thymosin and Anemia--Aplastic

Thymus tissue implants, thymic epithelial cells obtained from third party donors sharing one HLA-A and -B locus with the recipient, or the thymic hormones thymosin fraction 5 and thymopentin were given to recipients of HLA-identical sibling bone marrow to prevent chronic graft-versus-host disease (GVHD) and accelerate immunologic reconstitution. The clinical courses of 17 patients receiving thymus tissue and 18 patients receiving thymic hormones were reported initially 5 years ago and showed no difference in the incidence of chronic GVHD or immunologic recovery from those of concurrent or historical controls. We report here for the first time nine new patients who received thymus tissue implants with modifications of the culture method to lower the number of lymphocytes in the transplanted tissue with the intent of reducing rejection of the thymus tissue grafts. The clinical outcomes and immunologic functions of these nine patients were similar to those of the recipients of the earlier thymus tissue implants. With follow-up now ranging from 2.2 to 12.3 years (median 6.7) for the total group, 16 patients are alive. Seven never developed chronic GVHD. Nine were treated for chronic GVHD, seven of whom recovered and are leading normal lives, one has chronic pulmonary insufficiency, and one is disabled from chronic GVHD. We conclude that thymus tissue grafts or thymic epithelial cells partially HLA-matched to the recipient, thymosin fraction 5, or thymopentin used as described were not effective in reducing the incidence of chronic GVHD, improving immunologic recovery, or altering long-term survival.

Topics: Adolescent; Adult; Anemia, Aplastic; Bone Marrow Transplantation; Child; Clinical Trials as Topic; Female; Follow-Up Studies; Graft vs Host Disease; Humans; Leukemia; Male; Middle Aged; Peptide Fragments; Thymopentin; Thymopoietins; Thymosin; Thymus Gland; Thymus Hormones

Topics: Anemia, Aplastic; Child; Child, Preschool; Clinical Trials as Topic; Follow-Up Studies; Hormones; Humans; Thymosin

To study the regulatory effect of thymosin α1 (Tα1) on immunosuppression of bone marrow mesenchymal stem cells (MSCs) from children with aplastic anemia (AA) through Toll-like receptor 9(TLR9)and indoleamine 2,3-dioxygenase (IDO) signaling pathway.. Bone marrow T cell subsets from children with AA and normal individuals were measured by using flow cytometry. Expressions of TLR9/IDO mRNA of MSCs cocultured with Tα1 were determined by reverse-transcription PCR (RT-PCR). Inhibition of PHA-activated T cell proliferation and activation by MSCs cocultured with Tα1 was detected by using MTT assay and flow cytometry.. CD4(+)/CD8(+) ratio (0.64 ± 0.02) in children with AA was significantly lower than that in normal individuals (1.42 ± 0.05); but CD8(+)/CD38(+) ratio (0.92 ± 0.04) was significantly higher than that in normal individuals (0.65 ± 0.05). AA MSCs obviously expressed TLR9, but not IDO; AA MSCs treated with Tα1 downregulated TLR9 expression but upregulated IDO expression in concentration- and time-dependent manners. The inhibition of AA MSCs on T cell proliferation (21.38% ± 12.34%) was lower than that in normal individuals (62.72% ± 17.79%, P < 0.05), while AA MSCs treated with Tα1 for 18 h exhibited a stronger inhibition (42.83% ± 16.54%, P < 0.05).. The immunosuppression mediated by MSCs could be improved by Tα1 through upregulation of IDO expression via TLR9-dependent signaling pathway. This research provides a new idea for targeted immunomodulatory therapy with bone marrow MSCs from children with AA.

Topics: Adolescent; Anemia, Aplastic; Bone Marrow Cells; Case-Control Studies; Child; Female; Humans; Immune Tolerance; Immunosuppression Therapy; Indoleamine-Pyrrole 2,3,-Dioxygenase; Male; Mesenchymal Stem Cells; Signal Transduction; Thymalfasin; Thymosin; Toll-Like Receptor 9

The purpose of this study was to explore the regulatory effect of thymosin α1 (Tα1) on expression of TOLL-like receptor 9 (TLR9)/indoleamine2, 3-dioxygenase (ido) mRNA in bone marrow mesenchymal stem cells (MSC) from children with aplastic anemia (AA). Culture system of bone marrow MSC from AA children and normal children in vitro was established, and the effects of Tα1 on expressions of tlr9 mRNA and ido mRNA of MSC from AA children and normal children were determined by RT-PCR. The results showed that the bone marrow MSC from normal children did not express tlr9 and ido mRNA. Bone marrow MSC from children with AA obviously expressed tlr9 mRNA , but did not express ido mRNA; AA children's MSC treated with Tα1 for 18 hours markedly down-regulated tlr9 mRNA expression, but up-regulated ido mRNA expression in the concentration- and time-dependent ways. It is concluded that Tα1 can up-regulate the expression of ido mRNA in bone marrow MSC from children with AA.

Topics: Adolescent; Anemia, Aplastic; Bone Marrow Cells; Cells, Cultured; Child; Female; Gene Expression Regulation; HL-60 Cells; Humans; Indoleamine-Pyrrole 2,3,-Dioxygenase; Male; Mesenchymal Stem Cells; RNA, Messenger; Thymalfasin; Thymosin; Toll-Like Receptor 9

More than 1 year is required for immunologic function to recover following human marrow grafting. In an attempt to shorten the time required for immunologic reconstitution, 14 patients were treated with thymosin fraction 5 after transplantation. Two died before administration of thymosin could be completed. In the remaining 12 patients, immunologic studies were compared to those of patients who were transplanted but did not receive thymosin. While five patients had transient elevation of in vitro lymphocyte blastogenesis during thymosin treatment, results of other immunologic studies from patients treated with thymosin were similar to those from patients not treated. The subsequent development of graft-versus-host disease, major or minor infection, and leukaemic relapse was not different between the groups. Six patients are alive and five are well without problems; one has chronic graft-versus-host disease. We conclude that thymosin fraction 5 administered as described was not toxic. Although modifying some immunological parameters, thymosin did not appear to alter the incidence of graft-versus-host disease, infection or leukaemic relapse or to accelerate immunologic reconstitution.

Topics: Adolescent; Adult; Anemia, Aplastic; Antibody Formation; Bone Marrow Transplantation; Child; Graft vs Host Disease; Humans; Immunity, Cellular; Immunoglobulins; Leukemia, Lymphoid; Leukemia, Myeloid, Acute; Lymphocyte Activation; Rosette Formation; Thymalfasin; Thymosin; Time Factors

Topics: Anemia, Aplastic; Animals; Antibody Formation; Cyclophosphamide; Humans; Immunoglobulins; Immunosuppressive Agents; Leukemia L1210; Lymphocytes; Rosette Formation; Thymosin