Multiple myeloma: altered CD4/CD8 ratio in bone marrow.

The expression of CD3, CD4 and CD8 antigens was simultaneously evaluated in peripheral blood and bone marrow lymphocytes from 22 multiple myeloma (MM) patients. The coexpression of CD11b and HLA-DR antigens was also analyzed within the CD4+ and CD8+ subpopulations in 4 MM patients. In peripheral blood the percentage of CD3+ and CD8+ cells was in the normal range, and the percentage of CD4+ was slightly reduced, leading to an altered CD4/CD8 ratio (less than 1) in only 7 patients. On the contrary, in bone marrow the percentage of CD4+ was profoundly reduced, leading to an altered CD4/CD8 ratio in all MM patients. As we previously reported in peripheral blood, an expansion of the CD11b+ and HLA-DR+ lymphocytes was observed within the CD4+ and CD8+ bone marrow T-cell subpopulations. A T-lymphocyte subset imbalance is more evident in bone marrow than in peripheral blood, and it is not due to a different lymphocyte distribution within the hematological compartments.