Immune Response to SARS-CoV-2 Infections in Children with Secondary Immunodeficiencies

Abstract

Background and Purpose It is a matter of research, whether children with immunodeficiencies are able to generate an effective immune response to prevent SARS-CoV-2 reinfection. This study aimed to evaluate and compare the seroconversion rates and changes of lymphocyte subsets during COVID-19 in immunocompetent children and those with secondary immunodeficiencies. Methods In 55 children — 28 immunocompromised and 27 immunocompetent — hospitalized with confirmed SARS-CoV-2 infection, the level of IgG antibodies against the Spike protein was determined on two to three occasions. In those children from the study group whose immunosuppressive treatment did not alter during the study (n = 13) and in selected children from the control group (n = 11), flow cytometric evaluation of lymphocyte subsets was performed twice — 2 weeks and 3 months post-infection. Results Seroconversion reached 96.3% in both studied groups; however, the immunocompromised cohort achieved lower titers of detectable anti-S antibodies. There was no correlation between seroconversion or titers of antibodies and the total number of lymphocytes or their subsets. In the immunocompetent cohort, we reported a significant decrease in NK cells during the infection. In this group and the entire study population, a positive correlation was noticed between the CD4 + /CD8 + T cell ratio and the severity of COVID-19 pneumonia. Conclusions Children with secondary immunodeficiencies seroconvert in equal percentages but with a significantly lower titer of anti-S antibodies compared to their immunocompetent peers. The lower number of NK cells in the immunocompetent cohort may result from their participation in antiviral immunity, whereas reduced CD4 + /CD8 + T cell ratios among immunocompromised children may be a protective factor against a severe COVID-19.

Immunophenotype of lymphocytes and real-world outcome of COVID-19 infection in children with hematology and oncology

“…However, Mahmoudi S et al found that lymphocytopenia rarely occurred in general children with mild infection of SARS-CoV-2, while lymphopenia mostly appeared in severe disease [ 11 ]. Kuczborska K et al found children have no tendency to lymphopenia, regardless of the severity of COVID-19 [ 12 ].…”

“…The values of specific lymphocyte subsets are controversial. Several researches present higher ratio of CD4+/CD8 + T cell with more severity and greater lung involvement in both general [ 20 ] and immunocompromised children [ 12 ], suggesting decreased CD4+/CD8 + T cell ratios in children with immunocompromise may be a protective factor for the prevention for severe COVID-19. However, opposite opinions have reported higher CD8 + T cell level [ 21 ] and lower CD4+/CD8 + T cell ratio [ 11 , 21 ] have been seen in children with pneumonia.…”

“…Another concern was the high rate for delays in chemotherapy that accompanied COVID-19. In the early pandemic phase, cancer-directed therapy was usually postponed with presuming a risk for severe COVID-19 due to their immunocompromise [ 12 ]. For most reports, the children with malignant diseases mostly showed non-severe clinical courses of COVID-19 infection.…”

“…Recent studies suggest that T lymphocytes play a significant role in the pathological process of COVID-19, particularly in CD4 + T and CD8 + T cells [ 11 , 12 ]. Additionally, Natural killer (NK) cells are an original protection against viruses [ 13 ].…”

Response to SARS-CoV-2 initial series and additional dose vaccine in pediatric patients with predominantly antibody deficiency

“…Healthy children are less likely to have severe COVID-19 compared to adults (4,5). Multiple studies have demonstrated worse COVID-19 infection outcomes and more severe disease in children who had received immunosuppressant medication or had an immunocompromising condition such as cancer compared to healthy children (6)(7)(8).…”