BACKGROUND AND OBJECTIVES: DNA variations in the NF-kappa-B essential modulator ( METHODS: Single-cell RNA (ribonucleic acid) sequencing (scRNAseq), using the HIVE single-cell system, was performed on a neonate with IP, before and after steroid treatment, compared with a sex-matched healthy control toddler. RESULTS: A total of 20,411 cells were sequenced and clustered into 10 cell types. In IP compared with control, upregulated significant gene set enrichment analysis gene ontology pathways (FDR <
0.05) included defense response, complement activation, humoral immune response, and phagocytosis across all cell types. After steroid treatment, these pathways were predominantly downregulated in monocytes and neutrophils. The upregulated genes in IP that became downregulated after steroid treatment were interferon-related genes, oligoadenylate synthases, and immunoglobulin genes. DISCUSSION: IP-associated loss of