Helper T cells (CD3 + /CD4 + ) within the autologous peripheral blood stem cell graft positively correlate with event free survival of multiple myeloma patients.

ABSTRACT

BACKGROUND: The microenvironment in the bone marrow - including lymphocytes - is part of the pathophysiology of multiple myeloma (MM). High dose chemotherapy followed by autologous stem cell transplantation is standard of care for younger patients. AIM: To determine the influence of reinfused lymphocyte subsets on event free survival (EFS) and overall survival (OS). METHODS: In peripheral blood (PB) and aphaeresis products (AP) of 41 MM patients lymphocyte subsets were determined by flow cytometry and were correlated with clinical outcome. RESULTS: PB lymphocyte subsets did not influence EFS or OS. Residual plasma cells in the AP were not correlated with poor outcome, whereas a high percentage of B cells (CD19+) showed a trend towards reduced EFS (P = 0.051). A high amount of CD4 cells and an increased CD4/CD8 ratio were significantly associated with prolonged EFS. In contrast, high percentage of HLA-DR positive lymphocytes showed negative impact on EFS and OS (P = 0.03 and 0.02, respectively). CONCLUSION: Obtained data suggest the non-activated (HLA-DR negative) helper CD4+ T cells in the AP to be tumour protective.