and C3 in human BAL and C3, C5, and factor B in mouse and rat BAL. Message for C1q-B, C1r, C1s, C2, C4, C3, C5, C6, factor B, and factor H, but not C9 or C4BP, was readily detectable by RT-PCR in normal mouse lung. Exposure to LPS enhanced factor B expression, decreased C5 expression, and did not affect C1q-B expression in mouse and rat lung. BAL from rats exposed to LPS had a greater ability to deposit C3b onto bacteria through complement activation than did BAL from control rats. In summary, these data demonstrate that complement levels, expression, and function are altered in acute lung injury and suggest that complement within the lung is regulated to promote opsonization of pathogens and limit potentially harmful inflammation.

Recombinant rat IL-1beta and IL-6 synergistically enhance C3 mRNA levels and complement component C3 secretion by H-35 rat hepatoma cells

Hepatic synthesis of complement component C3 is regulated in part by inflammatory cytokines. Rat models are frequently employed to investigate pathogenic roles of complement and cytokines. However, cytokines obtained from species other than the rat were used in previous studies of cytokine regulation of C3 synthesis in rat hepatocytes or hepatoma cells. It is not known whether these prior reports predict hepatocellular responses evoked by rat cytokines. Therefore, H-35 rat hepatoma cells were employed to measure the effect of recombinant rat IL-1beta, IL-6, IFN-gamma, and TNF-alpha on C3 protein secretion and C3 mRNA levels quantified by ELISA and quantitative RT-PCR. Compared to untreated control cells, H-35 cells treated with IL-1beta, IL-6, and IFN-gamma increased C3 secretion approximately 10-, 4-, and 2-fold, respectively. TNF-alpha was toxic, precluding further analysis. IL-1beta and IL-6 demonstrated synergy with respect to the quantity and rate of increase of C3 mRNA measured and the magnitude of C3 protein secretion. Previous reports using non-rat cytokines did not consistently predict H-35 responses to rat cytokines. Consequently, we recommend the use of rat cytokines in rat models that include analysis of cytokine-mediated events.

Increased acylation stimulating protein concentrations in nonalcoholic fatty liver disease are associated with insulin resistance

OBJECTIVES

As acylation stimulating protein (ASP) acts on adipocytes mainly as a paracrine factor to increase triglyceride synthesis and storage; hypothetically, it may play a similar role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD).

METHODS

Forty-six male patients with NAFLD (group A), age-matched 30 male patients with chronic viral hepatitis (group B) and 30 age-matched and body mass index (BMI)-matched healthy male subjects were enrolled in the study.

RESULTS

Among the NAFLD patients, 10 patients (24.4%) had simple steatosis and 36 patients (69.6%) had nonalcoholic steatohepatitis (NASH). The mean levels of ASP, complement 3, insulin, C-peptide, HOMA-IR, triglyceride, and very low-density lipoprotein (VLDL) were significantly higher in group A patients than both controls and group B. ASP levels correlated significantly in a positive manner with BMI, insulin, and HOMA-IR.

CONCLUSIONS

Dysregulation of the ASP pathway may have important metabolic consequences in NASH and is associated with insulin resistance.

Effects of prasterone on disease activity and symptoms in women with active systemic lupus erythematosus

OBJECTIVE

To determine whether prasterone administration results in improvement or stabilization of systemic lupus erythematosus (SLE) disease activity and its symptoms.

METHODS

Women with active SLE were treated with prasterone 200 mg/day plus standard SLE treatments or with placebo plus standard SLE treatments for up to 12 months in this randomized, double-blind investigation conducted at 27 centers. Standard SLE treatments included prednisone (</=10 mg/day), antimalarials, and immunosuppressive agents; dosages were required to be stable for >/=6 weeks prior to enrollment and remain unchanged during protocol treatment. Responders were patients who experienced no clinical deterioration and had improvement or stabilization over the duration of the study in 2 disease activity measures (the SLE Disease Activity Index [SLEDAI] and the Systemic Lupus Activity Measure) and 2 quality of life measures (patient's global assessment and the Krupp Fatigue Severity Scale).

RESULTS

A total of 381 women with SLE were enrolled. Among patients with clinically active disease at baseline (SLEDAI score >2), 86 of 147 in the prasterone group (58.5%) demonstrated improvement or stabilization without clinical deterioration, as compared with 65 of 146 in the placebo group (44.5%) (P = 0.017). Acne and hirsutism were reported in 33% and 16%, respectively, of the prasterone group and in 14% and 2%, respectively, of the placebo group (P < 0.05 for both comparisons). However, most cases of acne and hirsutism were mild and did not require withdrawal from therapy. Myalgias and oral stomatitis were reported less frequently in the prasterone group (22% and 15%, respectively) than in the placebo group (36% and 23%, respectively) (P < 0.05 for both comparisons). Serum levels of high-density lipoprotein cholesterol, triglycerides, and C3 complement significantly decreased, while levels of testosterone and, to a lesser extent, estradiol increased in the prasterone group.

CONCLUSION

In adult women with active SLE, administration of prasterone at a dosage of 200 mg/day improved or stabilized signs and symptoms of disease and was generally well tolerated.

