Microvascular abnormalities and autoantibody profile in systemic lupus erythematosus (SLE)

Background: The greater part of microvascular studies concerning SLE patients did not define if the nailfold capillaroscopy (NC) findings could be due to SLE or to overlapping diseases.Objectives: Aim of the study was the assessment of NC changes in a cohort of SLE patients to compare these data with the main clinical, demographic and laboratory parameters.Methods: 44 consecutive SLE patients (F/M = 40/4; mean age = 37 yrs, range 25-47; mean disease duration = 70 months, range 18-96) fulfilling the 1982 ARA revised criteria, were included in the study.Global disease activity was assessed using the European Consensus Lupus Activity Measurement (ECLAM) and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Laboratory investigations included full blood count; erythrocyte sedimentation rate (ESR); C-reactive protein (CRP); complement factors C3 and C4; antinuclear antibodies (ANA) and anti-dsDNA antibodies detected by indirect immunofluorescence; anti-ENA antibodies (including anti-RNP, anti-Sm, anti-SSA/Ro, anti-SSB/La), IgG and IgM anticardiolipin antibodies detected by ELISA; urynanalysis, creatine clearance and 24 h urinary protein levels.The following NC parameters were considered: capillary density; capillary length variability; presence of morphological abnormalities such as meandering, bizarre, ramified and/or bushy capillaries; irregular distribution; microhaemorrhages, changes of the blood flow. A semiquantitative rating scale was adopted to score these changes: 0= no changes; 1= < 4 alterations; 2= 4 to 6 alterations; 3 = > 6 alterations per linear millimeter.Results: 15 patients (34%) complained of Raynaud's phenomenon; 9 (20%) showed relevant capillaroscopic changes (capillaroscopic score > 1). In details: 3 patients (6.8%) had a reduction of capillary density, while 18 (41%) presented a capillary length variability. Microhaemorrhages were found in 4 cases (9%).A capillaroscopic score > 1 was more frequently associated with higher ECLAM (p<0.005) and SLEDAI (p<0.01) scores. Besides, the presence of capillary lenght variability significantly correlated with higher values of SLEDAI (p<0.05).Moreover, in our SLE patients a capillaroscopy score > 1 was more frequently associated with the presence of anti-cardiolipin (IgG and/or IgM)(p<0.043) and anti-Sm (p<0.044) antibodies, and with the presence (p<0.039) and higher titer (p<0.001) of anti-dsDNA antibodies.No statistically significant correlation among the different capillaroscopy findings and/or demographic and clinical manifestations of the disease was found.Conclusion: The presence of relevant NC changes (capillaroscopic score >1) in 20% of our SLE patients, although not specific of any defined subset, confirms the importance of the microvascular involvement in the pathogenesis of this disease.Moreover, in our SLE patients the NC abnormalities seem to be related to the disease activity, as assessed by ECLAM and SLEDAI score systems, and to the presence of different antibodies, such as anti-dsDNA, anti-Sm and anti-cardiolipin antibodies, which are highly involved in the expression of the disease.Our report shows how NC, an easy-to-perform non-invasive technique, is able to add useful data to better evaluate the microvascular damage in such a pleomorphic disease as SLE.References: Caspary L, et al. J Rheumatol 1991; 18:559;Cutolo M, et al. J Rheumatol 2000; 27:155;Furtado RNV, et al. Lupus 2002; 11:35.