LETTERS 1263

might expect to see a more comparable experimental model of vasculitis in our mice or even a full clinical picture of WG.

Y . Tomer, MD Y . Shoenfeld, MD Sheba Medical Center Tel-Hashomer, Israel

1. Blank M, Tomer Y, Stein N, Kopolovic J, Wiik -4, Meroni P-L, Conforti G, Shoenfeld Y : Immunization with anti-neutrophil cyto- plasmic antibody (ANCA) induces the production of mouse ANCA and perivascular lymphocyte infiltration. Clin Exp Immunol 102:

2. Mendlovic S, Brocke S , Shoenfeld Y, Ben-Bassat M, Meshorer A, Bakimer R: Induction of an SLE-like disease in mice by a common anti-DNA idiotype. Proc Natl Acad Sci U S A 85:2260-2264, 1988

3. Bakimer R, Fishman P, Blank M, Sredni B, Djaldetti M, Shoenfeld Y : Induction of primary antiphospholipid syndrome in mice by immunization with human monoclonal anti-cardiolipin antibody (H-3). J Clin Invest 89:1558-1563, 1992

4. Shoenfeld Y: Idiotypic induction of autoimmunity: a new aspect of idiotypic network. FASEB J 8:1296-1301, 1994

120-130, 1995

Tenidap in rheumatoid arthritis: comment on the article by Blackburn et a1

To the Editor: We read with interest the article by Blackburn et al

describing the efficacy of tenidap in the treatment of rheuma- toid arthritis (RA) (1). The authors state in the introduction that the mechanism of action of tenidap is mediated by its inhibition of cyclooxygenase and the modulation of the release of several cytokines, such as interleukin-1, tumor necrosis factor a, and interleukin-6. They found that in tenidap-treated RA patients, the levels of circulating C-reactive protein (CRP) and serum amyloid A (SAA), 2 well-known acute-phase reac- tants, decrease. We would like to suggest that in addition to the above observations, another mechanism plays an important role in the antiinflammatory activity of tenidap. We reported recently that tenidap markedly inhibits the synthesis of proin- flammatory type I1 secretory phospholipase A, (sPLA,) (2). It was found that tenidap inhibits sPLA, expression at the post-transcriptional level ( 2 ) .

There is compelling evidence that sPLA, plays an important role in the induction/propagation of the inflamma- tory process in RA (3,4). Secretory PLA, is highly concen- trated in inflammatory synovial fluids (5), and its activity in the circulation significantly correlates with disease activity in pa- tients with RA (6). In animal experiments, intraarticular injections of purified (7) or recombinant human (8) sPLA, induce dose- and time-dependent synovitis, which can be attenuated by sPLA, inhibitors (7,8). Of interest is the fact that CRP was found to act as an inhibitor of sPLA, (9), whereas S A A increased sPLA, activity (10). The fact that tenidap is effective in the therapy of RA is important not only for the value of this agent as an addition to the armamentarium of antiarthritic drugs, but also as a further line of evidence that

several mediators of inflammation, including sPLA,, play an important role in RA.

W. Pruzanski, MD, FRCPC, FACP P. Vadas, MD, PhD The Wellesley Hospital Toronto, Ontario, Canada

1. Blackburn WD Jr, Prupas HM, Silverfield JC, Poiley JE, Caldwell JR, Collins RL, Miller MJ, Sikes DH, Kaplan H, Fleischmann R, Scoville CD, Rutstein JE, Hurd ER, Louie JS, Bankhurst AD, Weaver AL, Sebba AI, Appelrouth DJ, Hudson NP, Gordon GV, Gordon RD, Ludivico CL, Austin MC, Sanders Kh4, Schuette PT, Moidel RA, Kraska AR, Ting N, Shanahan WR Jr, Loose LD: Tenidap in rheumatoid arthritis: a 24-week double-blind compar- ison with hydroxychloroquine-plus-Piroxicam, and Piroxicam alone. Arthritis Rheum 38:1447-1456, 1995

