Roux-En-Y Gastric Bypass (RYGB) Surgery during High Liquid Sucrose Diet Leads to Gut Microbiota-Related Systematic Alterations.

Roux-en-Y gastric bypass (RYGB) surgery has been proven successful in weight loss and improvement of co-morbidities associated with obesity. Chronic complications such as malabsorption of micronutrients in up to 50% of patients underline the need for additional therapeutic approaches. We investigated systemic RYGB surgery effects in a liquid sucrose diet-induced rat obesity model. After consuming a diet supplemented with high liquid sucrose for eight weeks, rats underwent RYGB or control sham surgery. RYGB, sham pair-fed, and sham ad libitum-fed groups further continued on the diet after recovery. Notable alterations were revealed in microbiota composition, inflammatory markers, feces, liver, and plasma metabolites, as well as in brain neuronal activity post-surgery. Higher fecal 4-aminobutyrate (GABA) correlated with higher Bacteroidota and Enterococcus abundances in RYGB animals, pointing towards the altered enteric nervous system (ENS) and gut signaling. Favorable C-reactive protein (CRP), serine, glycine, and 3-hydroxybutyrate plasma profiles in RYGB rats were suggestive of reverted obesity risk. The impact of liquid sucrose diet and caloric restriction mainly manifested in fatty acid changes in the liver. Our multi-modal approach reveals complex systemic changes after RYGB surgery and points towards potential therapeutic targets in the gut-brain system to mimic the surgery mode of action.

Cellular Origin and Functional Relevance of Collagen I Production in the Kidney.

Background Interstitial fibrosis is associated with chronic renal failure. In addition to fibroblasts, bone marrow-derived cells and tubular epithelial cells have the capacity to produce collagen. However, the amount of collagen produced by each of these cell types and the relevance of fibrosis to renal function are unclear.Methods We generated conditional cell type-specific collagen I knockout mice and used (reversible) unilateral ureteral obstruction and adenine-induced nephropathy to study renal fibrosis and function.Results In these mouse models, hematopoietic, bone marrow-derived cells contributed to 38%-50% of the overall deposition of collagen I in the kidney. The influence of fibrosis on renal function was dependent on the type of damage. In unilateral ureteral obstruction, collagen production by resident fibroblasts was essential to preserve renal function, whereas in the chronic model of adenine-induced nephropathy, collagen production was detrimental to renal function.Conclusions Our data show that hematopoietic cells are a major source of collagen and that antifibrotic therapies need to be carefully considered depending on the type of disease and the underlying cause of fibrosis.

A reduced 12-joint ultrasound examination predicts lack of X-ray progression better than clinical remission criteria in patients with rheumatoid arthritis.

To study the predictive value of clinical remission definitions and ultrasound (US) examination on X-ray progression in rheumatoid arthritis (RA). This was an observational prospective multicenter 1-year follow-up cohort of RA patients with moderate disease activity (3.2 < DAS28 ≤ 5.1) who started anti-TNF therapy. DAS28ESR, DAS28CRP, SDAI, CDAI, and ACR/EULAR remission criteria were applied and reduced 12-joint US examination was performed at baseline and at 6 and 12 months. At baseline and month 12, radiographs of hands and feet were obtained in a subset of patients. A blind independent reader scored radiographs. X-ray progression was defined as Sharp van der Heijde change score >1 and no progression was defined as ≤0. 319 of 357 patients completed the study; patients had a mean (SD) age of 53.5 (13.1) years, with a disease duration of 7.5 (7.1) years. Laboratory, clinical, and US values significantly improved at month 6, except CRP, with additional improvement at month 12. Remission and low disease activity rates increased at follow-up. In the subset of 115 patients with radiological studies, clinical remission by any definition was not significantly associated with X-ray progression. Patients without PD signal at baseline and month 6 were a lower risk of X-ray progression than patients with PD signal, OR 0.197 (95% CI 0.046-0.861) and 0.134 (95% CI 0.047-0.378), respectively. Absence of PD signal, but not clinical remission predicts lack of X-ray progression. A feasible 12-joint US examination may add relevant information to RA remission criteria.

