Fig. 4

(A) Volcano plot of differentially expressed proteins in skin biopsy specimens before and after kidney transplantation. Each dot represents an individual protein. The x-axis shows the log₂ fold change (log₂FC) of protein expression after transplantation compared to before transplantation, and the y-axis indicates the –log₁₀ adjusted p-value (FDR-corrected). Proteins significantly upregulated post-transplantation (log₂FC > 1, p < 0.05) are marked in red, while those significantly downregulated (log₂FC < − 1, p < 0.05) are marked in green. Selected proteins of interest, including KRT7, KRT19, and PTGDS, are annotated. (B) Hierarchical clustering heatmap of differentially expressed proteins in paired skin biopsy samples pre- and post-kidney transplantation. Each column represents a tissue sample, and each row corresponds to a differentially expressed protein. The color scale ranges from green (low expression) to red (high expression), indicating relative protein expression levels. Samples were collected at two time points: before transplantation (Pre) and one month after transplantation (Post). The clustering pattern illustrates distinct global proteomic profiles between Pre and Post samples, suggesting transplantation-induced molecular changes in the skin. (C) Heatmap of selected differentially expressed proteins (DEPs) pre- and post-transplantation. The heatmap shows the expression patterns of representative DEPs across paired skin samples collected before and after kidney transplantation. Rows represent proteins, and columns represent individual patient samples. Red and blue colors indicate upregulation and downregulation, respectively, relative to the mean expression. The color intensity reflects the magnitude of differential expression (log2 scale).