Integrated Reanalysis of Childhood Infectious Diarrhea Whole-Blood Transcriptomes Defines Robust Pathway-Level Remodeling and Limited Regulatory Concordance

Background: Whole-blood transcriptomics captures systemic responses to infectious diarrhea, but pooled public-dataset reanalysis can be confounded by leukocyte composition and does not by itself establish cell-intrinsic regulation. Methods: We performed a profile-level secondary analysis of GSE69529 (255 profiles from 246 children; 203 diarrhea and 52 control profiles, including nine repeated profiles) using differential expression, functional enrichment, exploratory network analysis, promoter-sequence analysis, motif discovery, and transcription-factor activity inference. Because the pooled GEO2R contrast did not adjust for leukocyte composition, age, sex, pathogen, or repeated-subject structure, differentially expressed genes were interpreted as a composite whole-blood response. Published results from GSE276395 were used only for cross-study concordance, not as an independently reanalyzed validation dataset. Results: The pooled analysis identified 7,050 genes at adjusted P < 0.05 among 15,740 analyzed genes and highlighted broad immune, RNA-processing, cell-cycle, intracellular-organization, apoptosis, trafficking, and metabolic programs. Promoter composition was similar between regulatory directions; no HOCOMOCO motif was supported by AME, no STREME motif met the prespecified E-value threshold, and no CollecTRI-ULM transcription factor remained significant after false-discovery-rate correction. GSE276395 showed concordant innate-immune, neutrophil-centered, and immunometabolic themes, whereas its recurrent 12-gene set did not overlap the 12-gene discovery-stage panel. Conclusions: The reproducible signal is broad pathway-level whole-blood remodeling. Gene-, motif-, and regulator-level findings are exploratory, and the present design cannot distinguish shifts in leukocyte composition from within-cell transcriptional regulation.