Histamine, part of the metabolome

Histamine, a decarboxylated amino acid with a molecular mass of 112 daltons reveals multicoloured functional activities. Its role in allergy and inflammation is abundantly characterized. Moreover histamine is one of the neuotransmitters, has a role in gastric acid production and in maintenance of blood-brain barrier. In the last decade, many data were collected suggesting an important function of histamine in events of immune response and also in both benign and malignant cell proliferation. Our group collected data on the relevance of histamine as an autocrine factor in human melanoma. The outcome of the action seems to be closely related to the local and actual balance of histamine receptors (H1R, H2R, H3R and H4R) on tumor cells. Recently, using a gene targeted mouse strain (lacking an enzyme, histidine decarboxylase, the only one responsible for histamine production) many phenotype of the histamine-free mice were demonstrated. Our data suggest, that histamine, as part of the poorly characterized metabolome of the mammalian cells plays significant role in many physiological and pathological processes.

Effects of prasterone on corticosteroid requirements of women with systemic lupus erythematosus: a double-blind, randomized, placebo-controlled trial

OBJECTIVE

To evaluate whether treatment with prasterone (dehydroepiandrosterone [DHEA]) would allow the dosage of prednisone (or an equivalent corticosteroid) to be reduced to < or = 7.5 mg/day for 2 months or longer while maintaining stable or reduced disease activity in steroid-dependent women with systemic lupus erythematosus (SLE).

METHODS

In a double-blind, randomized trial, 191 female SLE patients receiving prednisone (10-30 mg/day) were treated daily with either placebo, 100 mg of oral prasterone (an adrenal androgen), or 200 mg of oral prasterone for 7-9-months. At monthly intervals, corticosteroid dosages were reduced by algorithm in patients whose SLE Disease Activity Index (SLEDAI) score was stable or improved. Patients for whom a sustained reduction in the dosage of prednisone (< or = 7.5 mg/day) was achieved for at least the last 2 months of the 7-9-month treatment period were classified as responders.

RESULTS

Response rates were 41% in the placebo group, 44% in the 100-mg prasterone group, and 55% in the 200-mg group (P = 0.110, 200 mg versus placebo). Among the 137 subjects (45 in the placebo group, 47 in the 100-mg group, and 45 in the 200-mg group) who had active disease at baseline (defined as SLEDAI score >2), 29%, 38%, and 51%, respectively, were responders (P = 0.031 for 200 mg prasterone versus placebo). Acne was the most common adverse event but was generally mild. Clinical and laboratory changes primarily reflected androgenic effects of prasterone.

CONCLUSION

Among women with lupus disease activity, reducing the dosage of prednisone to < or = 7.5 mg/day for a sustained period of time while maintaining stabilization or a reduction of disease activity was possible in a significantly greater proportion of patients treated with oral prasterone, 200 mg once daily, compared with patients treated with placebo.

Modulation of C3 gene expression in HepG2 human hepatoma cells

Inflammation elicits an acute phase response, which includes changes in plasma concentrations of a number of cytokines, reflecting changes in their gene transcription in the liver. In this study, the induction of complement factor 3 (C3) was investigated in HepG2 cells, a human hepatoma cell line often used as a model system for cytokine-dependent expression of acute phase proteins of the liver. By using a very sensitive RT-PCR assay, the amount of mRNA for C3 was measured after induction with lipopolysaccharide (LPS) and interleukin-6 (IL-6). Both substances were found to up-regulate C3 gene expression. C3 mRNA level was lower in LPS-treated cells compared to IL-6 induction and also reached maximum expression at an earlier time point. These findings suggest a coordinate stimulation of C3 expression in the hepatocytes, which then maintains the host response to infectious agents.

Control of apolipoprotein E secretion in the human hepatoma cell line KYN-2

Even though it is known that apolipoprotein E (apoE) is deeply involved in major age-related disorders such as atherosclerosis or Alzheimer's disease (AD), the control of cell-specific apoE expression is still poorly understood. We compared the apoE secretion as previously described in astrocytic cell17 to hepatic cell apoE secretion. We used the human hepatoma cell line KYN-2 to better delineate the characteristics of apoE secretion and to validate it with respect to the classical human hepatoma cell line HepG2. Interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) significantly inhibited, while IL-2, IL-6 and tumour necrosis factor-alpha (TNF-alpha) were inactive on apoE secretion by KYN-2 as well as HepG2 cells. Cholesterol and 25-OH cholesterol had no effect, while forskolin exerted a significant inhibitory effect, on apoE secretion in KYN-2 cells. Our results suggest that the KYN-2 cell line represents an appropriate cell model, and in any case an alternative model to the HepG2 cell line, to study the control of apoE secretion. The response of KYN-2 cells to both cytokines and cholesterol differs from that found in astrocytoma cells, suggesting that blood variations of apoE concentrations in AD may not reflect the dysregulations taking place in the brain.

