A comparison of etanercept and methotrexate in patients with early rheumatoid arthritis.

BACKGROUND: Etanercept, which blocks the action of tumor necrosis factor, reduces disease activity in patients with long-standing rheumatoid arthritis. Its efficacy in reducing disease activity and preventing joint damage in patients with active early rheumatoid arthritis is unknown. METHODS: We treated 632 patients with early rheumatoid arthritis with either twice-weekly subcutaneous etanercept (10 or 25 mg) or weekly oral methotrexate (mean, 19 mg per week) for 12 months. Clinical response was defined as the percent improvement in disease activity according to the criteria of the American College of Rheumatology. Bone erosion and joint-space narrowing were measured radiographically and scored with use of the Sharp scale. On this scale, an increase of 1 point represents one new erosion or minimal narrowing. RESULTS: As compared with patients who received methotrexate, patients who received the 25-mg dose of etanercept had a more rapid rate of improvement, with significantly more patients having 20 percent, 50 percent, and 70 percent improvement in disease activity during the first six months (P<0.05). The mean increase in the erosion score during the first 6 months was 0.30 in the group assigned to receive 25 mg of etanercept and 0.68 in the methotrexate group (P= 0.001), and the respective increases during the first 12 months were 0.47 and 1.03 (P=0.002). Among patients who received the 25-mg dose of etanercept, 72 percent had no increase in the erosion score, as compared with 60 percent of patients in the methotrexate group (P=0.007). This group of patients also had fewer adverse events (P=0.02) and fewer infections (P= 0.006) than the group that was treated with methotrexate. CONCLUSIONS: As compared with oral methotrexate, subcutaneous [corrected] etanercept acted more rapidly to decrease symptoms and slow joint damage in patients with early active rheumatoid arthritis.

Etanercept in the treatment of psoriatic arthritis and psoriasis: a randomised trial.

BACKGROUND: Etanercept, a tumour-necrosis-factor inhibitor, has shown efficacy in the treatment of rheumatoid arthritis. Psoriatic arthritis and psoriasis are disease states in which tumour necrosis factor, a proinflammatory cytokine, is present in increased concentrations in joints and in the skin. Therefore, psoriatic arthritis and psoriasis may be appropriate therapeutic targets for etanercept. METHODS: This randomised, double-blind, placebo-controlled, 12 week study assessed the efficacy and safety of etanercept (25 mg twice-weekly subcutaneous injections) or placebo in 60 patients with psoriatic arthritis and psoriasis. Psoriatic arthritis endpoints included the proportion of patients who met the Psoriatic Arthritis Response Criteria (PsARC) and who met the American College of Rheumatology preliminary criteria for improvement (ACR20). Psoriasis endpoints included improvement in the psoriasis area and severity index (PASI) and improvement in prospectively-identified individual target lesions. FINDINGS: In this 12 week study, 26 (87%) of etanercept-treated patients met the PsARC, compared with seven (23%) of placebo-controlled patients. The ARC20 was achieved by 22 (73%) of etanercept-treated patients compared with four (13%) of placebo-treated patients. Of the 19 patients in each treatment group who could be assessed for psoriasis (> or = 3% body surface area), five (26%) of etanercept-treated patients achieved a 75% improvement in the PASI, compared with none of the placebo-treated patients (p=0.015). The median PASI improvement was 46% in etanercept-treated patients versus 9% in placebo-treated patients; similarly, median target lesion improvements were 50% and 0, respectively. Etanercept was well tolerated. INTERPRETATION: Etanercept offers patients with psoriatic arthritis and psoriasis a new therapeutic option for control of their disease.

Tumor necrosis factor-alpha regulates secretion of the adipocyte-derived cytokine, leptin.

