Comparison of total, free and bioavailable 25-OH vitamin D determinations to evaluate its biological activity in healthy adults: the LabOscat study.

Determination of different forms of 25-OHD (total, free and bioavailable) in healthy young women does not offer additional advantages over standard 25-OHDT for evaluating vitamin D deficiency. In these subjects 25-OHDT values <15 ng/ml would be more appropriate for defining this deficiency. INTRODUCTION: Determination of 25-OH vitamin D serum levels (25-OHD) constitutes the method of choice for evaluating vitamin D deficiency. However, vitamin D-binding protein (DBP) may modulate its bioavailability thereby affecting correct evaluation of 25-OHD status. We analysed the impact of the determination of 25-OHD (total, free and bioavailable) on the evaluation its biologic activity (estimated by serum PTH determination) in healthy young women. METHODS: 173 premenopausal women (aged 35-45 yrs.) were included. We analysed serum values of total 25-OHD (25-OHDT), DBP, albumin, PTH and bone formation (PINP,OC) and resorption (NTx,CTx) markers. Free(25-OHDF) and bioavailable (25-OHDB) serum 25-OHD levels were estimated by DBP and albumin determinations and also directly by ELISA (25-OHDF-2). We analysed threshold PTH values for the different forms of 25-OHD and the correlations and differences according to 25-OHDT levels <20 ng/ml. RESULTS: 62% of subjects had 25-OHD values <20 ng/ml and also had significantly lower 25-OHDF and 25-OHDB values, with no significant differences in bone markers and PTH values. The PTH threshold value was similar for all forms of 25-OHD (∼70 pg/ml). Women with PTH values >70 had lower 25-OHDT (15.4 ± 1.4 vs. 18.3 ± 2.7, p < 0.05) and 25OHDB values (1.7 ± 0.2 vs. 2.2 ± 0.09, p < 0.05). The different forms of 25OHD were significantly intercorrelated, with marginal correlations between PTH and 25-OHDT (r = -0.136, p = 0.082). CONCLUSIONS: Determination of different forms of 25-OHD in healthy young women does not offer additional advantages over standard 25-OHDT for evaluating vitamin D deficiency. In these subjects 25-OHDT values <15 ng/ml would be more appropriate for defining this deficiency.

A genome-wide association study identifies a new locus associated with the response to anti-TNF therapy in rheumatoid arthritis.

Anti-Tumor Necrosis Factor (anti-TNF) drugs are biologic agents commonly used to treat rheumatoid arthritis (RA). However, anti-TNFs are not effective in approximately one out of four treated patients. We conducted a Genome-Wide Association Study (GWAS) to identify the genetic variation associated with the response to anti-TNF therapy in RA. In the discovery stage, 372 RA patients treated with an anti-TNF agent (infliximab, adalimumab or etanercept) were analyzed and treatment response was defined at 12 weeks of therapy. We found a genome-wide significant association in the MED15 gene with the response to etanercept (P<1.5e-8). Using an independent cohort of 245 RA patients, we performed a replication study of the most significant GWAS associations. We replicated the association at the MED15 locus and found suggestive evidence of association in the previously associated MAFB locus. The results of this study suggest novel mechanisms associated with the response to anti-TNF therapies.

Adsorptive granulocyte/monocyte apheresis for the treatment of refractory rheumatoid arthritis: an open pilot multicentre trial.

OBJECTIVE: To assess the efficacy and safety of adsorptive granulocyte and monocyte apheresis (GCAP) in patients with refractory rheumatoid arthritis (RA). METHODS: Patients with active and refractory RA were treated with weekly GCAP sessions using a column filled with acetate beads (Adacolumn) over five consecutive weeks. Clinical assessments and response to therapy were analysed at weeks 5, 7, 12 and 20 in an open multicentre trial. The primary outcome measure of clinical response was 20% improvement in the American College of Rheumatology criteria (ACR20) at week 20. EULAR (European League Against Rheumatism) response criteria, based on the disease activity score for 28 joints (DAS28) and disability using the Health Assessment Questionnaire (HAQ), were also assessed. RESULTS: Of 27 patients, 81.5% were women with mean disease duration of 14.4 yr. The mean number of previous disease-modifying antirheumatic drugs (DMARDs) was 3.7, and 48.1% of patients had previously failed on biologicals. On an intention-to-treat basis, 40.7% of patients achieved an ACR20 and 44.4% a therapeutic EULAR response at week 20. These percentages were 50 and 54.5% in 22 patients who completed the trial. In the 10 completers who had previously failed on biologicals, an ACR response was achieved in four patients (ACR20, two; ACR50, one; ACR70, one). A significant decrease was recorded in different ACR response components, including the tender joint and swollen joint counts, pain score and patient and physician global disease assessments, as well as the DAS28 index; most of them improved after week 5. ESR and CRP, but not the HAQ score, had decreased significantly at week 20. The treatment was well tolerated and only one serious adverse event related to the study procedure was documented (sepsis due to a catheter infection). CONCLUSIONS: GCAP treatment led to significant clinical improvement in a subset of patients with RA who had failed to respond to DMARDs or biologicals. Further large, placebo-controlled studies are warranted to fully assess the therapeutic value of GCAP for refractory RA.