The Correlations With 25(OH)D,IL-17 And The Cathelicidin Antimicrobial Peptide LL-37 In Peritoneal Dialysis Patients

Objective:Patients with chronic kidney disease or peritoneal dialysis for end-stage renal disease were showed significant immune dysfunction.51 to 96 percent of patients with peritoneal dialysis may show vitamin D deficiency.There is no literature reported whether there is a relationship in vitamin D deficiency with autoimmune dysfunction in peritoneal dialysis patients.Plasma 25(OH)D level was an important indicator of the state of vitamin D in adults.Interleukin 17 was a characteristic cytokine produced by Th17 cells.It played an important role in host immunization and preventing infection.While excessive IL-17 caused inflammation and autoimmune diseases.The human cathelicidin antimicrobial peptide LL-37 which was expressed in the skin,mucous membranes was the only natural antimicrobial peptide.In the human,the antibacterial peptide LL-37 was the only natural antimicrobial peptide of the first barrier,and it was also the inherent immune active molecules.Analyze the correlations among the 25-hydroxyvitamin D,interleukin-17,the human cathelicidin antimicrobial peptide LL-37,to investigate the impact of 25-hydroxyvitamin D on the immune function of continuous ambulatory peritoneal dialysis who have experienced dialysis both in six months to two years.Methods: Based on the criteria of inclusion and exclusion,Seventy patients who underwent CAPD were selected as the objects of study,excluding autoimmune diseases,malignancies,and combined with active infectious diseases(without new infection in two months),kidney transplant,pregnancy,the last 6 months received the treatment of immunosuppressive agents,stress situation(such as severe infections,severe craniocerebral trauma,surgery,wasting-diseases,gastrointestinal bleeding)and nearly 3 month taking active vitamin D.25-hydroxyvitamin D,IL-17 and LL-37 were detected by enzyme-linked immunosorbent assay(ELISA).Based on the 25(OH)D levels,the objects were divided into normal and deficiency group.Results were expressed as mean ± standard deviation(SD)or the median,quartile pitch for numerical variables,constituent ratio or ratio for categorical variables.The two samples were compared with t-test or Mann-Whitney U.?2 test was used in rate comparison.Pearson or Spearman correlation analysis and multiple stepwise regression analysis were used in the influencing factors,and differences were considered significant at p-value <0.05.Result:1.The levels of 25-hydroxyvitamin D in the serum of the normal group and the deficiency group of vitamin D were 33.32±2.52ng/ml and 17.91± 3.75 ng/ml,respectively.The difference between two groups was statistically significant.The deficient ratio of 25(OH)D was 62.8%.2.The levels of IL-17 in the serum of the normal group and the deficiency group of vitamin D were 263.72±34.67 pg/ml and 241.52± 37.97pg/ml,respectively.The difference between the two groups was statistically significant.LL-37 levels in the normal group and the deficiency group of vitamin D were 2692.84±559.53pg/ml and 1957.67±312.74pg/ml,respectively.The difference between the two groups was statistically significant.3.IL-17 was correlated positively with serum creatinine,parathyroid hormone(PTH)and serum phosphorus.And it was correlated negatively with 25(OH)D,eGFR,triglyceride,prealbumin,serum albumin,corrected calcium.Multivariate linear regression analyses showed that IL-17 was independently associated with 25(OH)D.The human cathelicidin antibacterial peptide LL-37 was correlated positively with 25(OH)D,corrected calcium,triglyceride,total number of lymphocytes,eGFR,prealbumin,BMI.And it was correlated negatively with parathyroid hormone(PTH),serum phosphorus and serum creatinine.Multivariate linear regression analyses shows that LL-37 was independently associated with(25(OH)D)and corrected calcium,but the effect of 25(OH)D on LL-37 was more obvious.Conclusion:1.62.8% of patients with peritoneal dialysis had a deficiency of 25(OH)D.2.Among the deficiency of 25(OH)D in peritoneal dialysis patients,IL-17 increased and LL-37 decreased suggested that 25-hydroxyvitamin D deficience may be one of mechanisms on immune dysfunction in Peritoneal dialysis patients.