Chimerism and T-cell receptor repertoire analysis after unrelated cord blood transplantation with a reduced-intensity conditioning regimen following autologous stem cell transplantation for multiple myeloma

A 65-year-old Japanese male was diagnosed as multiple myeloma with Bence Jones kappa type, clinical stage IIIA. His disease status reached partial remission after chemotherapy. Thereafter, he received tandem transplantation, consisting of high-dose chemotherapy with autologous stem cell transplantation (ASCT), followed by unrelated cord blood transplantation (U-CBT). U-CBT with a reduced-intensity conditioning regimen (RI-CBT) was performed in August 2003. HLA mismatch between the patient and the CBT donor was present at two serological loci (B and DR). A total nucleated CBT cell dose of 2.45 x 10(7)/kg body weight was infused on day 0. Graft-vs.-host disease (GVHD) prophylaxis consisted of cyclosporine A and short-term methotrexate. Neutrophil engraftment (>0.5 x 10(9)/l) was obtained on day 46. He developed positive cytomegalovirus antigenemia, grade II acute GVHD involving skin and liver, varicella-zoster virus infection, septic shock, hemorrhagic cystitis caused by adenovirus and acute hepatitis B virus infection after U-CBT. We retrospectively analyzed T-cell receptor (TCR) repertoire diversity and found that TCR repertoire diversity decreased continuously after U-CBT. Therefore, low-TCR repertoire diversity in this patient appears to be associated with various infections caused by immunodeficiency.

Serum macrophage migration inhibitory factor (MIF) levels after allogeneic hematopoietic stem cell transplantation

Macrophage migration inhibitory factor (MIF) may play an important role in the pathogenesis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), as MIF plays an important role to regulate the production of tumor necrosis factor-alpha (TNF-alpha), one of the inflammatory cytokines which induces and exacerbates aGVHD. We examined the association between serum MIF levels and aGVHD vs. chronic GVHD (cGVHD) in allo-SCT patients in this study. We found a significant increase in the peak serum MIF (14.46 ng +/- 1.47 ng/ml) at onset in patients that developed aGVHD (n = 23, P = 0.009). We also found that mean serum MIF levels in patients who developed extensive type cGVHD within 6 months (12.58 +/- 2.18 ng/ml, n = 13) were significantly higher than MIF levels before allo-HSCT (7.86 +/- 1.17 ng/ml, n = 19, P = 0.04). Therefore, we speculated that serum MIF levels increase during the active phase of both aGVHD and cGVHD.

Regulation of the expression of MHC class I-related chain A, B (MICA, MICB) via chromatin remodeling and its impact on the susceptibility of leukemic cells to the cytotoxicity of NKG2D-expressing cells

Innate immune cells such as natural killer (NK) cells play a crucial role in antitumor immune responses. NKG2D is a major activating immunoreceptor expressed in not only NK cells but also CD8+ T cells and shows cytotoxicity against tumors by recognizing its ligands major histocompatibility complex class I-related chain A and B (MICA and MICB) on tumor cells. Recently, it has been suggested that NKG2D-mediated cytotoxicity correlates with the expression levels of NKG2D ligands on target cells. In this study, we were able to increase the expression levels of MICA and MICB on leukemic cell lines and patients' leukemic cells by treatment with trichostatin A (TsA), a histone deacetylase (HDAC) inhibitor. Chromatin immunoprecipitation (ChIP) assays revealed that treatment with TsA resulted in increased acetylation of histone H3 and decreased association with HDAC1 at the promoters of MICA and MICB. Intriguingly, upregulation of MICA and MICB by treatment with TsA led to enhancement of the susceptibility of leukemic cells to the cytotoxicity of NKG2D-expressing cells. Our results suggest that regulation of the expression of NKG2D ligands by treatment with chromatin-remodeling drugs may be an attractive strategy for immunotherapy.

