Anti-CD47 antibody synergizes with rituximab to promote phagocytosis and eradicate non-Hodgkin lymphoma.

Monoclonal antibodies are standard therapeutics for several cancers including the anti-CD20 antibody rituximab for B cell non-Hodgkin lymphoma (NHL). Rituximab and other antibodies are not curative and must be combined with cytotoxic chemotherapy for clinical benefit. Here we report the eradication of human NHL solely with a monoclonal antibody therapy combining rituximab with a blocking anti-CD47 antibody. We identified increased expression of CD47 on human NHL cells and determined that higher CD47 expression independently predicted adverse clinical outcomes in multiple NHL subtypes. Blocking anti-CD47 antibodies preferentially enabled phagocytosis of NHL cells and synergized with rituximab. Treatment of human NHL-engrafted mice with anti-CD47 antibody reduced lymphoma burden and improved survival, while combination treatment with rituximab led to elimination of lymphoma and cure. These antibodies synergized through a mechanism combining Fc receptor (FcR)-dependent and FcR-independent stimulation of phagocytosis that might be applicable to many other cancers.

Invariant NKT cell-augmented GM-CSF-secreting tumor vaccine is effective in advanced prostate cancer model.

Invariant natural killer T cells (iNKT cells) express a semi-invariant T cell receptor that recognizes certain glycolipids (including α-galactosylceramide, αGC) bound to CD1d, and can induce potent antitumor responses. Here, we assessed whether αGC could enhance the efficacy of a GM-CSF-producing tumor cell vaccine in the transgenic SV40 T antigen-driven TRAMP prostate cancer model. In healthy mice, we initially found that optimal T cell responses were obtained with αGC-pulsed TRAMP-C2 cells secreting GM-CSF and milk fat globule epidermal growth factor protein-8 (MFG-E8) with an RGD to RGE mutation (GM-CSF/RGE TRAMP-C2), combined with systemic low dose IL-12. In a therapeutic model, transgenic TRAMP mice were then castrated at ~ 20 weeks, followed by treatment with the combination vaccine. Untreated mice succumbed to tumor by ~ 40 weeks, but survival was markedly prolonged by vaccine treatment, with most mice surviving past 80 weeks. Prostates in the treated mice were heavily infiltrated with T cells and iNKT cells, which both secreted IFNγ in response to tumor cells. The vaccine was not effective if the αGC, IL-12, or GM-CSF secretion was eliminated. Finally, immunized mice were fully resistant to challenge with TRAMP-C2 cells. Together these findings support further development of therapeutic vaccines that exploit iNKT cell activation.

Adipose tissue invariant NKT cells protect against diet-induced obesity and metabolic disorder through regulatory cytokine production.

Invariant natural killer T (iNKT) cells are evolutionarily conserved innate T cells that influence inflammatory responses. We have shown that iNKT cells, previously thought to be rare in humans, were highly enriched in human and murine adipose tissue, and that as adipose tissue expanded in obesity, iNKT cells were depleted, correlating with proinflammatory macrophage infiltration. iNKT cell numbers were restored in mice and humans after weight loss. Mice lacking iNKT cells had enhanced weight gain, larger adipocytes, fatty livers, and insulin resistance on a high-fat diet. Adoptive transfer of iNKT cells into obese mice or in vivo activation of iNKT cells via their lipid ligand, alpha-galactocylceramide, decreased body fat, triglyceride levels, leptin, and fatty liver and improved insulin sensitivity through anti-inflammatory cytokine production by adipose-derived iNKT cells. This finding highlights the potential of iNKT cell-targeted therapies, previously proven to be safe in humans, in the management of obesity and its consequences.

Impact of Continuous Education and Training in Reduction of Central Line-associated Bloodstream Infection in Neurointensive Care Unit.

