Serum vitamin D level correlates with disease activity and health-related quality of life in antineutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND AND OBJECTIVE: The association between vitamin D levels and disease activity has been established in patients with several autoimmune rheumatic diseases. We aimed to examine the association between vitamin D and disease activity of antineutrophil cytoplasmic antibody-associated vasculitis (AAV). METHODS: Fifty-four AAV patients and 50 age- and sex-matched healthy controls without vitamin D supplements were included. Clinical and laboratory data were evaluated during the assessment of vitamin D levels. Two different forms of vitamin D in the sera-25(OH)D, which is the sum of 25(OH)D2 and 25(OH)D3, and 25(OH)D3, which only includes 25(OH)D in its D3 form-were measured, and the relationship between vitamin D and the obtained data was assessed. Variations in vitamin D levels relative to the season were also evaluated. RESULTS: Patients with AAV demonstrated considerably lower 25(OH)D serum levels than healthy controls (16.0 vs. 20.4 ng/mL, p = 0.016), and the proportion of individuals with vitamin D deficiency was higher in patients with AAV than in healthy controls (68.5% vs. 48.0%, p = 0.035). Both serum 25(OH)D and 25(OH)D3 were positively associated with the 36-item Short-form Health Survey (SF-36) physical component summary and SF-36 mental component summary (MCS) scores. A negative correlation was observed between 25(OH)D and 25(OH)D3 serum levels and Birmingham vasculitis activity score (BVAS), C­reactive protein (CRP), and white blood cell count. Linear regression analysis indicated haemoglobin and 25(OH)D levels to be independently associated with BVAS and CRP and 25(OH)D levels with SF-36 MCS score. No seasonal variations were observed in vitamin D levels. CONCLUSION: The results from this study suggest that vitamin D levels could provide clinically useful information in AAV.

Delta neutrophil index as a marker for differential diagnosis between flare and infection in febrile systemic lupus erythematosus patients.

Fever is a common symptom of systemic lupus erythematosus (SLE), and because of this it is difficult to discriminate between SLE flare and infection. The delta neutrophil index (DNI), automatically determined by the ADVIA 2120 electronic cell analyzer, has been reported to reflect the fraction of circulating immature granulocytes and to be associated with the presence of infection. In this study, we investigated the utility of DNI in discriminating infections from SLE flares in febrile SLE patients. In total, 111 episodes in 92 febrile SLE patients were reviewed. The infection group showed significantly higher white blood cell counts, neutrophil counts, C-reactive protein and procalcitonin than the SLE flare group. Complement (C)3 and C4 levels were decreased significantly in the SLE flare group. Patients in the SLE flare group had significantly lower DNI than those in both infection groups, with or without bacteremia. In a multivariate logistic regression analysis, only DNI was a significant independent factor for the presence of infection (odds ratio (OR): 18.9). When we selected a DNI value of 2.8% as the cutoff for infection, SLE patients with DNI ≥ 2.8% were found to be at higher risk for infection than those with DNI <2.8% (relative risk 8.48-fold). Our data suggest that DNI may be a marker to differentiate infections from SLE flares in febrile SLE patients.