Enhanced glucocorticoid-induced leucine zipper in dendritic cells induces allergen-specific regulatory CD4(+) T-cells in respiratory allergies

BACKGROUND

Respiratory allergies rely on a defect of IL-10-secreting regulatory CD4(+) T-cells (IL-10-Tregs ) leading to excessive Th2-biased immune responses to allergens. According to clinical data, the restoration of allergen-specific IL-10-Tregs is required to control respiratory allergies and cure patients. The discovery of mechanisms involved in the generation of IL-10-Tregs will thus help to provide effective treatments. We previously demonstrated that dendritic cells (DCs) expressing high levels of the glucocorticoid-induced leucine zipper protein (GILZ) generate antigen-specific IL-10-Tregs .

OBJECTIVE

We suspect a defective expression of GILZ in the DCs of respiratory allergic patients and speculate that increasing its expression might restore immune tolerance against allergens through the induction of IL-10-Tregs .

METHODS

We assessed GILZ expression in blood DCs of patients and healthy nonallergic donors by qPCR. We compared the ability of patients' DCs to induce allergen-specific IL-10-Tregs before and after an in vivo up-regulation of GILZ expression by steroid administration, steroids being inducers of GILZ.

RESULTS

We report lower levels of GILZ in DCs of respiratory allergic patients that return to normal levels after steroid administration. We show that patients' DCs with increased levels of GILZ generate allergen-specific IL-10-Tregs again. We further confirm unequivocally that GILZ is required in patients' DCs to activate these IL-10-Tregs .

CONCLUSION

This proof of concept study shows that the re-establishment of GILZ expression in patients' DCs to normal levels restores their capacity to activate allergen-specific IL-10-Tregs . We thus highlight the up-regulation of GILZ in DCs as a new interventional approach to restore the immune tolerance to allergens.

Risk of tuberculosis is higher with anti-tumor necrosis factor monoclonal antibody therapy than with soluble tumor necrosis factor receptor therapy: The three-year prospective French Research Axed on Tolerance of Biotherapies registry

OBJECTIVE

Tuberculosis (TB) is associated with anti-tumor necrosis factor (anti-TNF) monoclonal antibody (mAb) therapy, but whether this association is drug-specific remains a concern. Our objective was to describe cases of TB associated with anti-TNF mAb therapy, identify risk factors, and estimate the incidence.

METHODS

We conducted an incidence study and a case-control analysis to investigate the risk of newly diagnosed TB associated with the use of anti-TNF agents. As part of the French Research Axed on Tolerance of Biotherapies (RATIO) registry, for 3 years we collected cases of TB among French patients receiving anti-TNF mAb therapy for any indication; for each case, 2 patients treated with anti-TNF agents served as control subjects.

RESULTS

We collected 69 cases of TB in patients treated for rheumatoid arthritis (n = 40), spondylarthritides (n = 18), inflammatory colitis (n = 9), psoriasis (n = 1) and Behçet's disease (n = 1) with infliximab (n = 36), adalimumab (n = 28), and etanercept (n = 5). None of the patients had received correct chemoprophylactic treatment. The sex- and age-adjusted incidence rate of TB was 116.7 per 100,000 patient-years. The standardized incidence ratio (SIR) was 12.2 (95% confidence interval [95% CI] 9.7-15.5) and was higher for therapy with infliximab and adalimumab than for therapy with etanercept (SIR 18.6 [95% CI 13.4-25.8] and SIR 29.3 [95% CI 20.3-42.4] versus SIR 1.8 [95% CI 0.7-4.3], respectively). In the case-control analysis, exposure to infliximab or adalimumab versus etanercept was an independent risk factor for TB (odds ratio [OR] 13.3 [95% CI 2.6-69.0] and OR 17.1 [95% CI 3.6-80.6], respectively). Other risk factors were age, the first year of anti-TNF mAb treatment, and being born in an endemic area.

CONCLUSION

The risk of TB is higher for patients receiving anti-TNF mAb therapy than for those receiving soluble TNF receptor therapy. The increased risk with early anti-TNF treatment and the absence of correct chemoprophylactic treatment favor the reactivation of latent TB.

Oocyte in-vitro maturation: BCL2 mRNA content in cumulus cells reflects oocyte competency

BCL2-associated X protein (BAX) and B-cell leukaemia/lymphoma gene-2 (BCL2), which are, respectively, pro- and anti-apoptotic proteins of the BCL2 gene family, participate in the mitochondria-dependent apoptosis pathway. A correlation between low incidence of apoptosis in cumulus cells and oocyte maturation has previously been suggested in ovarian stimulation. However, little is known in unprimed ovaries. These authors have investigated whether BAX and BCL2 expression in cumulus cells affects the competency of in-vitro matured oocytes. We have studied 100 cumulus-oocyte-complexes (COC) recovered from unprimed ovaries of 13 women diagnosed with polycystic ovary syndrome (PCOS) and undergoing in-vitro maturation (IVM) with their informed consent. COC were matured for 24 h in a specific maturation medium and the cumulus was stripped from the oocyte. BAX and BCL2 mRNA content was measured in each COC using real-time polymerase chain reaction. We found that BCL2 mRNA expression was significantly higher in cumulus cells associated with mature oocytes than those associated with immature oocytes while BAX mRNA concentrations did not vary in cumulus cells. Regarding fertilization, higher BCL2 mRNA content was found in cumulus cells enclosing fertilized oocytes (0.140 versus 0.075; P = 0.03). These results suggest that BCL2 expression is strongly associated with the ability of oocytes to complete nuclear maturation and to be fertilized.

Leukocytes and the kidney contribute to interstitial inflammation in lupus nephritis

Interstitial leucocyte infiltration, a prominent feature of lupus nephritis, predicts deterioration of renal function. We used two models of lupus nephritis in mice, one with chronic spontaneous disease and the other with acute interferon-alpha (IFN alpha)-mediated disease. The latter is characterized by the virtual absence of interstitial infiltration. In vivo migration assays showed that splenic leukocytes from spontaneously nephritic mice tended to migrate into non-inflamed syngeneic kidneys. This was enhanced if the recipient kidneys were already inflamed. Kidneys from both chronically and acutely nephritic mice showed similar ability to recruit splenic leukocytes from chronically diseased mice. Leukocytes from acutely diseased mice, however, failed to migrate into chronically inflamed kidney. Compared with those with chronic nephritis, the kidneys of acute nephritic mice expressed less of the inflammatory chemokine CXCL13/BLC. Moreover, leukocytes from acute nephritic mice displayed impaired migration, in vitro, to T-cell chemokine attractants. This study links leukocyte infiltration to both kidney chemokine expression, and leukocyte chemotaxis to kidney-expressed chemokines.

