Levinus B. A. van de Putte

Influence of prognostic features on the final outcome in rheumatoid arthritis: a review of the literature.

Abstract The literature on prognostic features on the final outcome in RA is reviewed. It is generally agreed that female sex and a positive RF are variables indicating a poor prognosis. Long-standing increased ESR and CRP values, decreased Hb, or the appearance of subcutaneous nodules are indicators of a less favorable clinical course. No conclusions can be drawn regarding other factors due to the incomplete and heterogeneous study designs.

Circulating soluble tumor necrosis factor receptors, interleukin‐2 receptors, tumor necrosis factor α, and interleukin‐6 levels in rheumatoid arthritis.

Objective. To assess whether circulating concentrations of soluble tumor necrosis factor receptors (sTNFR; p55 and p75), soluble interleukin-2 receptors (sIL-2R), tumor necrosis factor α (TNFα), and interleukin-6 (IL-6) reflect clinical response and whether changes are dependent on the drug used in rheumatoid arthritis (RA) patients taking methotrexate (MTX) or azathioprine (AZA). Methods. These cytokines and soluble receptors were assessed in 20 control subjects and serially for up to 48 weeks in 61 RA patients, by bioassay (IL-6) and immunoassays (sTNFR, sIL-2R, TNFα, and IL-6). Results. Concentrations of p55 and p75, sIL-2R, and TNFα (but not IL-6) were significantly higher in RA patients than in controls. Significant decreases in sIL-2R and p55 concentrations were associated with clinical improvement and were observed in patients treated with MTX, but not AZA. Both treatments induced decreases in IL-6 concentrations, but circulating AZA (or its metabolites) appears to interfere with the measurement of IL-6 bioactivity. TNFα and p75 levels did not show significant changes. Conclusion. Measurement of circulating sIL-2R, p55, and IL-6 may be useful in the evaluation of RA disease activity and response to therapy. Interference by circulating levels of drugs must be ruled out when bioassays are used to evaluate cytokine levels.

Influence of Methotrexate and Azathioprine on Radiologic Progression in Rheumatoid Arthritis: A Randomized, Double-Blind Study

OBJECTIVE To compare the effects of azathioprine and methotrexate on progression of radiologic damage in patients with rheumatoid arthritis. DESIGN Double-blind, randomized 48-week trial. PATIENTS Sixty-four patients with active rheumatoid arthritis who either have not responded to or who have reacted with side effects to at least parenteral gold and D-penicillamine. INTERVENTIONS Either azathioprine, 100 mg daily, or methotrexate, 7.5 mg weekly, was administered orally. Depending on the clinical effect after 8 weeks, the dosage was increased to either azathioprine, 150 mg, or methotrexate, 15 mg. The dosages for nonsteroidal anti-inflammatory drugs and prednisone were held stable. MEASUREMENTS Clinical and laboratory assessments were done by the same physician every 4 weeks for the first 24 weeks and every 8 weeks thereafter. Radiographs of hands, wrists, and feet obtained at baseline and after 24 and 48 weeks were scored by one rheumatologist blinded to medication and clinical findings. MAIN RESULTS Initial radiologic scores were comparable in both groups and correlated with disease duration (r = 0.38). An intention-to-treat analysis after 24 and 48 weeks showed significantly fewer new erosions in the methotrexate group compared with the azathioprine group (difference, 2.0 [95% CI, 0.2 to 3.9] and 3.5 [CI, 1.3 to 5.8], respectively). The change in total joint score was also significantly less pronounced in the methotrexate group compared with the azathioprine group after 24 weeks (difference, 2.8 [CI, 0.2 to 5.2]) and after 48 weeks (difference, 3.9 [CI, 0.3 to 7.4]). Radiologic stabilization after 48 weeks was present in 10% of the azathioprine group compared with 29% of the methotrexate group. CONCLUSIONS Patients with rheumatoid arthritis treated with low-dose methotrexate showed significantly less radiologic progression than patients treated with azathioprine. This result suggests that methotrexate therapy is clinically superior in these patients.

