The enigma of mixed connective tissue disease-challenges in routine care.

OBJECTIVES: As a rare and heterogeneous disease, mixed connective tissue disease (MCTD) represents a challenge. Herein, we aimed to unravel potential pitfalls including correct referral diagnosis, distinction from other connective tissue diseases (CTD) and treatment modalities. METHODS: We characterised the MCTD cohort at our tertiary referral centre. All patients were evaluated for fulfilment of classification criteria of various CTDs. SLEDAI-2 K and EUSTAR-AI were used in accordance with previous research to evaluate disease activity and treatment response. RESULTS: Out of 85 patients initially referred as MCTD, only one-third (33/85, 39%) fulfilled the diagnostic MCTD criteria and the other patients had undifferentiated CTD (16/85, 19%), non-MCTD overlap syndromes (11/85, 13%) and other rheumatic diseases. In our final cohort of 33 MCTD patients, 16 (48%) also met the diagnostic criteria of systemic sclerosis, 13 (39%) these of systemic lupus erythematosus, 6 (18%) these of rheumatoid arthritis and 3 (9%) these of primary myositis. Management of MCTD required immunomodulating combination therapy in most cases (15/28, 54%), whereas monotherapy was less frequent (10/28, 36%), and only a few (3/28, 11%) remained without immune modulators until the end of the follow-up period. Treatment led to a significant decline in disease activity. CONCLUSIONS: Our study showed a high risk for misdiagnosis for patients with MCTD. As a multi-organ disease, MCTD required prolonged immunomodulating therapy to achieve remission. The establishment of an international registry with longitudinal data from observational multi-centre cohorts might represent a first step to address the many unmet needs of MCTD.

Evaluation of the RIDA®GENE RT-PCR assays for detection of sapovirus, astrovirus, adenovirus, and rotavirus in stool samples of adults in Switzerland.

Sapovirus (SaV) and astrovirus (AstV) increasingly are recognized as cause of acute viral gastroenteritis (AGE). We evaluated the real-time RT-PCR assays RIDA®GENE SaV and viral stool panel II (RGN RT-PCR) for detection of SaV, AstV, adenovirus (AdV) F40/41 and rotavirus (RoV) in clinical stool samples (n = 69). Results were compared with reference singleplex RT-PCRs. The sensitivity for SaV, AstV and RoV are 100%, the specificity ranges from 98.1% to 100%. In 10 out of 11 AdV (all types) samples, the RGN RT-PCR for AdV F40/41 displayed negative results. Retrospectively, 196 stool specimens from adult patients previously tested negative for norovirus (NoV) were analyzed. In about 10% of NoV-negative stool samples, AdV (n = 9), RoV (n = 6), AstV (n = 3) or SaV (n = 3) were found. The RGN RT-PCR assays are useful for detection of enteric viruses other than NoV. This study emphasizes the need for further testing of NoV-negative stool samples in patients with AGE.