Data Sheet 1_Single-cell landscape of lymphoid and myeloid heterogeneity across type-stratified craniofacial lesions in polyostotic fibrous dysplasia.pdf

Ligand–receptor interactions were inferred using CellChat.</p>Results<p>Four major lineages were resolved: mesenchyme, lymphoid, myeloid, endovascular. Lymphoid representation differed across subtypes (Type I 1.00%, Type II 5.10%, Type III 10.90%), whereas endovascular fractions showed an inverse pattern (Type I 25.10%, Type II 9.90%, Type III 4.50%). Sub-clustering identified five lymphoid and six myeloid subsets.

CD4⁺ T cells were most abundant in Type I (51.10%) but less represented in Type II (36.50%) and Type III (29.30%). CD8⁺ T cells constituted 2.10%, 11.90%, and 11.20% across Types I-III, respectively; germinal-center (GC) B cells were undetectable in Type I, minor in Type II (~1.60%), and prominent in Type III (~29.20%). Among myeloid cells, M1 macrophages comprised 9.90% in Type I, 25.70% in Type II, and 15.30% in Type III; osteoclasts were abundant in Type I (35.40%) but scarce in Types II and III (<5%).

Dendritic cells (DCs) were absent in Type I yet detectable in Type II (1.90%) and Type III (2.60%). Network-central genes included LTB, TXNIP, FTH1, and PABPC1 for CD4⁺ and GC B cells, and S100A8/9, CXCL8, CCL2/3/4, and IL1B for M1 macrophages and monocytes. Inter-cellular communication networks differed markedly by subtype: Type I and II displayed relatively simple interactomes, whereas Type III exhibited densely interconnected signaling with strengthened M2 macrophage-monocyte, M2 macrophage-GC B cell (CXCL12-CXCR4, APP-CD74), and GC B cell-monocyte axes, alongside attenuated CD4⁺ T cell-GC B cell (CLEC2D-KLRB1, ADGRE5-CD55) and M1 macrophage-CD4⁺ T cell crosstalk.

Pathway enrichment revealed subtype-specific activation of oxidative phosphorylation, NF-κB, and antigen-presentation cascades across lymphoid and myeloid compartments.</p>Conclusions<p>This study provides the first single-cell immune atlas of POFD, delineating lymphoid and myeloid heterogeneity across three histological subtypes. The identified subtype-specific markers and inter-cellular communication architectures offer candidate biomarkers for diagnostic stratification and reveal potential immunomodulatory targets for this disfiguring bone disorder.</p>