The seminal observation that secretion of the adipocyte-derived hormone leptin was induced by inflammatory challenge has been expanded upon to demonstrate the importance of the pro-inflammatory cytokines, especially tumor necrosis factor (TNF)-alpha, in inflammatory hyperleptinemia. Initially, it was thought that cytokine-induced hyperleptinemia might somehow be involved in the anorexia and cachexia that often accompany chronic infectious, neoplastic, and autoimmune disease. While the role of leptin in disease-associated anorexia and cachexia appears tenuous in light of recent findings, there is evidence that the hyperleptinemia induced by cytokines is an integral part of the acute phase response and necessary for comprehensive immunocompetence. This hints at the existence of an integrated communication network, wherein the energy status of the animal impacts its ability to fight pathogens.

Multicenter prospective study of children with sickle cell disease: radiographic and psychometric correlation.

After obtaining familial informed consent, between January 1996 and July 1997, 173 children (5 to 15 years old) with sickle cell disease were enrolled in a prospective multicenter study using blood screening, transcranial Doppler ultrasonography (n = 143), cerebral magnetic resonance imaging (n = 144), and neuropsychologic performance evaluation (n = 156) (Wechsler Intelligence tests WISC-III, WIPPSI-R), which were also performed in 76 sibling controls (5 to 15 years old). Among the 173 patients with sickle cell disease (155 homozygous for hemoglobin SS, 8 sickle cell beta0 thalassemia, 3 sickle cell beta+ thalassemia, 7 sickle cell hemoglobin C disease SC), 12 (6.9%) had a history of overt stroke, and the incidence of abnormal transcranial Doppler ultrasonography (defined as mean middle cerebral artery velocity > 200 cm/sec or absent) was 8.4% in the overall study population and 9.6% in patients with homozygous sickle cell anemia The silent stroke rate was 15%. Significantly impaired cognitive functioning was observed in sickle cell disease patients with a history of stroke (Performance IQ and Full Scale IQ), but also in patients with silent strokes (Similarities, Vocabulary, and Verbal Comprehension). However, infarcts on magnetic resonance imaging were not the only factors of cognitive deficit: Verbal IQ, Performance IQ, and Full Scale IQ were strongly impaired in patients with severe chronic anemia (hematocrit < or = 20%) and in those with thrombocytosis (platelets > 500 x 10(9)/L). Multivariate logistic regression analysis showed that abnormal magnetic resonance imaging (odds ratio [OR] = 2.76) (P = .047), hematocrit < or =20% (OR = 5.85) (P = .005), and platelets > 500 x 10(9)/L (OR = 3.99) (P = .004) were independent factors of cognitive deficiency (Full Scale IQ < 75) in sickle cell disease patients. The unfavorable effect of low hematocrit has already been suggested, but this is the first report concerning an effect of thrombocytosis and showing that silent stroke alone is not a factor of cognitive deficit when not associated with low hematocrit or thrombocytosis. The effect of hydroxyurea, which is known to increase hematocrit and decrease platelet count, on cognitive functioning of sickle cell patients should be evaluated prospectively.

Interleukin (IL)-10 inhibits IL-6 production in microglia by preventing activation of NF-kappaB.

The purpose of this study was to determine if interleukin (IL)-10 inhibits lipopolysaccharide (LPS)-induced IL-6 production in microglia by inhibiting activation of nuclear factor-kappaB (NF-kappaB). N13 microglia (a murine microglial cell line) and primary microglia from neonatal mice were cultured in the presence or absence of LPS and increasing amounts of murine IL-10 for 24 h. As predicted, LPS treatment increased supernatant IL-6 concentration in both N13 and primary microglia cultures. Pretreatment with IL-10, however, decreased LPS-induced IL-6 secretion in a dose-dependent manner in both culture systems. Likewise, ribonuclease protection assays showed that LPS increased steady-state IL-6 mRNA levels, but that pretreatment with IL-10 blocked the LPS-induced increase in IL-6 mRNA. Because NF-kappaB is the predominant transcription factor responsible for IL-6 transcription in response to inflammatory stimuli, it was hypothesized that IL-10 inhibited IL-6 production by preventing nuclear translocation of NF-kappaB. Consistent with this idea, LPS increased nuclear translocation of NF-kappaB as assessed by gel mobility shift assay. Supershift assays and immunocytochemical staining showed that both the p50 and p65 subunits of NF-kappaB translocated from the cytoplasm to the nucleus upon LPS stimulation. Pretreatment with IL-10, however, inhibited LPS-induced activation of NF-kappaB. Furthermore, inhibition of NF-kappaB activity with tosyl-Phe-chloromethlyketone (a serine protease inhibitor that prevents degradation of the NF-kappaB-IkappaB complex), completely blocked LPS-induced IL-6 production. These data suggest that IL-10 inhibited IL-6 production in microglia by decreasing the activity of NF-kappaB and, therefore, extend what little is known of the intricate relationship between anti-inflammatory and inflammatory cytokines in the central nervous system.