BACKGROUND: Patients in the neurointensive care unit have high utilization of devices, thereby increased chance of getting device-associated infection (DAI). Central line-associated bloodstream infection (CLABSI) remains one of the most important DAI. Education remains an important part of the hospital infection control and improves the infection-control practices. MATERIALS AND METHODS: To evaluate the effectiveness of a quality initiative in reducing incidence of CLABSI, a prospective study (January 2017-December 2018) was done estimating CLABSI incidence before and after the intervention. Continuous teaching and training for hand hygiene practice and central-line catheter hub care were used as the tool for this study. RESULTS: The quality improvement (QI) initiative achieved a 48% reduction in the CLABSI rate from the baseline rate of 8.7 to 4.5 per 1000 catheter days. The overall mortality showed a reduction from 1.5 to 0.05% during the post-intervention period. There was a significant improvement in compliance with the hand hygiene practice and catheter hub care in the post-intervention period. DISCUSSION AND CONCLUSION: This study demonstrates adherence to hand hygiene and catheter hub care with continuous teaching, training, and supervision was highly effective in reducing the CLABSI rate. CLINICAL SIGNIFICANCE: Central line-associated bloodstream infection is one of the most important DAI causing significant morbidity and mortality in critically ill patient. Our findings support that continuous educational intervention of hand hygiene with and training on the catheter hub care are two most important preventive measures in the reduction of CLABSI incidence. HOW TO CITE THIS ARTICLE: Mohapatra S, Kapil A, Suri A, Pandia MP, Bhatia R, Borkar S, et al. Impact of Continuous Education and Training in Reduction of Central Line-associated Bloodstream Infection in Neurointensive Care Unit. Indian J Crit Care Med 2020;24(6):414-417.

Folate receptor-ß in activated macrophages: ligand binding and receptor recycling kinetics.

Activated macrophages overexpress a receptor for the vitamin folic acid termed the folate receptor ß (FR-ß). Because conjugation of folate to low molecular weight drugs, genes, liposomes, nanoparticles, and imaging agents has minor effects on FR binding, the vitamin can be exploited to target both therapeutic and imaging agents to activated macrophages without promoting their uptake by other healthy cells. In this paper, we characterize the binding, internalization, and recycling kinetics of FR-ß on activated macrophages in inflamed tissues of rats with adjuvant-induced arthritis. Our results demonstrate that saturation of macrophage FR is achieved at injection doses of ∼150-300 nmol/kg, with more rapidly perfused tissues saturating at lower doses than inflamed appendages. After binding, FR-ß internalizes and recycles back to the cell surface every ∼10-20 min, providing empty receptors for additional folate conjugate uptake. Because the half-life of low molecular weight folate conjugates in the vasculature is usually <1 h, these data suggest that targeting of folate conjugates to activated macrophages in vivo can be maximized by frequent dosing at conjugate concentrations that barely saturate FR (∼150 nmol/kg), thereby minimizing nonspecific binding to receptor-negative tissues and maximizing the probability that unoccupied cell surface receptors will be exposed to folate-drug conjugate.

A CpG-loaded tumor cell vaccine induces antitumor CD4+ T cells that are effective in adoptive therapy for large and established tumors.

We designed a whole tumor cell vaccine by "loading" lymphoma tumor cells with CG-enriched oligodeoxynucleotide (CpG), a ligand for the Toll-like receptor 9 (TLR9). CpG-loaded tumor cells were phagocytosed, delivering both tumor antigen(s) and the immunostimulatory CpG molecule to antigen-presenting cells (APCs). These APCs then expressed increased levels of costimulatory molecules and induced T-cell immunity. TLR9 was required in the APCs but not in the CpG-loaded tumor cell. We demonstrate that T cells induced by this vaccine are effective in adoptive cellular therapy for lymphoma. T cells from vaccinated mice transferred into irradiated, syngeneic recipients protected against subsequent lymphoma challenge and, remarkably, led to regression of large and established tumors. This therapeutic effect could be transferred by CD4(+) but not by CD8(+) T cells. A CpG-loaded whole-cell vaccination is practical and has strong potential for translation to the clinical setting. It is currently being tested in a clinical trial of adoptive immunotherapy for mantle-cell lymphoma.

Imaging sites of infection using a 99mTc-labeled folate conjugate targeted to folate receptor positive macrophages.

EC20, a folate-targeted (99m)Tc based radioimaging agent with a high folate receptor (FR) binding affinity, has been used for both the diagnosis and the staging of FR positive malignancies (currently in phase III trials) and also for the localization of inflamed lesions characterized by the accumulation of FR+ macrophages. Because recent evidence has suggested that FR+ macrophages might accumulate at sites of infectious disease, this study evaluated whether EC20 might prove similarly useful for imaging bacterial infection foci. Using gamma scintigraphic imaging, it was demonstrated that EC20 accumulated at sites of Staphylococcus aureus infection with a significant difference (P < 0.0001, n = 12) in enrichment noted between infected and noninfected limbs. Confirmation that the elevated uptake of EC20 in infected limbs was FR-mediated was supported by suppression of EC20 accumulation in the presence of a 200-fold excess of free folic acid (P < 0.0001, n = 12). This study establishes for the first time the use of EC20 to image and localize sites of infectious disease.