Incidence, associated factors and clinical impact of severe infections in a large, multicentric cohort of patients with systemic lupus erythematosus.

OBJECTIVES: To estimate the incidence of severe infection and investigate the associated factors and clinical impact in a large systemic lupus erythematosus (SLE) retrospective cohort. METHODS: All patients in the Spanish Rheumatology Society Lupus Registry (RELESSER) who meet ≥4 ACR-97 SLE criteria were retrospectively investigated for severe infections. Patients with and without infections were compared in terms of SLE severity, damage, comorbidities, and demographic characteristics. A multivariable Cox regression model was built to calculate hazard ratios (HRs) for the first infection. RESULTS: A total of 3658 SLE patients were included: 90% female, median age 32.9 years (DQ 9.7), and mean follow-up (months) 120.2 (±87.6). A total of 705 (19.3%) patients suffered ≥1 severe infection. Total severe infections recorded in these patients numbered 1227. The incidence rate was 29.2 (95% CI: 27.6-30.9) infections per 1000 patient years. Time from first infection to second infection was significantly shorter than time from diagnosis to first infection (p < 0.000). Although respiratory infections were the most common (35.5%), bloodstream infections were the most frequent cause of mortality by infection (42.0%). In the Cox regression analysis, the following were all associated with infection: age at diagnosis (HR = 1.016, 95% CI: 1.009-1.023), Latin-American (Amerindian-Mestizo) ethnicity (HR = 2.151, 95% CI: 1.539-3.005), corticosteroids (≥10mg/day) (HR = 1.271, 95% CI: 1.034-1.561), immunosuppressors (HR = 1.348, 95% CI: 1.079-1.684), hospitalization by SLE (HR = 2.567, 95% CI: 1.905-3.459), Katz severity index (HR = 1.160, 95% CI: 1.105-1.217), SLICC/ACR damage index (HR = 1.069, 95% CI: 1.031-1.108), and smoking (HR = 1.332, 95% CI: 1.121-1.583). Duration of antimalarial use (months) proved protective (HR = 0.998, 95% CI: 0.997-0.999). CONCLUSIONS: Severe infection constitutes a predictor of poor prognosis in SLE patients, is more common in Latin-Americans and is associated with age, previous infection, and smoking. Antimalarials exerted a protective effect.

Comorbidities in Patients With Primary Sjögren's Syndrome and Systemic Lupus Erythematosus: A Comparative Registries-Based Study.

OBJECTIVE: To compare the prevalence of the main comorbidities in 2 large cohorts of patients with primary Sjögren's syndrome (SS) and systemic lupus erythematosus (SLE), with a focus on cardiovascular (CV) diseases. METHODS: This was a cross-sectional multicenter study where the prevalence of more relevant comorbidities in 2 cohorts was compared. Patients under followup from SJOGRENSER (Spanish Rheumatology Society Registry of Primary SS) and RELESSER (Spanish Rheumatology Society Registry of SLE), and who fulfilled the 2002 American-European Consensus Group and 1997 American College of Rheumatology classification criteria, respectively, were included. A binomial logistic regression analysis was carried out to explore potential differences, making general adjustments for age, sex, and disease duration and specific adjustments for each variable, including CV risk factors and treatments, when appropriate. RESULTS: A total of 437 primary SS patients (95% female) and 2,926 SLE patients (89% female) were included. The mean age was 58.6 years (interquartile range [IQR] 50.0-69.9 years) for primary SS patients and 45.1 years (IQR 36.4-56.3 years) for SLE patients (P < 0.001), and disease duration was 10.4 years (IQR 6.0-16.7 years) and 13.0 years (IQR 7.45-19.76 years), respectively (P < 0.001). Smoking, dyslipidemia, and arterial hypertension were associated less frequently with primary SS (odds ratio [OR] 0.36 [95% confidence interval (95% CI) 0.28-0.48], 0.74 [95% CI 0.58-0.94], and 0.50 [95% CI 0.38-0.66], respectively) as were life-threatening CV events (i.e., stroke or myocardial infarction; OR 0.57 [95% CI 0.35-0.92]). Conversely, lymphoma was associated more frequently with primary SS (OR 4.41 [95% CI 1.35-14.43]). The prevalence of severe infection was lower in primary SS than in SLE (10.1% versus 16.9%; OR 0.54 [95% CI 0.39-0.76]; P < 0.001). CONCLUSION: Primary SS patients have a consistently less serious CV comorbidity burden and a lower prevalence of severe infection than those with SLE. In contrast, their risk of lymphoma is greater.

