The expression of CLEC4D was associated with the up-regulated pathway of African trypanosomiasis, Legionellosis, Leishmaniasis, Malaria, Neutrophil extracellular trap formation, PPAR signaling pathway, Staphylococcus aureus infection, Systemic lupus erythematosus, TNF signaling pathway, and Toll-like receptor signaling pathway. The gene discussed is PPARA; the disease is legionellosis.