Calculation of free and bioavailable vitamin D and its association with bone mineral density in Malaysian women.

INTRODUCTION: Low 25-hydroxyvitamin D [25(OH)D] levels have not been consistently associated with bone mineral density (BMD). It has been suggested that calculation of the free/bioavailable 25(OH)D may correlate better with BMD. We examined this hypothesis in a cohort of Malaysian women. MATERIALS AND METHODS: A cross-sectional study of 77 patients with rheumatoid arthritis (RA) and 29 controls was performed. Serum 25(OH)D was measured using the Roche Cobas E170 immunoassay. Serum vitamin D binding protein (VDBP) was measured using a monoclonal enzyme-linked immunosorbent assay (ELISA). Free/bioavailable 25(OH)D were calculated using both the modified Vermuelen and Bikle formulae. RESULTS: Since there were no significant differences between RA patients and controls for VDBP and 25(OH)D, the dataset was analysed as a whole. Calculated free 25(OH)D by Vermeulen was strongly correlated with Bikle (r = 1.00, p < 0.001). A significant positive correlation was noted between measured total 25(OH)D with free/bioavailable 25(OH)D (r = 0.607, r = 0.637, respectively, p < 0.001). Median free/bioavailable 25(OH)D values were significantly higher in Chinese compared with Malays and Indians, consistent with their median total 25(OH)D. Similar to total 25(OH)D, the free/bioavailable 25(OH)D did not correlate with BMD. CONCLUSION: In this first study of a multiethnic female Malaysian population, free/bioavailable 25(OH)D were found to reflect total 25(OH)D, and was not superior to total 25(OH)D in its correlation with BMD. Should they need to be calculated, the Bikle formula is easier to use but only calculates free 25(OH)D. The Vermuelen formula calculates both free/bioavailable 25(OH)D but is more complex to use.

A multicentre UK study of GVHD following DLI: rates of GVHD are high but mortality from GVHD is infrequent.

DLIs are frequently used following haematopoietic SCT (HSCT) in patients with risk of relapse but data on GVHD following DLI are scarce. We report on 68 patients who received DLI following HSCT. Most patients developed GVHD following DLI (71%), which was acute in 22 patients (32%) almost half of whom had grade III-IV acute GVHD (aGVHD). Thirty patients (44%) developed cGVHD which followed aGVHD in four patients and was graded severe in nine patients. Corticosteroids were the most common first-line therapy for both acute and chronic GVHD. A wide range of second/third-line agents included cyclosporin, mycophenolate, tacrolimus, imatinib, infliximab and ECP. Relapse of initial malignancy occurred in 37%. Relapse was significantly less frequent in those receiving pre-emptive DLI. Relapse rates were also lower in those with GVHD (31%) than those without GVHD (50%), but this did not reach statistical significance. At 55 months post DLI, 34% of patients had died most commonly from relapse and 22% had on-going GVHD. Although GVHD was an important cause of morbidity post DLI (71%), only 6% died from GVHD. Although most patients develop GVHD post DLI and may require consecutive therapies, mortality from GVHD is infrequent. DLI remains an important option for relapse post transplant and manipulation of the GVT effect needs to be optimised to induce remission without morbidity from GVHD.