682 Letters rected for the total amount of the corresponding classspeciﬁc immunoglobulin (2), i.e., IgG anti-CCP (unit)/total IgG (gm/liter). In our study, this approach showed that RA patients with serum anti-CCP had synovial ﬂuid anti-CCP/ IgG ratio higher than that in RA patients with no serum anti-CCP antibodies (see Table 1). Moreover, in this last group 2 patients exhibited anti-CCP/IgG ratio values above the cut-off (2.22 units/gm/liter) calculated as the value for the upper 95th percentile in synovial ﬂuid of osteoarthritis patients. In conclusion, our results suggest that the synovial ﬂuid determination of anti-CCP antibodies should be reserved for selected cases (i.e., seronegative patients for these autoantibodies) taking into account the correction for the total amount of the corresponding immunoglobulin. Antonio Spadaro, Prof Valeria Riccieri, MD Rossana Scrivo, MD Cristiano Alessandri, MD Guido Valesini, Prof University of Rome Rome, Italy 1. Caspi D, Anouk M, Golan I, Paran D, Kaufman I, Wigler I, et al. Synovial ﬂuid levels of anti– cyclic citrullinated peptide antibodies and IgA rheumatoid factor in rheumatoid arthritis, psoriatic arthritis, and osteoarthritis. Arthritis Rheum 2006;55: 53– 6. 2. Vossenaar ER, Smeets TJ, Kraan MC, Raats JM, van Venrooij WJ, Tak PP. The presence of citrullinated proteins is not speciﬁc for rheumatoid synovial tissue. Arthritis Rheum 2004;50: 3485–94. 3. Arnett FC, Edworthy SM, Bloch DA, McShane DJ, Fries JF, Cooper NS, et al. The American Rheumatism Association 1987 revised criteria for the classiﬁcation of rheumatoid arthritis. Arthritis Rheum 1988;31:315–24. 4. Weinberger A, Simkin PA. Plasma proteins in synovial ﬂuids of normal human joints. Semin Arthritis Rheum 1989;19:66 – 76. DOI 10.1002/art.22114 Reply To the Editors: We thank Drs. Spadaro et al for their interest in our article and for their results, which indeed support our observation, that anti-CCP can be found in synovial ﬂuid of patients with RA. We found signiﬁcant correlation between serum and synovial ﬂuid anti-CCP levels, without considering the anti-CCP/IgG ratio suggested by Spadaro et al. The calculation of anti-CCP/IgG ratio presented by the authors, although theoretically reasonable did not seem to signiﬁcantly improve the sensitivity or speciﬁcity of the assay. In contrast, the calculation disclosed results above the cut-off in 2 of the osteoarthritis patients’ synovial ﬂuid samples. Our study aimed at detecting the presence of anti-CCP in synovial ﬂuids of patients with RA, and at showing that these ﬁndings are speciﬁc for RA. We do not suggest synovial ﬂuid anti-CCP as a routine diagnostic test, in accordance with the view of Spadaro et al. However, some patients with anti-CCP seronegative RA may demonstrate positive synovial ﬂuid anti-CCP results (in our study 3 of 14 patients, data not shown). In conclusion, elevated levels of anti-CCP are present in the synovial ﬂuid of RA patients, and their testing may offer some additive diagnostic value in selected cases. Dan Caspi, MD Ori Elkayam, MD Tel Aviv Medical Center Tel Aviv, Israel Submissions Invited for Themed Issue of Arthritis Care & Research: Cost and Social and Psychological Impact of Rheumatic Diseases Arthritis Care & Research is soliciting manuscripts for a themed issue addressing the economic cost and social and psychological impact of rheumatic diseases. Manuscripts covering a broad range of topics related to the major theme are invited; for example, economic cost, and social and psychological impacts on individuals, health care providers, and society; extent of and risk factors for disability in activities; and evaluation of public policies to reduce the impact of rheumatic diseases. Submissions from a range of disciplines are welcome, and we will entertain both original research articles and review articles. The issue will include regular submissions as well, but a certain number of pages will be reserved for manuscripts accepted in response to this solicitation. All manuscripts will be peer-reviewed. All types of manuscripts (e.g., original articles, contributions from the ﬁeld, case studies, trainee rounds, reviews) are included in this solicitation. The deadline for submission is June 1, 2007. For further information, contact the editors of Arthritis Care & Research, Edward H. Yelin, PhD ([email protected]) or Patricia P. Katz, PhD ([email protected]).