In undernutrition 65% + infection group, PD-1 (P = 0.0231), TCR (P = 0.0075), Bcl-2 (P = 0.0110) and Caspase-3 (P = 0.0475) were all upregulated, and TCR was also upregulated the most. The gene discussed is PDCD1; the disease is infection.