Frequency of CD4^dimCD8⁺ T cells, but not of CD38^high/HLA-DR⁺ CD8⁺ T cells, is significantly associated to the clinical severity score. (A-B) Correlations between clinical severity score and frequencies of CD38^high/HLA-DR⁺ CD8⁺ T cells and CD4^dimCD8⁺ T cells. Correlations were tested using Spearman’s rank order test. The clinical severity score is based on the following 4 variables: death, length of hospitalization, stay in intensive care unit, and dose of glucocorticoids, scored as described in the "Materials and methods" section.