IL17A and myeloid sarcoma: Our research revealed that IL-17A concentration in blood serum was statistically significantly higher for patients with ON in comparison with control group (median, IQR): 18.33 (7.41–37.6) pg/ml versus 8.19 (5.85–11.31) pg/ml, p < 0.001), but IL-17A concentration in blood serum of patients with ON with or without MS was not statistically significantly different (average (SD): 27.76 (24.13) pg/ml versus 31.57 (21.89) pg/ml, respectively; p = 0.641).