Chimeric anti-tumor necrosis factor-alpha monoclonal antibody treatment of patients with rheumatoid arthritis receiving methotrexate therapy

OBJECTIVE: To evaluate the safety and efficacy of single and multiple doses of a chimeric anti-TNF-alpha monoclonal antibody (infliximab) in patients with rheumatoid arthritis (RA) who had active disease despite therapy with methotrexate (MTX). METHODS: Twenty-eight patients with active RA despite receiving therapy with 10 mg/week of MTX were randomized to receive a single, blinded infusion of either placebo or 5, 10, or 20 mg/kg infliximab. Twenty-three patients who completed the blinded study entered an open, multiple dose extension study in which they received up to 3 additional infusions of 10 mg/kg infliximab at Weeks 12, 20, and 28. Safety, efficacy, and pharmacokinetics were evaluated during the blinded and open trial. RESULTS: There were no serious infusion related reactions. In the blinded phase, 17 (81.0%) of 21 patients receiving infliximab achieved an American College of Rheumatology (ACR) 20% response at some point during the 12 weeks of followup compared to one (14.3%) of 7 patients receiving placebo (p = 0.003). Clinical improvement was evident by the first week and was sustained through Week 12. For the 19 patients who received infliximab during the blinded part of the trial and continued into the open label trial, 53% maintained an ACR 20% response with multiple infusions of 10 mg/kg infliximab through Week 40. Three patients withdrew from the trial during the open continuation phase because of adverse events: cellulitis, infusion related dizziness and headache, and vasculitic rash. Infliximab in doses of 5 to 20 mg/kg had a mean terminal half-life ranging from 9 to 12 days and was detectable in sera from most patients 8 to 12 weeks after dosing. CONCLUSION: Infliximab is generally well tolerated during 40 weeks of therapy. A single infusion of 5 to 20 mg/kg infliximab significantly decreases the signs and symptoms of RA compared to placebo in patients with active disease receiving MTX. Multiple doses of infliximab produce sustained clinical benefit for up to 40 weeks.     

Protein biomarker analysis by mass spectrometry in patients with rheumatoid arthritis receiving anti-tumor necrosis factor-alpha antibody therapy

OBJECTIVE: To investigate the mechanism of action of anti-tumor necrosis factor-alpha (TNF-alpha) antibody in patients with rheumatoid arthritis (RA), we analyzed serum or plasma proteins by mass spectrometry system. METHODS: Ten RA patients who received treatment with anti-TNF-alpha antibody were studied. Samples obtained before and after therapy were analyzed by a two-dimensional liquid chromatography tandem mass spectrometry (2D LC-MS/MS) system after pretreatment by a recently developed method to remove high molecular weight proteins. RESULTS: Using this system, certain proteins were identified after treatment with anti-TNF-alpha antibody, including proteins related to the TNF-alpha-mediated pathway for nuclear factor kappa B (NF-kappaB) activation and/or to the metabolism (including regeneration) of articular cartilage. CONCLUSION: Our mass spectrometry system appears to be useful for proteomic analysis. The efficacy of anti-TNF-alpha antibody therapy for RA may be related to various consequence of the inhibition of TNF-alpha activity.     

Septic arthritis caused by Actinobacillus ureae in a patient with rheumatoid arthritis receiving anti-tumor necrosis factor-alpha therapy

Actinobacillus ureae, formerly known as Pasteurella ureae, is a rare human pathogen. We describe a case of septic arthritis and abscess formation caused by this unusual organism in a patient with rheumatoid arthritis, who was being treated with tumor necrosis factor-alpha inhibitors.     

