Difference in megakaryocyte expression of GATA-1, IL-6, and IL-8 associated with maintenance of platelet counts in patients with plasma cell neoplasm with dysmegakaryopoiesis.

Dysmegakaryopoiesis is a diagnostic criterion for myelodysplastic syndrome (MDS), which accompanies thrombocytopenia. Recently, dysmegakaryopoiesis was reported in patients with plasma cell neoplasm (PCN). Although these patients maintained normal platelet counts, disease progressed, with most bone marrow cells being replaced by plasma cells. Several studies reported that dysmegakaryopoiesis was induced by inflammatory mechanisms; however, the exact mechanism underlying dysmegakaryopoiesis remains unknown. This study aimed to investigate whether changes in the megakaryocytic expression of GATA-1, pro-inflammatory cytokines (interleukin [IL]-6 and IL-8), and CD9 affect platelet counts and dysmegakaryopoiesis in patients with PCN and MDS. A total 114 patients were examined and categorized into four groups: MDS with dysmegakaryopoiesis (34 patients), PCN without dysmegakaryopoiesis (36 patients), PCN with dysmegakaryopoiesis (19 patients), and lymphoma without bone marrow infiltration (25 patients). Expression of GATA-1, IL-6, IL-8, and CD9 in megakaryocytes was assessed by immunohistochemical (IHC) staining of paraffin-embedded bone marrow sections. Localized expression of transcription factor and cytokines was observed in megakaryocytes. Furthermore, expression of GATA-1, IL-6, and IL-8 significantly differed (all p values < 0.05). Decreased GATA-1 expression was identified in MDS. Decreased IL-6 expression was observed in PCN and MDS. Moreover, decreased IL-8 expression was associated with dysmegakaryopoiesis, regardless of whether platelet counts were maintained. In conclusion, PCN patients with dysmegakaryopoiesis had normal platelet counts, and their megakaryocytes showed decreased IL-6 and IL-8 expression and normal GATA-1 expression. The differences in the megakaryocytic expression of cytokines in PCN and MDS with dysmegakaryopoiesis may be applicable to future therapeutic strategies.