Fig. 1

Increased CD99 expression in immune cells from men. A Sex-specific differentially expressed (pseudo)autosomal genes in spleen samples (n = 87 women and 154 men) from the Genotype-Tissue Expression (GTEx) dataset. B, C Corresponding mRNA expression levels of CD99, SRY and XIST in spleen. D CD99 surface protein expression on subsets of cryoconserved peripheral blood mononuclear cells (PBMCs) from male (n = 30) and female (n = 30) healthy individuals as analyzed by flow cytometry. Cell subsets were identified as following: CD4⁺ and CD8⁺ memory (gated as living CD3⁺-CD4⁺/CD8⁺-CD45RA^– cells) and naïve (gated as living CD3⁺-CD4⁺/CD8⁺-CD45RA⁺ cells) T cells; pDCs (gated as living CD45⁺-Lineage(CD3, CD14, CD19, CD20, CD56)^–-HLA-DR⁺-CD11c^–-CD123⁺-CD304⁺ cells); cDCs (gated as living CD45⁺-Lineage(CD3, CD14, CD19, CD20, CD56)^–-HLA-DR⁺-CD11c⁺ cells); B cells (gated as living CD45⁺- CD19⁺-CD20⁺ cells); NK cells (gated as living CD45⁺- CD19^–-CD20^–-CD3^–-CD14^–-CD56⁺ cells) and monocytes (gated as living CD45⁺- CD19^–-CD20^–-CD3^–-CD14⁺ cells). E Representative flow cytometry plots of CD99 surface expression on immune cells shown in (D). Data are shown as violin plots including median. Statistics: A–C DESeq2 false discovery rate-adjusted P value; D two-way ANOVA with Tukey post-hoc; *P < 0.05; **P < 0.01; ***P < 0.001