Complement Synthesis Influencing Factors Produced by Acute Myeloid Leukemia Blast Cells

In a previous study, we found hypercomplementaemia in the sera of acute myeloid leukemia patients. In this study we show that the supernatants of mononuclear cells, derived from peripheral blood taken in the blastic phase, from patients with acute myeloid leukemia (CM-AML) increased the in vitro complement protein synthesis of HepG2 hepatocellular carcinoma cells. This effect of CM-AML was mediated by heat labile soluble factors and involved the synthesis of mRNA and protein. Inhibition experiments with anti-cytokine antibodies and immunoaffinity chromatography revealed that this effect of CM-AML is mostly mediated by IL-1 and IL-6.

The acute phase response in Sicilian patients with boutonneuse fever admitted to hospitals in Palermo, 1992-1997

OBJECTIVES

To study the modifications of some components of the acute phase response (APR) in Sicilian patients with boutonneuse fever (BF) caused by Rickettsia conorii.

METHODS

Sera from 500 Sicilian patients with confirmed BF were studied at the time of diagnosis and every week after treatment, and after recovery for the presence of various inflammatory mediators. Tumour necrosis factor alpha (TNFalpha), interleukin(IL)-6, IL-1alpha, IL-8, soluble TNF receptors (sTNF-R) and sIL-6R were assayed by commercially ELISA kits. C3, C4, factor B, C-reactive protein (CRP), fibrinogen, ceruloplasmin (Cp) and alpha(1)-antitrypsin (AAT) were assayed by a rate nephelometry.

RESULTS

Interferon gamma (IFNgamma), IL-6, TNFalpha, and IL-10 cytokines were significantly modified, whereas IL-1 and IL-8 were not detectable in the blood in any phase of infection. sTNF-RI, sTNF-RII and sIL-6 were significantly increased in the first 2 weeks of infection, but sTNF-R levels were not related to the plasma levels of TNFalpha, whereas sIL-6 was directly related to serum IL-6 concentrations. C3, C4, factor B and CRP were significantly increased in the first 2 weeks of infection, but afterwards returned to the normal range, even though CRP was still high in the third week and C3 persisted high after the fourth week. Fibrinogen was high only in the first week in relation to the injury to the endothelial cells (ECs). The anti-inflammatory proteins, Cp and AAT, were extremely high in the first 2 weeks of infection acting as a buffer of APR activation.

CONCLUSIONS

These results suggest that R. conorii is able to elicit, after invasion and proliferation in the ECs, the activation of APR. Further work is required to establish if active inhibitory mechanisms are operating during APR, or if there is a spontaneous decay in the initiation events.

Evidence of a role for local complement expression in a murine model of progressive glomerulonephritis

C57/B6 mice received intraperitoneal horse spleen apoferritin (4 mg) with lipopolysaccharide (0.05 mg); control mice received 0.15 M NaCl. Control and treated animals were killed weekly for 6 wk; blood and urine specimens were obtained, and tissue samples were secured. Treated animals showed evidence of significant chronic disease, with proteinuria, hematuria, and uremia. A mild glomerulonephritis was present at 2 wk, with significant proliferative glomerulonephritis at 4 wk, progressing to chronic disease with tubulointerstitial changes at 6 wk. Changes at each time period were uniform between animals. C3 mRNA was first detected by in situ hybridization at 3 wk. Message was restricted to proximal tubular and periglomerular epithelial cells. Presence of C3 message preceded the development of interstitial inflammation and fibrosis by 1-2 wk, and its location and intensity paralleled the evolving interstitial disease. Although extensive mesangial C3 protein deposits appeared early, there was never C3 message in glomeruli or infiltrating cells. Before C3 message became apparent, two cytokines known to up-regulate C3 transcription in vitro, IL-1 and IL-6, were detected by immunohistochemistry. The temporal sequence in this model is consistent with our hypothesis that local synthesis and activation of C3 in tubular epithelium is important to the interstitial component of chronic glomerulonephritis. The process is independent of the deposition of circulating complement in the glomerulus, but may be triggered by glomerular cytokines.

Cytokine-mediated up-regulation of CD55 and CD59 protects human hepatoma cells from complement attack

Hepatic parenchymal cells respond in many different ways to acute-phase cytokines. Some responses may protect against damage by liver-derived inflammatory mediators. Previous investigations have shown that cytokines cause increased secretion by hepatoma cells of soluble complement regulatory proteins, perhaps providing protection from complement attack. More important to cell protection are the membrane complement regulators. Here we examine, using flow cytometry and Northern blotting, the effects of different cytokines, singly or in combination, on expression of membrane-bound complement regulators by a hepatoma cell line. The combination of tumour necrosis factor-alpha, IL-1beta, and IL-6 caused increased expression of CD55 (three-fold) and CD59 (two-fold) and decreased expression of CD46 at day 3 post-exposure. Interferon-gamma reduced expression of CD59 and strongly antagonized the up-regulatory effects on CD59 mediated by the other cytokines. Complement attack on antibody-sensitized hepatoma cells following a 3-day incubation with the optimum combination of acute-phase cytokines revealed increased resistance to complement-mediated lysis and decreased C3b deposition. During the acute-phase response there is an increased hepatic synthesis of the majority of complement effector proteins. Simultaneous up-regulation of expression of CD55 and CD59 may serve to protect hepatocytes from high local concentrations of complement generated during the acute-phase response.