Etanercept in children with polyarticular juvenile rheumatoid arthritis. Pediatric Rheumatology Collaborative Study Group.

BACKGROUND: We evaluated the safety and efficacy of etanercept, a soluble tumor necrosis factor receptor (p75):Fc fusion protein, in children with polyarticular juvenile rheumatoid arthritis who did not tolerate or had an inadequate response to methotrexate. METHODS: Patients 4 to 17 years old received 0.4 mg of etanercept per kilogram of body weight subcutaneously twice weekly for up to three months in the initial, open-label part of a multicenter trial. Those who responded to treatment then entered a double-blind study and were randomly assigned to receive either placebo or etanercept for four months or until a flare of the disease occurred. A response was defined as an improvement of 30 percent or more in at least three of six indicators of disease activity, with no more than one indicator worsening by more than 30 percent. RESULTS: At the end of the open-label study, 51 of the 69 patients (74 percent) had had responses to etanercept treatment. In the double-blind study, 21 of the 26 patients who received placebo (81 percent) withdrew because of disease flare, as compared with 7 of the 25 patients who received etanercept (28 percent) (P=0.003). The median time to disease flare with placebo was 28 days, as compared with more than 116 days with etanercept (P<0.001). In the double-blind study, there were no significant differences between the two treatment groups in the frequency of adverse events. CONCLUSIONS: Treatment with etanercept leads to significant improvement in patients with active polyarticular juvenile rheumatoid arthritis. Etanercept is well tolerated by pediatric patients.

Tumor necrosis factor (TNF)-alpha induces leptin production through the p55 TNF receptor.

Tumor necrosis factor (TNF)-alpha acts directly on adipocytes to increase production of the lipostatic factor, leptin. However, which TNF receptor (TNFR) mediates this response is not known. To answer this question, leptin was measured in plasma of wild-type (WT), p55, and p75 TNFR knockout (KO) mice injected intraperitoneally with murine TNF-alpha and in supernatants from cultured WT, p55, and p75 TNFR KO adipocytes incubated with TNF-alpha. Leptin also was measured in supernatants from C3H/HeOuJ mouse adipocytes cultured with blocking antibodies to each TNFR and TNF-alpha as well as in supernatants from adipocytes incubated with either human or murine TNF-alpha, which activate either one or both TNFR, respectively. The results using all four strategies show that the induction of leptin production by TNF-alpha requires activation of the p55 TNFR and that although activation of the p75 TNFR alone cannot cause leptin production, its presence affects the capability of TNF-alpha to induce leptin production through the p55 TNFR. These results provide new information on the interplay between cells of the immune system and adipocytes.

Intracerebroventricular injection of lipopolysaccharide increases plasma leptin levels.

Leptin regulates adiposity by reducing caloric intake and increasing energy expenditure. Because loss of body weight is common during infectious, neoplastic, and autoimmune diseases of the central nervous system, we examined whether an injection of lipopolysaccharide (LPS) into the lateral cerebral ventricle increases circulating leptin levels in fasted mice. Centrally injected LPS (100 ng) induced a two-fold elevation in plasma leptin 6, 12, and 18 h post-injection. Peripheral injection of the same dose of LPS did not affect leptin secretion. This suggests that inflammatory stimuli localized in the CNS are sufficient to induce leptin secretion in the periphery. The induction of leptin by inflammatory stimuli in the brain may be part of a feed-back loop that contributes to anorexia and cachexia in many CNS-oriented diseases.