2. Pruzanski W, Kennedy BP, van den Bosch H, Stefanski E, Wloch M, Vadas P: Tenidap sodium inhibits secretory non-pancreatic phospholipase A, synthesis by foetal rat calvarial osteoblasts. Mediat Inflamm 4:67-70, 1995

3. Vadas P, Browning J, Edelson J, Pruzanski W: Extracellular phospholipase A, expression and inflammation: the relationship with associated disease states. J Lipid Mediat Cell Signal 8:l-30, 1993

4. Bomalaski JS, Clark M A Phospholipase A, and arthritis. Arthritis Rheum 36:190-198, 1993

5. Pruzanski W, Scott K, Smith G, Rajkovic I, Stefanski E, Vadas P: Enzymatic activity and immunoreactivity of extracellular phospho- lipase A, in inflammatory synovial fluids. Inflammation 16:451- 457, 1992

6. Pruzanski W, Koo Seen Lin M, Vadas P Secretory phospholipase A, in rheumatic diseases. In, Phospholipase A2 in Clinical Inflam- mation: Molecular Approaches to Pathophysiology. Edited by KB Glaser, P Vadas. Boca Raton, FL, CRC Press, 1995

7. Vadas P, Pruzanski W, Kim J, Fornasier V: The proinflammatory effect of intra-articular injection of soluble human and venom phospholipase A,. Am J Pathol 134:807-811, 1989

8. Bomalaski JS, Lawton P, Browning J: Human extracellular recom- binant phospholipase A, induces an inflammatory response in rabbit joints. J Immunol 146:3904-3910, 1991

9. Vadas P, Stefanski E, Grouix B, Schouten BD, Pruzanski W: Inhibition of human group I1 phospholipase A, by C-reactive protein in vitro. J Lipid Mediat Cell Signal 11:187-200, 1995

10. Pruzanski W, de Beer FC, de Beer MC, Stefanski E, Vadas P: Serum amyloid A protein enhances the activity of secretory non-pancreatic phospholipase A,. Biochem J 309:461-464, 1995

Reply To the Editor:

We appreciate the comments of Drs. Pruzanski and Vadas regarding our recent report. We agree that tenidap is effective therapy in RA and is an important addition to the treatment armamentarium for this and perhaps other inflam- matory disorders. At this point, the intracellular mechanisms by which tenidap’s effects are mediated have not been fully elucidated. Certainly, inhibition of certain cytokines and the cyclooxygenase pathway have been demonstrated in vivo. As Drs. Pruzanski and Vadas point out, there may be additional mechanisms, such as inhibition of sPLA,. Further investigation

LETTERS

of this promising drug should help delineate the specific role of each of these potential pathways.

Warren D. Blackburn, Jr., M D Binninghani Veterans Administration Hospital and

Leland D. Loose, PhD @zer Inc. Groton. CT

The University of Alabama at Biriningliani

Cytokines in polymyalgia rheumatica

To the Editor: Polymyalgia rheumatica (PMR) is usually associated

with a pronounced acute-phase response, which is reflected by an elevation of the erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) level. However, in some patients with PMR, these laboratory results can be discordant with the clinical assessment of disease activity. Cytokines, such as tumor necrosis factor a (TNFa), interleukin-6 (IL-6), and IL-8, mediate different aspects of the acute-phase response (l), and therefore are potentially more direct and sensitive markers of disease activity in diseases such as PMR. Recently, Roche et a1 reported that in PMR, IL-6 levels were elevated and were more closely correlated with the therapeutic response to steroids, compared with the ESR (2). These data raise the possibility of using serum cytokines as a more accurate guide to the use of steroid therapy in patients with PMR.