Developing understanding of the roles of CD1d-restricted T cell subsets in cancer: reversing tumor-induced defects.

Invariant natural killer T-cells ('iNKT') are the best-known CD1d-restricted T-cells, with recently-defined roles in controlling adaptive immunity. CD1d-restricted T-cells can rapidly produce large amounts of Th1 and/or Th2//Treg/Th17-type cytokines, thereby regulating immunity. iNKT can stimulate potent anti-tumor immune responses via production of Th1 cytokines, direct cytotoxicity, and activation of effectors. However, Th2//Treg-type iNKT can inhibit anti-tumor activity. Furthermore, iNKT are decreased and/or reversibly functionally impaired in many advanced cancers. In some cases, CD1d-restricted T-cell cancer defects can be traced to CD1d(+) tumor interactions, since hematopoietic, prostate, and some other tumors can express CD1d. Ligand and IL-12 can reverse iNKT defects and therapeutic opportunities exist in correcting such defects alone and in combination. Early stage clinical trials have shown potential for reconstitution of iNKT IFN-gamma responses and evidence of activity in a subset of patients, with rational new approaches to capitalize on this progress ongoing, as will be discussed here.

Generation of CD8+ T cell-mediated immunity against idiotype-negative lymphoma escapees.

We investigated the ability of CpG-oligodeoxynucleotide to generate an anti-tumor CD8+ T-cell immune response and to synergize with passive antibody therapy. For these studies, we generated an antibody against the idiotype on the A20 B-cell lymphoma line. This antibody caused the regression of established tumors, but ultimately the tumors relapsed. The escaping surface IgG-negative tumor cells were resistant to both antibody-dependent cellular cytotoxicity and signaling-induced cell death. Addition of intratumoral CpG to antibody therapy cured large established tumors and prevented the occurrence of tumor escapees. The failure of the combination therapy in mice deficient for CD8+ T cells demonstrates the critical role of CD8+ T cells in tumor eradication. When mice were inoculated with 2 tumors and treated systemically with antibody followed by intratumoral CpG in just one tumor, both tumors regressed, indicating that a systemic immune response was generated. Although antibody therapy can eliminate tumor cells bearing the target antigen, it frequently selects for antigen loss variants. However, when a poly-specific T-cell response was generated against the tumor by intratumoral CpG, even large established tumors were cured. Such an immune response can prevent the emergence of antibody selected tumor escapees and provide long-lasting tumor protection.

Toll-like receptor-3 as a target to enhance bioactivity of cancer immunotherapy.

OBJECTIVE: The purpose of this study was to explore the potential of toll-like receptor-3 stimulation, with polyI:C(12)U (poly[l].poly[C(12),U]; rintatolimod [Ampligen; Hemispherx Biopharma, Philadelphia, PA]) to enhance bioactivity of cancer immunotherapies. STUDY DESIGN: Several models of immune activation were assessed with polyI:C(12)U at concentrations that were achieved clinically. Dendritic cell maturation and antigen-specific immune responses were evaluated in vitro and in a murine model. The potential for polyI:C(12)U to enhance antibody-dependent cellular cytotoxicity against tumor was also evaluated. RESULTS: Dendritic cells are matured and T-cell stimulation is enhanced in the presence of polyI:C(12)U. In addition, polyI:C(12)U induced the release of proinflammatory chemokines and cytokines. Prostate-specific antigen-specific T-cell and antibody responses were enhanced significantly in a BALB/c prostate-specific antigen transgenic mouse model. Finally, rituximab-mediated antibody-dependent cellular cytotoxicity against tumor targets was improved significantly by the addition of polyI:C(12)U. CONCLUSION: PolyI:C(12)U shows promise as a potential agent for selective enhancement of effect with currently available and future cancer immunotherapies.

Eosinophilic Meningitis: Report of Three Cases from a Hilly Area in Kerala.

