The immunopathological role of vitamin D in patients with SLE: data from a single centre registry in Hungary.

OBJECTIVES: Disproportionate vitamin D levels may play an important role in the development of certain systemic autoimmune and rheumatic diseases. The aim of the present study was to investigate the prevalence of vitamin D insufficiency in patients with systemic lupus erythematosus (SLE) and to compare serological and clinical parameters in patients with different vitamin D levels from a single centre registry in Central-Eastern Europe. METHODS: A total of 177 patients with SLE were enrolled in the study. 25-Hydroxyvitamin D [25(OH)D] levels were measured by chemiluminescent immunoassay (CLIA). Autoantibody profiles, complement 3 (C3) and C4, clinical symptoms, and disease activity (using the SLE disease activity index, SLEDAI) of the patients were assessed. RESULTS: Vitamin D concentration in the total SLE group investigated was 26.88 ± 13.25 ng/mL. Vitamin D levels were normal (≥ 30 ng/mL) in 18.1% of patients, insufficient (15-30 ng/mL) in 44.6%, and deficient (< 15 ng/mL) in 37.3%. The vitamin levels were significantly reduced in postmenopausal compared to premenopausal patients (p = 0.02). Patients with pericarditis (p = 0.013), neuropsychiatric diseases (p = 0.01), and deep vein thrombosis (p = 0.014) had reduced vitamin D levels. SLEDAI score was significantly increased in patients with reduced vitamin D levels (p = 0.038). Anti-double-stranded (ds)DNA autoantibody concentrations increased from normal to insufficient and further increased from insufficient to deficient patient subsets (p = 0.021). Anti-Smith antigen (anti-Sm) concentrations increased (p < 0.001), C4 levels decreased (p = 0.027), and immunoglobulin (Ig)G concentration increased (p = 0.034) in patients with reduced vitamin D levels. CONCLUSIONS: Our data suggest that vitamin D deficiency in SLE may play a role in perpetuation of the disease.

Inhibition of lymphoproliferative responses by SK&F 105685, a novel anti-arthritic agent.

SK&F 105685 (N,N-Dimethyl-8,8-dipropyl-2-azaspiro[4.5]decane-2-propanamine+ ++ dihydrochloride) is a novel azaspirane with beneficial activity in animal models of autoimmune diseases such as adjuvant-induced arthritis and experimental autoimmune encephalomyelitis in the Lewis rat and lupus-like disease in the MRL mouse. The effect of SK&F 105685 on the proliferation of rat lymphoid cells was examined in vitro. The compound inhibited the proliferative response of spleen, thymus and lymph node cells to the mitogen concanavalin A (Con A) in a dose-dependent manner but had little or no effect on the mitogenic response of peripheral blood lymphocytes. Although less potent than cyclosporin A, SK&F 105685 was able to inhibit the proliferation of spleen cells stimulated with PMA and ionomycin or the mitogens phytohemagglutinin (PHA), Con A and pokeweed mitogen (PWM). Relatively early event(s) in cell proliferation were affected by SK&F 105685 since delaying addition of the drug by 24 to 48 hours after Con A stimulation of rat spleen cells resulted in reduced levels of suppression. The mode of action of SK&F 105685 appeared to differ from that of cyclosporin A or rapamycin. Unlike cyclosporin A, SK&F 105685 did not affect IL-2 production by Con A-stimulated spleen cells or the IL-2-producing Jurkat cell line, but, like rapamycin, the compound significantly reduced the IL-2-induced proliferation of rat ConA blasts. These results suggest that inhibition of lymphocyte proliferation by SK&F 105685 may require the activity of an intermediate effector cell(s) present in susceptible populations such as cells from the spleen, thymus, lymph nodes and Con A blast preparations but absent or present in low numbers in resistant populations such as peripheral blood cells. Indomethacin and NG-monomethyl-L-arginine (NGMMA), a competitive inhibitor of nitric oxide synthase, were both unable to relieve SK&F 105685-induced suppression of splenic Con A responses thereby ruling out a role for the production of prostaglandins or nitric oxide by macrophages as an intermediate in drug-mediated suppression. In summary, SK&F 105685 was unable to inhibit lymphoproliferative responses by a mechanism distinct from that of cyclosporin A or rapamycin and which appears to involve regulation of cellular interactions rather than a direct effect on responding lymphocytes.