We used enzyme-linked immunosorbent assays (ELISAs) to compare serum levels of TNFa, IL-6, IL-8, and CRP (measured by nephelometry), and the ESR (Westergren) with the clinical assessment of disease activity in patients who presented with PMR and were then treated with cortico- steroids for 6 months. These laboratory investigations were performed prior to the initiation of treatment with steroids, and then monthly for 6 months. Symptom severity was re- corded by patients, using a 10-point visual analog scale of pain and a 0-4 scale for the degree of stiffness (0 = <5 minutes; 1 = <60 minutes; 2 = 1-2 hours; 3 = 2-3 hours; 4 = >3 hours), monthly for 6 months. All patients were treated with oral prednisolone in the evening (10-20 mg), and the dose was subsequently tailored according to symptoms.

Four patients completed the study. All were female and had a diagnosis of PMR based on a clinical history of shoulder and/or pelvic girdle pain, accompanied by fatigue or stiffness for at least 6 weeks duration. All 4 patients were negative for rheumatoid factor both at baseline and at 6

Table 1. Clinical and laboratory features of the study patients*

months. Two patients underwent temporal artery biopsy to exclude giant cell arteritis (GCA). Serial data over 6 months for each of these parameters are shown in Table 1.

Blood was collected between 9:00 AM and 11:OO AM from all patients on all occasions. Samples were collected in EDTA, since some batches of lithium heparin have been reported to be contaminated with endotoxin (3). All cytokine ELISAs were developed in-house using commercially available antibodies. Each assay was calibrated against international reference standards (IL-6 88514, IL-8 89520, and T N F a 87:650). To ensure assay-to-assay uniformity, a control serum with established cytokine levels was run in each assay. All assays were optimized to minimize the effects of heterophilic antibodies and rheumatoid factor, by the addition of nonim- mune animal serum to all diluents. Normal levels were estab- lished using samples from 44 healthy volunteers (normal T N F a <20 pg/ml, IL-6 <20 pg/ml, and IL8 <23 pdrnl).

We found that levels of IL-6 in particular, but also IL-8 and TNFa, were not elevated in PMR, either a t diagnosis or at any time during the 6 months of the study. At presentation, an elevated ESR was found in all 4 patients, and the CRP level was elevated in 3 of them. In 3 of the 4 patients, the ESR and the CRP level fell with successful treatment. However, the findings for patients 2-4 illustrate that the CRP level and the ESR were not always concordant. Patient 4 had the highest CRP level at presentation and required the most prednisolone at 6 months.

Fifty percent of the patients described by Roche et a1 had IL-6 levels >20 pp/ml. Although the detection limit of our assay was not as low as that used by Roche et al, none of our patients had levels >20 pg/ml, in spite of impressive elevations in ESR and CRP levels. In view of known diurnal variation in cytokine levels and rapid cytokine clearance from the circula- tion, we standardized the time of blood collection and chose 9-11 AM to overlap with the period of morning stiffness. W e were careful to ensure that blood was drawn from all patients at this time, that none of the patients had been treated with steroids prior to the first cytokine estimations, and that pa- tients were excluded if they had GCA or if their disease was evolving into rheumatoid arthritis.

The acute-phase response associated with PMR, as reflected by elevation of the ESR and CRP levels, suggests the prior influence of cytokines such as IL-6, TNFa, and IL-8. However, optimal timing of sample collection and highly sensitive cytokine assays may both be necessary in order to reliably identify these mediators in the peripheral circulation. From our data, the ESR and the CRP would appear to be

ESR (normal range

Disease 0-20 mmhour) duration, Age,

Patient weeks years Baseline 6 months

1 26 72 87 45 2 13 66 88 103 3 6 68 64 12 4 10 68 94 <1

CRP (normal <6 mg/liter)

Baseline 6 months

15 <1 17 4 4 3

111 8

Pain, Stiffness VAS score score

(range 0-10) (range 0-4)

Baseline 6 months Baseline 6 months

10 5 3 0 8 6 4 0

10 2 4 0 10 4 3 0

Prednisolone dose (mdday)

Baseline 6 months - 5

7 5

13

-

-

-

* ESR = erythrocyte sedimentation rate; CRP = C-reactive protein; VAS = visual analog scale.