Changes in the acute phase complement component and IL-6 levels in patients with chronic hepatitis C receiving interferon alpha-2b

In order to study the effect of interferon alpha on the levels of acute phase complement proteins in vivo, serum concentrations of C9 and C1-inhibitor (C1-INH) were measured in patients with chronic hepatitis C before and 3 months after the beginning of interferon alpha2b therapy. Serum levels of the activation product of terminal complement pathway, C5b-9, HCV RNA and IL-6 were also determined. IFN alpha treatment significantly (P<0.0001) increased the serum concentrations of both complement proteins. C5b-9 levels were found to significantly decrease during the same period of time. When the patients were divided into responders or non-responders (more or less than 50% decrease in plasma HCV RNA concentrations) C9 and C1-INH levels were elevated only in the responder patients. There was no correlation between the changes of IL-6 levels or the amounts of IFN alpha administrated on one hand, and the changes in the complement protein levels on the other. These findings suggest that the marked increase in the serum concentrations of the acute phase complement proteins is a secondary phenomenon due to the IFN alpha-caused diminution of the viral load and the resulting immune complex-induced complement activation.

Host response to tissue engineered devices

The two main components of a tissue engineered device are the transplanted cells and the biomaterial, creating a device for the restoration or modification of tissue or organ function. The implantation of polymer/cell constructs combines concepts of biomaterials and cell transplantation. The interconnections between the host responses to the biomaterial and transplanted cells determines the biocompatibility of the device. This review describes the inflammatory response to the biomaterial component and immune response towards transplanted cells. Emphasis is on how the presence of the transplanted cell construct affects the host response. The inflammatory response towards a biomaterial can impact the immune response towards transplanted cells and vice versa. Immune rejection is the most important host response towards the cellular component of tissue engineered devices containing allogeneic, xenogeneic or immunogenic ex vivo manipulated autologous cells. The immune mechanisms towards allografts and xenografts are outlined to provide a basis for the mechanistic hypotheses of the immune response towards encapsulated cells, with antigen shedding and the indirect pathway of antigen presentation predominating. A review of experimental evidence illustrates examples of the inflammatory response towards biodegradable polymer scaffold materials, examples of devices appropriately integrated as assessed morphologically with the host for various applications including bone, nerve, and skin regeneration, and of the immune response towards encapsulated allogeneic and xenogeneic cells.

Cytokine regulation of the acute-phase protein levels in multiple myeloma

BACKGROUND

Interleukin (IL) 6 has an important role in the regulation of acute-phase proteins (APPs) during an acute-phase response. We studied IL-6 and other cytokines to determine if they regulate serum APP levels in the same way under the condition of the aberrant, long-lasting 'acute-phase response' that occurs in patients with chronic inflammation and cancer.

METHODS

Serum levels of nine positive APPs [CRP, SAA, C1-INH, Bf, C5, C8, C9, alpha 1-acidic glycoprotein (AGP) and haptoglobin] and two negative APPs [transferrin and alpha 2-HS glycoprotein (AHSG)] were measured using immunochemical methods in 59 multiple myeloma patients and in 72 healthy control subjects. Serum IL-6 and tumour necrosis factor (TNF) alpha levels were determined by bioassays.

RESULTS

IL-6 was negatively correlated with five out of nine (C1-INH, C8, C9, AGP and haptoglobin) positive APPs but positively correlated with C-reactive protein (CRP). When patients with high and low IL-6 serum concentration were compared, CRP levels were higher, AGP and haptoglobin levels were lower in the high- than in the low-L-6 group, whereas no significant difference between the two groups was found in levels of the other positive and negative APPs. TNF-alpha levels were negatively correlated with transferrin and AHSG levels. No difference in the levels of positive APPs was observed between patients with low and high TNF-alpha serum concentration. By contrast, levels of both transferrin and AHSG were significantly lower in the high- than in the low-TNF-alpha group.

CONCLUSIONS

These findings indicate that, except for regulation of the negative APPs by TNF-alpha, the mechanism of APP regulation is different under the conditions of the short-term and the chronic, long-lasting 'acute-phase reaction'.

IL-6 receptor blockage inhibits the onset of autoimmune kidney disease in NZB/W F1 mice

In the present study, we examined the preventive effect of anti-mouse IL-6 receptor (IL-6R) antibody, MR16-1, on the development of autoimmune kidney disease in female NZB/W F1 (BWF1) mice. Immunological tolerance to MR16-1 or isotype-matched control antibody, KH-5, was induced by the simultaneous administration of anti-CD4 MoAb in mice. Thereafter, mice were intraperitoneally given 0.5 mg of MR16-1, 0.5 mg of KH-5 or saline once a week from 13 to 64 weeks of age. MR16-1 treatment dramatically suppressed proteinuria and prolonged the survival time of BWF1 mice. Only one out of 10 mice died with high levels of proteinuria throughout the experiment. MR16-1 almost completely suppressed the production of IgG forms of anti-DNA and anti-TNP antibodies, but not the IgM forms of these antibodies. In particular, all IgG subclasses (IgG1, IgG2a, IgG2b and IgG3) of anti-DNA antibody production were significantly suppressed. Moreover, serum IgG1, IgG2a and IgG3 levels in MR16-1-treated mice were lower than those in saline- and KH-5-treated mice, whereas serum IgM and IgA levels were not influenced. In conclusion, MR16-1 potently suppressed the development of autoimmune disease in BWF1 mice, and this was attributed to its effect of specific suppression of IgG class antibody production.