Fibromyalgia prevalence and related factors in a large registry of patients with systemic lupus erythematosus.

OBJECTIVES: The objective of this study is to determine the prevalence of fibromyalgia (FM) in systemic lupus erythematosus (SLE) patients and to study its relationship to depression and other SLE-related factors. METHODS: A cross-sectional data analysis from the RELESSER-Transversal Spanish Registry, which includes SLE patients in a national multicentre retrospective charts review, was performed. INCLUSION CRITERIA: patients who fulfilled ≥4 ACR 1997 SLE criteria. Main variables were disease duration, depression, sociodemographics, comorbidities, SLE activity symptoms, serological findings, therapies and different disease status indices. Statistical analyses included a descriptive, associative and logistic regression analyses. A literature review was performed. RESULTS: 3,591 SLE patients were included, 90.1% women, 34.6 years of age at diagnosis (SD 14.6 years) and 93.1% Caucasians. FM prevalence was 6.2%. SLE patients with disease duration >5 years showed more FM than those with duration <5 years: 6.9% vs. 4.0%, respectively (p<0.05). SLE-FM patients showed higher prevalence of depression compared to non-FM-SLE patients: 53.1% vs. 14.6%, respectively (p<0.001). After adjusting by risk factors, the OR (CI) of suffering depression in FM-SLE patients was 6.779 (4.770-9.636), p<0.001. The OR of having secondary Sjögren's 2.447 (1.662-3.604), p<0.001, photosensitivity 2.184 (1.431-3.334), p<0.001, and oral ulcers 1.436 (1.005-2.051), p=0.047. CONCLUSIONS: Prevalence of FM in Caucasian SLE patients was high compared to the general population, and was significantly higher in those in later stages of disease. SLE patients with depression showed a strong risk of developing FM. Photosensitivity, oral ulcers and secondary Sjögren's were the only SLE-related factors associated with FM.

B-cell inhibition by cross-linking CD79b is superior to B-cell depletion with anti-CD20 antibodies in treating murine collagen-induced arthritis.

Depletion of B cells with the anti-CD20 antibody rituximab is an established therapy for rheumatoid arthritis. However, rituximab has only moderate efficacy, most likely due to insufficient depletion of B cells in lymphoid organs and expansion of pathogenic B cells. We found that an antibody against mouse CD79b profoundly blocks B-cell proliferation induced via the B-cell receptor, CD40, CD180, and chondroitin sulfate, but not via TLR4 or TLR9. Treatment with anti-CD79b also induces death in resting and activated B cells. B-cell inhibition is mediated by cross-linkage of CD79b, but independent of Fc-receptor engagement. In the model of collagen-induced arthritis, an antibody against mouse CD20 depletes B cells very efficiently but fails to suppress the humoral immune response against collagen and the development of arthritis. In contrast, the antibody against CD79b, and a deglycosylated variant of this antibody, almost completely inhibits the increase in anti-collagen antibodies and the development of arthritis. In mice with established arthritis only the fully glycosylated antibody against CD79b is effective. Our data show that targeting B cells via CD79b is much more effective than B-cell depletion with anti-CD20 antibodies for therapy of arthritis. These findings may have important implications for treatment of B-cell-mediated autoimmune diseases.

Basophils inhibit proliferation of CD4⁺ T cells in autologous and allogeneic mixed lymphocyte reactions and limit disease activity in a murine model of graft versus host disease.

