IRF8 and pelvic inflammatory disease: In this review, we explore what is known about dendritic cells and monocytes in PID, highlight the recently described dendritic cell deficiency syndromes related to GATA binding protein 2 (GATA2) and interferon regulatory factor 8 (IRF8) mutations, suggest a practical solution to dendritic cell analysis in clinical practice, and speculate how best to further our understanding of dendritic cells in PID and immunity in general.