---

Background and Objective: Pterygium is a fibrovascular lesion of the ocular surface with unknown origin, decrease in the vision. This study was done to evaluate the possible role of Epstein-Barr virus (EBV) in the formation of pterygia. Methods: This case-control study was done on 50 tissue specimens of pterygium from the patients who underwent pterygium surgery as the case group and 10 conjunctival biopsy specimens of individuals without pterygium including the patients whom underwent cataract surgery, as controls. The evidence of EBV infection was tested by polymerase chain reaction (PCR). Results: EBV was detected in three (6%) patients with pterygia. EBV was not detected in controls. There was not any significant correlation between pterygium and the presence of EBV. Conclusion: According to this study, EBV virus is not associated with pterygium formation.

---

Background and Objective: Chronic infection with Hepatitis B virus (HBV) is one of the main causes of cirrhosis and hepatocellular carcinoma (HCC). The pathogenicity of the virus is determined by the multi-functional protein x (HBx). Changing the sequence of the gene encoding this protein causes the regulation of transcription and pathogenicity factors. This study was done to analyze the genetic dynamics of the HBx coding gene in a person with chronic HBV.
Methods: In this descriptive laboratory study, an infected person with chronic hepatitis B virus infection was first amplified and cloned into complete sequence of HBx encoder. Then, the reference sequences of genotypes, serotypes and different virus subtypes of the GenBank database were matched by CLC Sequence Viewer software. The comparative result was used to plot the phylogenic tree by T-rex server and population genetic analysis using DnaSP software. Natural selection at the nucleotide and protein level was performed by the Tajima's D test.
Results: No known mutation at the level of the protein was found in the chronic sequence of the HBx encoder. The results of natural selection indicated neutral mutations in the HBx gene. The phylogenetic results showed that the HBx encoding sequences in the chronic infected individual had a genetic affinity with genotype D and ayw2 subtype.
Conclusion: Neutrality polymorphism takes place in HBx coding region. Also, the phylogenetic results of the present study are consistent with the previous findings of Golestan province and Iran which have reported the prevalence of genotype D and subspecies ayw2.

---

Background and Objective: Single Nucleotide Polymorphisms in programmed cell death which expressed at high level in T cells, plays an important role in the development and cause autoimmune disorders. This study was done to evaluate the frequncy of rs11568821 polymorphism in patients with systemic lupus erythematosus (SLE).
Methods: This case-control study was done on 76 patients with SLE and 56 healthy controls. After DNA extraction, frequncy of polymorphisms PDCD1.3 by polymerase chain reaction and sequencing methods in subjects were determined.
Results: There was a significant diference between frequency of allele and genotype at rs11568821 Polymorphism in region of intron 4 of PDCD1.3 gene in case and control groups (P<0.05). A allele and AG genotype was significantly higher in patients than healthy controls (9.5% vs 0.09%, P<0.05). There was no significant association between clinical and laboratory findings with genotype frequencies.
Conclusion: rs11568821 single nucleotide polymorphism in intron 4 gene region PDCD1 can be used as a genetic factor to be involved the SLE susceptibility.

---

Background and Objective: Since the onset of the COVID-19 (Corona Virus Disease 2019) pandemic, several challenges have been proposed to the disease and the causing viral agent. Accurate and rapid diagnosis of the virus is essential to control the spread and progression of the disease. Choosing a suitable sample in different phases of the disease will reduce the false-negative results. This study was performed to identify the SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) genome in the blood samples of COVID-19 patients.
Methods: This descriptive-analytical study was performed by census method on 100 whole blood samples of patients (50 recovery and 50 deceased) with a definitive diagnosis of COVID-19 (positive Real-Time RT-PCR test of nasopharyngeal swab samples) admitted to Shahid Sayyad Shirazi educational and medical center in Gorgan during 2020-21. Clinical and laboratory findings were compared in the two groups of patients. The viral nucleic acid was extracted from the whole blood samples of the patients, and the presence of the virus genome was investigated using primer and probes via the Real-Time RT-PCR method.
Results: The age of the recovered patients (49.06±15.1 years) was significantly was lower than deceased patients (58.3±12.4 years) (P<0.05). Clinical symptoms including cough, shortness of breath, sputum secretion, and vomiting in deceased patients were significantly more than recovery group (P<0.05). The lymphocytes count and platelet level in the deceased group were lower than in the recovered group. Level of lactate dehydrogenase (LDH) was higher in the deceased group in compare to recovered group (P<0.05). The virus genome identified in the blood samples of 7 patients (3 recovered and 4 deceased), which had no significant relationship with the outcome of the disease.
Conclusion: The use of blood samples for the diagnosis of COVID-19 is not appropriate.