Detection and quantification of experimental joint inflammation in mice by measurement of99mTc-pertechnetate uptake

We adapted the method of99mTc-pertechnetate (99mTc) uptake measurements to the mouse knee for detection and quantification of arthritis because clinical assessment of mouse knee-joint arthritis is not reliable. The main points to ensure reproducibility of measurements were proper fixation and positioning of the knee and careful shielding of the rest of the body from the gamma-radiation detector.99mTc uptake was calculated as the mean of three countings. The variation coefficient of these countings ranged from 0.007 to 0.082 in non-arthritic joints and from 0.025 to 0.081 in arthritic joints. Arthritis was scored as the ratio of the99mTc uptake in the right knee versus that in the left knee. This ratio averated 1.06 (S.D. 0.05) in non-arthritic mice 20 minutes after99mTc administration i.p. On the second day after induction of arthritis in the right knee, this ratio ranged from 1.44 to 1.96; this was significantly higher (P<0.005) than in non-arthritic mice, and the increase remained significant during at least 20 days.99mTc uptake measurements seem to be a useful method to detect and quantify arthritis of the knee joint in mice.

Quantitation of arthritis by99mTc-uptake measurements in the mouse knee-joint: correlation with histological joint inflammation scores

A method is described to detect and to quantitate inflammation in knee-joints of mice. Approximately 10 μCi99mTechnetium pertechnetate (99mTc) is injected subcutaneously in the neck region and the accumulation of the short-lived isotope in the knee-joint is detected by external gamma counting.99mTc-uptake values correlate well with histological grading of joint inflammation at various intervals after induction of the inflammation. The method can be used to detect changes in activity of unilateral as well as bilateral joint inflammation using either the ratio of99mTc uptake in the right knee versus that in the left knee or absolute99mTc-uptake values.

Radio-synovectomy in chronic synovitis of the knee joint in patients with rheumatoid arthritis

The influence of intra-articular (i.a.) colloidal 198Au (5 mCi) or 90Y-silicate (5 mCi) on synovitis of the knee joint in patients older than 45 years with rheumatoid arthritis (RA), who had been treated since 1970 in our hospital, was investigated. Of the 89 knee joints of 77 patients studied, 65 had no or minimal radiological abnormalities of the knee joint treated (group I), whereas 24 patients had moderate to severe changes (group II). Before and at regular intervals after radio-synovectomy the clinical response was scored using pain, hydrops and warmth as parameters. The results indicated that 1 year after treatment the percentage of knee joints with a favourable response was greater in group I than in group II (58% versus 25%, P=0.001). This difference was still present 3 years after treatment. Clinical response showed no correlation with initial inflammatory activity as measured by 99mTc-pertechnetate uptake measurements. However, in group I, those patients with an ESR below 60 mm/h, measured just before radio-synovectomy, more often had a favourable response than those with an ESR in excess of 60 mm/h (P=0.01). No or only slight complications of radio-synovectomy were noted, whereas leakage of radioactivity from the knee joints was minimal.It is concluded that radio-synovectomy is an effective and safe procedure in those patients with rheumatoid synovitis of the knee joint without the presence of significant radiological damage and the absence of active systemic disease.

Inhibition of glycosaminoglycan synthesis in anatomically intact rat patellar cartilage by paracetamol-induced serum sulfate depletion

We have studied the effect of low sulfate concentrations on the glycosaminoglycan synthesis in rat patellar cartilage in vivo as well as in vitro. The oral administration of 200 mg/kg paracetamol to male Wistar rats resulted in a significant reduction of the serum sulfate concentration. Reduced serum sulfate availability resulted in a 34% decrease of glycosaminoglycan synthesis in patellar cartilage. This is due to sulfate depletion since paracetamol had no direct effects on glycosaminoglycan synthesis and a slight but significant inhibitory effect on the catabolism of radiolabeled glycosaminoglycans in vitro. The glycosaminoglycans synthesized at low sulfate concentrations in vivo were similar to the glycosaminoglycans synthesized at physiological sulfate concentrations. Studying the effect of sulfate availability in vitro on glycosaminoglycan synthesis in patellar cartilage we found that incubation of rat patellae in medium containing less than 0.5 mM inorganic sulfate led to a decreased sulfate incorporation. The use of potential sulfate decreasing drugs can lead to inhibition of glycosaminoglycan synthesis. This argues for a reconsideration of the use of these drugs in patients with already dysfunctioning cartilage metabolism as in rheumatoid arthritis and osteoarthrosis.

