 |
|
|
 |
Dr. Bogliolo, et al reply To the Editor: We are grateful to Dr. Marchesoni and colleagues for their interest in our study and for their data so nicely reported. We think some additional comments are required to compare results of the 2 studies. First of all the aims of the studies are different: while Marchesoni, et al try to establish the usefulness of anti-cyclic citrullinated peptide (CCP) antibodies in discriminating psoriatic arthritis (PsA) and rheumatoid arthritis (RA), our study1 focused on the clinical characterization of anti-CCP positive patients with PsA. As stated1, we included in our study all patients with idiopathic arthritis and psoriasis, according to Moll and Wright2, without any additional exclusion criteria. Of course, a number of patients with RA and psoriasis may have been included3. However we think that a single expert's opinion may be questionable as an inclusion/exclusion criterion and may be less reproducible than a definite set of criteria4. We agree with Dr. Marchesoni in that patients with clear clinical and radiographic evidence of RA do have RA; however, some patients may present with signs and symptoms typical of both disorders. Moreover, since the anti-CCP assay has become very popular, we wonder how the expert's opinion might have been influenced by a positive test for anti-CCP. Dr. Marchesoni and colleagues state that Moll and Wright's classification has proven to be sensitive and specific when RF positive cases are excluded; however RF positivity was considered to have poor discriminating value in their study. Surprisingly enough, their approach in determining true PsA, based on their expert ruling out RA, led to the highest frequency of RF positive patients reported in PsA so far1,5. It would be interesting to know how many patients fulfilling Moll and Wright's criteria were excluded, as well as the clinical picture and autoantibody profile of these patients. A careful analysis of these patients might be useful to support the need for the expert's opinion as an additional criterion and the usefulness of anti-CCP antibodies, rather than RF, in discriminating PsA and RA. We hope the efforts of Dr. Marchesoni will lead to a suitable set of true diagnostic criteria for PsA in the near future6. At present, however, we think that a pragmatic approach to the selection of patients for clinical studies involves looking for prognostic factors (and we feel that anti-CCP antibodies may be among them) according to widely accepted classification criteria, particularly as therapeutic strategies in poor-prognosis PsA and RA are quite similar7. LAURA BOGLIOLO, MD; ROBERTO CAPORALI, MD; CARLOMAURIZIO MONTECUCCO, MD, Department of Rheumatology, IRCCS Policlinico S. Matteo, University of Pavia, Piazzale Golgi 2, 27100 Pavia, Italy. 1. Bogliolo L, Alpini C, Caporali R, Scire CA, Moratti R, Montecucco C. Antibodies to cyclic citrullinated peptides in psoriatic arthritis. J Rheumatol 2005;32:511-5. 2. Moll JMH, Wright V. Psoriatic arthritis. Semin Arthritis Rheum 1973;3:55-78. 3. McGonagle D, Conaghan PG, Emery P. Psoriatic arthritis. A unified concept twenty years on. Arthritis Rheum 1999;42:1080-7. 4. Gorter S, van der Heijde DM, van der Linden S, et al. Psoriatic arthritis: performance of rheumatologists in daily practice. Ann Rheum Dis 2002;61:219-24. 5. Gladmann D, Shuckett R, Russell ML, Thorne JC, Schachter RK. Psoriatic arthritis: clinical and laboratory analysis of 220 patients. Q J Med 1987;62:127-41. 6. Taylor WJ, Helliwell PS, Gladman DD, Mease P, Mielants H, Marchesoni A. A validation of current classification criteria for the diagnosis of psoriatic arthritis – preliminary results of the CASPAR study [abstract]. Ann Rheum Dis 2005;64 Suppl III:OP0157. 7. Pipitone N, Kingsley GH, Manzo A, Scott DL, Pitzalis C. Current concept and new developments in the treatment of psoriatic arthritis. Rheumatology 2003;42:1138-48. |