Dendritic cell recruitment in lesions of human and experimental pulmonary hypertension

In the present study, the hypothesis that dendritic cells (DCs), key players in immunity and tolerance, might be involved in the immunopathology of idiopathic pulmonary arterial hypertension (IPAH) was tested. The phenotype and localisation of DCs were characterised by immunohistochemistry and double-labelling immunofluorescence in lung samples from controls, human IPAH patients and an experimental pulmonary hypertension model (monocrotaline-exposed rats). As compared with controls, morphometric analysis demonstrated increased numbers of dendritic cell-specific intercellular adhesion molecule-grabbing nonintegrin (DC-SIGN)-positive cells in muscular pulmonary arteries in IPAH and OX-62-positive DCs in monocrotaline-induced pulmonary hypertension. In human samples, the mean+/-SEM number of DC-SIGN-positive cells.artery(-1) of 100-300 microm diameter was 1.4+/-0.4 in controls versus 26.4+/-2.7 in IPAH. In rats, the number of OX-62-positive cells.artery(-1) of 50-150 microm diameter was 0.5+/-0.2 in controls, and 0.7+/-0.5, 3.1+/-0.5 and 8.4+/-0.6 at day 7, 14 and 28 after monocrotaline exposure, respectively. Human complex lesions of muscular pulmonary arteries showed transmural DC infiltration. Phenotyping revealed an immature DC profile in human and experimental pulmonary hypertension. The results support the concept that immature dendritic cells accumulate in remodelled pulmonary vessels and hence could be involved in the immunopathology of pulmonary hypertension.

Chemokine receptor expression on allergen-specific T cells in asthma and allergic bronchopulmonary aspergillosis

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is a rare variant of severe asthma resulting from hypersensitivity to Aspergillus fumigatus (Asp f) present in the airways.

AIMS OF THE STUDY

We analyzed the expression of a panel of six chemokine receptors (CCR3, CCR4, CCR8, CCR5, CXCR3 and CXCR4) on total blood CD4(+) T cells and Asp f-specific-T cells in ABPA patients. We hypothesized that chemokine receptor pattern on T cells differs between ABPA patients, non-ABPA allergic asthmatics sensitized to Dermatophagoides pteronyssinus (Der p) or Phleum pratense (Phl p) and healthy controls.

METHODS

We used the fluorescent dye PKH26, a membrane bound marker, to identify accumulated proliferating (cell-sorted PKH26(low)) CD4(+) T cells in response to allergens (Asp f, Der p, Phl p) or recall antigens (PPD and TT). Chemokine receptor expression was analyzed by flow cytometry on proliferating CD3(+) CD4(+) PKH26(low) cells.

RESULTS

Stimulation of CD4(+) T cells with the relevant allergen resulted in different patterns of chemokine receptor expression in ABPA and non-ABPA allergic asthmatics. Upon Asp f exposure, proliferating CD4(+) T cells from ABPA patients down-regulated the expression of CCR4 and CXCR3 while CCR4 and CXCR3 were up-regulated in allergen-specific T cells from non-ABPA allergic asthmatics. Considering each group of patients, the pattern of chemokine receptors expressed on proliferating allergen-specific CD4(+) T cells was similar to that expressed by recall antigen-specific T cells.

CONCLUSIONS

The down-regulation of CCR4 and CXCR3 after allergen exposure in Asp f-specific T cells seems to be a characteristic feature of ABPA patients and requires further evaluation.

Fractalkine-induced smooth muscle cell proliferation in pulmonary hypertension

Pulmonary hypertension is characterised by a progressive increase in pulmonary arterial resistance due to endothelial and smooth muscle cell proliferation resulting in chronic obstruction of small pulmonary arteries. There is evidence that inflammatory mechanisms may contribute to the pathogenesis of human and experimental pulmonary hypertension. The aim of the study was to address the role of fractalkine (CX3CL1) in the inflammatory responses and pulmonary vascular remodelling of a monocrotaline-induced pulmonary hypertension model. The expression of CX3CL1 and its receptor CX3CR1 was studied in monocrotaline-induced pulmonary hypertension by means of immunohistochemistry and quantitative reverse-transcription PCR on laser-captured microdissected pulmonary arteries. It was demonstrated that CX3CL1 was expressed by inflammatory cells surrounding pulmonary arterial lesions and that smooth muscle cells from these vessels had increased CX3CR1 expression. It was then shown that cultured rat pulmonary artery smooth muscle cells expressed CX3CR1 and that CX3CL1 induced proliferation but not migration of these cells. In conclusion, the current authors proposed that fractalkine may act as a growth factor for pulmonary artery smooth muscle cells. Chemokines may thus play a role in pulmonary artery remodelling.

Impact of highly active antiretroviral therapy on the maturation of anti-HIV-1 antibodies during primary HIV-1 infection

OBJECTIVES

To study the impact of highly active antiretroviral therapy (HAART) on isotype switching and avidity maturation of HIV-1-specific immunoglobulin G (IgG) in patients with primary HIV-1 infection (PHI).

METHODS

We studied the emergence and the evolution of anti-HIV IgG antibodies by quantitative immunoblotting to analyse IgG subclasses and IgG avidity. Serum samples were obtained from 16 PHI patients from the French PRIMO Cohort Study at various points in the first year of infection: eight patients received no treatment (group I), and eight patients received efficient HAART (group II) during the study period.

RESULTS

Early initiation of HAART in PHI patients partially prevented an increase in anti-HIV-1 IgG levels. Within IgG subclasses, the amount of anti-HIV-1 IgG1 gradually increased with time in both groups, although levels remained lower in treated patients. The anti-p24 IgG2 level was always lower in group II. We observed a decrease in anti-p24 IgG3 over time in both groups. Treatment did not affect the maturation of HIV-1 IgG avidity, which increased in both groups until month 3 and then remained high until the end of the 12-month follow-up period.

CONCLUSIONS

HAART in PHI partially prevents the emergence of HIV-1 IgG antibodies, but does not affect the quality of these antibodies, as reflected in their isotype and avidity.

