Detection of Serum Interleukin-21 Associated with Chronic Periodontitis

Objective: To examine the level of interleukin-21 (IL-21) in serum of patients with chronic periodontitis in different stages, and to study the relationship between IL-21 and the extent of periodontitis.

Methods: 63 subjects were recruited as generalized periodonititis group (GP, the sites with attach loss/total examined sites was over 30%), and 51 subjects as localized periodonititis group (LP, the value was below 30%), according to the percentage of attachment loss (AL) sites. Bleeding on probe (BOP), Probing Depth (PD), and AL were examined and recorded. The blood serums were sampled and IL-21 levels were detected using ABC-ELISA. Independent-Samples T test and Bivariate Correlation was used for statistic analyzing.

Results: The average serum IL-21 levels were 209.50±95.82 pg/ml in GP group and 167.96±80.82 pg/ml in LP group. The difference was significant between two groups (P<0.05). The serum IL-21 levels were positively correlated with AL sites. This positive relationship became evident when severe attachment loss (SAL) sites and the ratio of AL sites to total sites were to be considered. But no statistically significant differences could be found between serum IL-21 levels and BOP.

Table1   the Serum IL-21 Levels in Generalized Periodontitis and in Localized Periodontitis

Groups	N	Sites	AL Sites/Person	SAL Sites/Person	IL-21(pg/ml)
GP	63	9694	116.54	55.25	209.50±95.82
LP	51	8300	14.45	1.90	167.96±80.82

*t=2.44,P=0.02

Table2   Analysis on the Correlation between Clinical Indices and Serum IL-21 Levels

Clinical Indices	IL-21(pg/ml)
	R	P value
Number of AL Sites	0.229	0.014
Number of SAL Sites	0.234	0.012
AL Sites/Total Sites	0.284	0.002
BOP	0.148	0.276

Conclusion: The serum IL-21 levels were increased in chronic periodontitis patients. It was positively associated with the extent and severity of periodontitis. There was no relationship between serum IL-21 level and inflammation in gingival tissues.