T cell responses to streptococcal antigens in rats: Relation to susceptibility to streptococcal cell wall-induced arthritis

Abstract In order to investigate the immunological mechanism of the chronic phase of streptococcal cell wall (SCW)-induced arthritis in Lewis rats, we compared the SCW-specific T cell response in arthritis-susceptible (female Lewis) and resistant (F344) rats. We present evidence that this T cell response is absent in F344 rats, while it is clearly present in Lewis rats. The T cell response was analyzed both in the spleen and in lymph nodes. In addition, we show, that injection of SCW in the F344 rat induces a general unresponsiveness in this strain: the response to mitogen was severely suppressed in SCW-injected F344 rats and, furthermore, when SCW was coinjected with ovalbumin, the response to ovalbumin was depressed. The fact that priming with ovalbumin alone induces a normal response in the F344 rat to both mitogen and ovalbumin implies that the observed abnormality after SCW priming is not a general immunological defect in this strain. Additionally, we demonstrate that adherent cells of both Lewis and F344 exert negative effects on an in vitro T cell response after injection with SCW, and that F344-adherent cells are more potent in this effect. Removal of OX8-positive cells leads to a restoration of the SCW-specific T cell response in SCW-injected F344 rats, indicating that the expression of this response is controlled by (SCW-specific?) suppressor T cells. Our results provide suggestive evidence for the obligatory role of SCW-specific T cells in the expression of chronic joint inflammation after systemic injection of SCW.

Naproxen kinetics and disease activity in rheumatoid arthritis: A within‐patient study

The effects of rheumatoid arthritis disease activity on the pharmacokinetics of the highly albumin‐bound nonsteroidal anti‐inflammatory drug naproxen were studied in six patients during chronic therapy. In the same patients, kinetics during active disease were compared with those in improvement. Active disease is commonly associated with hypoalbuminemia: 30 ± 4 gm/L vs. 41 ± 2 gm/L (mean ± SD) at the time of improvement. Total naproxen concentrations were significantly lower in active disease, together with a larger apparent volume of distribution (10.6 ± 1.8 L vs. 8.4 ± 1.3 L; P < 0.05) and total body clearance (0.79 ± 1.8 L/hr vs. 0.59 ± 0.14 L/hr; P < 0.001). Peak unbound naproxen concentrations were 29% ± 19% (P < 0.05) lower at the time of improvement. The unbound clearance was found diminished during active disease (390 ± 277 L/hr) in comparison with improvement (488 ± 343 L/hr; P < 0.05). Clinical implications of the alterations in naproxen kinetics induced by polyarticular inflammation in patients with rheumatoid arthritis are discussed.

Determination of small quantities of sulfate (0–12 nmol) in serum, urine, and cartilage of the mouse

The colorimetric benzidine method of K. S. Dodgson and B. Spencer (1953, Biochem. J. 55, 436-440) for the measurement of inorganic sulfate can be scaled down about 100 times by using disposable 96-well microplates instead of individual cuvettes. Ten-microliter samples of serum and urine, derived from mice, can be analyzed in a simple, rapid, and reliable way without sacrificing the animals. Without prior isolation of sulfated glycosaminoglycans, ester sulfate in mouse patellar cartilage is liberated quantitatively as inorganic sulfate upon acid hydrolysis in 3 M HCl for 16 h at 80 degrees C. To this end the articular cartilage layer of the patella must be separated in toto from the underlying bone. Subsequent hydrolysis in polypropylene tubes gives accurate results. In contrast, hydrolysis in borosilicate glass vials is useless, since nanomoles of sulfate added cannot be recovered adequately. The thin patellar cartilage layer obtained from 10-week-old male mice contains about 5 nmol of sulfate, an amount easily measured with the developed microplate benzidine method.