Dexamethasone and IL-10 stimulate glucocorticoid-induced leucine zipper synthesis by human mast cells

BACKGROUND

Glucocorticoids (GCs) decrease tissue mast cell (MC) number and prevent their activation via their high-affinity IgE receptor. Glucocorticoid-induced leucine zipper (GILZ) is one of the GC-induced genes, which inhibits the functions of the transcriptional activators AP-1 and NF-kappaB. GILZ appears to be a critical actor in the anti-inflammatory and immunosuppressive effects of GCs in human T lymphocytes, macrophages and dendritic cells.

AIMS OF THE STUDY

We investigated whether GILZ was produced by human MCs and whether GILZ synthesis was stimulated by GCs. We also investigated whether GILZ production was modulated by (i) IL-10, because of its common immunosuppressive properties with GCs, (ii) histamine because of its pro-inflammatory properties and (iii) IL-4 and IL-5 because of their ability to favour MC survival and proliferation with SCF.

METHODS

The human MC lines HMC-1 5C6 and LAD-2, and cord blood-derived MCs (CB-MCs) were cultured alone or in the presence of GCs, IL-10, histamine, IL-4 or IL-5. The expression of GILZ was evaluated by using RT-PCR, Western blotting or immunocytochemistry.

RESULTS

We found that human MC lines and CB-MCs constitutively produce GILZ. We also show that GCs and IL-10 stimulate GILZ production by human MCs. Our present results indicate that histamine, IL-4 and IL-5 alone or in combination with SCF do not downregulate GILZ production by MCs.

CONCLUSIONS

These results show that GCs and IL-10 stimulate GILZ production by human MCs. As GILZ mediates anti-inflammatory effects of GCs in immune cells, we speculate that GILZ could account for the deactivation of MCs by GCs and IL-10.

Induction of tolerance by Porphyromonas gingivalis on APCS: a mechanism implicated in periodontal infection

The periodontal pathogen Porphyromonas gingivalis (Pg) is a potent inducer of the production of pro-inflammatory cytokines by neutrophils, monocytes, and macrophages, and can desensitize immune cells in vitro and in vivo. We analyzed the ability of Pg lipopolysaccharide (LPS) to induce endotoxin tolerance. Treatment of dendritic cells (DC), the human macrophage cell line THP-1, and monocytes (antigen-presenting cells, APC) with Pg.LPS inhibited APC maturation assessed by CD80 and CD86 expression, and inhibited chemokine (CCL3 and CCL5) production. Pre-treatment with glucocorticoids (GC) and interleukin-10 (IL-10) abolished the effect of Pg.LPS on CD80, CD83, and CD86, and on CCL3 and CCL5 production. We also showed that Pg.LPS enhanced the tolerogenic properties of APCs and up-regulated ILT-3 and B7-H1 expression.

Predictors of Plasma Human Immunodeficiency Virus Type 1 RNA Control after Discontinuation of Highly Active Antiretroviral Therapy Initiated at Acute Infection Combined with Structured Treatment Interruptions and Immune‐Based Therapies

Thirty patients with acute human immunodeficiency virus (HIV) type 1 infection received a combination of 3 antiretroviral drugs (n=15) or 4 antiretroviral drugs plus hydroxyurea and interleukin-2 (n=15) for 24 months, followed by 1-3 structured therapeutic interruptions (STIs). Viral control, defined as maintaining plasma viremia <5000 copies/mL without therapy, was achieved in 14 cases. Lymphocyte subsets, plasma HIV-1 RNA loads, proviral DNA loads in peripheral blood mononuclear cells (PBMCs), residual HIV-1 RNA loads in PBMCs and in lymph node cells, and anti-p24 lymphoproliferative response were measured. In the multivariate analysis, proviral DNA loads in PBMCs and anti-p24 lymphoproliferative response assessed at 24 months were independently correlated with viral control after STI. These results enabled us to define a subgroup of patients for whom safe discontinuation of therapy initiated at acute infection was suitable and contributed to ascertaining priority for biological parameter assessment in future clinical trials.

Cytokines, chemokine receptors, and homing molecule distribution in the rectum and stomach of pediatric patients with ulcerative colitis

BACKGROUND

Cytokines appear to play a significant role in the pathogenesis of inflammatory bowel disease (IBD) with a predominant Th2 pattern in colonic mucosa of patients with ulcerative colitis (UC). Chemokines and their receptors also regulate the migration of Th1 or Th2 lymphocytes to inflammatory tissues during the immune response. Although adult UC is usually confined to the colon, pediatric UC not uncommonly affects the stomach.

AIMS

The aim of this study was to compare expression of cytokines, chemokine receptors, and homing molecules in the rectal and the histologically characterized gastric mucosa of pediatric patients with UC. SUBJECTS Sixteen patients (11 girls and 5 boys; median age, 9 years) having all the features of UC were included in the study.

METHODS

Rectal and gastric mucosa obtained from UC cases were immunostained with antibodies against L-selectin, beta 7 integrin, CXCR3, CCR3, and CCR5. IL-4 and IL-12 p40 transcript expression was studied by in situ hybridization.

RESULTS

Chronic gastritis was found in 93.7% of cases and Helicobacter pylori (Hp) was found in 2 (13.3%) cases. In the rectal and gastric mucosa, CXCR3 was found in perivascular lymphocytes and CCR5 in a subset of CXCR3+ cells in the lamina propria. CCR3+ lymphocytes and IL-4-positive cells were always found, but there was no evidence of IL-12 production. Most of the lymphocytes infiltrating the gastric mucosa expressed beta 7 but not CD62L. In contrast, beta 7-positive cells were randomly dispersed in the rectal lamina propria, and the fraction of CD3+beta 7+ was low.

CONCLUSIONS

The authors conclude that gastritis is common in pediatric UC. The presence of CCR3+ lymphocytes, IL-4 transcript expression, without IL-12 p40 production in the stomach and in the rectum suggests a Th2 immune response. The presence of CCR3+, CD62L- activated Th2 cells may suggest that these gastric cells are recruited from colorectal primary lesions.

Card15 gene overexpression in mononuclear and epithelial cells of the inflamed Crohn's disease colon

BACKGROUND

Crohn's disease is one of the principal human chronic inflammatory bowel diseases. Although its aetiology is still unknown, its complex pathogenesis has environmental, immunological, and genetic determinants. CARD15 is the first susceptibility gene implicated in the predisposition to Crohn's disease and is known to be expressed only in monocytes. However, its expression in situ has not yet been studied.

