Session Type: Abstract Submissions (ACR)
The existence of Mixed Connective Tissue Disease (MCTD) has often been discussed in literature and its diagnostic criteria are very heterogeneous. Anti-U1-RNP antibodies are not specific, but their presence is obligatory for the diagnosis of MCTD. To determine whether MCTD exist as a distinct entity, we analyse their frequency in a group of anti-U1-RNP positive patients and their diagnostic evolution rate at the end of follow-up. We studied the predictive value of some clinical and biological factors for diagnostic transformation.
We have selected retrospectively 103 patients from January 2006 to May 2011. The only inclusion criterion was the presence of anti-U1-RNP antibodies. We have studied medical information at the time of first presentation, at each visit and at the last follow-up visit. The selected patients were classified into one group of connective tissue disease if they fulfilled the following classification criteria: ARA for Rheumatoid Arthritis (RA), ACR for Systemic Lupus Erythematous (SLE), Leroy and Medsger for Systemic Scleroderma (SS), American and European criteria for Sjögren’s Disease (SD), Bohan and Peter for myopathies, Alarcón-Segovia for MCTD. Patients fulfilling more than one or respectively none of the connective tissue disease criteria were classified as Overlap Syndrome (OS) or Undifferentiated Connective Tissue Disease (UCTD) respectively. The initial diagnosis was reviewed after each visit. Anti-U1-RNP antibodies were detected by immune-dot or radial immune-diffusion. We used Student’s test or Fisher’s test for statistical analyze (p≤0.05).
103 patients were anti-U1-RNP positive. 98 patients had a diagnosis of a connective tissue disease at the initial presentation and were followed up between January 2006 and May 2011: 20 UCTD, 10 MCTD, 5 OS, and 63 defined connective tissue diseases (48 SLE; 7 SD, 5 SS; 3 RA). The diagnosis of MTCD was rare (10.2% at first presentation and only 5.1% at the end of follow-up). 60% of the initial MCTD’s have evolved into 2 SLE and 4 OS in a medium delay of 7.3 years [2-16] by the end of follow-up. No predictive factors for diagnostic evolution were identified (p>0.05). Anti-U1-RNP antibodies were associated with a high proportion of SLE (49%) and OS (26%) at the end of follow-up. Visceral complications were frequently observed in our patient group (54%).
MCTD is probably an intermediate stage towards an evolution into a well-defined connective tissue disease. We underline the importance of a systematic and long follow-up for all anti-U1-RNP positive patients which are at high risk to develop more than one connective tissue disease and visceral complications over time.
R. M. Javier,
J. E. Gottenberg,
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