Figure 1.

Principal problems linked to classification of systemic lupus erythematosus (SLE). Classification of SLE patients according to The American College of Rheumatology (ACR) (A1,A2) or by The Systemic Lupus International Collaborating Clinics Criteria (SLICC) (B1,B2) classification criteria are descriptively problematized. Each of the classification systems identify a substantial diversity of clinical phenotypes. The 11 ACR criteria is presented by numbers (A1, the classification criteria are presented as a focused table in A2). Five patients are demonstrated. The patients share some criteria, but diverge with respect to others, and their clinical phenotypes differ individually. Similarly, each of 11 clinical and 6 immunological SLICC criteria are presented by numbers (B1, the classification criteria are presented as a focused table in B2). These chaotic figures (A1, B1) demonstrate that the use of the ACR and the SLICC criteria is problematic as bases for scientific analyses covering genetics, etiology, pathogenesis, and response to experimental therapy in patient cohorts as the study objects do not represent a homogenous group of patients. The patients in these figures are fictive but they reflect problems with the ACR and SLICC criteria in real life (Part of this figure (A) is a reprint with permission of Figure 1 in Rekvig (3).