In addition, the CD4+ T cell lymphopenia observed during the acute phase of scrub typhus may lead to a defect in generating long-lived functional memory CD8+ T cells, i.e. the helpless CD8+ T cell responses, because CD4+ T-cell help is critical for generating functionally-competent memory CD8+ T-cells, [43], [44]. The gene discussed is CD4; the disease is lymphopenia.