Immune reconstitution after autologous selected peripheral blood progenitor cell transplantation: comparison of two CD34+ cell-selection systems

T-lymphocyte depleted transplants for inborn errors of immunity

INTRODUCTION

Hematopoietic stem cell transplantation is a curative treatment for many inborn errors of immunity (IEI). Incremental improvements and advances in care have led to high rates of >85% survival and cure in many of these diseases. Improvements in HLA-classification and matching have led to increased survival using HLA-matched donors, but survival using T-lymphocyte-depleted mismatched grafts remained significantly worse until fairly recently. Advances in T-lymphocyte depletion methods and graft engineering, although not specific to IEI, have been widely adopted and instrumental in changing the landscape of donor selection, such that a donor should now be possible for every patient.

AREAS COVERED

A literature review focusing on T-lymphocyte depletion methodologies and treatment results was performed. The importance of early T-lymphocyte immunoreconstitution to protect against viral infection is reviewed. Two main platforms now dominate the field - immune-magnetic selection of specific cell types and post-transplant chemotherapeutic targeting of rapidly proliferating allo-reactive T-lymphocytes - the emerging literature on these reports, focusing on IEI, is explored, as well as the impact of serotherapy on early immunoreconstitution.

EXPERT OPINION

Pharmacokinetic monitoring of serotherapy agents, and use of co-stimulatory molecule blockade are likely to become more widespread. Post-transplant cyclophosphamide or TCR depletion strategies are likely to become the dominant methods of transplantation for nonmalignant diseases.

Approaches to the removal of T-lymphocytes to minimize graft-versus-host disease in patients with primary immunodeficiencies who do not have a matched sibling donor

PURPOSE OF REVIEW

Since the advent of T-lymphocyte depletion in hematopoietic stem cell transplantation (HSCT) for primary immunodeficiency, survival following this procedure has remained poor compared to results when using matched sibling or matched unrelated donors, over the last 40 years. However, three new techniques are radically altering the approach to HSCT for those with no matched donor, particularly those with primary immunodeficiencies which are not severe combined immunodeficiency.

RECENT FINDINGS

Three main techniques of T-lymphocyte depletion are altering donor choice for patients with primary immunodeficiencies and have improved transplant survival for primary immunodeficiencies to over 90%, equivalent to that for matched sibling and matched unrelated donor transplants. CD3 T cell receptor (TCR)αβ CD19 depletion, CD45RA depletion and use of posttransplant cyclophosphamide give similar overall survival of 90%, although viral reactivation remains a concern. Further modification of CD3 TCRαβ CD19 depletion by adding back inducible caspase-9 suicide gene-modified CD3 TCRαβ T-lymphocytes may further improve outcomes for patients with systemic viral infection.

SUMMARY

Over the last 5 years, the outcomes of HSCT using new T-lymphocyte depletion methods have improved to the extent that they are equivalent to outcomes of matched sibling donors and may be preferred in the absence of a fully matched sibling donor, over an unrelated donor to reduce the risk of graft versus host disease.

Recent advances in the management of graft-versus-host disease

Graft-versus-host disease (GvHD) remains a significant hurdle in overcoming the morbidity and mortality associated with haemopoietic stem cell transplantation in children. Better understanding of its pathobiology is facilitating the development of biomarkers for the severity of acute GvHD and treatment response, and has led to the introduction of a more prognostically relevant grading system for chronic GvHD. These enable stratification of appropriate prophylactic and treatment strategies according to the risk profiles of individual patients. Steroid-refractory acute GvHD has a poor prognosis, but early reports of the use of new immunosuppressive drugs and especially cellular treatments with extracorporeal photopheresis and mesenchymal stem cells suggest improved short-term outcomes and offer the promise of increased longer-term survival rates.

Hematopoietic stem cell transplantation for primary immunodeficiency diseases

Hematopoietic stem cell transplantation (HSCT) is now highly successfully curing a widening range of primary immunodeficiencies (PIDs). Better tissue typing, matching of donors, less toxic chemotherapy, better virus detection and treatment, improved supportive care, and graft-versus-host disease prophylaxis mean up to a 90% cure for severe combined immunodeficiency patients and a 70-80% cure for other PIDs given a matched unrelated donor, and rising to 95% for young patients with specific PIDs, such as Wiskott-Aldrich syndrome. Precise molecular diagnosis, detailed data on prognosis, and careful pre-HSCT assessment of infective lung and liver damage will ensure an informed benefit analysis of HSCT and the best outcome. It is now recognized that the best treatment option for chronic granulomatous disease is HSCT, which can also be curative for CD40 ligand deficiency and complex immune dysregulation disorders.

