Abstract
Serum Lactate Dehydrogenase (LDH) activity and soluble IL-2 Receptor-alpha (sIL-2R) levels are monitored as a marker of
disease activity in patients with lymphoma. Although adult T-cell leukemia (ATL) cells are well known to release large amounts of
sIL-2R,it remains unclear to what extent B-cell lymphoma cells shed sIL-2R in sera. Subtypes of mature B-cell lymphoma, including
CD25+ hairy leukemic cells, were examined for the characteristics of sIL-2R levels in each subtype. In normal controls, the
serum sIL-2R mean value was 260u/mL.The median serum sIL-2R value for 64 B-cell lymphoma cases was 506 u/mL;by subtype
the median values were as follows: 1157 u/mL for 7 cases of chronic lymphocytic leukemia/hairy cell leukemia (CLL/HCL), 451
u/mL for 38 cases of diffuse large B-cell lymphoma (DLBCL), and 456 u/mL for 19 cases of follicular Lymphoma (FL). The median
values of serum LDH activity by the above subtypes were 175 IU/mL, 204 IU/mL, and 198 IU/mL, respectively. There was
distinct inter-subtype and inter-patient variation of serum sIL-2R.In particular, inter-case variation could be grouped into value for
three concentration ranges: less than 300 u/mL, 300-1000 u/mL, and greater than 1000 u/mL. Cases with serum sIL-2R values
of 1000 u/mL or more tended to have an especially high sIL-2R to LDH ratio, suggesting a close relationship between high sIL-2R
and CD25-expressing lymphoma cells. With respect to sIL-2R and LDH levels, CLL/HCL, DLBCL, and FL showed similar distributions.
Moreover, for sIL-2R levels exceeding 1000u/mL, sIL-2R levels were randomly high according to the LDH status. Conclusively,
the combination of serum sIL-2R level and LDH activity can provide a better understanding of characteristics of subtypes
of mature B-Cell Lymphoma and can be used as a reliable surrogate marker for evaluating numerical and biological data.