Normal cerebrospinal fluid (CSF) does not contain eosinophils. The presence of >10 eosinophils/µL in CSF or at least 10% eosinophils in total CSF leukocyte count confirms eosinophilic meningitis. We present three patients with eosinophilic meningitis from the same locality with peripheral eosinophilia.

Optimization of Folate-Targeted Immunotherapy for the Treatment of Experimental Arthritis.

Folate-targeted immunotherapy constitutes a powerful method for the treatment of established arthritis in multiple animal models of the disease. The therapy involves immunization of the animal against a hapten to induce anti-hapten antibodies, followed by injection with a folate-hapten conjugate to decorate the surface of folate receptor-positive (activated) macrophages with the antigenic hapten. The hapten-marked macrophages are then recognized by the anti-hapten antibodies and eliminated by immune mechanisms, leading to attenuation of disease symptoms. In the following paper, we optimize the therapy for elimination of inflammatory macrophages and suppression of rheumatoid arthritis symptoms. We also demonstrate a tight correlation between folate receptor-positive macrophage abundance in the liver and inflammation of affected joints. The results suggest that therapies that reduce folate receptor-positive macrophage populations in the body should constitute effective treatments for rheumatoid arthritis.

A novel, native-format bispecific antibody triggering T-cell killing of B-cells is robustly active in mouse tumor models and cynomolgus monkeys.

Bispecific antibodies, while showing great therapeutic potential, pose formidable challenges with respect to their assembly, stability, immunogenicity, and pharmacodynamics. Here we describe a novel class of bispecific antibodies with native human immunoglobulin format. The design exploits differences in the affinities of the immunoglobulin isotypes for Protein A, allowing efficient large-scale purification. Using this format, we generated a bispecific antibody, REGN1979, targeting the B cell marker, CD20, and the CD3 component of the T cell receptor, which triggers redirected killing of B cells. In mice, this antibody prevented growth of B cell tumors and also caused regression of large established tumors. In cynomolgus monkeys, low doses of REGN1979 caused prolonged depletion of B cells in peripheral blood with a serum half-life of approximately 14 days. Further, the antibody induced a deeper depletion of B cells in lymphoid organs than rituximab. This format has broad applicability for development of clinical bispecific antibodies.

Adoptive cell therapy for lymphoma with CD4 T cells depleted of CD137-expressing regulatory T cells.

Adoptive immunotherapy with antitumor T cells is a promising novel approach for the treatment of cancer. However, T-cell therapy may be limited by the cotransfer of regulatory T cells (T(reg)). Here, we explored this hypothesis by using 2 cell surface markers, CD44 and CD137, to isolate antitumor CD4 T cells while excluding T(regs). In a murine model of B-cell lymphoma, only CD137(neg)CD44(hi) CD4 T cells infiltrated tumor sites and provided protection. Conversely, the population of CD137(pos)CD44hi CD4 T cells consisted primarily of activated T(regs). Notably, this CD137(pos) T(reg) population persisted following adoptive transfer and maintained expression of FoxP3 as well as CD137. Moreover, in vitro these CD137(pos) cells suppressed the proliferation of effector cells in a contact-dependent manner, and in vivo adding the CD137(pos)CD44(hi) CD4 cells to CD137(neg)CD44(hi) CD4 cells suppressed the antitumor immune response. Thus, CD137 expression on CD4 T cells defined a population of activated T(regs) that greatly limited antitumor immune responses. Consistent with observations in the murine model, human lymphoma biopsies also contained a population of CD137(pos) CD4 T cells that were predominantly CD25(pos)FoxP3(pos) T(regs). In conclusion, our findings identify 2 surface markers that can be used to facilitate the enrichment of antitumor CD4 T cells while depleting an inhibitory T(reg) population.

Topiramate for anger control: A systematic review.