Basophils are known to modulate the phenotype of CD4(+) T cells and to enhance T helper type 2 responses in vitro and in vivo. In this study, we demonstrate that murine basophils inhibit proliferation of CD4(+) T cells in autologous and allogeneic mixed lymphocyte reactions. The inhibition is independent of Fas and MHC class II, but dependent on activation of basophils with subsequent release of interleukin-4 (IL-4) and IL-6. The inhibitory effect of basophils on T-cell proliferation can be blocked with antibodies against IL-4 and IL-6 and is absent in IL-4/IL-6 double-deficient mice. In addition, we show that basophils and IL-4 have beneficial effects on disease activity in a murine model of acute graft-versus-host disease (GvHD). When basophils were depleted with the antibody MAR-1 before induction of GvHD, weight loss, GvHD score, mortality and plasma tumour necrosis factor levels were increased while injection of IL-4 improved GvHD. Basophil-depleted mice with GvHD also have increased numbers of CD4(+) T cells in the mesenteric lymph nodes. Our data show for the first time that basophils suppress autologous and allogeneic CD4(+) T-cell proliferation in an IL-4-dependent manner.

Chondroitin sulfate activates B cells in vitro, expands CD138+ cells in vivo, and interferes with established humoral immune responses.

Glycosaminoglycans have anti-inflammatory properties and interact with a variety of soluble and membrane-bound molecules. Little is known about their effects on B cells and humoral immune responses. We show that CS but not dextran or other glycosaminoglycans induces a pronounced proliferation of B cells in vitro compared with TLR4 or TLR9 ligands. With the use of inhibitors and KO mice, we demonstrate that this proliferation is mediated by the tyrosine kinases BTK and Syk but independent of CD44. Antibodies against Ig-α or Ig-ß completely block CS-induced B cell proliferation. Injection of CS in mice for 4-5 days expands B cells in the spleen and results in a marked increase of CD138(+) cells in the spleen that is dependent on BTK but independent of CD4(+) T cells. Long-term treatment with CS for 14 days also increases CD138(+) cells in the bone marrow. When mice were immunized with APC or collagen and treated with CS for up to 14 days during primary or after secondary immune responses, antigen-specific humoral immune responses and antigen-specific CD138(+) plasma cells in the bone marrow were reduced significantly. These data show that CD138(+) cells, induced by treatment with CS, migrate into the bone marrow and may displace other antigen-specific plasma cells. Overall, CS is able to interfere markedly with primary and fully established humoral immune responses in mice.

El software educativo en el proceso de enseñanza-aprendizaje de la disciplina Historia de Cuba / The educative software in the teaching-learning process of the History of Cuba discipline

En el estudio diagnóstico realizado por los profesores de la disciplina Historia en la Facultad de Tecnología de la Salud en Villa Clara, se detectaron las necesidades de literatura docente, bibliografía y materiales para facilitar la comprensión de los contenidos que se imparten en la asignaturaHistoria de Cuba, lo que afecta la calidad del proceso de enseñanza-aprendizaje. Se utilizaron en la investigación métodos de nivel teórico como el tránsito de lo concreto a lo abstracto, histórico-lógico, sistémico_estructural, inductivo_deductivo, analítico_sintético y la modelación; y del nivel empírico: análisis de documentos, observación, entrevista, encuesta. A partir de sus resultados se elabora un software multimedia educativo, Cubanahis, que sirve como medio de enseñanza para la clase, el estudio independiente y de soporte bibliográfico de la asignatura, además propicia la asequibilidad y comprensión en la asimilación de contenidos con cierto nivel de complejidad, lo que garantiza un aprendizaje desarrollador.

The diagnostic study carried out by the professors of the History of Cuba discipline in the Health Technology Faculty in Villa Clara detected the necessity of teaching literature, bibliography and material aids to facilitate the comprehension of contents present in the History of Cuba subject which affect the teaching-learning process. Theoretical and empirical methods were used, for instance, from the abstract level to the concrete one, historical logical, systemic_structural, inductive_deductive, analytical_synthetically and modeling; analysis of documents, observation, interview and surveys. According to their results it was elaborated a multi-media educative software "Cubanahis" which serves as a class teaching aid, the independent study and bibliographic support of the subject, besides, it facilitates the assimilation and comprehension of difficult contents and the grasping of a meaningful learning.

