GCAT and HIV infectious disease: One pathway, hsa00260 (glycine, serine, and threonine metabolism) featured two genes associated with CD4 recovery: CDCH and GCAT. Enrichment of genes in the hsa00260 pathway has been highlighted in several studies of HIV infection.[91, 92] Because we identified HIV-related genes that were associated with CD4 cell recovery pattern, it is possible that ongoing HIV replication at very low levels might have been a contributor to CD4 cellular expansion.