Background Although lupus spectrum illness contains at least four variants (antibody only, undifferentiated autoimmune disease, typical SLE, and overlap SLE), clinical, epidemiological, and basic science publications do not use distinguish among these groups when they speak of SLE, thereby muddling interpretation of the results.

Methods We systematically reviewed clinical, epidemiological, and basic science publications from the last 5 years to determine definitions they used for SLE.

Results Of 366 papers on human SLE, 197 were suitable for analysis. Of these, 32 were basic/translational, 151 clinical trials and studies, and 14 epidemiological. Between 66% and 79% of papers specified or implied use of ACR criteria, of which 0%–16% also required presence of anti-DNA or anti-Sm antibody. 19%–29% of papers specified exclusion criteria, of which 10%–14% specifically excluded patients with overlap disease. Disease activity was considered in 14%–22% and stable disease was required in 7%–14% of papers. 0%–3% of papers considered disease duration (table 1).

Of 132 studies on mouse SLE, 24% use NZB variants, 36% MRL-lpr variants and 39% used variants/induced illness in C57Bl/6J mice. Definition of SLE required presence of anti-DNA antibody in 47% of studies, ANA in 10%, proteinuria in 39% and immunohistochemistry (usually renal) in 57%. 15% of papers defined disease onset ≤8 weeks, 15% 8–16 weeks, and 57% did not indicate time of disease onset. The fact that the paper spoke of animal SLE was indicated in the titles of 46% of papers.

Criteria used in 197 studies on human SLE, indicating criteria for diagnosis, inclusions, exclusions, serology, activity, and disease duration.

Conclusion Publications on SLE use a wide variety of definitions, inclusion, and exclusion criteria and often use the term SLE without specifying animal or human. Consensus definitions and stratification rules are necessary to obtain greater homogeneity in studies of SLE. (We will propose methods by which greater consensus can be obtained.)

Acknowledgements Supported by the Barbara Volcker Center and the Weill Cornell Medicine AOC program.