Assessment of changes in immune status linked to COVID-19 convalescent and its clinical severity in patients and uninfected exposed relatives

INTRODUCTION

The immune response during and after SARS-CoV-2 infection can be complex and heterogeneous, and it can be affected by the severity of the disease. It can also contribute to an unfavorable evolution and bring about short and long term effects. The aim of this study was to characterize the lymphocyte composition according to the severity of COVID-19, as well as its degree of relationship to the specific humoral response to SARS-CoV-2 in convalescents up to 106 days after the infection and in their exposed relatives.

METHODS

An applied research was carried out with a cross-section analytical design, from March 11 to June 11, 2020 in Cuba. The sample consisted of 251 convalescents from COVID-19 over 18 years of age and 88 exposed controls who did not become ill. The B and T cell subpopulations, including memory T cells, as well as the relationship with the humoral immune response against SARS-CoV-2, were identified by flow cytometry and enzyme immunoassay.

RESULTS

Convalescent patients, who evolved with severe forms, showed a decrease in frequency and a greater proportion of individuals with values ​​lower than the minimum normal range of B cells, CD3 + CD4 + cells and the CD4 + / CD8 + ratio, as well as a higher frequency and a greater proportion of individuals with values ​​above the normal maximum range of CD3 + CD8 + and NK cells. Convalescent patients with severe forms of COVID-19 that exhibited IgG / RBD titers ≥ 1/200 had a lower frequency of TEMRA CD8 + cells (p = 0.0128) and TEMRA CD4 + (p = 0.0068). IgG / RBD titers were positively correlated with the relative frequency of CD4 + CM T memory cells (r = 0.4352, p = 0.0018).

CONCLUSIONS

The identified alterations of B and T lymphocytes suggest that convalescent patients with the severe disease could be vulnerable to infectious, autoimmune or autotinflammatory processes; therefore, these individuals need medical follow-up after recovering from the acute disease. Furthermore, the role of T cells CD4 + CM in the production of antibodies against SARS-CoV-2 is confirmed, and it is noted that the defect of memory T cells CD8 + TEMRA could contribute to the development of severe forms of COVID-19.

A16974C polymorphism of the IL-12 p40 gene in Cuban patients having recovered from COVID-19

COVID-19 has had severe consequences worldwide. It has been estimated that the contribution of genetic factors to the disease is about 50%. The A16974C polymorphism of the IL-12 p40 gene has been described as being related to resistance or susceptibility to other infectious diseases; therefore, it is likely that it can also be related to COVID-19. The objective of this study was to describe the relationship between the A16974C polymorphism of the IL12 p40 gene with clinical forms of COVID-19 in Cuban patients. The genotypes of the A16974C polymorphism of gene IL-12 p40 were determined through PCR in 102 persons with a COVID-19 epidemiologic discharge from the hospital. In this research, the CC genotype of this polymorphism was found only in symptomatic cases of this disease; since there are signs of relationship between the A16974C polymorphism of the IL12 p40 gene with clinical forms of COVID-19 in the studied Cuban patients, the variations of this polymorphism may be a predisposing risk factor in the development of COVID-19.

TaqI polymorphism of the VDR gene: aspects related to the clinical behavior of COVID-19 in Cuban patients

Purpose

To determine the relationship between the genotypes of the TaqI polymorphism of VDR gene and the clinical forms of COVID-19 in Cuban patients.

Methods

TaqI polymorphism was determined by the PCR in 104 Cuban patients, who suffered different clinical forms of COVID-19.

Results

There was a greater possibility of presenting symptomatic forms [OR = 2.081, 95% CI: 0.243-17.842], even severe [OR = 1.200, 95% CI: 0.217-6.638], related to the tt genotype.

Conclusion

There are signs of association between the risk of developing COVID-19 and the genotypes of the TaqI polymorphism of the VDR gene in the studied Cuban patients.