BACKGROUND: Uncontrolled anger while being most commonly associated with personality disorders could also be part of many other conditions such as chronic low back ache and post-traumatic stress disorder. The intensity of anger as an emotional state at a particular time is known as "State Anger," whereas how often angry feelings are experienced over time is known as "Trait Anger." Anger could also manifest as expression of anger toward other persons or objects in the environment (Anger-Out), holding in or suppressing angry feelings (Anger-In) and controlling angry feelings by preventing the expression of anger toward other persons or objects in the environment or controlling suppressed angry feelings by calming down or cooling off (Anger Control). OBJECTIVE: To prove the effectiveness of topiramate in the control of anger as compared to placebo and to disprove that its use leads to psychiatric adverse events by systematically reviewing the available randomized controlled trials. MATERIALS AND METHODS: The basic search was performed in MEDLINE (1966 through November 2008) combined with the optimal search strategy for randomized controlled trials described in the Cochrane Reviewers' Handbook. To update this search, we regularly screened citations from PubMed till November 2008 for eligible studies or reviews that might include eligible studies. The Cochrane Central Register of Controlled Trials (CENTRAL) was searched using the terms "topiramate" and "anger or aggression." In addition, we screened bibliographies of reviews and identified articles. Randomized clinical trials wherein study participants were aggressive adults were included. RESULTS: We could arrive at a weighted mean difference of -3.16 (-3.64 to -2.68) in State Anger. The reduction in the score was highest in borderline personality disorder (BPD) patients as compared to those with low back ache. Trait Anger dropped by -2.93 (-3.49 to -2.37), especially in female BPD patients. Anger In reduced more or less uniformly across the studies by -1.43 (-1.84 to -1.03). Anger Out decreased by -2.8 (-3.19 to -2.42). This effect was minimal among the male BPD patients. Anger Control uniformly increased across the four studies by 2.32 (2.00-2.64). There is sufficient evidence to suggest that topiramate is significantly effective in stabilizing the "trait anger" while reducing the "state anger." "Anger Out" and "hostility" were significantly reduced. "Anger In" was the feature that was the least affected, although this was significant. This suggests that topiramate is effective in controlling anger. There was no suggestion of topiramate precipitating psychomorbidity. CONCLUSIONS: Topiramate appears to be a safe and effective drug in the management of anger/aggression. Additional research is needed to determine whether these results can be reproduced and how long lasting are the benefits of long-term treatment with topiramate.

Imaging of atherosclerosis in apoliprotein e knockout mice: targeting of a folate-conjugated radiopharmaceutical to activated macrophages.

UNLABELLED: Early detection of heart disease is essential for the implementation of intervention strategies that reduce the risk of cardiovascular events. Radioimaging methods that have been explored for this purpose include (18)F-FDG, which measures sites of elevated metabolic activity; (99m)Tc-annexin A5, which reveals regions of enhanced apoptosis and thrombosis; and (99m)Tc-labeled anti-lectinlike oxidized low-density lipoprotein receptor 1 antibody, which detects the lectinlike oxidized low-density lipoprotein receptor 1 that is overexpressed on a variety of vasculature-associated cells. In this study, we examine the use of a folate-targeted chelate of (99m)Tc, termed (99m)Tc-EC20, for imaging of folate receptor (FR)-expressing macrophages that accumulate in atherosclerotic plaques, internalize cholesterol-rich lipoprotein particles, and evolve into foam cells that form components of vulnerable atherosclerotic lesions. METHODS: (99m)Tc-EC20 was injected into apoliprotein E knockout (apoE-/-) mice fed a normal or Western (high-fat) diet for 25 wk and imaged by gamma-scintigraphy. Treated mice were also dissected, and radioactivities in excised aortas were quantified by gamma-counting and imaged by autoradiography. The role of FR-expressing macrophages in uptake of (99m)Tc-EC20 was also examined by comparing images of apoE-/- mice before and after treatment with clodronate liposomes to deplete tissue macrophages, comparing the sites of (99m)Tc-EC20 enrichment with sites of macrophage accumulation in thin sections of atherosclerotic tissues, and examining the expression of FRs on atherosclerotic plaque-derived macrophages by flow cytometry. RESULTS: ApoE-/- mice on Western chow exhibited significantly greater accumulation of (99m)Tc-EC20 in atherosclerotic lesions than their counterparts on normal chow. The aortas of apoE-/- mice on a Western diet demonstrated greater numbers of FR-positive macrophages by flow cytometry than did those of apoE-/- mice on a normal diet. Clodronate liposome treatment significantly reduced the accumulation of (99m)Tc-EC20 in atherosclerotic tissues, suggesting that macrophages or monocytes are responsible for uptake of the folate-linked radioimaging agent. Histologic and autoradiographic analysis of tissue sections demonstrated that macrophage accumulation correlated with regions of (99m)Tc-EC20 uptake. CONCLUSION: (99m)Tc-EC20 can be used for the imaging of atherosclerosis by selectively targeting FR-positive activated macrophages.

