T-cell large granular lymphocyte proliferation in myelodysplastic syndromes: Clinicopathological features and prognostic significance

• Clonal LGL proliferation in MDS patients is not uncommon.
• The peripheral blood CD3+/CD57+ cell counts were higher in MDS patients with LGL proliferation.
• Bone marrow showed more frequent hypocellularity and lineage hypoplasia in these patients.
• No overall survival difference was noted between patient groups with or without treatment.

Inflammatory and immune dysregulation are crucial in the initiation and development of myelodysplastic syndromes (MDS). It is noted that clonal T-cell large granular lymphocyte (T-LGL) proliferation associated with MDS is not uncommon. However, clinicopathological features, and prognostic and predictive value of presence of T-LGL proliferation in MDS patients is not very clear. This study compared 35 MDS patients with T-LGL proliferation with 36 MDS patients without T-LGL proliferation and summarized clinicopathologic features, including peripheral blood LGL cell counts, immunophenotype, T cell receptor gene rearrangement, bone marrow hematopoietic status, and adjuvant immunosuppressive therapy. The peripheral blood CD3+/CD57+ cell counts were significantly different (p < 0.01) between the two groups. Notably, on examination of the bone marrow, MDS patients with T-LGL proliferation showed more frequent hypocellularity and/or lineage hypoplasia, particularly erythroid hypoplasia. On survival analysis, no overall difference was noted between MDS patients with T-LGL proliferation and those without T-LGL proliferation, and between the patients who received therapy for LGL and those who did not receive adjuvant therapy for LGL in the same risk group. In conclusion, T-LGL proliferation present in MDS patients can be associated with bone marrow hypocellularity and lineage hypoplasia. Although immunosuppressive therapy to eliminate T-LGL cells is potentially beneficial to the MDS patients with associated T-LGL proliferation, there is no overall survival benefit to the patients who received such treatment.