[Systemic lupus erythematosus and antiphospholipid syndrome - diagnostic and therapeutic problems]

Recognizing the antiphospholipid syndrome (APS) in patients with lupus (SLE) can be difficult and therefore underestimated. Detection of antiphospholipid antibodies (aPL) in each patient with SLE should be done as a rule. Introduction of the new classification criteria of this syndrome will certainly improve the recognition of APS in the future. The Sapporo APS classification criteria (1998) were replaced by the Sydney criteria in 2006. Based on the most recent criteria, classification with APS requires one clinical and one laboratory manifestation. The modified criteria do not include a number of clinical symptoms and laboratory test. Antiphospholipid syndrome can be primary (pAPS) or secondary (sAPS), connected with other autoimmune diseases, such as SLE. In approximately 40% of patients with SLE, aPL is present, while less than 40% of them have episodes of thrombosis. However, it is estimated that APS may develop in up to 50-70% of aPL-positive SLE patients during 20 years of follow-up. Difficulties in the diagnosis of APS in SLE patients result from the fact, that a number of symptoms typical of primary APS also occurs in the ACR/SLICC classification criteria for SLE. Patients with SLE and APS/aPL have an increased risk of neuropsychiatric complications and more often develop chronic kidney disease. Kidney involvement in this syndrome is well defined and is characterized by thrombosis, potentially in every kidney vessel. Renal biopsy is obligatory for differential diagnosis between lupus nephropathy and APS-associated nephropathy (APSN). It is necessary to actively search for changes typical of APSN in kidney biopsy. The incidence of APSN in patients with SLE and aPL is 11.4% to 39.5%, while in the SLE-APS group in which the biopsy was performed, renal damage was found in 67-100%. The diagnosis of APS is crucial because the presence of aPL exacerbates the course of SLE, and the appropriate treatment reduces the mortality and morbidity in these patients.