In vivo and in vitro evidence for the involvement of tumor necrosis factor-alpha in the induction of leptin by lipopolysaccharide.

To examine the role of tumor necrosis factor-alpha (TNF alpha) in mediating leptin secretion during an immunological challenge, we studied the effects of lipopolysaccharide (LPS) and TNF alpha on leptin secretion in endotoxin-sensitive C3H/HeOuJ (OuJ) mice, endotoxin-insensitive C3H/HeJ (HeJ) mice, and primary adipocytes cultured from both. Intraperitoneal injection of LPS increased plasma concentrations of TNF alpha and leptin in OuJ mice, but not in HeJ mice, suggesting a causal relationship between the induction of TNF alpha and leptin. Consistent with this idea, i.p. injection of recombinant murine TNF alpha increased plasma leptin in both OuJ and HeJ mice. To determine whether TNF alpha induces leptin secretion by acting directly on fat cells, primary adipocytes from OuJ and HeJ mice were cultured in the presence of TNF alpha or LPS. Whereas LPS was without effect on leptin secretion by adipocytes, TNF alpha induced a marked increase in the cell supernatant leptin concentration. These data demonstrate that TNF alpha plays a role in regulating the increase in leptin caused by LPS. Moreover, they show that TNF alpha can act directly on adipocytes to stimulate leptin secretion. Our results are consistent with the emerging view that leptin is a key hormone coupling immune system activity to energy balance.

Enhanced lymphoproliferation and diminished autoimmunity in CD4-deficient MRL/lpr mice.

MRL/lpr mice spontaneously develop an autoimmune disease with features of systemic lupus erythematosus. They also develop a lymphoproliferative disorder characterized by a massive accumulation of double-negative (DN) T cells that lack both CD4 and CD8. To clarify the role of CD4 in autoimmunity and lymphoproliferation in these mice, CD4-deficient MRL/lpr mice were generated. CD4-deficient MRL/lpr mice developed massive expansion of DN T cells in the blood, spleen, and lymph nodes, which significantly exceeded the degree of lymphoproliferation in CD4-expressing control MRL/lpr mice. Despite this lymphoproliferation, CD4-deficient MRL/lpr mice produced little, if any, antibodies to double-stranded DNA, and they had prolonged survival relative to CD4-expressing littermates. However, they eventually developed moderately severe nephritis, characterized by immunoglobulin and complement deposition in glomeruli, vasculitis, and renal infiltration by CD8+ T cells. These findings indicate that (1) lymphoproliferation in MRL/lpr mice does not require the expression of CD4; (2) autoantibody production in MRL/lpr mice is dependent on the expression of CD4 and not on the accumulation of DN T cells; and (3) the development of nephritis in MRL/lpr mice involves both CD4-dependent and CD4-independent mechanisms.

Long-term inhibition of murine lupus by brief simultaneous blockade of the B7/CD28 and CD40/gp39 costimulation pathways.

Murine lupus in NZB/NZW F1 (B/W) mice can be retarded by sustained administration of CTLA4Ig and by brief treatment early in life with mAb that block CD40/gp39 interactions. We sought to determine whether brief therapy with CTLA4Ig could provide sustained benefit in B/W mice and whether a synergistic effect could be derived by blockade of both the B7/CD28 and the CD40/gp39 pathways. We found that a short course of CTLA4Ig at the onset of disease produced only short-term benefit. However, when CTLA4Ig was combined with anti-gp39, there was long-lasting inhibition of autoantibody production and renal disease. Ten months after the 2-wk course of therapy, 70% of these mice were alive, compared with only 18% and 0% of those that received only anti-gp39 or CTLA4Ig, respectively. These findings demonstrate that brief simultaneous blockade of the B7/CD28 and CD40/gp39 costimulation pathways can produce benefit that lasts long after treatment has been discontinued.

Anorexia, weight loss and increased plasma interleukin-6 caused by chronic intracerebroventricular infusion of interleukin-1beta in the rat.