Peripheral blood expression of nuclear factor-kappab-regulated genes is associated with rheumatoid arthritis disease activity and responds differentially to anti-tumor necrosis factor-alpha versus methotrexate

OBJECTIVE: To evaluate peripheral blood expression of genes regulated by nuclear factor-kappaB (NF-kappaB), a key mediator of tumor necrosis factor-alpha (TNF-alpha) signaling, in patients with rheumatoid arthritis (RA) before and during treatment with anti-TNF-alpha or methotrexate (MTX). We analyzed association of gene expression with disease activity, rheumatoid factor (RF), age, sex, disease duration, treatment modality, and clinical response. METHODS: Sixty patients consented for RNA analysis at baseline and after 2 and 6 weeks of treatment. Disease activity was quantified using Disease Activity Score (DAS28) and C-reactive protein (CRP). Expression of 67 TNF-alpha-responsive, NF-kappaB-regulated genes was measured using Affymetrix arrays and RT-PCR. RESULTS: Expression of 34 genes was associated with DAS28-CRP, notably S100A12/calgranulin C, IL7R, and aquaporin 3. No association was observed with age, sex, RF, or disease duration. Expression of 16 genes changed in a manner that differed significantly between treatment groups. Eleven were reduced in anti-TNF-alpha-treated patients relative to MTX, while 5 were increased. The majority of these observations were confirmed using RT-PCR. Gene expression was not associated significantly with change in disease activity. CONCLUSION: NF-kappaB-dependent gene expression in peripheral leukocytes is highly correlated with RA activity as measured by DAS28-CRP. Expression of many genes responds differentially to anti-TNF-alpha versus MTX, suggesting fundamentally different effects on the NF-kappaB pathway. This peripheral blood expression signature provides candidate markers that could lead to development of a simple, minimally invasive pharmacodynamic assay for RA treatments directed at the NF-kappaB pathway. Combination of gene expression data with clinical scores and serum markers may provide more sensitive and predictive measures of RA disease activity.     

Impaired granulocytopoiesis in patients with chronic idiopathic neutropenia is associated with increased apoptosis of bone marrow myeloid progenitor cells

To probe the pathophysiologic mechanisms underlying neutropenia in patients with chronic idiopathic neutropenia (CIN) with hypoplastic and left-shifted granulocytic series in the bone marrow (BM), we have studied granulocytopoiesis in 32 adults with CIN by evaluating the number and survival characteristics of cells in several stages of granulocyte differentiation using flow cytometry and BM culture assays. We found that patients with CIN displayed a low percentage of CD34(+)/CD33(+) cells, defective granulocyte colony-forming unit (CFU-G) growth potential of BM mononuclear or purified CD34(+) cells, and low CFU-G recovery in long-term BM cultures (LTBMCs), compared with controls (n = 46). A low percentage of CD34(+)/CD33(+) cells in patients was associated with accelerated apoptosis and Fas overexpression within this cell compartment compared with controls. No significant difference was documented in the percentage of apoptotic cells or the Fas(+) cells within the fractionated CD34(+)/CD33(-), CD34(-)/CD33(+), and CD34(-)/CD33(-)/CD15(+) BM subpopulations or the peripheral blood neutrophils, suggesting that the underlying cellular defect in CIN probably concerns the committed granulocyte progenitors. LTBMC stromal layers from patients produced abnormally high amounts of tumor necrosis factor alpha and cytokine levels in culture supernatants inversely correlated with the number of myeloid progenitor cells and positively with the proportion of apoptotic CD34(+) cells. Patient LTBMC stromal layers displayed pathologic interferon gamma and Fas-ligand mRNA expression and failed to support normal myelopoiesis. These data suggest that impaired granulocytopoiesis in CIN is probably due to overproduction of inflammatory cytokines by immune cells within the BM microenvironment that may exert an inhibitory effect on myelopoiesis by inducing Fas-mediated apoptosis in the granulocyte progenitors.     

Requirement of methotrexate in combination with anti-tumor necrosis factor-alpha therapy for adequate suppression of osteoclastogenesis in rheumatoid arthritis