El software educativo en el proceso de enseñanza-aprendizaje de la disciplina Historia de Cuba / The educative software in the teaching-learning process of the History of Cuba discipline

En el estudio diagnóstico realizado por los profesores de la disciplina Historia en la Facultad de Tecnología de la Salud en Villa Clara, se detectaron las necesidades de literatura docente, bibliografía y materiales para facilitar la comprensión de los contenidos que se imparten en la asignatura Historia de Cuba, lo que afecta la calidad del proceso de enseñanza-aprendizaje. Se utilizaron en la investigación métodos de nivel teórico como el tránsito de lo concreto a lo abstracto, histórico-lógico, sistémico_estructural, inductivo_deductivo, analítico_sintético y la modelación; y del nivel empírico: análisis de documentos, observación, entrevista, encuesta. A partir de sus resultados se elabora un software multimedia educativo, Cubanahis, que sirve como medio de enseñanza para la clase, el estudio independiente y de soporte bibliográfico de la asignatura, además propicia la asequibilidad y comprensión en la asimilación de contenidos con cierto nivel de complejidad, lo que garantiza un aprendizaje desarrollador.

The diagnostic study carried out by the professors of the History of Cuba discipline in the Health Technology Faculty in Villa Clara detected the necessity of teaching literature, bibliography and material aids to facilitate the comprehension of contents present in the History of Cuba subject which affect the teaching-learning process. Theoretical and empirical methods were used, for instance, from the abstract level to the concrete one, historical logical, systemic-structural, inductive-deductive, analytical-synthetically and modeling; analysis of documents, observation, interview and surveys. According to their results it was elaborated a multi-media educative software "Cubanahis" which serves as a class teaching aid, the independent study and bibliographic support of the subject, besides, it facilitates the assimilation and comprehension of difficult contents and the grasping of a meaningful learning.

Basophils support the survival of plasma cells in mice.

We have previously shown that basophils support humoral memory immune responses by increasing B cell proliferation and Ig production as well as inducing a Th2 and B helper phenotype in T cells. Based on the high frequency of basophils in spleen and bone marrow, in this study we investigated whether basophils also support plasma cell survival and Ig production. In the absence of basophils, plasma cells of naive or immunized mice rapidly undergo apoptosis in vitro and produce only low amounts of Igs. In contrast, in the presence of basophils and even more in the presence of activated basophils, the survival of plasma cells is markedly increased and continuous production of Igs enabled. This effect is partially dependent on IL-4 and IL-6 released from basophils. Similar results were obtained when total bone marrow cells or bone marrow cells depleted of basophils were cultured in the presence or absence of substances activating basophils. When basophils were depleted in vivo 6 mo after immunization with an Ag, specific Ig production in subsequent bone marrow cultures was significantly reduced. In addition, depletion of basophils for 18 d in naive mice significantly reduced the number of plasma cells in the spleen. These data indicate that basophils are important for survival of plasma cells in vitro and in vivo.

Power Doppler ultrasonography assessment of entheses in spondyloarthropathies: response to therapy of entheseal abnormalities.

OBJECTIVE: To investigate the response to therapy of entheseal abnormalities assessed with power Doppler (PD) ultrasound (US) in spondyloarthropathies (SpA). METHODS: A total of 327 patients with active SpA who were starting anti-tumor necrosis factor (TNF) therapy were prospectively recruited at 35 Spanish centers. A PDUS examination of 14 peripheral entheses was performed by the same investigator in each center at baseline and at 6 months. The following elementary lesions were assessed at each enthesis (presence/absence): morphologic abnormalities (hypoechogenicity and/or thickening), entheseal calcific deposits, cortical abnormalities (bone erosion and/or proliferation), adjacent bursitis and intraenthesis and perienthesis (tendon body and/or bursa) PD signal. Response to therapy of each elementary lesion was assessed by calculating change in the cumulative presence from baseline to 6 months. Intraobserver reliability of PDUS was evaluated by blindly assessing the stored baseline images 3 months after the real-time examination. RESULTS: Complete data were obtained on 197 patients who received anti-TNF therapy for 6 months. In 91.4% of the patients there were gray-scale or PD elementary lesions at baseline and at 6 months. Cumulative entheseal morphologic abnormalities, intraenthesis PD, perienthesis PD, and bursitis showed a significant decrease from baseline to 6 months (p < 0.05). There was high intraobserver reliability for all elementary lesions (interclass correlation coefficient > 0.90, p < 0.0005). CONCLUSION: Entheseal morphologic abnormalities, PD signal, and bursitis were US abnormalities that were responsive to anti-TNF therapy in SpA. PDUS can be a reproducible method for multicenter monitoring of therapeutic response in enthesitis of SpA.