AIMS

To analyse the tissue distribution of CARD15 and identify cells producing CARD15 in samples of colon from patients with Crohn's disease and control subjects.

PATIENTS AND METHODS

We analysed CARD15 gene expression in surgical specimens of colon from eight children with Crohn's disease and nine controls by immunohistochemistry, in situ hybridisation, and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

We showed that CARD15 was present only in the cytoplasm of macrophages in the normal colon. Increased CARD15 expression was detected in Crohn's disease lesions. There were more CARD15 positive cells in Crohn's disease lesions than in uninvolved areas. Both intestinal epithelial cells, macrophages, and their derivatives overproduced CARD15 in Crohn's disease. To further assess CARD15 expression by intestinal epithelial cells, we performed RT-PCR on freshly isolated intestinal epithelial cells, and showed that these cells isolated from Crohn's disease samples contained more CARD15 mRNA than intestinal epithelial cells from controls.

CONCLUSIONS

We have demonstrated that colonic involvement in active Crohn's disease is associated with increased CARD15 gene expression in both macrophages and intestinal epithelial cells. Therefore, this deregulation can affect the host-environment interaction and thus contribute to the pathogenesis of this disease.

Evaluation of CD4+ T cells proliferating to grass pollen in seasonal allergic subjects by flow cytometry

Our objective was to characterize T-cell responses to Phleum pratense in grass pollen allergic individuals and healthy controls using the fluorescent dye PKH26. Peripheral blood mononuclear cells were stimulated with P. pratense, or with recall antigens, and CD3+/CD4+ and CD3+/CD8+ T-cells that had proliferated were analysed by flow cytometry. In the presence of P. pratense CD4+/CD3+ T-cells proliferated more in grass pollen sensitive atopic patients than in nonallergic controls or in nongrass pollen sensitive atopic subjects. PPD and TT recall antigens elicited uniformly high proliferation in all T-cell subsets. Only half of pollen sensitive patients also had an increased proliferation of CD3+/CD8+ T-cells in response to P. pratense. We determined precursor frequency of CD4+ T cells in the original population that responded to P. pratense and found values ranging from 1 x 10-3 to 0.6 x 10-1, in the same range as those measured for PPD and TT. In conclusion, grass pollen sensitive atopic patients show enhanced CD4+ T-cell reactivity to P. pratense, and this could be related to the presence of elevated numbers of circulating allergen-specific CD4+ T cells. This flow cytometric method should allow the identification of other phenotypic markers such as intracellular cytokines in allergen specific responding CD4+ T cells.

[Interleukin 10 in disseminated lupus erythematosus]

A number of years ago several groups reported that Interleukin 10 (IL10) was vigorously overproduced in disseminated lupus erythematosus (reviewed in Llorente et al., 2000). This hyperproduction obeys two different patterns. In one pattern, IL10 serum concentrations become elevated during disease and evolve in parallel with them. In the other, the patients' blood mononucleated cells spontaneously release increased IL10 quantities; contrary to serum variations in the first pattern, this increased output is not correlated with disease spurts. Interestingly an increase of this type is frequently found in disease-free parents of these patients (Llorente et al., 1997; Gröndal et al., 1999). Some studies relate this IL10 hyperproduction to a genetic origin (Mehrian et al., 1998; Mok et al., 1998), while others seem to indicate an environmental cause (Gröndal et al., 1999). Together these findings suggest two different possible origins for lupus IL10 overproduction. The first would be due to intrinsic anomalous IL10 production by some immune cells, the second would result from high IL10 output by tissues damaged by the inflammatory process. Considering the properties of IL10, which activates B lymphocytes and inhibits T lymphocytes, overproduction in lupus could explain the immune anomalies of this disease, which is characterized by anti-self antibodies production and by deficient T responses. Interestingly several of these anomalies are found independently from disease outbreaks and, in the case of some, in relatives of patients. The part played by IL10 in lupus has been inferred from the murine NZB-W model, in which an anti-IL10 monoclonal antibody prevents development of the disease (Ishida et al., 1994); this antibody also prevents the appearance of human anti-ADN autoantibodies in immune-deficient mice restored with patients' lymphocytes. A direct demonstration of the role of IL10 in the etiology of lupus symptoms has recently been adduced in a pilot study bearing on six lupus patients, refractory to anti-inflammatory and immuno-suppressive treatments, who were treated for 3 weeks with a murine anti-IL10 monoclonal antibody (Llorente et al., 2000). This treatment brought about a rapid amelioration of the clinical picture, in particular of the cutaneous and articular symptoms, which was maintained for six months after this trial. This symptomatic amelioration was accompanied by a decrease of the biological signs of immune system hyperactivity and a partial amelioration of T lymphocyte function. The better clinical control of the disease allowed a significant decrease of corticotherapy. While this was an open study, without a control group and without randomisation, the rapid and important evolution of clinical and biological parameters towards normal strongly pleads for a favorable effect of the treatment. While confirming previous hypotheses about the rote of IL10 in lupus, this study leaves several points unexplained. First the clinical and biological amelioration in these patients treated with anti-IL10 monoclonal antibody occurred independently of circulating anti-ADN auto-antibodies, indicating that the role of this interleukin in the disease is more complex than could be thought from the initial experiments in mouse. This unexpected result does not exclude that the beneficial effect of the antibody could be mediated by its action on B lymphocytes, since it is well known that these cells play important parts in development auto-immune processes other than only the production of auto-antibodies. It is also possible that the negative effect of IL10 in this disease exerts on other targets than B lymphocytes, in particular on fibroblasts and endothelial cells. Indeed it should be recalled that, while IL10 has often been held as an anti-inflammatory cytokine, its biological properties are more ambiguous, since it can immuno-stimulate some cell types. Among other remaining unknowns, the reason why some IL10 overproducing individuals, belonging to the family of lupus patients, do not develop lupus, is not understood. This fact underlines the multi-factorial origin of this disease, which must stem from associated genetic and environmental causes. IL10 overproduction, while it apparently promotes the symptoms, is certainly not sufficient. The efficiency of anti-IL 10 monoclonal antibodies during lupus, which are well tolerated, points to their usefulness in the therapeutic arsenal, especially in forms that are refractory to conventional anti-inflammatory and immunosuppressive treatments. In order to be validated, this hypothesis must be submitted to more in depth, randomized, studies. Moreover humanized antibodies should be developed, which would make it possible to reiterate the treatment during further outbreaks. Once all these conditions are fulfilled, the place of anti-IL10 treatment in lupus and the benefice-risk ratio should be compared to these of therapeutic approaches currently used in refractory forms. If further studies confirm the efficiency of- and tolerance to- IL10 neutralizing antibodies in lupus, it is well possible that these antibodies will eventually equate, for this disease, the recent use of TNF antagonists in the treatment of rheumatoid arthritis.

