Consistent with the premise that IL2 is not related to HLH, the sensitivity of elevated IL2 for HLH was 0.06 (Table 4); although the only patient with an abnormal IL2 (39 pg/mL, normal range <38 pg/mL) had HLH and thus the specificity was 1.0, this would not support IL2 testing as a diagnostic criterion of HLH. This evidence concerns the gene IL2 and hemophagocytic syndrome.