The RVd therapy, combining lenalidomide, bortezomib, and dexamethasone, is a mainstay treatment for multiple myeloma. A multiple myeloma patient developed pure red cell aplasia (PRCA) following RVd treatment, despite the absence of common PRCA triggers. In vitro analyses revealed lenalidomide as a pivotal disruptor of erythropoiesis. Single-cell transcriptome analysis unveiled hyperactive CD8+ T cells and impaired erythropoiesis in the patient's bone marrow. Unexpectedly, the patient's erythroid cells displayed abnormally high expression of genes in the antigen presentation pathway, particularly those for major histocompatibility class I (MHC-I) molecules. Functional assays demonstrated that lenalidomide treatment further augmented MHC-I expression in the patient's erythroid cells. Blocking MHC-I or depleting T cells alleviate the defective erythropoiesis of PRCA, suggesting that the interaction between erythroid cells with elevated MHC-I and T cells in the bone marrow might contribute to PRCA. Taken together, our study revealed a novel mechanism underlying lenalidomide-induced PRCA in treating cancer patients.