Acute phase proteins and transformed cells

Acute phase proteins (APP) are plasma proteins whose concentration and glycosylation alters in response to tissue injury, inflammation, or tumor growth. Significant interspecies and sex differences in APP response exist. APP are produced mainly by hepatocytes, and their synthesis and glycosylation are controlled by a network consisting of cytokines, their soluble receptors, and glucocorticoids. The major cytokines involved in these processes belong to a group of interleukin-6-type cytokines that act through the hematopoietin receptor complex on hepatocytes and JAK-STAT signal transduction pathway. Transformed cells (hepatoma) display significant differences in synthesis of APP, cytokine responsiveness, expression of cytokine-receptor subunits and signal-transduction machinery. The most striking variability relates to the glycosylation alterations induced by cytokines. However, transformed cells (hepatoma) form a basic model for studying and understanding mechanisms controlling the synthesis and glycosylation of APP. Furthermore, APP may be secreted by transformed (tumor) cells of various origins and may display a growth factor-like function in certain cancer types.

Regulation of early complement components C3 and C4 in the synovium

To determine the cytokine inducibility of early complement component (C3 and C4) expression in the synovium, explant tissue was maintained in culture for 7 days. C3 and C4 production was measured by specific enzyme-linked immunosorbent assay, and RNA was evaluated by semiquantitative PCR. The effects of leukemia inhibitory factor (LIF), gamma interferon (IFN-gamma), IFN-alpha, and estrogen on C3 and C4 expression were evaluated. C3 levels were unaffected by 7 days of LIF, IFN-gamma, or IFN-alpha treatment. In contrast, C4 levels were significantly induced in synovial samples treated for 7 days with either IFN-gamma or IFN-alpha. LIF had no effect on C4 levels in this system. Estrogen was found to down-modulate the induction of expression due to IFN-gamma. These data provide evidence for cytokine regulation of C4 expression in the synovium and for estrogen modulation of those effects.

The acute phase protein response in patients receiving subcutaneous IL-6

IL-6, tumour necrosis factor-alpha (TNF-alpha) and IL-1 are thought to be the key mediators of the acute phase response although much of the evidence is based on in vitro studies. It is not clear to what extent each of the acute phase proteins are regulated in vivo by each of these cytokines. The aim of this study was to examine the effects of IL-6 treatment in eight patients with cancer on the concentrations of an extensive range of positive and negative acute phase proteins. It was part of a larger investigation to assess the value of IL-6 in the management of chemotherapy-induced thrombocytopenia. IL-6 was administered by a daily subcutaneous injection for 7 days at a dose level of 1, 3, or 10 micrograms/kg/day. Increases in the positive acute phase proteins, serum amyloid A, C-reactive protein, alpha 1-acid glycoprotein, alpha 1-antichymotrypsin, haptoglobin, alpha 1-antitrypsin, fibrinogen, complement component C3, and caeruloplasmin, were observed, with the greatest incremental changes and fastest responses being seen for C-reactive protein and serum amyloid A protein. The negative acute phase proteins transferrin, transthyretin and retinol binding protein all fell to a nadir within 48-96 h after the first IL-6 injection. Increases in complement component C4 were only found in two patients, which may be related to the increase in circulating TNF-alpha concentrations found only in these patients. This study has therefore shown that IL-6 is capable of causing changes in the majority of acute phase proteins in vivo. Although secondary induction of TNF-alpha was not observed in the majority of patients examined, it is still possible however that other cytokines involved in regulation of the acute phase response, such as IL-1, may have been induced and contributed to the overall response.

Biosynthesis of C3 by human mesangial cells. Modulation by proinflammatory cytokines

Deposits of complement (C) components are found in the glomeruli of patients with various glomerulonephritides without detectable immunoglobulins, thus suggesting a pathogenetic role of the locally produced proteins of this system. In the present study, we have examined human mesangial cells (HMC) for their ability to secrete C3. Three different cell lines were examined and all showed a basal production of C3, which was up-regulated following stimulation with IL-1 beta. IL-6 had no direct stimulatory effect on its own, but synergized with IL-1 to induce an increased production of C3 in the culture supernatant and its relative amount was confirmed by SDS-PAGE and immunoblot. Another agonist such as lipopolysaccharide was not able to induce any significant C3 synthesis. Analysis of C3 HMC gene expression, performed by both reverse transcription-polymerase chain reaction of isolated RNA and Northern blot, confirmed the parallel increase of the specific transcript under IL-1 beta and IL-1 beta + IL-6 stimulation. From these data we conclude that production of C3 in the mesangium could have a pathophysiologic relevance.

