Most patients display a decreased HLA-DR expression on monocyte (mHLA-DR) (median of 6,793 [4,789–10,239]) and a marked CD4+ T lymphopenia (median of 275 [188–595] CD4+ cells/μl) compared with normal values (>15,000 AB/C for mHLA-DR; 336–1,126 CD4+ cells/μl). Here, CD4 is linked to lymphopenia.