A high sIL-2R/ferritin ratio is a useful marker for the diagnosis of lymphoma-associated hemophagocytic syndrome

Takahiro Tsuji, Taichi Hirano, Hiroshi Yamasaki, Mayumi Tsuji, Hiroyuki Tsuda

Lymphoma-associated hemophagocytic syndrome (LAHS), which is the major subtype of adult-onset secondary hemophagocytic lymphohistiocytosis (HLH), has a poor outcome. Although the early diagnosis and treatment of LAHS contributes to a better outcome, the lack of mass formation and the absence of distinct lymph node enlargement often delay the diagnosis of underlying lymphoma. A recent study, which statistically analyzed HLH cases in the literature, showed that the serum soluble interleukin-2 receptor (sIL-2R)/ferritin ratio could be used as a marker to diagnosis of LAHS. To verify this finding, we retrospectively analyzed the laboratory findings of 21 patients with HLH (10 benign disease-associated HLH and 11 LAHS). No significant differences were observed in the levels of LDH or CRP levels. The mean sIL-2R levels (units per milliliter) were significantly higher in the LAHS group (4,176 vs. 13,451, p = 0.0031), and ferritin levels (nanogram per milliliter) were higher in the benign disease-associated HLH group (20,462 vs. 2,561, p = 0.0031). Consequently, the mean serum sIL-2R/ferritin ratio of patients with LAHS was markedly higher than that of patients with benign disease-associated HLH (0.66 vs. 8.56, p = 0.0004). Thus, the results of this study demonstrated that the serum sIL-2R/ferritin ratio is a very useful marker for diagnosing of LAHS, which was further supported by clinical case analysis. Further studies to clarify the pathophysiology of secondary HLH caused by various triggers are needed.