Role of protein kinase C activation in synthesis of complement components C2 and factor B in interferon-gamma-stimulated human fibroblasts, glioblastoma cell line A172 and monocytes

The synthesis of C2 and factor B, the key components of complement system, is performed by various kinds of cells and is also up-regulated by interferon-gamma (IFN-gamma). By using human fibroblasts, human glioblastoma cell line A172 and monocytes, we investigated the signal-transduction mechanism for IFN-gamma-induced synthesis of C2 and factor B. The C2 and factor B synthesis induced by IFN-gamma in all three cell types was inhibited by a protein kinase C (PKC) inhibitor, 1-(5-isoquinolinyl-sulphonyl)-2-methylpiperazine (H-7). The depletion of PKC in these cell types after treatment with phorbol 12-myristate 13-acetate (PMA) resulted in inhibition of IFN-gamma-induced C2 production. In addition, IFN-gamma treatment elicited a decrease in cytoplasmic PKC in A172 cells, indicating that PKC is activated by IFN-gamma. These results suggest that PKC is crucial for IFN-gamma-induced C2 and factor B synthesis. Northern-blot analysis showed that the effects at H-7 were at least partly mediated by modulation of C2 and factor B mRNA abundance in A172 cells. Since treatment of fibroblasts and A172 cells with IFN-gamma had no effect on intracellular Ca2+ concentration, and since neither EGTA nor nifedipine inhibited C2 or factor B synthesis induced by IFN-gamma, we concluded that intracellular Ca2+ mobilization was not involved in the effect of IFN-gamma. In addition, genistein, herbimycin A and N-(6-aminohexyl)-5-chloro-1-naphthalene-sulphonamide (W-7) had no inhibitory effect on IFN-gamma-mediated action in any of the three cell types, which suggests that IFN-gamma acts independently of tyrosine kinases and calmodulin-dependent protein kinases.

Immunological pattern in patients with 21-hydroxylase deficiency

The aim of this work was to perform an immunological study in six patients with 21 hydroxylase deficiency in mild form (M210HD) and in 2 patients with 21-hydroxylase deficiency in classical form (C210HD) and in their parents, in whom a previous HLA,C4,Bf typing demonstrated high prevalence of DR5 and phenotypic absence of fraction C4B of complement (C4BQO). This study contains the evaluation of C3, IgA, IgG, IgM levels, anticardiolipin antibodies (IgG and IgM) and circulating immunocomplexes. A study of lymphocyte subsets was also performed. Among M210HD 1 patient showed presence of anticardiolipin antibodies both IgM and IgG; this patient had shown antinuclear antibodies in a previous study. Among parents, some subjects showed presence of anticardiolipin antibodies and high levels of circulating immunocomplexes. No alterations in C3 and Ig levels were observed. A reduced percentage of CD4 suppressor-inducer (CD4-SI) (p < 0.05 in M210HD and in parents vs controls) and increased percentage of CD4 helper-inducer (CD4-HI) (p < 0.05 in both groups vs controls) were found. No alterations were evidenced in C210HD patients. Data about association between 21-hydroxylase deficiency and autoimmune diseases are rare. Our results confirm that 210HD could be associated to an unbalancement of immune system function and suggest that non immune genes, like 21-hydroxylase one, may influence the expression of autoimmune diseases at least in presence of peculial extended haplotypes.

Immune function of patients receiving recombinant human interleukin-6 (IL-6) in a phase I clinical study: induction of C-reactive protein and IgE and inhibition of natural killer and lymphokine-activated killer cell activity

Interleukin-6 (IL-6) is a cytokine that acts on a variety of cell types, including myeloid progenitor cells and B and T lymphocytes. It has been found to activate cytotoxic T cells and natural killer (NK) cells and to induce T-cell-mediated antitumour effects in animal models. In a phase I clinical trial of recombinant human IL-6, 20 patients with advanced cancer were entered to receive daily subcutaneous injections of IL-6 over 7 days followed by a 2-week observation period and another 4 weeks of daily IL-6 injections. Doses varied between 0.5 microgram/kg and 20 micrograms/kg body weight and immune functions were monitored throughout. At all dose levels IL-6 administration led to a marked increase in serum levels of C-reactive protein and a moderate rise in complement factor C3. The proportions of CD4, CD8 or HLA-DR lymphocytes in peripheral blood did not alter with IL-6 treatment nor did the in vitro proliferation of peripheral blood mononuclear cells induced by either phytohaemagglutinin, pokeweed mitogen or fixed Staphylococcus aureus. By contrast, NK cell activity, lymphokine-activated killer (LAK) cell activity and proliferation induced by in vitro culture with interleukin-2 (IL-2) were suppressed at doses exceeding 2.5 micrograms/kg. Serum IgE levels were consistently elevated over the IL-6 dose range but IgM, IgG and IgA levels were unaffected. In summary there is a dose-dependent induction of acute-phase proteins by in vivo IL-6 treatment. At higher IL-6 doses there is a suppressive effect on NK and LAK activity measured in vitro. IL-6 may thus be useful in combination cytokine therapies that seek to suppress LAK and favour cytotoxic T lymphocyte responses. The rise in IgE levels in response to IL-6 was unexpected and suggests a more pivotal role than previously known for the control of IgE production; this could include IgE-related diseases.

