Background Antiphospholipid antibodies (aPL) are included in diagnostic criteria of antiphospholipid syndrome (APS) as good as systemic lupus erythematosus (SLE). There are a few cases of SLE onset in patients with isolated APS and vice versa development of APS in lupus patients in several years.
Objectives To analyze the mutual clinical and serologic features of APS and SLE, to determine the number of patients going on to develop other autoimmune disease after long-term follow-up and to define risk factors of “transformation” from APS to SLE or lupus onset in APS patients.
Methods The study included 314 unselected patients (141 with SLE, 98 with SLE+APS and 75 with “primary” APS (PAPS)) who had admitted to the department of systemic connective tissue diseases of Nasonova Scientific Research Institute of Rheumatology (Moscow, Russia) between June 2004 and September 2012. Patients fulfilled the 1997 ACR classification criteria for SLE and the Sapporo International Criteria of APS respectively. After staying in the hospital 195/314 (62%) patients continued to attend the Institute outpatiently. We excluded 64 patients with both SLE and APS, and the final study group was composed of 131 patients (83 SLE and 48 PAPS) with a mean age 36.4±12 years and mean follow-up 7±3 years (from 3 to 11)). Thromboses were registered in all patients with PAPS and in 1 (1%) patient with SLE (without aPL). Immunologic disorders included high and mild positive anticardiolipin antibodies (in 10% SLE and 100% PAPS), anti-beta-2-glicoprotein-1 antibodies (in <1% SLE and 32% PAPS), anti-DNA-antibodies (in 100% SLE and <1%PAPS) and lupus anticoagulant (only in 29% PAPS).
Results The main mutual manifestations were livedo reticularis (in 12% SLE and 64% PAPS) and sick headache (in 14% SLE and 35% PAPS). The other mutual features were seen with the next prevalence: hemolytic Coomb's positive anemia (in 24% SLE and 12% PAPS), thrombocytopenia (in 11% SLE and 19% PAPS), heart valve disease (in 9% SLE and 43% PAPS), recurrent fetal losses (in 8% SLE and 38% PAPS), Raynaud's phenomenon (in 38% SLE and 7% PAPS), cutaneous ulcers (in 3% SLE and 22% PAPS), avascular bone necroses (in 25% SLE and <1% PAPS). 36/83 (43%) patients with SLE had glomerulonephritis. And just 1/48 (<1%) patient with PAPS demonstrated persistent proteinuria. Kidney biopsy indicated APS-nephropathy: focal segmental glomerulosclerosis with thrombotic microangiopathy. During the follow-up 11/48 (23%) PAPS patients developed SLE and 2/48 (<1%) - cutaneous vasculitis; 6/83 (<1%) SLE patients developed “secondary” APS, 1 patient developed rupus and in 1 patient diagnosis “SLE” was changed to scleroderma. The results of univariate logistic regression analysis showed high positive aPL (OR 5,84; 95% Cl 3,18-10,98; p<0,001) and livedo reticularis (OR 3,07; 95% Cl 1,62-5,79; p=0,0003) as independent risk factors for development of “secondary” APS in lupus patients and recurrent fetal losses (OR 1,27; 95% Cl 1,05-1,55; p=0,009) as possible factors related to the joining of SLE to APS.
Conclusions SLE and APS have several mutual manifestations and can run into each other. Positive aPL and livedo reticularis are risk factors for development of “secondary” APS in lupus patients. Recurrent fetal losses can be possible factors related to the joining of SLE to APS.
Disclosure of Interest None declared