Introduction:The Mean Platelet Volume (MPV) is a platelet activation biomarker that has been recently correlated with disease activity in SLE. We aimed to evaluate the MPV in patients with SLE comparing it with healthy individuals, to study the correlation between MPV and SLE Disease Activity Index (SLEDAI) in SLE patients and to analyze possible correlation between MPV and Erythrocyte Sedimentation Rate (ESR), C-Reactive Protein (CRP), and complement components C3 and C4.Methods:This is a cross-sectional study in which 81 patients with SLE according to the American College of Rheumatology (ACR) diagnostic classification criteria and 58 healthy controls were included. Active disease was defined as SLEDAI>0.Results:Patients with active SLE had decreased MPV when compared to inactive disease group (10.0±0.7fL vs. 10.7±1.0fL, p=0.005, respectively) and when compared to control group (10.9±1.0fL, p<0.001). Our study found a weak negative correlation between the SLEDAI and the MPV (r=-0.29, p=0.009). There was no correlation between MPV and CRP, ESR, C3 and C4. Also, no correlation between SLEDAI and CRP, ESR, C3 and C4 was found.Conclusion: MPV decreases in patients with active SLE and is inversely correlated with SLEDAI.

BackgroundSystemic lupus erythematosus (SLE) is a multisystem inflammatory autoimmune disease that evolves with periods of remission and exacerbation activity, whose intensity can be measured by the SLEDAI. This tool is complex and has limitations. The mean platelet volume (MPV) is a marker of platelet activation and has been shown to be associated with inflammation, which makes it a potential biomarker to aid in the assessment of disease activity in SLE.ObjectivesTo evaluate VPM in SLE patients at the active and inactive stages according SLEDAI and assess a possible correlation between VPM with SLEDAI, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement 3 (C3), and complement 4 (C4).MethodsThis cross-sectional study consisted of 40 patients with SLE, according to American College of Rheumatology (ACR) classification criteria, that were evaluated in Rheumatology Clinic of the Hospital de Clínicas de Porto Alegre in the second half of 2015. Interview during medical consultation and medical chart review were used to collect demographic, clinical and laboratory data. Disease activity was assessed with SLEDAI and chronicity was assessed with SLICC damage index (SDI). The blood count and platelets are measured in automation equipment Sysmex XE 5000. Platelets are analyzed by impedance, and the mean platelet volume is an index calculated by the machine when the examination of platelets. VSG was carried out by automated method by capillary photometry kinetics, PCR and C3 and C4 complement were determined in automation by immunoturbidimetry with intensification of reaction particles. Comparisons between groups were made with t-test or Mann-Whitney test.ResultsAll patients studied were female, 25 (62.5%) were classified as European-derived, mean age was 42.7±12.6 years and the average age at diagnosis was 29.9±9.9 years. At the time of the study, the median (IQR) for SLEDAI was 1.50 (0.0,4.0) and for SDI was 0.0 (0.0,1.0). Patients were divided into two groups (SLEDAI=0 and SLEDAI>0). The VPM had an inverse significant correlation with SLEDAI (r=-0.38; p=0.01). However, the MVP did not correlate significantly with ESR, CRP, C3 and C4. Patients were divided into two groups (SLEDAI=0 and SLEDAI>0) and the results for classification criteria were similar, but lymphopenia was most prevalent in group SLEDAI>0.ConclusionsThere is a correlation between the VPM and the SLEDAI in our SLE patients, making it a possible tool to be used in the evaluation of disease activity.ReferencesCeylan B, Fincanci M, Yardimci C, Eren G, Tozalgan U, Muderrisoglu C, Pasaoglu E. Can mean platelet volume determine the severity of liver fibrosis or inflamation in patients with chronic hepatitis B? European Journal of Gastroenterology & Hepatology 2013, Vol 25 No. 5.Gasparyan AY, Ayvazyan L, Mikhailidis DP, Kitas GD. Mean platelet volume: a link between thrombosis and inflammation? Curr Pharm Des. 2011;17(1):47–58.Review.Yavuz S, Ece A. Mean platelet volume as an indicator of disease activity in juvenile SLE. Clin Rheumatol. 2014...

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