Evaluation of the peripheral blood T and B cell subsets and IRF‐7 variants in adult patients with severe influenza virus infection

Abstract

Background and Aims Influenza virus is one of the leading infections causing death among human being. Despite known risks, primary immune deficiency due to Interferon Regulatory Factor‐7 (IRF7) gene defect was reported as a possible cause of the risk factors for complicated influenza. We aimed to investigate the changes in peripheral T and B cell subsets in adult patients with severe seasonal influenza virus infection and the investigation of variants of IRF7 gene. Methods In this study, 32 patients, hospitalized due to influenza infection‐related acute respiratory failure were included. Results The median age of the patients was 76 years (26‐96), and 13/32 (40.6%) were in the intensive care unit. Central memory Th, effector memory Th, TEMRA Th, cytotoxic T lymphocytes (CTL), central memory CTL of the patients were found to be increased, naive CTL were decreased. There was a significant increase in the percentage of effector memory Th, and a decrease in the percentage of naive CTL in patients ≥65 years‐old compared to patients <65 years old (P = .039, and P = .017, respectively). IRF7 gene analysis revealed two different nucleotide changes in three patients; c.535 A > G; p.Lys179Glu (K179E) and c584A > T; p.His195Leu (H195L), located in the fourth exon of the IRF7 gene. Discussion The increases in central and effector memory Th, central memory CTL and decrease of naive CTLs may be secondary to the virus infection. K179E (rs1061502) and H195L (rs139709725) variants were not reported to be related with susceptibility to an infection yet. It is conceivable to investigate for novel variants in other genes related to antiviral immunity.

Acute Respiratory Illness Is Associated with Memory T Cell Differentiation and Other Immune Cell Changes in an Age-Associated Manner

“…This suggests a differentiation toward more effector-like T cell populations with acute infection, which is not unexpected given observations of T cell differentiation in viral infection models ( 17 , 18 ). It also fits with a previous study showing increases in memory T cell subsets and decrease in naive T cells in hospitalized adults with influenza ( 12 ). The reduced frequency of regulatory T cells in young infected individuals could indicate a shift from an anti-inflammatory to an inflammatory response to infection.…”

“…In this regard, previous studies have made observations on certain cell populations in a limited range of individuals. For example, one study showed increases in central and effector memory T cell populations, with a concomitant decrease in naive T cells, in hospitalized adults with acute influenza ( 12 ). Another study showed decreases in total T and NK cell counts in children hospitalized with acute influenza ( 13 ).…”

Shufeng Jiedu capsule alleviates influenza A (H1N1) virus induced acute lung injury by regulating the lung inflammatory microenvironment

“…On the other hand, high level of inflammatory cytokines and excessive infiltration of neutrophils and macrophages [ 24 ] can suppress adaptive immune response, and cause activation-induced cell death (AICD) of lymphocytes, which results in lymphopenia. The exhausted lymphocytes lose their activation, proliferation, differentiation and antiviral ability, and lead to virus evasion [ 28 , 29 ]. Clinical evidences have shown that lymphopenia in peripheral blood is common at the early stage of respiratory virus infection [ [29] , [30] , [31] , [32] ], which often predicts a poor prognosis and even death [ 29 , 33 ].…”

“…The exhausted lymphocytes lose their activation, proliferation, differentiation and antiviral ability, and lead to virus evasion [ 28 , 29 ]. Clinical evidences have shown that lymphopenia in peripheral blood is common at the early stage of respiratory virus infection [ [29] , [30] , [31] , [32] ], which often predicts a poor prognosis and even death [ 29 , 33 ]. Proportion of immune cells infiltrated in lung tissue in our experiments showed that SFJDC reduced the proportion of neutrophils and macrophages, while increasing the proportion of T and B cells.…”