Due to its advantageous effect as a T cell amplifier, exogenous IL-7 therapy has been extensively utilized in clinical trials to overcome TLP caused by viral infection (HIV, COVID-19, progressive multifocal leukoencephalopathy), idiopathic CD4 lymphocytopenia, and sepsis (NCT0047732, NCT02797431, NCT00839436, NCT03821038) (37–44). This evidence concerns the gene IL7 and lymphopenia.