Stromal-derived factor-1 in human tumors recruits and alters the function of plasmacytoid precursor dendritic cells

Dendritic-cell (DC) trafficking and function in tumors is poorly characterized, with studies confined to myeloid DCs (DC1s). Tumors inhibit DC1 migration and function, likely hindering specific immunity. The role of plasmacytoid DCs (DC2s) in tumor immunity is unknown. We show here that malignant human ovarian epithelial tumor cells express very high levels of stromal-derived factor-1, which induces DC2 precursor (preDC2) chemotaxis and adhesion/transmigration, upregulates preDC2 very late antigen (VLA)-5, and protects preDC2s from tumor macrophage interleukin-10-induced apoptosis, all through CXC chemokine receptor-4. The VLA-5 ligand vascular-cell adhesion molecule-1 mediated preDC2 adhesion/transmigration. Tumor preDC2s induced significant T-cell interleukin-10 unrelated to preDC2 differentiation or activation state, and this contributed to poor T-cell activation. Myeloid precursor DCs (preDC1s) were not detected. Tumors may weaken immunity by attracting preDC2s and protecting them from the harsh microenvironment, and by altering preDC1 distribution.

Tumor necrosis factor soluble receptor p55 and lipid peroxidation in patients with acute alcoholic hepatitis

OBJECTIVES

In experimental models, liver injury induced by ethanol, cytotoxic activity of tumor necrosis factor (TNF) -alpha is principally mediated by TNF receptor p55 (TNFRp55). Among the various mechanisms underlying the toxic effects of TNF-alpha, overproduction of reactive oxygen species seems to play a key role in mediating TNF-alpha-induced cytotoxicity. The aim of this study was to evaluate, in patients with alcoholic liver disease, whether alcohol TNFRp55-mediated hepatotoxicity could account for lipid peroxidation expressed by significant increase in serum thiobarbituric reactive acid substances (TBARS) content, and could be amplified by decrease in blood total glutathione content and decrease in plasma antioxidant protective capacity.

METHODS

We studied 27 patients with histological alcoholic liver disease (five fibrosis, six acute alcoholic hepatitis (AAH) without cirrhosis, four cirrhosis without AAH, and 12 cirrhosis with AAH. TNFsRp55 and TNFsRp75 plasma levels were measured using ELISA assays. Plasma lipid peroxidation was evaluated by the content of TBARS. Total glutathione (tGSH) content in blood was determined by a kinetic assay. The sensitivity of erythrocytes to an oxidative stress and the plasma antioxidant protective capacity were simultaneously determined by a simple method.

RESULTS

In the 18 patients with mild or severe AAH, the plasma levels of TNFsRp55 were negatively correlated with tGSH and were positively correlated with TBARS, with total bilirubin and with discriminant function. tGSH was positively correlated with plasma selenium. The plasma levels of TNFsRp75 were positively correlated with TBARS and with total bilirubin. There was no significant correlation with the mean inhibitory 50% plasma volume or with the percentage of hemolyzed erythrocytes.

CONCLUSIONS

Our data support the notions that, in patients with AAH, TNFsRp55 probably mediates cytotoxicity of TNF-alpha, and that cytotoxic effect could be amplified by tGSH depletion in enhancing lipid peroxidation.

Preferential and persistent depletion of CCR5+ T-helper lymphocytes with nonlymphoid homing potential despite early treatment of primary HIV infection

Strains of human immunodeficiency virus (HIV) transmitted between individuals use the CCR5 coreceptor, but no preferential depletion of particular Th-lymphocyte subpopulations has been reported during primary HIV infection (PHI). In contrast, gut-associated Th lymphocytes are preferentially depleted in macaques recently infected by simian immunodeficiency virus. The expression of CCR5 and the intestinal homing receptor integrin alpha4beta7 on subpopulations of Th lymphocytes was studied in 12 patients with PHI. There was a profound decrease of circulating alpha4beta7+ Th lymphocytes and CCR5+ memory Th lymphocytes with nonlymphoid homing potential (CD62L-CD45RO+). Unlike other Th lymphocytes, this cell population remained depleted despite early control of viral replication under antiretroviral treatment. Therefore, HIV preferentially targets a specific CCR5+ subpopulation of Th lymphocytes early during infection, inducing its persistent depletion despite treatment. Protective immunity in vivo depends on Th lymphocytes carrying homing capacity to nonlymphoid tissue, and therefore these data may explain the persistent abnormalities of immune functions in patients infected with HIV.

[Chemokines and defense-system cell homing]

The general properties of chemokines and their receptors are described, and the perspectives raised for cellular therapy are discussed. Specific examples are provided in the cases of the CXC chemokine SDF1 and of chemokines ligands of CCR5.

Deregulation of the expression of the fractalkine/fractalkine receptor complex in HIV-1-infected patients

Fractalkine is the only member of the CX3C chemokine family. Polymorphism of the fractalkine receptor gene may influence the prognosis of human immunodeficiency virus (HIV) infection, but the nature of the cells expressing fractalkine or its receptor in HIV-infected patients remains unknown. We show that, in contrast to HIV-uninfected individuals, a large number of cells expressed fractalkine in T-cell zones of lymph nodes from HIV-infected patients. CD83(+) mature and CD123(+) plasmacytoid dendritic cells as well as plasma cells are involved in this increased expression of fractalkine. Increased numbers of plasmacytoid dendritic cells and plasma cells were present in T-cell zones of HIV-infected patients. CD83(+) dendritic cells were present in similar number in HIV-infected patients and controls, but an increased fraction of these cells produced fractalkine in HIV-infected patients. Many plasma cells in the gut-associated lymphoid tissue from HIV-infected patients also produced fractalkine, whereas few cells produced fractalkine in the gut of controls. The fraction of CD45RO(+) and CD45RO(-) T helper (Th) cells expressing the fractalkine receptor CX3CR1 was higher in HIV-infected patients than in healthy individuals, and these cells were abnormally sensitive to fractalkine stimulation. This increased response correlated with HIV viremia, and it returned to normal levels in patients successfully treated with antiretroviral drugs. The increased expression of the fractalkine/fractalkine receptor complex associated with HIV infection may affect adhesion and migration of Th lymphocytes and their interaction with dendritic cells. Thus, it may influence the equilibrium between depletion and renewal of the Th lymphocyte compartment.

