Cell-surface antigen expression of hematopoietic stem cells has a crucial role in characterizing cell subpopulation with distinct functional properties. The Eph receptors are the largest receptor tyrosine kinase family being involved in processes like vascular remodelling during development and physiological and pathological angiogenesis. Some EphlEphrin members are expressed in hematopoietic cells. The ability to isolate purified cell populations co-expressing CD34 and CD133 antigens as most commonly used markers for identification of hematopoietic progenitors has provided the opportunity to identify their surfacereceptor profile, As positively expressed CD34 and CD133 cells take place not only in hematopoietic but also in endothelial differentiation, we aimed to define the EphlEphrin characteristic ofthese cells and relate these findings to new therapy strategies. Positive selections of CD34 and CD133 cells from PBPC in lymphoma patients were performed using magnetic beads and AutoMACS (Miltenyi Biotec) device. The purity of isolated cells was tested by flow cytometry. Immunocytochemistry was used to assess the EphlEphrin expression profile of positively selected samples. Our study revealed that all samples (10 from CD34+ and 8 from CD133+ cells) expressed one or more of EphlEphrin antigens in different proportions. AU CD34 + cell samples, and 6 of 8 in the CD133+ cell fraction were strongly immunoreactive for EphA2. EphB2 was strongly expressed in all CD133+ cases, but 50% of the CD34 positive group lacked or weakly expressed this receptor. EphB4 was negative in 9 of 10 CD34+ cases and in all CD133 +cells. Thus, we have shown the surface marker profile of positively selected CD34 and CD133 cells in leukapheresis samples from lymphoma patients with regard to EphlEphrin receptors and discussed their biological clinical potential.

Enriched CD34+ peripheral blood progenitor cells (PBPC) are frequently used as stem cell support in cancer patients following high dose therapy. Since precursor dendritic cells (DCs) originate from haematopoietic progenitor cells, purified CD34+ cells might also serve as starting cells for ex-vivo production of DC. In the present study we developed a clinical grade procedure for ex-vivo production of DC derived from enriched CD34+ cells. Different concentrations of CD34+ cells were grown in gas-permeable Teflon bags with different serum-free and serum-containing media supplemented with GM-CSF, IL-4, TNF-ex, SCF, Flt-3L and INF-ex. Serum-free CellGroSCGM medium for 7 days followed by CellGroDC medium in 7 days gave the same results as serum-containing medium. After incubation the cultured cells containing immature DCs were concentrated and transfected with tumour mRNA from human prostate cancer cell lines employing a highly efficient electroporation procedure. Thawed transfected DCs were able to elicit primary T-cell responses in vitro against antigens encoded by the prostate cancer mRNA as shown by ELlSPOT assay using mocktransfected DCs as control. Our results show that frozen enriched CD34+ cells can be an alternative and efficient source for production of DCs for therapeutic purpose.Dendritic cells (DCs) are the most powerful antigen-presenting cells (APe) specialized to initiate and regulate immune responses (1-2). The clinical use as cellular adjuvants in vaccination strategies has been aided by the development of methodologies to generate these cells on a large scale in culture. DCs can be grown ex-vivo from blood monocytes (3-5) or enriched CD34+ progenitors (6-7), using combinations of several cytokines/growth factors. Since we routinely use in our laboratory enriched CD34+ stem cells as stem cell support following high dose radio-and chemotherapy it was of interest to test if such cells could also be applied for vaccine purposes (8)(9), with a long term strategy of combining the two forms of therapy.Some published data indicate that CD34+ derived DC may work more efficiently as APC than those derived from monocytes (10), and recent data indicate that vaccine programs using CD34+ cell derived DCs results in improved clinical results (11). But most in vitro culture systems for production of DCs include serum (9-12). Since DCs are able to take up and process serum-derived antigens that are present in the cell cultures, such DC can, when injected create unwanted reactions in the patients, in particular when fetal calf serum (PCS) is used. Serum-free culturing condition is thus preferable, but in most previous culture experiments these conditions resulted in a lower yield of DCs. (13)(14).

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Autoimmune diseases are characterized by recurrent attacks and remissions, but as a rule they progress and eventually cause a severe disability and death. The present chapter contains general characteristics of autoimmune disease pathogenesis, ways to cause immune tolerance by hematopoietic cell transplantation (HCT), clinical aspects of the treatment for established autoimmune diseases with a special attention to multiple sclerosis (MS) and systemic sclerosis (SSc). A profound analysis of authors' point of view and of the available literature has been performed. The promising results allows to consider HCT as a relevant treatment option for a certain autoimmune diseases.