Chidamide-maintained long-term clinical remission with persistent T-Cell clone in refractory T-LGL leukemia-associated pure red cell aplasia: A six-year follow-up.

Secondary pure red cell aplasia (PRCA) is one of the most common cytopenic complications in T-cell large granular lymphocyte (T-LGL) leukemia and requires therapeutic intervention. Refractory T-LGL-associated PRCA lacks a unified salvage regimen, and effective targeted agents remain scarce. In recent years, epigenetic modifications have been implicated in the pathogenesis of T-LGL leukemia, yet relevant clinical evidence is limited. We report a case of refractory T-LGL leukemia complicated by PRCA that was resistant to cyclosporine (CsA). Then the patient achieved rapid disease control with chidamide plus thalidomide in the early phase, and has maintained long-term remission for six years on chidamide monotherapy after thalidomide discontinuation. Notably, clonal T-cell receptor (TCR) variable β-chain (Vβ) 3 persisted on flow cytometry throughout the treatment course. As an epigenetic modulator, chidamide represents a more convenient and promising therapeutic strategy for managing T-LGL leukemia, prompting us to present this case.