[Association between serum interleukin-17 level and abnormal cellular immunological status in patients with severe...

To explore the role of interleukin-17 (IL-17) in the pathogenesis of severe aplastic anemia (SAA).

Peripheral blood samples were obtained from 40 SAA patients (25 untreated, 15 recovery) and 10 normal controls from October 2012 to October 2013. The level of IL-17 in peripheral blood was measured with cytometric bead array (CBA). The correlations between IL-17 and T cells subset (CD4(+)/CD8(+)), dendritic cells (DC) subset (mDC/pDC), regulatory T cells (Treg) and hemogram were analyzed.

The serum level of IL-17 in untreated patients was higher than that in recovery patients and normal controls ((17.07 ± 15.18) vs (7.09 ± 3.84) and (3.53 ± 2.08) ng/L, both P < 0.01). Also significant differences existed between the latter two groups (P < 0.05). The ratio of CD4(+)/CD8(+) was (0.32 ± 0.08) in untreated patients and it was lower than that in recovery patients (1.11 ± 0.31, P < 0.01) and normal controls (1.07 ± 0.26, P < 0.01). The ratio of mDC/pDC was (3.16 ± 0.55) in untreated patients was higher than that in recovery patients (1.60 ± 0.43, P < 0.01)and normal controls (1.43 ± 0.38, P < 0.01). The percentage of Tregs in peripheral blood lymphocyte (CD4(+)CD25(+)CD127(dim)/PBL) was 0.80% ± 0.31% in untreated patients and it was lower than that in recovery patients (1.78% ± 0.69%, P < 0.01) and normal controls (2.23% ± 0.66%, P < 0.01). The serum level of IL-17 in untreated SAA patients was related positively with mDC/pDC ratio (r = 0.414, P < 0.05) and negatively with CD4(+)/CD8(+) ratio (r = -0.421, P < 0.05) and CD4(+)CD25(+)CD127(dim)/PBL(r = -0.650, P < 0.01). And significant negative correlations existed between serum IL-17 and white blood cells in untreated patients (r = -0.689, P < 0.01) and recovery patients (r = -0.640, P < 0.05).

The elevated serum level of IL-17 in SAA is related with the immunological status and disease severity.