Pro-inflammatory cytokines produced in the central nervous system (CNS) have been suggested to have a role in the anorexia and cachexia of disease. In the present study, the effects of chronic exposure of the CNS to interleukin-1beta (IL-1beta) on several indicators of cachexia were studied. Rats were prepared with an intracerebroventricular (i.c.v.) cannula and an osmotic minipump that delivered vehicle or 1.56 ng/h recombinant murine IL-1beta for 4 days. Food intake and body weight were determined daily during the 4-day infusion period and plasma IL-6 and corticosterone concentrations were determined from plasma collected postinfusion. Chronic i.c.v. infusion of IL-1beta resulted in a chronic reduction in food intake. Rats infused i.c.v. with IL-1beta ate less food each day compared to vehicle controls and, at the end of the 4-day infusion period, consumed an average of 17.2 g less. Intracerebroventricular infusion of IL-1beta also caused an immediate and substantial loss of body weight that was sustained throughout the infusion period. In addition, rats infused with IL-1beta had plasma levels of IL-6 double those of vehicle controls (401 pg/ml vs. 185 pg/ml). Plasma corticosterone concentrations were similar between treatments. These results suggest that chronic exposure of the CNS to cytokines such as IL-1beta may be sufficient to induce anorexia and cachexia.

Central lipopolysaccharide elevates plasma IL-6 concentration by an alpha-adrenoreceptor-mediated mechanism.

High circulating levels of interleukin-6 (IL-6) are evident after intracerebroventricular injection of lipopolysaccharide (LPS). To investigate the pathway of centrally induced IL-6 production, in the present study we evaluated the effects of specific alpha-adrenergic receptor antagonists administered peripherally on IL-6 production and hypertriglyceridemia induced by LPS administered centrally. In the first study, adult male Wistar-Furth rats were injected intracerebroventricularly with LPS. Centrally injected LPS increased plasma IL-6 and triglycerides (TG) in a dose-dependent fashion. To determine if LPS increased plasma IL-6 and TG through an alpha-adrenoreceptor mechanism, rats were pretreated intraperitoneally with either vehicle, phentolamine (alpha 1- and alpha 2-receptor antagonist), prazosin (alpha 1-receptor antagonist), or yohimbine (alpha 2-receptor antagonist). Thirty minutes later, rats were injected intracerebroventricularly with LPS. Whereas prazosin and yohimbine attenuated the increases in plasma IL-6 caused by LPS, phentolamine completely blocked the peripheral effects of central LPS. These data suggest that increased sympathetic activity and subsequent activation of alpha 1- and alpha 2-adrenergic receptors are important for controlling peripheral metabolic and endocrine systems when inflammatory stimuli are present in the brain.

Coincidental changes in behavior and plasma cortisol in unrestrained pigs after intracerebroventricular injection of tumor necrosis factor-alpha.

The coincidental behavioral and physiological responses to inflammatory stimuli administered either peripherally or centrally were evaluated. In the first study, twenty castrated male pigs were injected ip with 0, 0.5, 5, or 50 microg/kg BW lipopolysaccharide (LPS). Body temperature was monitored telemetrically, and serial blood samples were collected via an indwelling jugular catheter for determination of plasma cortisol and tumor necrosis factor-alpha (TNF-alpha) concentrations. Sickness behaviors were measured during 10-min tests at 0, 2, 4, 8, 12, and 24 h post injection. The 5 and 50 microg/kg doses of LPS increased plasma concentrations of cortisol and TNF-alpha, while inducing anorexia, hypersomnia, and fever. In contrast, although 0.5 microg/kg LPS induced acute anorexia, hypersomnia, and fever, it did not increase plasma TNF-alpha; and the cortisol response was small and transient, suggesting the behavioral system in pigs is more responsive to LPS than the hypothalamic-pituitary-adrenal (HPA) axis. Because LPS-induced behavior and activation of the HPA axis involve proinflammatory cytokines in the brain, in a second study, unrestrained pigs with jugular catheters were injected intracerebroventricularly (I.C.V.) with recombinant porcine TNF-alpha. Vehicle or TNF-alpha (0, 5, or 50 ng/kg) was injected I.C.V., and plasma cortisol and behavior were determined as before. Pigs injected I.C.V. with 50 ng/kg TNF-alpha showed anorexia, hypersomnia, and an abrupt increase in plasma cortisol concentration. Whereas 5 ng/kg TNF-alpha I.C.V. also induced marked sickness behavior, it failed to stimulate the HPA axis, as indicated by plasma cortisol levels. That there was a distinct difference in the magnitude of behavioral and endocrine responses to LPS and TNF-alpha suggests that different systems that are responsive to inflammatory stimuli exhibit different sensitivities.