Early control of HIV replication in primary HIV-1 infection treated with antiretroviral drugs and pegylated IFN alpha: results from the Primoferon A (ANRS 086) Study

IFN alpha has both antiviral and immunostimulating properties. The ANRS086 Primoferon A Study evaluated in 12 patients with primary HIV infection the tolerance and efficacy of an early and transient administration of pegylated IFN alpha, in addition to highly active antiretroviral therapy. Tolerance was good, and this regimen allowed the early control of HIV replication and rapid decay of the viral reservoir. These results support the initiation of comparative studies with pegylated INF alpha in primary HIV infection.

Characterisation of cytokine mRNA expression in tumour-infiltrating mononuclear cells and tumour cells freshly isolated from human colorectal carcinomas

The in situ function of tumour-infiltrating leukocytes (TIL) in human colorectal adenocarcinoma (CRC) is unclear. Local cytokine expression probably regulates the anti-tumour immune response and tumour immune surveillance. We examined the distribution of mRNA for IFN-gamma, TNF-alpha, IL-10 and IL-4 in TIL, and tumour cells freshly isolated from 21 surgically removed primary CRC, using a semiquantitative RT-PCR. Lamina propria-infiltrating leukocytes (LPL) and epithelial cells from normal colon mucosa of 10 CRC patients served as negative controls. Median levels of IFN-gamma and TNF-alpha mRNA were higher in TIL than LPL (p = 0.0002 and 0.0001). IL-10 mRNA was generally observed in TIL and LPL, but no or very small amounts of IL-4 transcripts were detected in TIL and LPL. TNF-alpha and IL-10 mRNA were more abundant in colorectal tumour cells than in the normal epithelial cells (p = 0.0136 and 0.0036). The number of IFN-gamma transcripts in TIL correlated negatively (p = 0.039) and the number of TNF-alpha transcripts in tumour cells correlated positively with the Dukes' stages (p = 0.0147). Our results suggest that TIL are characterized by a type 1 (Th1/Tc1-like) pattern of cytokine expression and function as T cells (and macrophages) in the local, cell-mediated anti-tumour immune response in early stages of CRC. Changes in IFN-gamma and TNF-alpha mRNA in TIL and tumour cells could be related to tumour progress (e.g. by T cell anergy) or forming of metastases, respectively.

Expression of the chemokine RANTES in pulmonary Wegener's granulomatosis

Wegener's granulomatosis (WG) is an inflammatory, destructive, angiotropic lesion. The inflammatory process involves accumulation of macrophages, lymphocytes, and polymorphonuclear neutrophils. We studied 6 lung biopsy specimens from patients with WG to characterize the cellular infiltrate and to analyze the mechanism of immune cell recruitment. We show that lymphocytes accumulating in WG lesions are mostly memory CD4(+)CD45RO(+) T lymphocytes and, although less numerous, CD8(+)CD45RO(+) T lymphocytes. Few if any B lymphocytes or natural killer cells are present within lesions. The chemokine RANTES (regulated upon activation in normal T cells, expressed and secreted) has been reported to recruit memory T lymphocytes and macrophages selectively. We used reverse-transcription polymerase chain reaction, in situ hybridization, and immunohistochemistry to study its production in WG. RANTES was expressed at a higher level in WG lungs than in normal controls, especially around microabscesses. As visualized immunohistochemically in serial sections with anti-RANTES monoclonal antibody, RANTES production was produced mainly by macrophages. Expression of the gene coding for interferon-gamma (IFN-gamma), a potent RANTES inducer, was also studied. Its expression was also much stronger in WG than in controls. Our observations are consistent with a cascade of events leading to the recruitment of immune cells in WG, sequentially involving production of IFN-gamma by T lymphocytes and RANTES production by macrophages, leading to the homing of memory T-helper lymphocytes and macrophages. HUM PATHOL 32:320-326.

Production of stromal cell-derived factor 1 by mesothelial cells and effects of this chemokine on peritoneal B lymphocytes

B1a lymphocytes accumulate and proliferate in the peritoneal cavity. Stromal cell-derived factor 1 (SDF-1) is a chemotactic and growth promoting factor for B cell precursors. It is required for fetal liver B cell lymphopoiesis, which generates mostly B1a lymphocytes. Using immunohistochemistry with an anti-SDF-1 monoclonal antibody, we found that SDF-1 was produced by peritoneal mesothelial cells in adult mice. Peritoneal B1a lymphocytes expressed a functional SDF-1 receptor, as shown by actin polymerization experiments. In vitro, SDF-1 stimulated migration, proliferation of a minority of peritoneal B1a lymphocytes, and prevented apoptosis in a large fraction of cells. B1a cells migrating in response to SDF-1 were largely enriched in the CD5(high)CD43(high)B220(-)CD1d(-) subpopulation. In vivo, neutralization of SDF-1 for 3 weeks significantly decreased the number of peritoneal B1 cells. SDF-1 also acted on peritoneal B2 cells. These findings show that after the cessation of B cell lymphopoiesis in the liver, around birth, the persistence of B1a cells remains SDF-1 dependent, and that SDF-1 production by mesothelial cells plays a role in the peritoneal location of B1a cells. Thus, the role of mesothelial cells for B1a cells in adults may be similar to that of SDF-1-producing biliary ductal plate cells in the fetus, and to that of bone marrow stromal cells for B2 cell precursors.

Enhanced production of IL-8 in chronic but not in early ileal lesions of Crohn's disease (CD)

Distinct Th1/Th2 patterns have been observed during the evolution of CD. The aim of this study was to compare neutrophil involvement and IL-8 mRNA and protein expression during early recurrent lesions and chronic phases of CD. Twenty-nine patients with CD having ileocolonic resection with anastomosis were studied. Biopsies were obtained during surgery from the non-inflamed ileal mucosa and from chronic ileal lesions. Endoscopic ileal biopsies were also taken from early recurrent ileal lesions occurring 3 months after surgery. Neutrophil counts were performed and mucosal IL-8 levels were evaluated by competitive reverse transcriptase-polymerase chain reaction and immunohistochemistry. Early recurrent ileal lesions were characterized by low neutrophil counts and IL-8 production at the mRNA and protein levels compared with the ileal chronic lesions. The main cellular sources of IL-8 in the early recurrent lesions were neutrophils, while in chronic lesions the majority of IL-8-stained cells were CD3+ T cells and macrophages. These results confirmed that the nature of the inflammatory infiltrate and the expression of cytokine profiles may differ between the acute and chronic phases of CD.

