Iranian Journal of Medical Microbiology

Subjects and Methods

Our study population comprises 200 individuals from the Shohadaye Ashayer Hospital of Khorramabad, Iran, between 20 March 2021 and 20 June 2021 who underwent laboratory tests and CT scans for COVID-19 diagnostic purposes. Ultimately, 100 individuals owning negative COVID-19 tests (control group) and 100 confirmed COVID-19 inpatients (case group) were chosen randomly and compared concerning the hematological profile. The risk factors of smoking, drug use, chronic blood and lung diseases, and asthma were investigated in two groups, which none of the people had a history of them.
After receiving the informed consent from all participants (Ethic code: IR.LUMS.REC.1399.332), we collected 5 mL venous blood for EDTA-containing tubes and 5 mL without EDTA. Then, blood samples containing EDTA were utilized for the ESR test by the Westergren method and blood cell count by a Sysmex cell counter. The serum isolated from the EDTA-free blood sample was employed to measure the BS by blood sugar test kit (Man Company, Iran) and the AutoAnalyzer. 
The COVID-19 positive cases were diagnosed using qRT-PCR method (Sansure Nucleic Acid Diagnostic Kit).

Statistical Analysis

The collected data were analyzed using SPSS 26 (SPSS Inc., Chicago, Ill., USA) and the descriptive data are presented for nominal and quantitative data. The Chi-squared and Fisher’s exact tests were used to analyze the nominal data. All the quantitative data was primarily analyzed for the normal distribution using the Kolmogorov-Smirnov normality test. The independent t-test was used for quantitative data with normal distribution, and P values under 0.05 were considered statistically significant.
 

According to previous studies, clinical manifestations of COVID-19 patients mainly comprise fever, dry cough, and fatigue (20-22). During the current study, we have recorded these clinical manifestations frequently in the patients affected by SARS-CoV-2. Moreover, other clinical presentations, such as diminished levels of consciousness, headache, dizziness, abdominal pain, diarrhea, anosmia, dysgeusia, convulsions, limb paralysis, dermal lesion, nausea, vomiting, and anorexia, have been analyzed in both the control and COVID-19 affected patients. Our results indicated no significant correlation between the clinical manifestations of these two groups. Although, by worsening the disease, some of these clinical manifestations, including diminished levels of consciousness, headache, dizziness, abdominal pain, and diarrhea, have been experienced in some patients. The severity of these manifestations indicates a correlation with the severity of the disease. In this study, we observed that the dominant strains of virus are alpha (B.1.1.7) variants. Also, we conducted a study and compared the laboratory findings and clinical manifestations of patients affected by the SARS-CoV-2 and healthy participants.
A slight WBC decline was observed in the case group, but it led to no significant correlation. However, augmenting the severity of the disease led to a further drop in the WBC level. In respect of this drop, encountering some viruses, including SARS-CoV, MERS-CoV, and SARS-CoV-2, can result in lymphopenia due to the active roles of lymphocytes against the viruses (23-25). The results acquired from the autopsy of the patients afflicted by the SARS-CoV-2 illustrated the necrosis of lymphatic tissues (including spleen and lymph nodes) and diminished bone marrow hematopoiesis levels (26). We found that patients with less WBC decline own a greater chance of recovery. Previous studies have elucidated that deceased patients have experienced more significant lymphopenia than surviving ones (20), and the ratio of lymphocyte/WBCs of patients afflicted by severe COVID-19 demonstrates a decline compared to recovered patients (27, 28). Also, the increase of lymphocytes has been reported seven days after the outset of symptoms in recovered individuals, contrary to deceased ones (29). Therefore, constant monitoring of lymphocyte counts may play a substantial role as an influential prognostic factor for the disease outcomes. A model based on lymphocyte counts has been proposed by Tan et al. whereby patients owning less than 20% and 5% lymphocyte during 10-12 days and 17-19 days of symptoms outset, respectively, demonstrate the worst prognosis (30).
According to the study conducted by Guan et al. concerning the clinical presentations of 1099 COVID-19 patients, approximately 83% of patients were diagnosed with lymphocytopenia, 36.2% with thrombocytopenia, and 33.7% with leukopenia. These percentages reach 96.1%, 57.7%, and 61.1%, respectively in patients experiencing severe clinical presentations (21).
It has been revealed that the risk of ARDS is directly correlated with increased and diminished counts of neutrophils and lymphocytes, respectively, and expanding the number of neutrophils is associated with an increased mortality rate (9). In the current study, despite no significant correlation between neutrophil and lymphocyte percentage in the patients experiencing ARDS compared to those without ARDS, the lower median of lymphocytes in ARDS-affected individuals (20.44) compared with individuals without this clinical manifestation (23.87) was recorded. Furthermore, the median of neutrophils was increased in ARDS-affected individuals (70.81) compared to those suffering from no ARDS (63.28). We have recorded no significant correlation between respiratory distress and platelet. However, the median was lower in patients suffering from respiratory distress (184.85 vs. 209.02). Therefore, the current study confirms that the levels of disease severity correlate with diminished levels of platelet and lymphocyte and the expanded number of neutrophils. In our study, ARDS was significantly correlated with BS levels in COVID-19 patients. Other studies confirm lymphocytopenia and mild thrombocytopenia in 69 and 20% of COVID-19 patients, respectively (31, 32).
Fan et al. have discovered that lymphocyte count was dramatically diminished in patients requiring intensive care unit (ICU) support at baseline (31). In another study comprising 52 patients suffering from severe COVID-19 in Wuhan, lymphopenia was reported in 85% of patients (33). During the current study, patients requiring intubation and ICU admission experienced declined levels of lymphocyte. However, there was not a significant correlation in comparison with patients who did not need intubation. The mean lymphocyte level was 9.00 and 22.46 in intubated and non-intubated individuals, respectively. Also, there was no significant correlation between the neutrophil level and intubation. We have found a significant correlation between intubation and the levels of RBC, BS, Hb, and HCT; except BS, which faced a significant increase, other mentioned hematological parameters have declined in individuals who underwent intubation.
In the current study, a significant correlation was detected between the presence of diabetes in COVID-19 patients and the levels of ESR, BS, Hb, neutrophil, and HCT. Diabetes can elevate the risk of infection and mortality in acute infections. Previous studies have revealed that the possibility of developing severe COVID-19 in diabetic patients ranges between 14 and 32% (9, 20, 21, 34-37). A study of 138 COVID-19 patients conducted by Wang et al. has illustrated that 72% of diabetic patients required ICU admission (20). During the current study, diabetic patients experienced a severe type of disease and required ICU admission. 
The expression of ACE2 on the cells of pancreatic islets attracts the SARS-CoV-1 virus and raises the BS in nondiabetic individuals (38). Thus SARS-CoV-2 may also infect these cells since it has similar receptors as SARS-CoV-1 and drives to the disruption and increase of BS regulation.

