Classification of an intermediate group of patients with antiphospholipid syndrome and lupus-like disease: Primary or secondary antiphospholipid syndrome?

Objective. (1) To classify an intermediate group of patients (IntAPS) with antiphospholipid syndrome (APS) and lupus-like disease tither as primary (PAPS) or secondary APS (SAPS) and to discuss 2 different classifications. (?) To compare patients of a division of rheumatology with either PAPS or SAPS. Methods. Patients with APS and patients with systemic lupus erythematosus (SLE) followed at the Department of Rheumatology, University Hospital Bichat, Paris, from 1987 to 1996 were analyzed. A chart review and a standardized telephone interview in 1997 completed the data of this study. Results. (1) We found a total of 108 patients with APS: 22 with PAPS, 69 with SAPS, and 17 with IntAPS. The group of IntAPS did not differ from PAPS in any clinical or laboratory signs with the exception of antibodies to dsDNA and to extractable nuclear antigen (ENA). Between IntAPS and SAPS, there were several significant differences in clinical signs of SLE (malar rash, discoid rash, arthralgia) and in laboratory values (leukocytopenia). (2) Comparison of PAPS and SAPS showed statistically significant differences for positive Coombs test, leukocytopenia. lymphocytopenia. antinuclear antibodies, antibodies to dsDNA and to ENA, and hypocomplementemia. Conclusion. The mainstay of the diagnosis of APS is the clinical event of thrombosis or miscarriage in the presence of antiphospholipid antibodies. Less important are laboratory values, which may help to differentiate PAPS from SAPS in order to initiate adequate therapy (e.g., anticoagulation in the first and additional corticosteroids in the second). Patients with IntAPS are more likely to be integrated into the group of PAPS than in the group of SAPS; therefore, special exclusion criteria for PAPS are not appropriate.