OBJECTIVE: To determine that concomitant use of methotrexate (MTX) is required to achieve adequate suppression of bone destruction in treating rheumatoid arthritis (RA) with tumor necrosis factor-alpha (TNF-alpha)-inhibiting biologic therapy. We quantitatively compared the suppressive effects of treatment with a combination of infliximab and MTX and treatment with each of these 2 agents alone on bone destruction in SCID-HuRAg-pit mice. METHODS: Tissue derived from human RA pannus was implanted with a slice of dentin subcutaneously in the backs of SCID mice (SCID-HuRAg-pit model). Infliximab was administered daily to SCID-HuRAg-pit mice using an osmotic pump for 2 weeks with or without oral administration of MTX. Histological changes in tissue and the pits formed on the dentin slice were examined 8 weeks after transplant. Serum concentrations of TNF-alpha and interleukin 6 (IL-6) were also measured. RESULTS: Treatment with a combination of infliximab and MTX suppressed pit formation significantly, while treatment with neither infliximab alone nor MTX alone had a significant effect on pit formation. Synovial inflammation and serum TNF-alpha and IL-6 levels were suppressed by infliximab with or without MTX. CONCLUSION: This is the first evidence in an animal model of arthritis that concomitant use of MTX is required to achieve adequate suppression of bone destruction when treating RA with a TNF-alpha-inhibiting biologic. Our findings suggest that infliximab suppresses bone destruction through a mechanism of action different from that mediating its antiinflammatory effects in the treatment of RA.     

Staphylococcus aureus in patients with rheumatoid arthritis under conventional and anti-tumor necrosis factor-alpha treatment

OBJECTIVE: To compare the prevalence of nasal and oral Staphylococcus aureus in patients with rheumatoid arthritis (RA) with the prevalence in controls with other rheumatic diseases, and to determine predictors of S. aureus carriage and the influence of treatment with anti-tumor necrosis factor-a (anti-TNF-alpha) agents. METHODS: Eighty-one patients with RA and 83 other control patients of 2 outpatient rheumatology clinics were cultured for nasal and oral carriage of S. aureus. Quantitative nasal cultures for S. aureus were performed from swabs of the anterior nares, the posterior pharynx, and the soft palate. Information on medications, medical conditions, and risk factors for S. aureus carriage was collected from all participants by a questionnaire and confirmed by chart review. RESULTS: The S. aureus carriage rate (nasal and/or oral colonization) was 34.6% among RA patients and 32.5% among controls (p = 0.87). Being treated with an anti-TNF-alpha agent plus methotrexate (MTX) was the only independent predictor of S. aureus carriage (OR 3.24, 95% CI 1.16-9.05, p = 0.025). The S. aureus carriage rate among RA patients treated with an anti-TNF-alpha agent plus MTX was 60% (9/15) versus 23.1% (3/13) in RA patients treated with an anti-TNF-alpha agent only (p = 0.049). All S. aureus isolates were susceptible to oxacillin. CONCLUSION: The S. aureus carriage rate among patients with RA was not higher than among controls. Treatment with anti-TNF-alpha agents was not associated with an increased S. aureus carriage rate. However, treatment with an anti-TNF-alpha agent plus MTX may predispose patients to S. aureus carriage.     

Tumor necrosis factor-alpha production is associated with less body cell mass in women with rheumatoid arthritis

OBJECTIVE: To examine the relationship between inflammatory cytokine production and body cell mass (BCM) in women with stable, medically well-controlled rheumatoid arthritis (RA). METHODS: Case-control study of 20 women with RA and 20 healthy women matched for age, race, and body mass index (kg/m2). Tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta), and IL-6 production were measured by specific, non-cross-reacting ELISA of peripheral blood mononuclear cells (PBMC) cultured with and without 100 ng/ml of endotoxin. Total BCM was assessed by the reference method of whole-body counting of naturally occurring radioactive potassium-40. RESULTS: Patients with RA were cachectic, with 14% less BCM (p < 0.001) and higher TNF-alpha production (p < 0.05) than controls. TNF-alpha production was inversely associated with BCM both without (r = -0.51, p = 0.03) and with (r = -0.57, p = 0.01) endotoxin stimulation in patients but not in controls. In multivariate linear regression models, these inverse associations remained significant after adjustment for age and physical activity. No association was found for IL-1beta or IL-6 production in these models. CONCLUSION: Women with stable, medically well-controlled RA have lower than normal BCM that is inversely associated with elevated TNF-alpha production.     

