Clinical and serological correlates of antinucleosome antibodies in South Africans with systemic lupus erythematosus.

Antinucleosome antibodies (AnuA) are increasingly recognized as an important biomarker in the diagnosis and subset stratification of patients with systemic lupus erythematosus (SLE). The aim of the study was to determine the sensitivity, specificity, and clinico-serological correlates of AnuA in black South Africans with SLE. We performed a cross-sectional study of 86 SLE patients attending a tertiary center and 87 control subjects. AnuA were tested using a second-generation enzyme-linked immunosorbent assay (ELISA). The sensitivity, specificity, positive predictive value, and negative predictive value of AnuA were 45.3, 94.3, 88.6, and 63.6%, respectively. The presence of AnuA were strongly associated with the co-presence of anti-dsDNA antibodies (OR = 3.4, p < 0.0005) and antihistone antibodies (OR = 15.7, p < 0.00001). Patients who were seropositive for AnuA were more likely to have skin involvement (discoid lupus and/or malar rash) and had higher SLE disease activity index (SLEDAI) scores and Systemic Lupus International Collaborative Clinics/American College of Rheumatology (SLICC/ACR) damage scores (p < 0.05). IgG anticardiolipin antibody (aCL) levels showed a significant correlation with AnuA ratios (p < 0.01). Our findings provide further evidence that AnuA are a sensitive and specific diagnostic biomarker in SLE. Moreover, our finding that the presence of AnuA, but not anti-dsDNA antibodies, are associated with worse SLICC/ACR damage scores suggest that AnuA may have a role in predicting disease outcome. The correlation between IgG aCL and AnuA is a novel finding that merits further studies to determine possible common peptide specificities of the antibodies.

Serum concentrations of C reactive protein, alpha1 antitrypsin, and complement (C3, C4, C1 esterase inhibitor) before and during the Vuelta a Espana.

OBJECTIVES: To determine serum concentrations of proinflammatory (C reactive protein, complement C3 and C4) and anti-inflammatory (alpha(1) antitrypsin, C1 esterase inhibitor (C1-INH)) acute phase proteins in elite cyclists before and during a three week cycle tour. METHODS: Seventeen professional cyclists participating in the Vuelta a Espana volunteered for the study. Their mean (SD) physical characteristics were: age 28 (1) years; height 1.7 (0.06) m; weight 65 (7) kg; body fat 7.6 (0.8)%; Vo(2)max 75.3 (2.3) ml/kg/min. Venepuncture was performed on each subject 24 hours before the tour began (T0), on day 11 (the first rest day; T1) and day 21 (the second to last stage of the tour; T2). Samples at T1 and T2 were taken about 17 hours after the previous stage. Analysis of variance was used to determine changes over time. Where significance was found, a Tukey post hoc test was performed. RESULTS: C reactive protein concentrations were consistently within the normal range, although there was a 228%, non-significant increase at T1. C3 concentrations fell within the normal range at all times assessed. C4 concentrations before the race were within the normal range and were significantly increased 10 days (T1) into the race. C1-INH concentrations did not change significantly throughout the race. alpha(1) Antitrypsin concentration before the race was at the lower end of the normal range and was only significantly raised at T2. CONCLUSIONS: Although not as pronounced as those reported in marathon/ultramarathon runners, elite cyclists participating in a three week cycle tour experienced increases in selected proinflammatory and anti-inflammatory acute phase proteins, indicating an acute phase/inflammatory response. It is tenable that the increase in alpha(1) antitrypsin and C1-INH (anti-inflammatory mediators) at T2 served to attenuate the acute phase/inflammatory response. The lower than normal resting concentrations of the acute phase proteins supports the notion that chronic aerobic exercise induces an anti-inflammatory state.