Treatment of rheumatoid arthritis with a DR4/1 peptide.

OBJECTIVE: To determine the safety and potential clinical efficacy of primary and booster injections of a DR4/1 peptide in patients with active rheumatoid arthritis (RA) despite methotrexate therapy. METHODS. Subjects with active RA were enrolled in a randomized, placebo controlled, double blind, dose-escalating clinical trial of synthetic DR4/1 peptide containing the shared epitope. The primary injection of the DR4/1 peptide in alum adjuvant was administered at one of 3 doses, 1.3, 4.0, and 13 mg, followed by up to 3 or 4 booster injections every 6 or 8 weeks at the same dose. The primary outcomes were the occurrence of adverse effects and changes in measures of immune function. Clinical efficacy was assessed using the American College of Rheumatology 20% criteria for clinical improvement. RESULTS: Fifty-three patients were entered into the trial, including 44 who completed the study. In the absence of any observations of a dose response to the DR4/1 peptide injections, the 3 dosage groups were combined for subsequent analysis into 3 groups: patients receiving DR4/1 peptide injections every 6 weeks, patients receiving DR4/1 peptide injections every 8 weeks, and a placebo group. At all doses and each dosing interval the primary and booster injections of synthetic DR4/1 peptide were well tolerated and did not produce any significant changes in lymphocyte counts or evidence of generalized immunosuppression. Analysis of clinical efficacy showed that the 6 week group had trends toward improvement in disease measures. CONCLUSION: Primary and booster injections of the DR4/1 peptide containing the shared epitope were safe and did not broadly suppress immune function.

First Report of Musk Thistle Rust (Puccinia carduorum) in Oklahoma.

Musk thistle, Carduus thoermeri (Carduus nutans subsp. leiophyllus), is an important, introduced pasture weed in central and northeastern Oklahoma. Puccinia carduorum was introduced into the United States from Turkey as a potential biological control for musk thistle. P. carduorum has not been reported previously in Oklahoma, thus precluding its field release for biological control research without APHIS approval. There is evidence the organism has moved westward since the initial field studies that began in 1987 in Virginia. In 1994 it was found in Missouri (1). In early November 1997, in Rogers County, Oklahoma, scattered populations of C. thoermeri were found that had moderate to heavy levels of infection with a rust fungus. The pustules contained mostly teliospores; based on teliospore and urediniospore morphology, the fungus was identified as P. carduorum. The morphology and dimensions of urediniospores (21 × 21 µm, avg.) and teliospores (35 × 21 µm, avg.), and the restriction of echinulations to the upper two-thirds to three-fourths of urediniospores, were consistent with P. carduorum. Infection studies with field inoculum were conducted at both Oklahoma State University and USDA-FDWSRU. Rust-infected leaves collected in Oklahoma were air dried and maintained at room temperature for 2 months prior to use as inoculum. Small, symptomless, first-year rosettes of musk thistle were transplanted from the field into a mixture of soil, sand, and peat moss in pots and placed into a growth chamber maintained at 20°C. Seeds of C. thoermeri planted into pots containing the same mixture were maintained in the same chambers. After approximately 6 to 8 weeks, when seedlings and transplants were growing vigorously, both groups of plants were dusted with urediniospores and teliospores from the dried leaves. Inoculated plants were placed either into a 20°C dew chamber for 24 h or were atomized with distilled water, placed into sealed, transparent, polyethylene bags and returned to the 20°C growth chamber for 24 h, after which time the bags were removed. Both sets of plants were then maintained at 20 to 25°C. Chlorotic flecks developed on inoculated leaves after 7 to 8 days; uredinia and urediniospores were present within 10 days after inoculation. Urediniospores from those leaves had the same dimensions and ornamentation pattern as those originally obtained from field collections. A DNA sequence analysis was conducted on the rRNA ITS2 region, which was polymerase chain reaction-amplified from genomic DNA (2) extracted from urediniospores of the Oklahoma isolate grown at FDWSRU. The sequence of the ITS2 region from those urediniospores was identical to the sequence (GenBank accession no. U57351) obtained from the isolate 7803 of P. carduorum from Turkey, used in the Virginia field studies. The confirmed presence of P. carduorum in Oklahoma will enable field research with this rust for management of musk thistle in the state. References: (1) A. B. A. M. Baudoin and W. L. Bruckart. Plant Dis. 80:1193, 1996. (2) Y. T. Berthier et al. Appl. Environ. Microbiol. 62:3037, 1996.

Double-blind, placebo-controlled multicenter trial using chimeric monoclonal anti-CD4 antibody, cM-T412, in rheumatoid arthritis patients receiving concomitant methotrexate.