Macrophage-derived dendritic cells have strong Th1-polarizing potential mediated by beta-chemokines rather than IL-12

Monocyte-derived dendritic cells (MDDCs) activate naive T lymphocytes to induce adaptive immunity, effecting Th1 polarization through IL-12. However, little is known about other potential DC Th1 polarizing mechanisms, or how T cell polarization may be affected by DCs differentiating in, or exposed to, a proinflammatory environment. Macrophages (MPhis) are DC precursors abundant in inflamed tissues, lymph nodes, and tumors. Thus we studied the T cell-activating and -polarizing properties of MPhi-derived DCs (PhiDCs). Monocytes were cultured in MPhi-CSF (M-CSF) to produce MPhis, which were then differentiated into DCs following culture with GM-CSF plus IL-4. PhiDCs activated a significant allogeneic MLR and were significantly better than MDDCs in activating T cells with superantigen. Most strikingly, PhiDCs elicited up to 9-fold more IFN-gamma from naive or Ag-specific T cells compared with MDDCs (with equivalent IL-4 secretion), despite producing up to 9-fold less IL-12. Neutralization of MDDC, but not PhiDC IL-12 significantly inhibited T cell IFN-gamma induction. PhiDCs produced up to 12-fold more beta-chemokines (macrophage-inflammatory protein-1alpha, -1beta, and RANTES) than MDDCs. Ab blockade of CCR5, but not CXC chemokine receptor 4, inhibited T cell IFN-gamma induction by PhiDCs significantly greater than by MDDCs. Thus DCs differentiating from MPhis induce T cell IFN-gamma through beta-chemokines with little or no requirement for IL-12. Myeloid DCs arising from distinct precursor cells may have differing properties, including different mechanisms of Th1 polarization. These data are the first reports of IFN-gamma induction through chemokines by DCs.

Pretreatment expression of the perforin gene by circulating CD8(+) T lymphocytes predicts biochemical response to interferon-alpha in patients with chronic hepatitis C

It would be of great value to be able to predict, before the initiation of treatment, which patients with hepatitis C virus-induced chronic hepatitis will be cured by interferon-alpha (IFN-alpha). Competitive RT-PCR was used to evaluate spontaneous expression of the perforin gene, a marker of cytotoxic cell activation, by circulating mononuclear cells in 17 patients undergoing IFN-alpha treatment. IFN-alpha increased perforin gene expression (p < 0.003), but this was not correlated with outcome. In contrast, pretreatment perforin gene expression levels were higher in the 8 patients with a sustained biochemical response after treatment than in the 9 non-responsive patients (p = 0.01). This factor predicted favorable clinical outcome with a sensitivity of 75% and a specificity of 89%. Thus, pretreatment immunological status has a major influence on the ability of IFN-alpha to cure chronic hepatitis C, and the evaluation of perforin gene expression may help to select patients that will benefit from IFN-alpha treatment.

Clinical and biologic effects of anti-interleukin-10 monoclonal antibody administration in systemic lupus erythematosus

OBJECTIVE

To evaluate the safety and clinical efficacy of administering an anti-interleukin-10 (anti-IL-10) monoclonal antibody (mAb) to systemic lupus erythematosus (SLE) patients with active and steroid-dependent disease. In addition, we sought to assess the effects of in vivo IL-10 neutralization on biologic markers of SLE.

METHODS

Treatment consisted of 20 mg/day intravenous administration of an anti-IL-10 murine mAb (B-N10) for 21 consecutive days, with a followup period of 6 months. Six patients were studied.

RESULTS

Treatment was safe and well tolerated. All patients developed antibodies against B-N10. Cutaneous lesions and joint symptoms improved in all patients beginning during B-N10 administration and continuing to month 6. The SLE Disease Activity Index decreased from a mean +/- SEM of 8.83+/-0.91 on day 1 to 3.67+/-0.67 on day 21 (P = 0.001), 1.50+/-0.84 at month 2, and 1.33+/-0.80 at month 6 (P<0.001). At the end of followup, the disease was clinically inactive in 5 of the 6 patients. Prednisone administration was decreased from a mean +/- SEM of 27.9+/-5.7 mg/day on day 1 to 9.6+/-2.0 mg/day at month 6 (P<0.005). Activity of immune and endothelial cells rapidly decreased, as assessed by the early evolution of several biologic markers.

CONCLUSION

This is the first report of IL-10 antagonist administration to humans. The study shows the involvement of IL-10 in the pathogenesis of SLE, and indicates that the use of IL-10 antagonists may be beneficial in the management of refractory SLE.

Pretreatment expression of the perforin gene by circulating CD8(+) T lymphocytes predicts biochemical response to interferon-alpha in patients with chronic hepatitis C

It would be of great value to be able to predict, before the initiation of treatment, which patients with hepatitis C virus-induced chronic hepatitis will be cured by interferon-alpha (IFN-alpha). Competitive RT-PCR was used to evaluate spontaneous expression of the perforin gene, a marker of cytotoxic cell activation, by circulating mononuclear cells in 17 patients undergoing IFN-alpha treatment. IFN-alpha increased perforin gene expression (p < 0.003), but this was not correlated with outcome. In contrast, pretreatment perforin gene expression levels were higher in the 8 patients with a sustained biochemical response after treatment than in the 9 non-responsive patients (p = 0.01). This factor predicted favorable clinical outcome with a sensitivity of 75% and a specificity of 89%. Thus, pretreatment immunological status has a major influence on the ability of IFN-alpha to cure chronic hepatitis C, and the evaluation of perforin gene expression may help to select patients that will benefit from IFN-alpha treatment.