Depletion of folate-receptor-positive macrophages leads to alleviation of symptoms and prolonged survival in two murine models of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease involving deposition of immune complexes in normal tissues and the consequent accumulation of immune cells and tissue injury. Activated macrophages are thought to contribute to disease pathogenesis by releasing inflammatory mediators that both cause direct tissue damage and attract other immune cells that augment inflammation. Previous studies in animal models of rheumatoid arthritis have shown that activated macrophages express a folate receptor that can be targeted with folate-linked haptens, leading to (1) marking of the activated macrophages with highly immunogenic haptens, (2) recognition of the marked cells by Fc receptor-expressing immune cells, and (3) destruction of the antibody-coated macrophages by the body's own immune system. Here we demonstrate that the same folate-hapten-targeted immunotherapy can greatly suppress symptoms of SLE in two animal models of the disease, resulting in reduced immune complex deposition, diminished damage to normal tissues, and prolonged animal survival.

Lymphoma immunotherapy with CpG oligodeoxynucleotides requires TLR9 either in the host or in the tumor itself.

Established widely metastatic tumor was cured in a transplanted mouse B cell lymphoma model, by the combination of chemotherapy plus intratumoral injection of oligodeoxynucleotides containing unmethylated C-G motifs (CpG). This therapeutic effect required that the CpG be injected directly into the tumor and was dependent on CD8 T cells. Although the efficacy of CpG oligodeoxynucleotides has been thought to depend on the expression of TLR9, we unexpectedly found that tumor rejection did not require host expression of TLR9. By using a TLR9-deficient tumor and a TLR9KO host, we demonstrate that TLR9 expression either by the host or the tumor is required. These results indicate that activation of Ag presentation by cells within the tumor via TLR9 stimulation can be an effective form of immunotherapy. This study forms the basis of an ongoing clinical trial in patients with lymphoma.

Folate receptor overexpression is associated with poor outcome in breast cancer.

The high affinity folate receptor is a membrane-associated glycoprotein that is preferentially expressed in cancers of epithelial origin and rarely expressed in normal cells. We examined its expression pattern in breast cancer, utilizing a tissue microarray containing samples from 63 invasive breast cancers from women with divergent clinical outcomes. Thirty-three women comprised the poor outcome group with a median time to recurrence of 1.9 years. Thirty women, the good outcome group, were free of recurrence for a minimum of 7 years after diagnosis. The intensity of folate receptor staining was strongly correlated with outcome. There were two summary categories of staining intensity: weak (n = 42) or strong (n = 21). In the strong staining group, 17 of 21 women (81%) have recurred and their median survival is 2.4 years. In the weak staining group, 16 of 42 women (38%) have recurred. Their median survival is not estimable. After adjustment for tumor size, nodal status, ER status, adjuvant therapy, histology and tumor grade, strong staining for the folate receptor remained significantly associated with poor outcome, p < 0.001. Our work requires validation in a larger cohort, but supports the possibility of using folate receptor-targeted approaches in the management of breast cancer.

Folate-targeted immunotherapy effectively treats established adjuvant and collagen-induced arthritis.

Activated macrophages express a cell surface receptor for the vitamin folic acid. Because this receptor is inaccessible or not measurably expressed on other normal cells, folic acid has been recently exploited to selectively deliver attached radio-emitters to sites of activated macrophage accumulation, allowing scintigraphic imaging of inflamed joints and organs of arthritic rats. We demonstrate here that folate-linked haptens can also be targeted to activated macrophages, decorating their cell surfaces with highly immunogenic molecules. Under conditions in which the rodent has already been immunized against keyhole limpet hemocyanine-(fluorescein isothiocyanate) FITC, activated macrophages are eliminated. Administration of folate-FITC conjugates to rodents with experimental arthritis attenuates (a) systemic and peri-articular inflammation, (b) bone and cartilage degradation, and (c) arthritis-related body weight loss. Treatment with folate-hapten conjugates is comparable to methotrexate, etanercept, anakinra, and celecoxib at alleviating the symptoms of arthritis. We conclude that reduction of activated macrophages by folate-targeted immunotherapy can ameliorate the symptoms of arthritis in two rodent models of the disease.