الفهرس 
TitleOnly 14 pages are availabe for public view
 |  | from | 186 |  |  |
| | | from | 186 | | |
Abstract
The COVID‐19 pandemic has spread worldwide. The SARS-CoV-2 represents a single
stranded RNA virus. Globally it has affected over 500 million causing more than 6 million
deaths. The ACE2 acts as a cellular receptor for the spike subunit of SARS CoV-2. It can
produce a wide range of clinical presentations from mild to critical COVID‐19 illness.
Innate and adaptive immune responses can be modulated by vitamin D. Vitamin
D/receptor signaling pathway may ameliorateacute respiratory distress syndrome through
decreasing cytokines storm, regulation of renin-angiotensin system activityas well as
modulation of neutrophil activity in addition to epithelial repair and maintenance of
pulmonary epithelial barrier integrity.
Vitamin D deficiency has been known as a global public health matter. It may lead to
higher risk infections. In addition, vitamin D supplementation may act to reduce upper
respiratory tract infections risk. VDR genetic variants, FokI and TaqI SNPS were reported to
be associated with increased susceptibility for viral infection.
The present work aimed to assess vitamin D receptor polymorphisms (rs2228570 and
rs731236) and serum levels of 25-hyroxyvitamin D and angiotensin‐converting enzyme 2 in
patients with COVID-19.
The study was conducted on 90 confirmed polymerase chain reaction positive COVID-
19 patients. According to clinical presentations, they were classified into: 40 patients with
mild / moderate illness and 50 patients with severe/critical illness. Genotyping of VDR
polymorphisms FokI and TaqI (rs2228570 and rs731236) were performed using the allelic
discrimination RT-PCR with dual labelled fluorogenic TaqMan® minor groove binder probes
in addition to measurement of serum levels of 25(OH)D and ACE2 using ELISA.
In the present study, the serum mean 25-hyroxyvitamin D was lower in severe/critical
and non -survivors than mild/moderate and survivorsCOVID-19 patients, respectively. The
recessive mode of inheritance of FokI SNP (ff versus FF+Ff) was associated with increased
COVID-19 severity risk while the dominant mode of inheritance of TaqI (Tt+tt versus TT)
and the mutant allele (t) were protective against COVID-19 severity. The median value of
serum angiotensin converting enzyme 2 was higher in severe/critical and non-survivors
compared to mild/moderate and survivors COVID-19 patients. Serum level of 25-
hyroxyvitamin D showed a negative correlation with age, serum C-reactive protein, ferritin,
procalcitonin and interleukin 6 levels as well as plasma D-dimer and INR levels, white blood
cells and neutrophils counts, neutrophils/lymphocytes ratio and serum alanine and aspartate
aminotransferases and lactate dehydrogenase activities while it showed a positive correlation
with oxygen saturation level and lymphocytes count.