IL-35 and IL-18 Serum Levels in Children With Acute Lymphoblastic Leukemia: The Relationship With Prognostic Factors.

Acute lymphoblastic leukemia (ALL) is the most common type of cancer among children. In this study, we investigated the serum levels of interleukin (IL)-35 and IL-18 in children with ALL to compare with healthy subjects and find their relationship with prognostic factors and response to therapy. IL-35 and IL-18 serum concentrations in 40 children diagnosed with ALL and 35 age-matched and sex-matched healthy children were measured using ELISA. The association between cytokine levels and patients' clinical and laboratory data were determined. A significant difference was found in IL-35 serum levels between the patients (3.6±1.5 ng/mL) and controls (2.5±1.8 ng/mL) (P=0.007). No significant difference in IL-18 serum levels between these groups was observed. A positive correlation between IL-35 and IL-18 levels was detected (P=0.001). The authors found that patients with lower platelet count had higher IL-35 concentration (P=0.003). By considering a cut-off value of 6.21 ng/mL (mean±2SD of controls) for IL-35, it was found that white blood cell (WBC) count was higher in patients with IL-35 >6.21 ng/mL (P=0.016), and the majority of these patients had T-ALL (P=0.01). Although the mean overall survival in patients with IL-35 >6.21 ng/mL was shorter (937±381 d) than in those with IL-35 ≤6.21 ng/mL (1567±103 d), but the result was not significant (P=0.1, log-rank test). The IL-18 level was associated with a lower hemoglobin level (P=0.027). These data suggested a role for IL-35 in ALL development. The significant relation of IL-35 to white blood cells and platelet counts may imply a possible influence of IL-35 on ALL prognosis.