Time course of increased plasma cytokines, cortisol, and urea nitrogen in pigs following intraperitoneal injection of lipopolysaccharide.

The emerging view is that reduced feed intake, lean muscle accretion, and growth in immunologically challenged pigs is the result of increased cytokine activity, but this has not been directly tested. To begin addressing this issue, 72 crossbred barrows and gilts (11.55 +/- .19 kg BW) were not fed for 12 h and then injected i.p. with 0, .5, or 5 micrograms/kg of Escherichia coli lipopolysaccharide (LPS). Blood was collected by jugular puncture at 0, 2, 4, 8, 12, and 24 h after injection. Plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), cortisol, plasma urea nitrogen (PUN), NEFA, and triglycerides were determined. Immunological stress was induced by LPS as indicated by increased secretion of TNF-alpha, IL-6, and cortisol. In pigs receiving 5 micrograms/kg of LPS, plasma TNF-alpha was increased 10-fold at 2 h after injection and was still elevated (P < .01) at 4 h. In these same pigs, plasma concentration of IL-6 was increased at 2 h and peaked at 4 h with levels exceeding baseline values by 200-fold (P < .01). Cortisol was elevated at 2, 4, and 8 h after injection (P < .01). The increased secretion of cytokines and cortisol in pigs injected with 5 micrograms/kg of LPS was followed by an increase in protein degradation, as evidenced by PUN values that were increased two- and threefold at 8 and 12 h after injection, respectively. However, unlike previous reports in laboratory animal species, plasma glucose, NEFA, and triglycerides were not altered by LPS. Nonetheless, as the period of feed deprivation progressed from 12 to 36 h, plasma NEFA and triglycerides increased (P < .05) and plasma glucose tended to decrease. We believe that immunological challenge induces cytokine synthesis and secretion in swine which, in turn, may induce protein catabolism.

Treatment of murine lupus with CTLA4Ig.

The interaction of B7-related molecules on antigen-presenting cells with CD28 or CTLA-4 antigens on T cells provides a second signal for T cell activation. Selection inhibition of the B7-CD28 or B7-CTLA-4 interactions produces antigen-specific T cell unresponsiveness in vitro and suppresses immune function in vivo. To determine whether selective inhibition of the B7-CD28 or B7-CTLA-4 interactions could suppress spontaneous autoimmune disease, a B7-binding protein was generated by genetic fusion of the extracellular domain of murine CTLA-4 to the Fc portion of a mouse immunoglobulin G2a monoclonal antibody (muCTLA4Ig). In lupus-prone NZB/NZW filial generation (F1) mice, treatment with muCTLA4Ig blocked autoantibody production and prolonged life, even when treatment was delayed until the most advanced stage of clinical illness. These findings suggest a possible role for human CTLA4Ig in the treatment of autoimmune diseases in humans.

Interleukin 6 promotes murine lupus in NZB/NZW F1 mice.

