Abstract: Objective  To explore the diagnostic value of pentraxin3 (PTX3) in peritoneal dialysis-related peritonitis (PDRP).   Methods  A total of 31 patients with PDRP and 58 patients without PDRP on normal peritoneal dialysis and hospitalized in the Nephrology Department, The Fifth Hospital of Sun Yat-sen University from January 2020 to June 2021 were recruited as the study subjects. Peritoneal effluent (PE) of the study subjects was collected and PTX3 in PE (pPTX3) was assayed in batches by enzyme-linked immunosorbent assay. The clinical data and pPTX3 of the study subjects were statistically analyzed.  Results  The expression level of pPTX3 in the PDRP group was significantly higher than that in the non-PDRP group (Z=-7.314, P＜0.001). Compared with blood contents of white blood cells, procalcitonin, lymphocyte to monocyte ratio and hypersensitive C-reactive protein, pPTX3 is more effective for the diagnosis of PDRP (area under the cure =0.972, 95% CI: 0.913～0.995, P<0.0001). There was no significant difference in pPTX3 and leukocytes in PE (AUC=0.991,95% CI: 0.943～1.000, P＜0.0001) for the diagnosis of PDRP (Z=1.161, P=0.246). Pathogens in PE were positive in 24 of the 31 patients with PDRP, of which 15 patients were Gram-positive bacterial infections and 9 patients were Gram-negative bacterial infections. pPTX3 was significantly higher in the patients with Gram-negative bacterial infections than in those with Gram-positive bacterial infections (Z=            -2.684, P=0.005). PE was collected at the 1st, 3rd, 5th, 9th and 13th day of treatment in 18 of the 31 patients with PDRP; in the 14 patients whose PDRP were cured, the pPTX3-treatment time curve gradually went downward and infinitely approached the X axis at the 11th day; in the 4 patients whose PDRP could not be cured, the pPTX3-treatment time curve gradually went downward from the 1st day to the 5th day then remained at this level after the 5th day.   Conclusions  pPTX3 is an effective biomarker for the diagnosis of PDRP, and may also be useful for the differentiation of Gram-negative bacterial infection from Gram-positive bacterial infection and for the evaluation of therapeutic efficacy and prognosis of PDRP.

Key words: Pentraxin3, Inflammatory marker, Peritoneal dialysis-associated peritonitis