Vitamin D serum levels comparison between a cohort of Myasthenia gravis patients and healthy subjects in Argentina

JUSTO ME; AGUIRRE F; CELA E; VILLA A; LEONI J; GONZALEZ MAGLIO DH; PAZ ML

Congreso; Reunión Conjunta SAIC SAI SAFIS 2018; 2018

Myasthenia Gravis (MG) is an autoimmune disease mediated generally by anti-acetylcholine receptor autoantibodies (ACRA), whose production is T cell dependent. Regulation of autoreactive T cells depends on regulatory T lymphocytes (Treg), which are diminished in MG patients. Vitamin D (VitD) has immunomodulatory effects, stimulating Treg and inhibiting effector T cells. As VitD synthesis depends on sunlight exposure, therefore on the country latitude, a controversial association between VitD deficiency and MG development and severity has been established. We aimed to compare 25-OH-VitD serum levels in 61 diagnosed MG patients (19 during MG exacerbation) and 30 healthy volunteers (hv), and to relate them with the severity of the disease (ADL and MGCscales)and other biomarkers in an Argentinian cohort. We collected samples equally distributed through the year. We measured: 25-OH-VitD (chemiluminescence), C3 and C4 (RID), C5a (ELISA), ACRA (RIA).There were no statistically significant (ss) differences in 25-OH-VitD mean serum levels between patients and hv, neither between basal and exacerbated patients. When we analyzed 25-OH-VitD mean serum levels of subjects grouped according to the season of sampling, we found a ss difference in spring (p=0,043) between patients (13,42 ng/ml) and hv (18,11 ng/ml). Deficient levels of 25-OH-VitD (<25 ng/ml) were found in 83,5% of MG patients vs 57,1% of hv, being this association ss (p=0,001). No ss association was found between basal and exacerbated patients using the same cut-off value.We found a strong association between VitD deficiency and illness, though no correlation with the severity of MG or other biomarkers could be established.We were not able to find general differences between VitD levels in MG patients and hv in our population. We aim to increase the number of samples and extent the analysis throughthe summer, to deepen in the analysis of this serum biomarker in our local population.