SAN FRANCISCO – A host of novel clinical and serologic findings that physicians can put to good use right now in helping to distinguish early SLE from its many mimickers have been identified in a large study conducted on four continents, Marta Mosca, MD, PhD, observed at an international congress on systemic lupus erythematosus.
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Dr. Marta Mosca
These useful findings aren’t incorporated into the current American College of Rheumatology (ACR) or Systemic Lupus International Collaborating Clinics (SLICC) lupus classification criteria, which have come under criticism for limited sensitivity in identifying early SLE. Some of the novel findings provide support for increased suspicion of early SLE, while others suggest a need to veer in another direction and assess a patient for a disease other than lupus. The study has served to provide input for the proposed new ACR/EULAR weighted SLE classification criteria, although that scheme is meant to be used only for research and not in clinical practice, explained Dr. Mosca of the University of Pisa (Italy).
She was lead author of the four-continent study, which included 616 patients referred to experienced academic lupus centers for possible SLE with a symptom duration of less than 1 year. During up to 3 years of follow-up, 389 patients were diagnosed as having SLE by experienced rheumatologists based upon their clinical judgment, without any requirement to meet the full ACR or SLICC classification criteria. The other 227 patients were determined to be SLE mimickers with conditions including lymphoma, Sjögren’s syndrome, systemic sclerosis, interstitial lung disease, fibromyalgia, antinuclear antibody–positive thyroiditis, and undifferentiated connective tissue disease.
Dr. Mosca also highlighted key recent work by other investigators aimed at speeding the diagnosis of SLE and shortening the duration of what she called “the gray zone” of diagnostic uncertainty, when autoantibodies and insidious symptoms are present but not yet sufficient to make the diagnosis of SLE by conventional criteria. It’s well established that 60%-70% of patients with mild undifferentiated connective tissue disease will remain stable without evolving into SLE during long years of follow-up.
The ultimate objective of all this work is to try to change the natural history of the disease through targeted early aggressive therapy aimed at minimizing the extent of active disease and preventing severe organ involvement.
Among the key takeaways from the four-continent study led by Dr. Mosca: Fever not related to infection was far more prevalent in early SLE than in mimicking conditions, by a margin of 34.5% versus 13.7%. On the other hand, Raynaud’s phenomenon was more than twice as prevalent among patients with mimicking conditions: 22.1% in early SLE, compared with 48.5% in SLE mimickers. Sicca symptoms were present in just 4.4% of early SLE patients versus 34.4% of SLE mimickers. Only 0.3% of early SLE patients complained of dysphagia; the rate was 20-fold higher in the SLE mimickers. Rashes atypical for lupus were twice as frequent in the SLE mimicking conditions (Arthritis Rheumatol. 2019 Jan;71[1]:91-8).
Turning to key differentiating serologic findings, Dr. Mosca noted that anti-double stranded DNA (anti-dsDNA) and anti-Sm antibodies were present in 71.7% and 30.2% of early SLE patients, respectively, compared with 6.9% and 2.6% of SLE mimickers. Anticardiolipin IgM, a positive Coombs test, anti-beta2 glycoprotein-I antibodies, leukopenia, autoimmune hemolytic anemia, and hypocomplementemia were all significantly more common in the early SLE cohort.
In contrast, antibodies to Ro (SS-A) and La (SS-B) were of no value in separating early SLE from its mimickers, according to Dr. Mosca.