Transcriptional regulation of the gene for the second component of human complement: promoter analysis

The 5' flanking region of the human gene for the second component of complement was sequenced and analyzed functionally. RNase protection demonstrated a cluster of four initiation sites in the 5' flanking region utilized in the hepatoma cell line, HepG2. Utilization of all four initiation sites increased in response to gamma-interferon (IFN-gamma). Transient transfection analysis was used to examine cis-acting sequence motifs controlling transcription from the 5'-flanking region. We identified a 228-bp minimal promoter fragment which was able to direct basal and IFN-gamma inducible transcription from authentic initiation sites. Sequence motifs outside of this region may modulate the transcriptional regulation of the second component of complement. Although complement components are not coordinately regulated, we identified four regions of significant homology with the promoters of multiple other complement components. Three of these regions were within the minimal promoter fragment.

Effect of cytokines on the secretion of the fifth and eighth complement components by HepG2 cells

Liver cells can be induced by interleukin-1, tumor necrosis factor and interleukin-6 to secrete higher amounts of complement components. Information, so far available only for the early components, indicates that these cytokines exhibit different effects on various complement proteins. For instance, they promote the biosynthesis of C3 and B but have no effect on that of C4 and C2. These observations led us to evaluate the ability of interleukin-1, tumor necrosis factor and interleukin-6 to modulate the secretion of the late complement components by HepG2 cells, a human hepatoma-derived cell line known to produce several complement proteins. The amount of complement components in the culture supernatant was evaluated by a sensitive enzyme-linked immunosorbent assay revealing picogram levels of these proteins. The HepG2 cells were found to secrete a substantial amount of C3 (approximately 1 microgram/10(6) cells), easily detectable C5 (approximately 150 ng/10(6) cells) and C8 (approximately 10 ng/10(6) cells) and a low amount of C6 (approximately 0.5 ng/10(6) cells), whereas the levels of both C7 and C9 could not be measured. The addition of interleukin-1, tumor necrosis factor and interleukin-6 to the cell culture resulted in an enhanced secretion of C8, whereas that of C5 was only marginally increased. None of these cytokines had a clear effect on the secretion of C6 nor induced the production of C7 and C9.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-1 and tumor necrosis factor-mediated regulation of C3 gene expression in human astroglioma cells

In this report, we show that in the human astroglioma cell line D54-MG, both interleukin-1 (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) enhance C3 gene expression in a time- and dose-dependent manner. Kinetic analysis demonstrates that after 96 h, C3 mRNA levels increase approximately 30-fold and 20-fold in response to IL-1 beta or TNF-alpha, respectively. C3 protein production increases proportionally, reaching levels 36-fold and 18-fold higher than untreated controls upon exposure to IL-1 beta or TNF-alpha, respectively. D54-MG cells require a minimal 1 h exposure to IL-1 beta in order to enhance C3 gene expression significantly, while 4 to 8 h are required for TNF-alpha. Simultaneous treatment of D54-MG cells with IL-1 beta and interferon-gamma (IFN-gamma) resulted in an additive increase in both C3 mRNA and protein expression, a finding not seen with the combination of TNF-alpha and IFN-gamma. Primary rat astrocytes also express increased C3 mRNA levels after 48 h in response to IL-1 beta (5.3-fold increase) and TNF-alpha (7-fold increase), while an additive effect was observed upon simultaneous treatment with both IL-1 beta and IFN-gamma. In the central nervous system (CNS), endogenous complement and cytokine production by astrocytes, and enhancement by IFN-gamma, a product of activated T cells often seen in the CNS in neural autoimmune disease, may contribute to the pathogenesis of inflammatory demyelinating diseases such as multiple sclerosis.

Complement research: biosynthesis, genetics, immunoregulatory role and clinical studies

Complementology is one of the major areas of immunological research in Hungary. Here, András Falus and colleagues describe studies on the control of biosynthesis of complement components and on the nature and function of receptors in the complement system.

Histamine modulates the interleukin-6-regulated acute phase protein synthesis in cultured murine hepatocytes

Murine hepatocytes cultured in the presence of human recombinant interleukin-6 (IL-6) show increased synthesis of fibrinogen and complement component C3 by the addition of histamine. No similar effect was achieved when murine hepatocytes were treated with histamine alone or with histamine and interleukin-1 alpha together. Using histamine-1 (H1) and H2 receptor antagonists a prevalence of histamine H1 receptor in the enhancement of IL-6-induced effect is suggested.

HLADR5 and C4BQO high frequency and antinuclear antibodies positivity in patients with 21 hydroxylase deficiency from Campania region

HLA haplotypes, complement C4 factor and factor B immunochemical concentrations and autoantibodies titer have been studied in six patients with mild congenital adrenal hyperplasia (MC-AH), in two patients with classical congenital adrenal hyperplasia (CCAH) and in their parents. A high frequency of DR5 and C4BQO alleles have been found in MCAH patients. Moreover, C4BQO allele is carried out in three out of four cases associated with DR5. In the two CCAH patients we found a B51 and a B14 allele, the last one usually described in the non classical form of the disease in population of different ethnic origin. Signs of autoimmunity in some patients and parents have been found. C4 null alleles were several-fold more frequent among our patients with respect to the same ethnic control group and the autoantibody positivity could be the result of an altered immune regulation. The presence of a positive correlation between cortisol basal levels and C4 and Bf concentrations in the six MC-AH patients suggests an interrelationship between hormonal factors and immunological findings in this disease. Our finding about HLA antigens not previously described in this syndrome may stimulate more profound studies by genomic and cDNA probes.

