Effect of Vitamin D Replacement on Immune Function and Cognition in MS Patients

We will compare the immune responses in patients with Vitamin D deficiency (serum level <20ng/ml) to those of patients with normal Vitamin D (serum level >35 ng/ml). We will focus on proliferation and cytokine production to myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) peptides and on the percentage of Th1 (IFN gamma producing cells) and Th17 (IL-17 producing cells) during in vitro polarization assays. Our hypothesis is that patients with low Vitamin D have increase proliferation to MBP and MOG and increased production of pro-inflammatory cytokines (IFN gamma and IL-17) and that Vitamin D supplementation will decrease this pro-inflammatory profile.

We will measure cognitive performance in patients with Vitamin D deficiency (serum level <20ng/ml) compared to those of patients with normal Vitamin D (serum level >35 ng/ml) after adjusting for educational levels and disease duration. We hypothesize that low Vitamin D has a negative effect on cognitive performance and that Vitamin D supplementation will improve cognitive function.

Inclusion criteria

• Definite diagnosis of Multiple Sclerosis following the revised McDonald MS diagnostic criteria
• Male and Female Aged 18 and above
• On interferon-β treatment (Rebif®, Avonex®, or Betaseron®)
• No signs of active inflammation or attack or new lesions on MRI

Exclusion criteria

• Treatment with immune modulating/ suppressive drugs other than IFN-b within 6 weeks prior to enrolment
• Pregnancy
• Hypercalcemia
• eglomerular filtration rate<60
• History of primary hyperparathyroidism, hypercalcemia, renal dysfunction, cardiac disease, malignancy, or granulomatous disease
• The occurrence of an exacerbation (defined as an episode of neurologic dysfunction lasting at least 24 hours) within 4 weeks of enrollment
• History of dementia or related disorders
• History of traumatic brain injury
• Diagnosis of epilepsy or history of seizure
• Diagnosis of psychiatric disease, substance abuse/dependence, alcohol abuse/dependence
• Currently, on any of the following medications Lithium, or Thiazide diuretics