OBJECTIVE: To evaluate the clinical response to and safety of single and repeat doses of a chimeric anti-CD4 monoclonal antibody, cM-T412, in patients with rheumatoid arthritis (RA) concomitantly treated with a stable regimen of low-dose methotrexate. METHODS: Sixty-four patients with refractory RA, who were already receiving stable doses of methotrexate, were randomized into a multicenter, double-blind, placebo-controlled trial to receive 3 monthly treatments with either a placebo, or 5, 10, or 50 mg cM-T412, given intravenously. RESULTS: Using > or = 50% improvement in swollen joint counts as a criterion for clinical response, 13%, 13%, 18%, and 13% of patients receiving 50, 10, or 5 mg cM-T412, or the placebo, respectively, exhibited a clinical response at 3 months of therapy. Using > or = 50% improvement in tender joint counts as a measure of clinical efficacy at 3 months, 19%, 13%, 12%, and 6% of patients receiving 50, 10, or 5 mg cM-T412, or the placebo, respectively, exhibited a clinical response. "Flu-like" symptoms (fever, chills, rigor) within 24 hours of the infusion occurred more frequently in the groups receiving 50-mg (29%) and 10-mg (31%) doses of cM-T412 than those receiving 5 mg cM-T412 (12%) or the placebo (13%). Significant CD4+ T cell depletion occurred in the 50-mg group (mean of 353 CD4+ T cells/mm3 at 6 months versus 856 CD4+ T cells/mm3 at baseline). All patients were followed up for 12 months after the final treatment; no opportunistic infectious complications occurred. CONCLUSION: Treatment with cM-T412 in this cohort of RA patients who were also taking methotrexate was not associated with clinical efficacy or enhanced toxicity from infectious complications, despite significant peripheral CD4+ T cell depletion.

Most African-American patients with rheumatoid arthritis do not have the rheumatoid antigenic determinant (epitope)

OBJECTIVE: To evaluate the relation between the presence of the "rheumatoid epitope," defined by a sequence motif in the HLA-DRB1 alleles, and disease severity in African-American patients with rheumatoid arthritis. DESIGN: Cross-sectional study. SETTING: Rheumatology outpatient clinics at two university medical centers. PATIENTS: 86 African-American patients with rheumatoid arthritis (66 seropositive and 20 seronegative for the rheumatoid factor) attending the clinics and 88 healthy African-American persons. MEASUREMENTS: HLA-DRB1 alleles were determined by restriction fragment length polymorphism and by allele-specific oligonucleotide typing of polymerase chain reaction-amplified HLA-DRB1 second exons. RESULTS: With the exception of an increased frequency of HLA-DRB1*04 alleles in seropositive patients with rheumatoid arthritis (27.3%) compared with controls (13.1%) (P = 0.02), the frequencies of HLA-DRB1 alleles were similar in patients and controls. Most seropositive (48 of 66) and seronegative (15 of 20) patients were HLA-DR4 negative, but some (7 of 48 seropositive patients and 3 of 15 seronegative persons) inherited the rheumatoid epitope on a non-DR4 allele. Disease features, including severity, were similar for patients without the epitope and for those with either a single or a double dose of an epitope-positive allele. Positivity for rheumatoid factor, but not for the rheumatoid epitope, was weakly associated with severity in these patients. CONCLUSION: Most African-American patients with rheumatoid arthritis did not express the rheumatoid epitope. The predisposition to and severity of rheumatoid arthritis in African-Americans appears to be independent of the presence and dose of the shared rheumatoid epitope.

Treatment of refractory rheumatoid arthritis with a chimeric anti-CD4 monoclonal antibody. Long-term followup of CD4+ T cell counts.

OBJECTIVE: To evaluate CD4+ T cell counts of rheumatoid arthritis (RA) patients at 18 and 30 months after treatment with a chimeric anti-CD4 monoclonal antibody (MAb), cM-T412, in a phase I trial. METHODS: Of the 25 RA patients who received the MAb, 23 were available for followup at 18 and 30 months. Levels of circulating CD4+ T cells were measured by flow cytometry. RESULTS: Circulating CD4+ T cell levels in these 23 RA patients remained below normal at 18 and 30 months posttreatment. More profound CD4+ T cell depletion was noted in the higher-dose groups (300 and 700 mg). CONCLUSION: Prolonged suppression of circulating CD4+ T cells was noted both in single-infusion and multiple-infusion groups 18 and 30 months after cM-T412 treatment. The depression was more pronounced in patients who received multiple infusions of cM-T412. The prolonged decrease in CD4+ T cell numbers suggests that the capacity to reconstitute CD4+ T cells in this patient population (treated with methotrexate) is limited. One patient, who was also receiving methotrexate and prednisone, died 18 months after receiving 100 mg of cM-T412. No other significant adverse effects, in particular, no opportunistic infections, were reported in these 23 RA patients at 18 and 30 months of followup.

Use of a chimeric monoclonal anti-CD4 antibody in patients with refractory rheumatoid arthritis.