CD4+ T cells control the differentiation of Gr1+ monocytes into fibrocytes.

Fibrocytes are collagen-type-I-producing cells that arise at low frequency from hematopoietic cells. We have analyzed in mice which leukocyte subsets are required for generation of fibrocytes and show that murine fibrocytes develop from the subpopulation of CD11b(+) CD115(+) Gr1(+) monocytes under the control of CD4(+) T cells. In the absence of CD4(+) T cells, differentiation of fibrocytes was markedly reduced in vitro and in vivo. In the presence of CD4(+) T cells, the characteristics of T-cell activation critically determined development of fibrocytes. Polyclonal activation of CD4(+) T cells induced the release of soluble factors that completely prevented the outgrowth of fibrocytes and could be identified as IL-2, TNF, IFN-gamma, and IL-4. Application of IL-2 and TNF significantly reduced the appearance of fibrocytes and the severity of fibrosis in the model of unilateral ureteral obstruction. In contrast, activation of CD4(+) T cells in the presence of calcineurin inhibitors, but not mTOR inhibitors, markedly enhanced the outgrowth of fibrocytes and renal deposition of collagen I. Taken together, we show that differentiation of fibrocytes is critically dependent on CD4(+) T cells and that the context of T-cell activation determines whether development of fibrocytes is supported or blocked. Our data may have implications for prevention of organ fibrosis in autoimmune diseases and transplantation.

Lactobacilli stimulate the innate immune response and modulate the TLR expression of HT29 intestinal epithelial cells in vitro.

The potentially probiotic strain Lactobacillus plantarum BFE 1685 isolated from a child's faeces and the probiotic strain Lactobacillus rhamnosus GG were investigated for their capability to influence the innate immune response of HT29 intestinal epithelial cells towards Salmonella enterica serovar Typhimurium. Furthermore, their capacity to modulate toll-like receptor expression of HT29 cells was investigated at the mRNA and protein levels. TNF-alpha was used in cell culture with HT29 cells to mimic an inflammatory background, and in the presence of this chemokine HT29 cells were sensitised to respond to the Lactobacillus strains as evidenced by an increased response in IL-8 production. In addition, when HT29 cells were first treated with lactobacilli and then infected with S. Typhimurium, the IL-8 levels in response to S. Typhimurium were significantly higher, indicating that HT29 cells were sensitised by lactobacilli. Neither of the lactobacilli was able to stimulate TLR4 production at the mRNA level, however, TLR2 and TLR9 transcription levels measured by quantitative PCR were up-regulated when HT29 cells were incubated with lactobacilli, but not with S. Typhimurium. Up-regulation of TLR9 expression was higher for L. rhamnosus GG than for L. plantarum BFE 1685. Expression levels of TLR2 and TLR5 were enhanced also at the protein level as determined by flow cytometry after staining with the respective antibodies. In contrast, TLR9 expression was not significantly up-regulated, which may be explained by protein degradation, or possible down-stream regulatory effects. These findings show that stimulation of specific signaling pathways occurs in the cross-talk between probiotic bacteria and gut epithelium cells, which can help to explain the adjuvant properties of probiotic lactobacilli.

Important role of interleukin-3 in the early phase of collagen-induced arthritis.

