Post Kala Azar Dermal Leishmaniasis (PKDL) genome wide transcriptional profiling by bulk RNA-sequencing

Post-kala-azar dermal leishmaniasis (PKDL), a dermal sequel of visceral leishmaniasis (VL), is considered an important reservoir that facilitates the transmission of VL. Although PKDL lesions demonstrate an overwhelming infiltration of CD8⁺ T cells, the molecular mechanisms regulating their recruitment to the skin remain poorly defined. To address this, bulk RNA sequencing was performed on dermal lesions from patients withPKDL and healthy controls to characterize the lesional chemokine and cytokine landscape associated with T-cell homing.Transcriptomic analysis revealed a significant upregulation of genes encoding T-cell chemoattractants, including CCL3, CCL4, CCL5, CCL17, CXCL9, and CXCL10, in PKDL lesions compared to healthy skin. In addition, sequencing data demonstrated increased expression of inflammatory cytokine transcripts such as IFN-γ, IL-5, IL-15, and TNF-α, indicating an activated inflammatory milieu. The transcriptomic profile further showed elevated expression of genes associated with chemokine receptor pathways, particularly CCR4, CCR5, and CXCR3, suggesting enhanced signaling pathways that promote CD8+ T cell migration from circulation and retention within lesional skin. Collectively, the RNA sequencing data highlights a chemokine-driven CD8+T cell recruitment and contributes to characterise the molecular markers related to the homing of lesional CD8+ T cells.