The Effect of Periodontitis on Expression of Interleukin-21: A Systematic Review
Table 3
Data summation table.
(a)
Sl. number
Author and journal
Study design
Groups
Parameters
Sample and Methodology
Statistical Analysis
Results
1
Dutzan et al. [29] Journal of Periodontology, 2011 “Levels of Interleukin-21 in Patients with Untreated Chronic Periodontitis”
Case control study
Group 1: controls, Group 2: CP,
PI, PD, CAL, PI, BOP, and presence of IL-21
Gingival and GCF IL-21 (healthy-extraction site, CP- periodontal lesions) were analysed by IHC and Western blot (for presence of IL-21) and quantification was done by ELISA
Unpaired -test and Mann-Whitney test Chi square test
Gingival IL-21 levels were significantly higher in CP group (3.35 pg/mg) than in controls (0.98 pg/mg) () Frequency of GCF IL-21 was greater in CP patients (8/10) than in controls (2/10) () The Western blot and IHC staining confirmed the presence of IL-21 in periodontal tissues and GCF
(b)
Sl. number
Author and journal
Study design
Groups
Parameters
Methodology
Statistical analysis
Results
2
Zhao et al. [30] Journal of Clinical Periodontology, 2011 “Effect of Non-Surgical Periodontal Therapy on the Levels of Th17/Th1/Th2 Cytokines and Their Transcription Factors in Chinese Chronic Periodontitis Patients”
Interventi-onal study
30 participants with CP,
IL-21
GCF (before and after treatment) IL-21 was analysed by ELISA
Linear correlation Paired -test
Downregulation of IL-21 ( versus 31.7741 ± 13.2558 pg/mL) () The quantity of Th17 cells in peripheral blood was decreased especially in IL-17 IFN-γ1 subgroup ()
(c)
Sl. number
Author and journal
Study design
Groups
Parameters
Methodology
Statistical analysis
Results
3
Napimoga et al. [32] Scandinavian Journal of Immunology 2011 “Possible Involvement of IL-21 and IL-10 on Salivary IgA Levels in Chronic Periodontitis Subjects”
Case control study
Group 1: healthy controls, : CP,
IL-21
Gingival IL-21 (healthy-gingivoplasty sites, CP-extraction sites due to advanced periodontitis) using RT-PCR
Student’s -test
The mRNA levels for IL-21 was higher in the CP (1.5-fold) when compared to the healthy group (0.4-fold) ()
(d)
Sl. number
Author and journal
Study design
Groups
Parameters
Methodology
Statistical analysis
Results
4
Dutzan et al. [31] Journal of Periodontology, 2012 “Interleukin-21 Expression and Its Association with Proinflammatory Cytokines in Untreated Chronic Periodontitis subjects”
Case control study
Group 1: controls, Group 2: CP,
IL-21 mRNA level
Gingival IL-21 (healthy-extraction site, CP- periodontal lesions) was analysed using RT-PCR
The RQ expressed as fold change for each studied cytokine Spearman rank correlation test
A significant overexpression of IL-21 in CP affected tissues compared to healthy gingival tissues (120-fold) Significant positive correlations of IL-21 with PD (0.71) () and CAL (0.60) ()
(e)
Sl. number
Author and journal
Study design
Groups
Parameters
Methodology
Statistical analysis
Results
5
Isaza-Guzmán et al., 2015 [33] Journal of Archives of Oral Biology “Association Study between Salivary Levels of Interferon (IFN)-Gamma, Interleukin (IL)-17, IL-21, and IL-22 with Chronic Periodontitis”
Cross-sectional study
Group 1: CP, Group 2: healthy controls,
IL-21 and IL-21R
Salivary IL-21 and levels were analysed using RT-PCR
Pearson’s chi square test
In healthy controls IL-21 (0.00–4.54) than CP (0.00 pg/mL) () Low detection frequency of Th17 cytokines in saliva No significant domination in periodontitis
(f)
Sl. number
Author and journal
Study design
Groups
Parameters
Sample and methodology
Statistical analysis
Results
6
Nizam et al. [28] Journal of Periodontology, 2014 “Salivary Cytokines and the Association between Obstructive Sleep Apnea Syndrome and Periodontal Disease”
Case-control study
Group 1: controls (non- OSAS), Group 2: mild/moderate OSAS, Group 3: severe OSAS,
PI, PD, CAL, BOP, and salivary IL-21
Salivary IL-21 was assessed by ELISA
Spearman rank correlation analysis
Significant correlation was between CAL and IL-21 () () Borderline significance between PI and IL-21 () () IL-21 levels in healthy controls, moderate OSAS, and severe OSAS (90 pg/mL, 85 pg/mL, and 75 pg/mL)