FcgammaR-Dependent Regulation of the Biosynthesis of Complement C3 by Murine Macrophages: the Modulatory Effect of IL-6

The effect of murine IgG isotypes on the gene expression and secretion of the third component of complement (C3) has been studied using the monocytoid cell line P388D1 and oil-elicited mouse peritoneal macrophages. It is demonstrated that the binding of IgG2a and IgG2b but not IgG1 and IgG3 augments the biosynthesis of C3 both in the presence and in the absence of the phorbol ester, phorbol myristate acetate in the case of both cell types. The multifunctional cytokine interleukin-6 (IL-6) alone reveals no effect on the gene expression of C3, but increases the effectiveness of mouse IgG2a and IgG2b. Confirming the role of Fc gamma RII, a strong up-regulation of C3 gene expression and C3 secretion was found when macrophages were cultured with the F(ab')2 fragment of the Fc gamma RII-specific monoclonal antibody 2.4G2.

Histamine influences the expression of the interleukin-6 receptor on human lymphoid, monocytoid and hepatoma cell lines

Based on our earlier data on the enhancing effect of histamine on the action of interleukin-6 (IL-6), we have studied the molecular mechanisms of these interactions. The effect of histamine was investigated on the binding of 125I-IL-6 by B lymphoma cell line CESS, monocytoid cell line U937 and hepatoma cell line HepG2. Histamine increases the IL-6 binding by CESS cells and inhibits that by U937 and HepG2 cells. Using H1 receptor (cetirizin and loderix) and H2 receptor (cimetidine and ranitidine) specific antagonists, an H1-dependent stimulation of IL-6 binding by CESS cells was found. In contrast, down-regulation of IL-6 binding by histamine was clearly mediated through H2 receptors. On U937 cells, using a monoclonal antibody reacting with the 80 kd chain of the human IL-6 receptor, and H2-receptor mediated inhibition of IL-6 receptor expression was found by FACS analysis.

Synthesis of C1 inhibitor in fibroblasts from patients with type I and type II hereditary angioneurotic edema

Patients with hereditary angioneurotic edema (HANE) have serum levels of functionally active inhibitor of the first component of complement (C1 INH) between 5 and 30% of normal, instead of the 50% expected from the single normal allele. Increases in rates of catabolism have been documented in patients with HANE and certainly account for some of decrease in C1 INH level. A possible role for a decrease in synthesis of C1 INH in producing serum levels of C1 INH below the expected 50% of normal has not been well studied. We studied the synthesis of C1 INH in skin fibroblast lines, which produce easily detectable amounts of C1 INH. In type I HANE cells, C1 INH synthesis was 19.6 +/- 4.0% (mean +/- SD) of normal, much less than the 50% predicted. In type II HANE cells, the total amount of C1 INH synthesis (functional and dysfunctional) was 98.9 +/- 17% of normal; the functional protein comprised 43% of the total. Thus, type II HANE cells synthesized functional C1 INH at a much greater rate than for the type I cells. In both type I and II HANE cells, amounts of steady-state C1 INH mRNA levels paralleled rates of C1 INH synthesis, indicating that control of C1 INH synthesis occurred at pretranslational levels. Both type I and type II fibroblasts synthesized normal amounts of C1r and C1s. These data suggest that the lower than expected amounts of functionally active C1 INH in type I HANE may be due, in part, to a decrease in rate of synthesis of the protein, and that the expressions of the normal C1 INH allele in HANE is influenced by the type of abnormal allele present.

Hormonal regulation of complement biosynthesis in human cell lines--I. Androgens and gamma-interferon stimulate the biosynthesis and gene expression of C1 inhibitor in human cell lines U937 and HepG2

C1 inhibitor (C1inh), a member of the serine protease inhibitor gene superfamily, is a glycosylated plasma protein inhibiting the proteolytic activities of C1r and C1s and involved in the regulation of coagulation, fibrinolysis and kinin-releasing systems. In this study, the in vitro effect of androgen hormones, dehydroepiandrosterone (DHEA), testosterone (TEST) and recombinant human gamma-interferon (gamma-IFN), has been determined on the production of C1inh in human cell lines. In both human monocytoid/histiocytoid cell line U937 and in hepatoma derived cell line HepG2, DHEA and TEST upregulated the gene expression and secretion of C1inh. The most pronounced effect was detected in the concn range 10(-7)-10(-9) M of the hormones. Under the same conditions DHEA and TEST had no detectable effect on the biosynthesis of C3, C2 and factor B by these cells, but DHEA at higher concn (10(-4) M) slightly increased that of C4 in HepG2 cells. Both in U937 and in HepG2 cells recombinant gamma-IFN markedly increased the gene expression and secretion of C1inh. This effect of gamma-IFN was abolished by histamine.