Immune Recovery of Lymphocyte Subsets 6 Years after Autologous Peripheral Blood Stem Cell Transplantation (PBSCT) for Lymphoproliferative Diseases. A Comparison between NHL, HD and MM in Group of 149 Patients

To evaluate the normalization of lymphocyte subsets several years after autologous peripheral blood stem cell transplantation (aPBSCT) and to detect any differences based on the underlying lymphoproliferative diseases, we analyzed the immunological recovery of 149 patients with Non Hodgkin's Lymphoma (NHL), Hodgkin's Disease (HD), Multiple Myeloma (MM). Lymphocyte recovery was assessed before the transplant, on days 15, 30, 60, 90, 120 and on years 1, 2, 4, 6. Analysis of a total of 709 lymphocytes, including total lymphocyte count, CD3 +, CD4 +, CD8 +, CD4 +/CD8 + ratio, CD19 +, CD3 + HLA-DR +, CD16 + 56 +, was performed. The normalization of total lymphocyte counts was achieved between days 14 to 22 following PBSCT. CD3 + cells count showed a normalization after 2 years in the HD and NHL groups and after 4 years in MM group. CD4 + subset achieved normalization during the sixth year in the 3 groups. The CD8 + and CD19 + lymphocytes subsets achieved normal values in the 3 groups at day 60 and at day 120 respectively. CD16 + 56 + and CD3 +/HLA-DR + lymphocytes showed median values above the normal range starting from day 30. Immunological recovery was similar in all 3 groups. Moreover, the recovery of all subsets evaluated was similarly demonstrated within 6 years after aPBSCT.

Long-term immune reconstitution after anti-CD52-treated or anti-CD34-treated hematopoietic stem cell transplantation for severe T-lymphocyte immunodeficiency

BACKGROUND

Results of treatment of severe T-lymphocyte immunodeficiencies by means of hematopoietic stem cell (HSC) transplantation have improved. T cell-depleted haploidentical transplantations are successful if there is no HLA-identical donor. Methods to remove T lymphocytes include addition of anti-CD52 antibodies and CD34(+) HSC selection.

OBJECTIVE

Assessment of long-term immune function is important after these treatments. We looked at immune reconstitution in 36 survivors for more than 2 years after HSC transplantation for severe T-lymphocyte immunodeficiencies and compared engraftment quality between the 2 T-lymphocyte depletion methods.

METHODS

Chimerism, T- and B-lymphocyte subsets, immunoglobulin levels, and specific antibody production at last follow-up were examined. The chi(2) (Fisher exact test) and Wilcoxon rank sum analyses were used to compare the groups.

RESULTS

Nineteen patients received anti-CD52-treated and 19 anti-CD34-treated HSCs. More anti-CD52-treated patients had full donor myeloid chimerism (P = .025). All patients had full donor T-lymphocyte chimerism. There was no difference in donor B-lymphocyte chimerism, but significantly more anti-CD52-treated patients had class-switched memory B lymphocytes (P = .024), normal IgG levels, and normal responses to tetanus and Haemophilus influenzae type B vaccination. More anti-CD52-treated patients with common gamma chain or Janus-associated kinase 3 severe combined immunodeficiency had donor B lymphocytes.

CONCLUSION

Long-term T-lymphocyte function is good with either treatment method, with a low incidence of graft-versus-host disease. The results imply more incomplete donor chimerism in anti-CD34-treated patients with less B-lymphocyte function.

Successful transplantation of haploidentically mismatched peripheral blood stem cells using CD133+-purified stem cells

OBJECTIVE

For recipients of haploidentically mismatched stem cell allografts, T-cell depletion is mandatory to prevent lethal graft-vs-host disease (GVHD). Prevention of GVHD can be accomplished by negative selection of T cells or positive selection of stem cells. Recently, a new method for positive selection of stem cells was introduced using monoclonal antibodies against CD133 antigen. We report five cases of successful application of immunomagnetic separation of CD133+ stem cells for haploidentically mismatched allogeneic stem cell transplantation.