OBJECTIVES: To evaluate the safety, immunogenicity, and biologic effects of chimeric monoclonal anti-CD4 (cM-T412) in patients with refractory rheumatoid arthritis (RA), and to obtain preliminary data on the clinical response to this treatment. METHODS: Twenty-five patients with active refractory RA were treated with incremental doses (10 to 700 mg) of cM-T412 in an open-label, escalating-dose phase I trial. RESULTS: Infusion with cM-T412 was followed by an immediate, rapid decline in CD4+ T cells. The level of circulating CD4+ T cells remained depressed in most patients even at 6 months posttreatment. Following antibody infusion, proliferative responses of peripheral blood lymphocytes to mitogens and antigens were determined; mitogen and antigen responses were decreased compared with pretreatment responses. Mitogen responses tended to return to baseline values more rapidly than did responses to antigen. Adverse events included fever (19 patients), which was associated with myalgias, malaise, and asymptomatic hypotension; these symptoms were self-limited and appeared to correlate with transient elevations in interleukin-6. No significant human antibody response to the cM-T412 variable region was detected; only 2 patients developed transiently low levels of antibodies reactive with cM-T412. Significant clinical improvement, defined as > or = 50% decrease in tender joint counts compared with baseline, was noted in 43% of patients at 5 weeks and 33% at 6 months following cM-T412 infusion. CONCLUSIONS: Treatment of refractory RA with cM-T412 appears to be safe and is associated with sustained decreases in circulating CD4+ T cell counts and depressed in vitro T cell responses. No significant human antichimeric antibody response was detected. Nonblinded assessment of clinical end points suggests that treatment with cM-T412 may have beneficial effects in these patients with refractory RA. A double-blind clinical trial is warranted to determine its clinical efficacy in treating RA.

Experience with a chimeric monoclonal anti-CD4 antibody in the treatment of refractory rheumatoid arthritis.

We have used a chimeric monoclonal anti-CD4 antibody (cM-T412) in a phase I trial involving patients with refractory RA. The objectives of this initial study were to evaluate the safety, immunogenicity, and biologic effects of cM-T412. Twenty-five patients with active refractory RA (all taking methotrexate concomitantly) were treated with incremental doses (10 to 700 mg) of cM-T412 in an open-label, escalating dose phase I trial. Levels of circulating CD4+ T-cells decreased rapidly post-infusion and remained significantly depressed even at 18 months following treatment. Repopulation of CD4+ T cells consisting of increased CD45RA+ (naive) and CD45RO+ (memory) CD4+ T-cells was observed in approximately 1/3 of the patients between day 14 and 6 months post-infusion. Proliferative responses of peripheral blood lymphocytes to mitogens and recall antigens were generally diminished following cM-T412 infusion, with mitogen responses normalizing more rapidly than responses to recall antigens. Adverse events during the first 6 months of follow-up included fever, often associated with myalgias, malaise, and asymptomatic hypotension; these symptoms were self-limited and appeared to correlate with transient elevations of interleukin-6. Negligible human antibody responses to the cM-T412 variable region were observed; indeed, only 2 patients developed transient low levels of antibodies reactive with cM-T412. Non-blinded assessment indicated that 43% of patients exhibited > or = 50% improvement in tender joint counts at 5 weeks, and 33% at 6 months post-infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

New approaches to the therapy of autoimmune diseases: rheumatoid arthritis as a paradigm.

Several therapeutic agents currently are used to treat rheumatoid arthritis (RA). However, there is no compelling evidence that any of these agents substantially alters the long-term destructive course of RA. Advances in biotechnology have led to a better understanding of mechanisms that underlie autoimmune diseases such as RA. Although the etiology of RA remains unknown, there now is considerable insight regarding the immune and inflammatory pathways that ultimately lead to cartilage and bone destruction. Therapies with monoclonal antibodies directed against cell surface constituents, fusion toxins against cell activation markers, and cytokine inhibitors all have been shown to be safe and possibly efficacious in early open trials in RA. They now are being more rigorously tested in double-blind, placebo-controlled trials. Early experience with these biologic agents in humans, as well as data obtained from the use of these agents in animal models of autoimmune disease, are reviewed. In addition, experimental studies with "blocking peptides" and immunization with autoreactive T cell receptor peptides will be reviewed, and implications for therapy in RA will be discussed.

Anatomic localization of a single electrical source within the boundary of the human torso.

A closed prolate ellipsoid was used to approximate the surface of the Rush torso model to permit recovery of the site and orientation of known dipoles in 15 cardiac locations. Localization was found to be reasonably close, usually within 2 cm. When body surface potential maps of 37 subjects with right ventricular pacemakers were similarly treated, the discrepancy between known pacemaker site and the site of earliest activation was relatively large (mean, greater than 4 cm) and rapidly increased within the ensuing millisecond. The discrepancy not only emphasizes the wide variation in body shape and tissue distribution in living subjects, but also points to probable physical separation between stimulus site and earliest detectable activation site because of ischemia, infarction, or myocardial response to variation in current strength of the stimulus.