In order to improve safety and target specificity of gene therapy in autoimmune and inflammatory diseases, various cell types have been used as carriers after ex vivo modification. Tissue cells such as fibroblasts, immune cells including lymphocytes, macrophages and dendritic cells (DCs) tas well as stem cells, primarily mesenchymal stem cells (MSCs), all have been used for cellular gene therapy. The use of immune cells has been evaluated extensively since these cells have the intrinsic ability to migrate into inflamed tissues and lymphoid organs, the key sites for therapeutic intervention using anti-inflammatory (e.g., cytokine inhibitors) and tissue-protective (e.g., enzyme inhibitors) gene products. Among the immune cells, DCs are powerful tools not only as gene carriers but also because of their own immunomodulatory capacity. Mesenchymal stem cells are attractive because of their potential for tissue regeneration in addition to gene product delivery. Further research is required to optimise the treatment strategies based on these cells and to utilise and control the special features of DCs and MSCs in order to advance towards human application.