 

The infection by COVID-19 would be followed by diverse clinical manifestations, including fever, cough, fatigue, muscle aches, diarrhea, vomiting, and others. However, these clinical manifestations will not be detected in all patients. Profound changes in hematological parameters are detectable, which would be augmented by COVID-19 progress. Drastic decreases of hematological parameters such as lymphocyte, RBC, WBC, platelet, Hb, and HCT elevate the mortality rate substantially. In contrast, the increased levels of neutrophil and BS are associated with the severity of the disease. Diabetes, the required intubation, and respiratory manifestations such as ARDS are correlated with vast alterations of some hematological parameters. Assessing of underlying medical conditions, clinical manifestations, and hematological parameters can significantly select the right and sufficient therapeutic directions at the disease’s outset. During their treatment, they can also enhance the current therapeutic methods and be employed as a valuable prognostic factor of patient condition.

 

We would like to thank the Hepatitis Research Center of the Lorestan University of Medical Sciences, Lorestan, Iran, and the staff of the Shohada Ashayer Hospital, who helped us conduct this study.

 

This study was accepted by the ethical committee of the Lorestan University of Medical Sciences, and written informed consent was obtained from all subjects (Ethic code: IR.LUMS.REC.1399.332).
 

 Conception and design: Mehdi Ajorloo; data collection: Seyed Majid Fatahi, Annahita Ghalandarian; statistical analyses: Rasool Mohammadi, Sayyad Khanizadeh; writing of manuscript: Seyed Majid Fatahi, Ali Safarzadeh, Ashkan Alamdary, Hadi Razavi Nikoo; revising the article for important intellectual content; and final approval: all authors
 

Financial resources for the design of the present study and writing the manuscript are provided by Lorestan University of Medical Sciences.
 

Conflicts of Interest

The authors declare that they have no competing interests.