Regulated on activation normal T expressed and secreted chemokine is induced by tumor necrosis factor-alpha in granulosa cells from human preovulatory follicle

We examined the production of regulated on activation normal T expressed and secreted (RANTES) chemokine, which may contribute to the recruitment and local accumulation of leukocytes in human preovulatory follicles. Cells were obtained from follicular aspirates collected from in vitro fertilization patients, then cultured. RANTES production in culture was measured by immunoenzymatic assay, RANTES-producing cells were measured by flow cytometry, and messenger ribonucleic acid as measured by RT-PCR and in situ hybridization. RANTES was detected in follicular fluids and culture supernatants; RANTES protein and messenger ribonucleic acid were expressed in granulosa cells. RANTES production was stimulated by tumor necrosis factor-alpha (TNFalpha) and was inhibited in cultures containing a neutralizing anti-TNFa antibody. p55 TNF receptors were detected by RT-PCR and visualized on granulosa cells by flow cytometry. RANTES production was increased by phorbol 12-myristate 13-acetate, but not by 8-bromo-cAMP. RANTES was produced by granulosa cells from human preovulatory follicles. This production was activated by TNFalpha, probably through TNF receptor p55. This suggests that RANTES may play an active role in ovarian processes involving the local accumulation of immune cells.

Fractalkine receptor expression by T lymphocyte subpopulations and in vivo production of fractalkine in human

Expression and function of the fractalkine receptor CX3CR1 by T lymphocyte subpopulations was evaluated in healthy individuals. In CD8(+) T lymphocytes, CX3CR1 was expressed by and functional in both CD45RO(-) and CD45RO(+) cells. In CD4(+) T lymphocytes, CX3CR1 was expressed mainly by CD45RO(+) cells, and almost exclusively by activated HLA-DR(+) T lymphocytes. This receptor was functional in CD45RO(+) cells, but not in CD45RO(-) cells. Expression of fractalkine was detected by in situ hybridization and immunohistochemistry in endothelial cells of normal lung and thymus. In hyperplastic lymph nodes, fractalkine was expressed by endothelial cells of high endothelial venules and of subcapsular vessels, by follicular dendritic cells (FDC) and by some follicle lymphocytes. Fractalkine mRNA was constitutively present in the HK FDC-like cell line, and it was induced in vitro in B lymphocytes stimulated by an anti-micro or by a CD40 mAb. These findings indicate that fractalkine may contribute to the recruitment of effector T helper lymphocytes, either in peripheral tissues or in lymphoid organs. In these tissues, fractalkine and its receptor may favor contact within follicles between activated T helper lymphocytes, activated B lymphocytes and FDC, thus contributing to the maturation of the B lymphocyte response.

Human interleukin-6 is in vivo an autocrine growth factor for human herpesvirus-8-infected malignant B lymphocytes

Human interleukin-6 (hIL-6) acts as a growth factor in several human B lymphoid cancers. As human herpesvirus-8 (HHV-8) encodes for a viral IL-6 (vIL-6), the viral cytokine may be responsible for several manifestations of HHV-8-related disorders. Using an anti-hIL-6 mAb (B-E8) which does not recognize vIL-6, we investigated the involvement of the human cytokine in the proliferation of HHV-8-positive primary effusion lymphoma (PEL) cells. In vitro, 5/5 PEL cell lines produced hIL-6 (4 to 1,200 pg/ml). The EBV- HHV-8+ cell line (BCBL-1) was adapted to grow in SCID mice. hIL-6 was detected in the serum of mice with grafts, as well as human soluble CD138 (sCD138) and human IL-10 (hIL-10). The serum level of these mediators increased with tumor progression. The effect of treatment with the B-E8 mAb on the tumor progression and survival was evaluated. This treatment significantly slowed down the tumor development: on day 54, there were more mice with low levels of sCD138 and hIL-10 in the treated group than in controls (p = 0.03 and 0.02, respectively); treatment also delayed death (median date of death was day 65 for control mice and day 84 for anti-hIL-6 mAb-treated mice; p < 0.02). Thus, hIL-6 is expressed in addition to vIL-6 in HHV-8-positive malignant B lymphocytes, and the viral cytokine does not totally substitute for human IL-6 in promoting tumor progression.

Prognostic value of the soluble interleukin-2 receptor in chronic hepatitis C treated with interferon-alfa. Multicenter GER-CYT 04 Group

BACKGROUND/AIMS

High serum levels of the soluble interleukin 2 receptor (sIL-2R) have been reported in patients with chronic hepatitis C. The aims of this study were to determine the evolution of sIL-2R considered as an indicator of activation of T cells in patients with hepatitis C virus (HCV) treated with IFN-alpha and to correlate sIL-2R serum levels with parameters reflecting ongoing liver disease and with outcome of interferon treatment.

METHODS

In a case-control study, we studied patients enrolled in a multicenter randomized clinical trial which had demonstrated the benefit of a reinforced regimen of interferon alpha. Each of the 26 sustained virological responders (SVR) was paired for treatment regimen with two non-responders (NR).

RESULTS

Prior to treatment, higher levels of sIL-2R were found in the sera of 78 patients compared with healthy controls (3791+/-210 pg/ml versus 956+/-88 pg/ml (p<0.001)). In the 78 patients after 4 weeks of treatment, the levels of sIL-2R were higher than pretreatment levels (4308+/-206 pg/ml (p<0.01)). In the NR, levels of sIL-2R increased significantly after 4 weeks of treatment compared with pretreatment levels (p<0.01), and levels of sIL-2R at week 72 were not significantly different from those at pretreatment. Conversely, in the SVR, levels of sIL-2R at week 4 did not significantly increase compared to pretreatment values, and thereafter gradually decreased. At week 72, levels of sIL-2R were significantly lower than before treatment (p<0.001). The difference between levels of sIL-2R at week 4 and before initiation of treatment (delta s IL-2R) was smaller in the SVR than in the NR (142+/-219 pg/ml versus 704+/-107 pg/ml (p<0.02). The disappearance of HCV RNA from the serum at week 4 showed a sensitivity of 92% (95% confidence interval 86-98) and a specificity of 60% (95% confidence interval 49-71), delta sIL-2R had a sensitivity of 42% (95% confidence interval 31-53) and a specificity of 81% (95% confidence interval 79-90) for the prediction of a sustained virological response 6 months after stopping treatment. The disappearance of HCV RNA from serum at week 4 and delta sIL-2R were independent and early predictive factors for a sustained virological response 6 months after stopping treatment.

CONCLUSIONS

At week 4, delta sIL-2R may be a more specific parameter than the disappearance of HCV RNA for assessing total, and hence more sustained, elimination of HCV infection 6 months after stopping treatment.