Outcomes of stem cell mobilization and engraftment in patients with multiple myeloma according to CD56 expression status.

BACKGROUND: The molecular mechanism underlying the mobilization and engraftment of CD34+ cells is poorly understood. The most relevant factors in the regulation of stem cell release and engraftment include chemokines, adhesion molecules, and chemokine receptors. Previously, it was suggested that the absence of CD56 expression could be used as a predictive factor for mobilization failure at the time of diagnosis. Here, we investigated the effect of CD56 expression status on both mobilization and engraftment processes. Additionally, other factors affecting mobilization and engraftment efficacy were investigated. METHODS: Data from 79 multiple myeloma patients undergoing autologous stem cell transplantation between 2015 and 2020 were analyzed for peripheral stem cell mobilization and posttransplant neutrophil and platelet engraftment according to CD56 expression on myeloma cells. RESULTS: No difference in either the median number of CD34+ cells collected or time to engraftment was found between the CD56+ and CD56- groups. The age of the patients (p = 0.025) and peak number of circulating CD34+ cells in peripheral blood (p = 0.005) were important predictors for a higher number of collected CD34+ cells. The average time to recovery of leukocytes and platelets after transplantation was markedly correlated with the number of transplanted stem cells and peak number of circulating CD34+ cells in peripheral blood, respectively (p = 0.049 and p = 0.003). CONCLUSIONS: Our results indicated no effect of CD56 expression status on the mobilization and engraftment of PBSCs. Our results also support the notion that the peak number of circulating CD34+ cells in peripheral blood is clinically important for rapid platelet engraftment following HPC transplantation.

Recurrent arthritis as an unexpected side effect associated with azacitidine in a patient with myelodysplastic syndrome.

INTRODUCTION: Hypomethylating agents have confirmed efficacy for myelodysplastic syndrome and acute myeloid leukemia and are widely used. Although arthralgia is common side effect associated with hypomethylating agents, arthritis has not been reported previously. CASE REPORT: We present the first recorded patient with arthritis after azacitidine treatment. The patient we presented here had severe cytopenias requiring transfusion with erythrocyte and platelet suspensions, and a complete hematological response was obtained for myelodysplastic syndrome after three cycles of azacitidine (AZA) treatment. However, interestingly, after each AZA treatment cycle, the patient had recurrent attacks of arthritis. MANAGEMENT AND OUTCOMES: The episodes of arthritis were possibly acute flares of pre-existing crystal-induced arthritis, as exhibited with azacitidine treatments and were managed effectively with nonsteroidal anti-inflammatory drugs. DISCUSSION: Because it is a rare condition, clinicians should not overlook AZA as a possible cause of arthritis exacerbations when arthritis of unknown etiology develops in patients treated with AZA.