Objective: To explore the proportion of Th22 cells in peripheral blood of patients with aplastic anemia (AA) and evaluate its significance.
Methods: From January 2011 to June 2012, a total of 47 AA patients were recruited and divided into 4 groups: severe aplastic anemia (SAA) pre-therapy (group A, n = 11), non-severe aplastic anemia (NSAA) pre-therapy (group B, n = 12), SAA post-therapy (group C, n = 12), NSAA post-therapy (group D, n = 12) and healthy donor controls (n = 12). The proportion of Th22 cells in peripheral blood of each group was evaluated by flow cytometry. The cytokines interleukin-22 (IL-22), transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured by ELISA. And the level of IL-22 mRNA was examined by reverse transcription-PCR (RT-PCR).
Results: The percentage of Th22 cells and the level of IL-22, TNF-α, IL-6 and IL-22 mRNA in group A (4.3% ± 1.4%, (57 ± 17) ng/L, (497 ± 123) ng/L, (323 ± 88) ng/L, 1.65 ± 0.51) and group C (2.6% ± 0.6%, (34 ± 10) ng/L, (314 ± 79) ng/L, (187 ± 45) ng/L, 0.92 ± 0.28) were significantly higher than that in control group (1.2% ± 0.3%, (19 ± 6) ng/L, (228 ± 50) ng/L, (134 ± 26) ng/L, 0.47 ± 0.09,all P < 0.05). The percentage of Th22 cells and the level of IL-22, TNF-α , IL-6 and IL-22 mRNA in group A were higher than those in group C (all P < 0.05). NSAA patients had similar results. The percentage of Th22 cells and the level of IL-22, TNF-α , IL-6 and IL-22 mRNA in group A were higher than those in group B (all P < 0.05). But the level of TGF-β in groups A and C were significantly lower than that in control group ((3.4 ± 1.1) and (5.8 ± 1.7) vs (9.7 ± 2.8) ng/L, P < 0.05). And the level of TGF-β in group A was lower than that of group B (P < 0.05).
Conclusions: The number of Th22 cells is elevated in AA patients. Th22 cells may be positively correlated with the development of AA. And a higher level of TNF-α, IL-6 and a lower level of TGF-β promote the differentiation of Th22 cells.