OBJECTIVE: Activation of basophils contributes to memory immune responses and results in exacerbation of collagen-induced arthritis (CIA). We undertook the present study to analyze the production and biologic effects of interleukin-3 (IL-3), a strong activator of basophils, in CIA. METHODS: Arthritis was induced by immunization with type II collagen. Mice were treated with blocking monoclonal antibodies against IL-3 or with recombinant IL-3. Clinical scoring, histologic analysis, fluorescence-activated cell sorter analysis, enzyme-linked immunosorbent assay, and cell culturing were performed to assess disease activity and IL-3 production. RESULTS: IL-3 was produced in large quantities by collagen-specific CD4+ T cells in the spleen and was present in the synovial tissue during onset of arthritis, but was down-regulated in paws with severe inflammation. Blockade of IL-3 during the time of arthritis onset resulted in profound improvement of the disease, with reductions in synovial leukocyte and cytokine levels, peripheral blood basophil levels, and anticollagen antibody titers. Blockade of IL-3 during the late phase of arthritis had no beneficial effect. Administration of recombinant IL-3 during onset of arthritis induced a marked exacerbation of the disease, with increased peripheral blood basophil and plasma IL-6 levels and increased titers of anticollagen antibody. In studies of the regulation of IL-3 expression in CD4+ T cells, IL-6 and IL-4 suppressed the release of IL-3 by activated CD4+ T cells, whereas lipopolysaccharide and CpG DNA up-regulated IL-3 secretion in activated CD4+ T cells by acting on costimulatory cells. CONCLUSION: Taken together, the present results demonstrate for the first time that IL-3 has an important role in the early phase of CIA.

Basophils enhance immunological memory responses.

The cellular basis of immunological memory remains a controversial issue. Here we show that basophils bound large amounts of intact antigens on their surface and were the main source of interleukins 6 and 4 in the spleen and bone marrow after restimulation with a soluble antigen. Depletion of basophils resulted in a much lower humoral memory response and greater susceptibility of immunized mice to sepsis induced by Streptococcus pneumoniae. Adoptive transfer of antigen-reactive basophils significantly increased specific antibody production, and activated basophils, together with CD4(+) T cells, profoundly enhanced B cell proliferation and immunoglobulin production. These basophil-dependent effects on B cells required interleukins 6 and 4 and increased the capacity of CD4(+) T cells to provide B cell help. Thus, basophils are important contributors to humoral memory immune responses.

Targeting of Gr-1+,CCR2+ monocytes in collagen-induced arthritis.

OBJECTIVE: The chemokine receptor CCR2 is highly expressed on monocytes and considered a promising target for treatment of rheumatoid arthritis. However, blockade of CCR2 with a monoclonal antibody (mAb) during progression of collagen-induced arthritis results in a massive aggravation of the disease. In this study we investigated why CCR2 antibodies have proinflammatory effects, how these effects can be avoided, and whether CCR2+ monocytes are useful targets in the treatment of arthritis. METHODS: Arthritis was induced in DBA/1 mice by immunization with type II collagen. Mice were treated with mAb against CCR2 (MC-21), IgE, or isotype control antibodies at various time points. Activation of basophils and depletion of monocyte subsets were determined by fluorescence-activated cell sorter analysis and enzyme-linked immunosorbent assay. RESULTS: Crosslinkage of CCR2 activated basophils to release interleukin-6 (IL-6) and IL-4. In vivo, IL-6 release occurred only after exposure to high doses of MC-21, whereas application of low doses of the mAb circumvented the release of IL-6. Regardless of the dose level used, the antibody MC-21 efficiently depleted Gr-1+,CCR2+ monocytes from the synovial tissue, peripheral blood, and spleen of DBA/1 mice. Activation of basophils with high doses of MC-21 or with antibodies against IgE resulted in a marked aggravation of collagen-induced arthritis and an increased release of IL-6. In contrast, low-dose treatment with MC-21 in this therapeutic setting had no effect on IL-6 and led to marked improvement of arthritis. CONCLUSION: These results show that depletion of CCR2+ monocytes may prove to be a therapeutic option in inflammatory arthritis, as long as the dose-dependent proinflammatory effects of CCR2 mAb are taken into account.