The latter is partly in line with the study by Cucurull et al., who reported higher prevalence rates of IgA aCL and anti\2GPI in an African American population with SLE compared to other ethnicities 15. organ damage. Exclusive IgA anti\2GPI occurrence associated inversely with Caucasian ethnicity [odds ratio (OR)?=?021, 95% confidence interval (CI)?=?006C072) and photosensitivity (OR?=?019, 95% CI?=?005C072). Nephritis, smoking, LA\positivity and statin/corticosteroid\medication associated strongly with organ damage, whereas hydroxychloroquine\medication was protective. In conclusion, IgA\aPL is not rare in SLE (16%) and IgA\aPL analysis may have additional value among SLE cases with suspected APS testing Mouse monoclonal to CD56.COC56 reacts with CD56, a 175-220 kDa Neural Cell Adhesion Molecule (NCAM), expressed on 10-25% of peripheral blood lymphocytes, including all CD16+ NK cells and approximately 5% of CD3+ lymphocytes, referred to as NKT cells. It also is present at brain and neuromuscular junctions, certain LGL leukemias, small cell lung carcinomas, neuronally derived tumors, myeloma and myeloid leukemias. CD56 (NCAM) is involved in neuronal homotypic cell adhesion which is implicated in neural development, and in cell differentiation during embryogenesis negative for other isotypes of aPL and LA. Keywords: anti\phospholipid antibodies, anti\phospholipid syndrome, autoantibodies, immunoglobulin A, systemic lupus erythematosus Introduction Systemic lupus erythematosus (SLE) is a potentially severe autoimmune condition with an unpredictable disease course, often with fluctuations in disease Kynurenic acid activity over time 1. Long\term inflammation and drug\related side effects may lead subsequently to irreversible organ damage, a consequence which is associated intimately with decreased quality of life and increased mortality 2, 3, 4. In SLE, accrual of organ damage and prognosis has been linked consistently to the presence of anti\phospholipid antibodies (aPL), with or without clinical events related to the anti\phospholipid syndrome (APS) 5, 6, 7. Presence of the lupus anti\coagulant (LA) has been identified as the laboratory finding with the highest predictive value regarding future organ damage in SLE 8. The 1997 update of the American College of Rheumatology (ACR) classification criteria for SLE incorporated the presence of anti\cardiolipin antibodies (aCL) of immunoglobulin (Ig)G/IgM isotype and/or a positive LA test and/or a persistent false\positive serological test for syphilis 9. Recent reviews conclude that 30C40% of all SLE cases display elevated levels of any aPL at some point during the disease course, yet only approximately half of these SLE cases will fulfil the APS classification criteria 10, 11, 12. According to the Sydney classification criteria 13, APS is defined by vascular thrombosis and/or pregnancy morbidity and repeated raised defined levels of IgG and/or IgM isotype aCL and/or anti\2 glycoprotein\I (anti\2GPI) antibodies and/or a positive LA test. Based on the results from some studies, it has been claimed that the assessment of IgA isotype aCL and/or anti\2GPI provides additional clinical value and identify IgG/IgM aPL and LA negative cases of APS in SLE 14, 15, 16, 17. Accordingly, the International Consensus Task Force on aPL antibodies recommends IgA isotype testing for both aCL and anti\2GPI when results of all Kynurenic acid other tests are negative and APS is still suspected 18. Recently, it has been suggested that the presence of IgA anti\2GPI in people with no history of APS\related events constitute an important independent risk factor for the development of such events 19. Conversely, other studies found that analysis of IgA aPL did not contribute to the recognition of APS in SLE patients 20, 21, 22, 23. Nevertheless, in addition to the IgG and IgM isotypes, IgA aPL was included in the most recent set of SLE classification criteria proposed by the Systemic Lupus International Collaborating Clinics (SLICC) group in 2012. In their validation set of the SLICC\12 criteria, a greater sensitivity (97 83%) but a slightly lower specificity (84 96%) compared with the 1997 ACR classification criteria was demonstrated 24. However, it remains to be elucidated whether or not this update helps to identify SLE cases prone to develop APS\related events Kynurenic acid and future organ damage.