There are contradictory data concerning the influence of mesenchymal stromal cells (MSC) on immunoglobulin (Ig) production. Most of them were obtained using MSC from bone marrow. Properties of MSC from other tissues are elusive. In the present work MSC cultures were derived from umbilical cord, adipose tissue, and bone marrow of healthy donors, as well as from bone marrow of patients with autoimmune diseases. MSC from all these sources had similar surface markers phenotype. The influence of co-cultivation with MSC at exponential or stationary phase on IgM and IgE content in Namalva and U266 cells was evaluated. MSC from bone marrow of healthy donors had no effect on IgM and IgE production. Proliferating MSC obtained from patients with Crohn's disease and multiple sclerosis stimulated Ig production. Exponentially growing MSC derived from umbilical cord and adipose tissue also stimulated Ig synthesis. MSC at stationary cultures amplified IgM production in Namalva cells and suppressed IgE synthesis in U266. Thus, MSC with similar phenotype but derived from different sources differ in their capacity to modulate Ig production in B-lymphoid cells. The effect of MSC depends on their growth stage and may differ for lymphoblastoid and myeloma cells.