The anti-asparagines antibodies correlate with L-asparagines activity and may affect clinical outcome of childhood acute lymphoblastic leukemia

The primary aim of the study was to evaluate the importance of anti-asparaginase antibodies for L-asparaginase activity in children with standard and medium risk acute lymphoblastic leukemia ( ALL). Forty-seven children with newly diagnosed ALL were included into the prospective study. Enzyme activity and the presence of anti-asparaginase antibodies ( IgG and IgM class) were determined. Anti-asparaginase antibodies were identified in 13/47 ( IgM class) and 10/ 47 ( IgG class) patients in the induction and in 19/47 ( IgM class) and 20/47 ( IgG class) patients in the reinduction phase of treatment. The enzyme activity was lower in patients that were positive for anti-asparaginase antibodies, especially in reinduction phase ( median 37 ( 20-180) vs 355 ( 141-499), p = 0.001). An association between anti-asparaginase antibodies and the allergic reaction to the drug was found. Besides, the children who developed anti-asparaginase antibodies in the induction phase of treatment showed lower event-free survival as well as overall survival in comparison with children without antibodies. Since our study was carried out in a small number of patients, this observation is only speculative and needs to be confirmed by a further study on a larger sample size, with multivariable analysis. However, our data suggest that L-asparaginase activity together with anti-asparaginase antibodies measurements may become useful for effective therapy of ALL.