Objective To explore the changes in serum energy metabolites in patients with peripheral T-cell lymphoma,and investigate serum biomarkers for monitoring peripheral T-cell lymphoma from the perspective of energy metabolism.Methods Multiple/selected reaction monitoring(MRM/SRM)was used to detect the energy-related metabolites in the sera of 16 patients with newly diagnosed peripheral T-cell lymphoma admitted in the Hematology Medical Center of the Second Affiliated Hospital of Army Medical University from November 2020 to December 2021,as well as 10 recruited healthy volunteers.The corresponding clinical data including medical history,laboratory results and image data were collected and retrospectively analyzed.Results Significant differences were seen in the contents and expression profiles of serum energy metabolism-related products between the patients and the healthy volunteers.The patients had significantly reduced serum contents of cyclic AMP,succinate,citrate and cis-aconitate(P＜0.05),and elevated D-glucose 6-phosphate content(P＜0.05).The serum contents of citrate and succinate were negatively correlated with the risk stratification(low-,moderate-and high-risk)and clinical stage of the disease(P＜0.05).Meanwhile,there was a negative correlation between the contents of L-malic acid and citrate and the mid-term efficacy evaluation results,such as complete/partial response(CR/PR)or stable disease(SD)(P＜0.05).For patients with extranodal NK/T cell lymphoma(n=10),there were also significant reductions in the contents of cyclic AMP,succinate,citrate,isocitrate and cis-aconitate in the sera of patients compared with healthy volunteers(P＜0.05),and the contents of citrate and succinate were negatively correlated with the clinical stage(P＜0.05)and were rather correlated with mid-term efficacy evaluation results(CR/PR or SD)(P＜0.05).For patients with angioimmunoblastic T-cell lymphoma(n=6),the serum contents of cyclic AMP,citrate and succinate were significantly lower,while the content of D-glucose 6-phosphate was higher when compared with the healthy volunteers(P＜0.05),and the content of succinate was negatively correlated with both clinical stage and risk grade of the patients(P＜0.05).Conclusion There are 5 serum differential metabolites identified between patients with peripheral T-cell lymphoma and healthy controls,and succinate and citrate are expected to be serum biomarkers of peripheral T-cell lymphoma.