To investigate the role of IL-6 in systemic lupus erythematosus (SLE), we selectively inhibited IL-6 in lupus-prone NZB/NZW F1(B/W) mice by chronic administration of a rat mAb to mouse IL-6. Anti-IL-6 alone elicited an anti-rat response that blocked its biologic effects. To circumvent this problem, we rendered B/W mice tolerant to the rat mAb by administration of anti-CD4 concurrent with the first dose of anti-IL-6. Thereafter, the mice received weekly injections of anti-IL-6 alone. There were two control groups: one group received the tolerizing regimen of anti-CD4 along with a control rat IgG1 mAb (GL113) instead of anti-IL-6; the other control group received PBS. Mice that received anti-CD4 were tolerant to the rat mAb for 6 mo. Throughout this period, treatment with anti-IL-6 prevented production of anti-dsDNA, significantly reduced proteinuria, and prolonged life. Mice that received anti-IL-6 without anti-CD4 developed an immune response to the rat mAb and then developed anti-dsDNA antibodies, proteinuria, and mortality comparable with control mice. These findings establish that IL-6 promotes autoimmunity in B/W mice. They further indicate that, although mAb to IL-6 can suppress murine lupus, the development of host immunity to the mAb abrogates its beneficial effects. Finally, this is the first study to demonstrate that a brief course of anti-CD4 can induce tolerance to another therapeutic mAb, in this case an anti-cytokine mAb.

The role of T-cell subsets in the response to anti-CD3 monoclonal antibodies.

Administration of monoclonal antibodies (mAb) to CD3 elicits an immune response to the mAb and an acute toxic syndrome that has been attributed to the release of cytokines from activated T cells. To clarify the cellular basis for these effects, we used anti-lymphocyte mAb to deplete selected T-cell subsets from BALB/c mice prior to administration of anti-CD3. In our first series of experiments, anti-CD4 repeatedly blocked the immune response to anti-CD3, but did not prevent severe toxicity. This observation suggested that other T-cell subsets might contribute to anti-CD3 induced toxicity. Therefore, we treated mice with mAb to CD8 as well as mAb to CD4 prior to administration of anti-CD3. Despite depletion of > 95% of CD8+ and CD4+ T cells, toxicity was not suppressed. This finding cast doubt on the belief that toxicity is due to activation of either CD4+ or CD8+ T cells by anti-CD3. Therefore, we assessed the role of thymocytes (which are not deleted by the mAb) and gamma delta + T cells. Thymectomy did not prevent toxicity in CD4/CD8-depleted mice, demonstrating that thymocytes are not responsible for toxicity. Anti-alpha beta TCR mAb produced a toxic reaction similar to anti-CD3 whereas anti-gamma delta TCR mAb did not, suggesting that gamma delta+ T cells are not the source of toxic cytokines. In addition, we proved that anti-CD3-induced toxicity was not due to direct effects on macrophages or to other nonspecific factors associated with the hamster mAb. These findings imply that a few residual mature T cells in mice treated with mAb to CD4 and CD8 are sufficient for the full expression of the anti-CD3-induced toxic syndrome. To confirm that both CD4+ and CD8+ T cells can mediate toxicity, we showed that:(i) SCID mice, which normally do not develop anti-CD3-induced toxicity, can be rendered susceptible by reconstitution with purified CD4+ T cells; and (ii) CD4-knockout mice that lack CD4+ T cells but have normal CD8+ T cells are susceptible to anti-CD3-induced toxicity. These findings establish that both CD4+ and CD8+ cells contribute to the toxic effects of anti-CD3, and that relatively few cells are required to mediate the full effect.

[The value of color Doppler ultrasound in the diagnosis of breast tumors]. / Intérêt de l'échographie Doppler couleur dans l'exploration des tumeurs du sein.

A prospective study was performed in 102 patients, including 40 malignant tumors (13 subclinical), to evaluate colour Doppler in breast tumours. All patients had abnormalities that led to their selection for this study. 92 patients had a mammographic examination. 10% of malignant tumours were not detected by mammography. Mammographic abnormalities without any ultrasonographic confirmation were excluded from this series. All the lesions have been proven by cytology or histology. In the assessment of malignancy only one false negative and two false positive results were obtained. The sensitivity and specificity of colour Doppler are both of 97% with radiate vessels beneath the tumour and intratumoral vessels as malignant criteria. This non invasive method should be performed in lesions with tissue ultrasonographic appearances even before fine needle puncture. So it may be possible to select more surgical indications considering an ultrasonographic abnormality atypical, subclinic or post-therapeutic (radiotherapy or surgery).