Bone marrow B-lineage cells in patients with rheumatoid arthritis following rituximab therapy

OBJECTIVE: To assess the presence and phenotype of B-lineage cells in the bone marrow (BM) of rheumatoid arthritis (RA) patients after rituximab therapy. METHODS: Six patients were studied. BM aspirates were collected 3 months after the treatment and analysed using the four-colour flow cytometry. RESULTS: CD19+ (B-lineage) cells in BM samples varied from 0.1 to 3.25% in the lymphoid gate. CD34+ cells varied from 1.23 to 4.86%. The proportion of CD34+ cells committed to the B-lineage varied between 0 and 42.19%. Pro-B-cells were undetectable in one case. The majority of B-cell precursors were pro-B-cells in Patients 5 and 6 (50 and 62% of CD19+ cells, respectively), pre-B-cells in Patients 3 and 4 (64 and 70%) and immature B-cells in Patient 1 (44%). Detectable CD20 expression on CD19+ cells was either low or absent. Plasma cells varied from 0.01 to 0.36% of the total nucleated cells. There was a trend towards longer duration of clinical response in patients with evidence of more complete depletion in BM. CONCLUSION: In this small cohort of RA patients treated with rituximab, differences in proportion and phenotype of CD19+ BM cells were detected. These differences suggest variation in the degree of depletion achieved and correlate with time to relapse. Although pro-B-cells are not targeted directly by rituximab as they do not express CD20, the levels were unexpectedly low.     

Anti-cyclic citrullinated protein antibodies as a predictor of response to anti-tumor necrosis factor-alpha therapy in patients with rheumatoid arthritis

OBJECTIVE:. The treatment of rheumatoid arthritis (RA) has changed dramatically with the introduction of anti-tumor necrosis factor (TNF) agents. Unfortunately, a subset of patients have partial or no response. No measurements were found to predict the efficacy of this therapy. Anti-cyclic citrullinated protein antibodies (anti-CCP) are highly specific and sensitive for RA, and their titer correlates with erosive disease. We investigated the correlation between the efficacy of infliximab therapy and the titer of anti-CCP. METHODS: Thirty consecutive seropositive patients with RA were treated with infusion of 3 mg/kg infliximab on Weeks 0, 2, 6, and 14. Clinical assessment and blood withdrawal were done before each treatment, i.e., at the minimal concentration of the drug. Disease activity was assessed by DAS28 score and by interleukin 6 (IL-6) level. Anti-CCP titer was measured by a commercial ELISA at Week 0 and Week 14. RESULTS: At baseline, 24 patients were positive for anti-CCP antibodies. In most patients there was a significant correlation between clinical response to therapy and anti-CCP titer. The results were especially noteworthy in those patients who showed a sustained and significant decrease in IL-6 levels through the entire period. CONCLUSION: Anti-CCP titer and IL-6 levels might be early predictors of the efficacy of anti-TNF therapy in patients with RA.     

Anemia in early rheumatoid arthritis is associated with interleukin 6-mediated bone marrow suppression, but has no effect on disease course or mortality

OBJECTIVE: Anemia of chronic disease (ACD) is the most common extraarticular manifestation of rheumatoid arthritis (RA), but there is limited information on the cause and consequences of ACD. We investigated the prevalence, relation with proinflammatory cytokines, and effect on disease outcome of ACD in patients with RA. METHODS: The presence of anemia was analyzed in a cohort of 111 consecutive patients with early RA. Anemia was related to markers of erythropoiesis and inflammation [clinically and by levels of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum interleukin 1beta (IL-1beta), IL-2, IL-6, IL-8, and tumor necrosis factor-alpha]. The frequency of various disease outcomes during the mean followup of 74 months was compared between ACD and nonanemic patients. RESULTS: ACD was present in 25% during the first year of disease. ACD was associated with higher CRP (45 vs 22 g/l; p = 0.04) and ESR levels (54 vs 33 mm/h; p = 0.002). Hemoglobin levels were inversely correlated with serum erythropoietin (p = 0.003) in univariate analysis, but in multivariate analysis only ESR (p = 0.005) and IL-6 (p = 0.056) remained as independent predictors of hemoglobin levels. Presence of ACD was not associated with later development of disease manifestations or mortality. CONCLUSION: While ACD affected 25% of patients with RA early in the disease course, this had no influence on disease outcome including mortality during the following 6 years. The association between IL-6 and ACD suggests that IL-6-mediated bone marrow suppression is the main mechanism for development of ACD in RA.