METHODS

Five patients with high-risk hematological malignancies, ages 7 to 63 years old (median, 17 years), underwent peripheral blood stem cell transplantation from haploidentically mismatched related donors. Conditioning protocol was tailored according to patient clinical situation and included combination of treosulfan/fludarabine/thiotepa/melphalan/Mabcampath. Two patients did not get thiotepa. One of them received a protocol that included infusion of 4.4 x 10(7) blood mononuclear cells from the donor (day -9), followed by a combination of fludarabine/cyclophosphamide/busulfex/MabCampath. Separation of CD133+ stem cells was done using CliniMACS with Miltenyi's CD133 reagent.

RESULTS

The procedure was well tolerated by all patients. Early 3-lineage engraftment was documented and none exhibited immune-mediated rejection. Time to recovery of absolute neutrophils count above 0.5 x 10(9)/L and 1.0 x 10(9)/L was 10 to 15 days (median, 14) and 11 to 29 days (median, 15), respectively. Time for platelet recovery to values greater than 20 x 10(9)/L and greater than 50 x 10(9)/L ranged from 12 to 25 days (median, 13.5), and from 14 to 34 days (median, 16), respectively. Transplant-related mortality did not occur in any of the patients.

CONCLUSION

Our successful pilot trial suggests that positive selection of CD133+ stem cells may be a useful method for safe transplantation with haploidentically mismatched stem cell allografts while avoiding lethal acute and chronic GVHD. Future studies will be required to assess the clinical benefits of stem cell purification with CD133+ in comparison with CD34+ stem cells.

Impaired stem cell function of CD34+ cells selected by two different immunomagnetic beads systems

We have been investigating the hematopoietic stem cell (HSC) activity of peripheral blood-derived CD34(+) cells selected by two different laboratory immunomagnetic beads systems (MiniMACS and Isolex 50). In this study, the quality of purified CD34(+) cells was directly compared using clonal cell culture, a cobblestone area-forming cell (CAFC) assay, and an in vivo severe combined immunodeficiency (SCID)-repopulating cell (SRC) assay. It was found that CD34(+) cells selected by these two immunomagnetic methods showed a reduced yield of colony-forming cells and CAFCs compared with cells enriched by the StemSep device (a negative selection method). However, these CD34(+) cells still showed significant SRC activity, including multilineage lymphomyeloid reconstitution. The percentage of human CD45(+) cells in murine bone marrow after transplanting 5 x 10(5) CD34(+) cells selected by the Isolex 50 was significantly lower than after transplanting cells selected by the MiniMACS or the StemSep. Our findings clearly demonstrated that CD34(+) cells selected by the MiniMACS system had superior HSC functions, including SRC activity, compared with cells separated by the Isolex 50 system. More detailed functional analysis of immunomagnetically separated CD34(+) cells may provide useful knowledge for basic research on HSCs as well as for clinical HSC transplantation.

The kinetics of immune reconstitution after cord blood transplantation and selected CD34+ stem cell transplantation in children: comparison with bone marrow transplantation

The present study compares immune reconstitution after allogeneic cord blood transplantation (CBT) and CD34+ stem cell transplantation (CD34-SCT) with that after bone marrow transplantation (BMT). Eighty-eight children who underwent CBT (20 patients), BMT (58), and CD34-SCT (10) were enrolled, and lymphocytes and T-, B-, and natural killer-lymphocyte subsets were monitored for more than 5 years after transplantation. CBT recipients showed significant ircreases in (1) total lymphocyte counts (P < .001), (2) CD4+/CD8+ cell ratios (P < .01), (3) CD4+ and CD4+CD45RA+ cells (P < .001), (4) CD8+CD11b+ cells (P < .001), and (5) CD19+ and CD19+CD5+ cells (P < .0001) and marked decreases in the frequencies of CD8+ and CD8+CD11b- cells (P < .0001). CD34-SCT recipients showed lower lymphocyte counts in the first 6 months and an emergence of lymphocyte and CD4+CD45RA+ cells at approximately 9 months and 1 year. Both CBT and CD34-SCT recipients showed increased frequencies of CD56+ cells at 1 month (CD34-SCT versus BMT, P < .001) but decreased frequencies after 6 months (CBT versus BMT, P < .001). Lymphoproliferative responses to exogenous interleukin 2 were constantly lower in CBT and CD34-SCT recipients than in BMT recipients. These results suggest that the delay in immune reconstitution after CBT in the early phase was mainly qualitative and related to the immaturity of cells, whereas the delay in CD34-SCT was mainly quantitative in the first several months.