Extended Data Fig. 5: Spatial heterogeneity analysis of cellular composition in hot spots and cold spots during mouse spleen disease progression.

(A) Spatial distribution of hot-spot (red) and cold-spot (blue) islands (connected components) in three representative samples spanning disease progression: healthy (BALBc-1), intermediate stage of disease (MRL-4), and late stage of disease (MRL-8). (B) Hot-spot island characterization. Top: Cell-type composition of individual hot-spot islands. Each row represents a non-contiguous hot-spot island, where colors denote different cell types and bar lengths indicate their counts. Bottom: Bray–Curtis dissimilarity⁸⁵ indices between hot-spot islands, quantifying compositional dissimilarity between islands, ranging from 0 (identical composition) to 1 (completely different composition). (C) Cold spot island characterization, following panel (B) format. Interestingly, hot-spot islands in healthy tissues (BALBc) show similar cellular compositions, reflected by relatively low Bray–Curtis dissimilarity indices. Disease progression correlates with increasing dissimilarity indices among hot-spot islands, indicating greater spatial heterogeneity. This analysis allows us to assess the degree of compositional variation across hot spots and cold spots within each sample, providing insights into systematic changes in tissue organization during disease progression.