Revised version with tracked changes oral Magnesium reduces levels of pathogenic autoantibodies and skin disease in murine lupus.

Background: Systemic Lupus Erythematosus (SLE) has a strong genetic susceptibility, but little is known about the impact of diet on disease severity. The Western diet is typically deficient in magnesium (Mg), and given the immunomodulatory effects of Mg, we hypothesized that the low Mg intake increases disease risk and that increasing Mg intake would reduce severity of murine lupus. Here, we placed 12-week old MRL/lpr female lupus mice on a normal (Mg500) or a high (Mg2800) Mg diet for 9 weeks. Urine and blood were collected during the study for quantification of urinary albumin, BUN, anti-dsDNA antibodies, and immune phenotyping.

Results: MRL/lpr lupus mice on high Mg2800 diet had significantly fewer skin lesions and less severe skin histology score, and reduced levels of pathogenic anti-dsDNA antibodies, compared with the Mg500 group (143.8±75.0 vs. 47.4±36.2 × 10⁶U/ml; P < 0.05). The high Mg2800 group had a nearly two-fold increase in the percentage of CD4⁺FOXP3⁺ Treg cells compared to controls (19.9±5.4 vs. 11.4±5.5%; P < 0.05). Treg percentages inversely correlated with the concentration of anti-dsDNA. None of the mice developed arthritis during the observation period and there were no significant differences in weight, proteinuria, BUN or kidney histology.

Conclusion: In conclusion, oral supplementation of Mg has a protective effect in a murine lupus model and may represent an inexpensive and safe adjuvant in the treatment of SLsE.