Abnormal expansion of naïve B lymphocytes after unrelated cord blood transplantation--a case report

A 33-year-old woman underwent unrelated cord blood transplantation (U-CBT) for myelodysplastic syndrome (MDS)-related secondary AML. She showed impressive increases in the number of CD19⁺ B cells in bone marrow and CD19⁺27⁻IgD⁺ B cells in peripheral blood from about 1 month to 3 months after U-CBT. The serum level of IL-6 temporarily increased after transplantation, and this increase seemed to be correlated with the expansion of CD19⁺ B cells. Although, compared with BMT, little is known about the kinetics of hematological and immunological reconstitution in U-CBT, there was initial B-cell recovery after CBT as some described. This B cell recovery may be associated with a high number of B-cell precursors present in cord blood (CB). The phenomenon of naïve B lymphocyte expansion that we found might be associated with a high number of B-cell precursors present in CB.

Analysis of donor-type chimerism in lineage-specific cell populations after allogeneic myeloablative and nonmyeloablative stem cell transplantation

We analyzed donor-type chimerism in CD3+, CD14.15+ and CD56+ cells from 36 patients who had undergone conventional-intensity allogeneic stem cell transplantation (CST) and 34 patients who had undergone non-myeloablative allogeneic stem cell transplantation (NST) for hematological malignancies. On day 28 after transplantation, all fractions in NST patients and CD3+ cells in CST patients who received a non-total body irradiation (TBI) regimen showed more frequent mixed chimerism (<90% donor cells) than those in patients who had received TBI. NST patients with acute graft-versus-host disease (grade II-IV) frequently showed more than 50% donor-type chimerism in CD3+ cells on day 14 (P=0.029). NST patients with <50% donor-type chimerism on day 14 and with <90% donor-type chimerism on day 28 in CD56+ cells had significantly poor 1-year overall survival (0 vs 91%, P<0.001 and 20 vs 74%, P=0.002, respectively). Both NST and CST patients with <90% donor-type chimerism in CD14.15+ cells on day 28 had significantly poor 1-year overall survival (14 vs 70%, P=0.005 and 0 vs 66%, P=0.002, respectively). Our data show that the extent of donor-type chimerism in lineage-specific cells appears to have an impact on outcome after allogeneic stem cell transplantation.

Differential expression of natural killer cell receptors (CD94/NKG2A) on T cells by the stimulation of G-CSF-mobilized peripheral blood mononuclear cells with anti-CD3 monoclonal antibody and cytokines: A study in stem cell donors

We investigated the expression of the inhibitory NKR (CD94/NKG2A) of the G-CSF mobilized peripheral blood mononuclear cells (G-PBMC) on T cells after stimulation for 7 days by immobilized anti-CD3 monoclonal antibody (mAb) with or without cytokines. We demonstrated increased expression of CD94/NKG2A on CD3+/CD8+ T cells. Also, addition of IL-12 induced significantly more CD94/NKG2A expression than addition of IL-15: CD94+CD3+/NKG2A+CD3+; 43.8 +/- 11.6%/33.7 +/- 11.4% by IL-12 versus 32.8 +/- 13.2%/21.3 +/- 9.6% by IL-15, respectively (n = 9, P < .05). However, >90% purified CD94+ cells CD94+ obtained from IL-15-treated G-PBMC by magnetic cell sorting (MACS) exhibited higher cytolytic (CTL) activity against K562 cells than that from IL-12-treated G-PBMC: E:T = 20:1, 40.7 +/- 18.4% vs 15.1 +/- 5.2% (n = 5, P < .05). Therefore, the cytokine effects on inhibitory NKR expression on T cells and CTL activity are differently regulated. Based on these findings, it may be possible to establish the effective strategy to expand inhibitory NKR-expressing T cells with CTL activity for cell therapy.

Mediastinal emphysema and bilateral pneumothoraces with chronic GVHD in patients after allogeneic stem cell transplantation

It is difficult to treat lung complications caused by chronic graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (allo-SCT). We retrospectively analyzed the characteristics of five patients with mediastinal emphysema (ME) and bilateral pneumothoraces (BP) caused by chronic lung GVHD after allo-SCT. Four of these patients had undergone unrelated SCT, and three had had HLA-identical unrelated donors. All patients received total body irradiation (TBI) during conditioning. Immunosuppressive agents were administered as GHVD prophylaxis, but two patients developed acute GVHD and all the five developed chronic GVHD. The onset of lung complications was 99-1915 days (median, 202 days) after SCT. The onset of ME and BP was 6-48 days (median, 23 days) after the onset of lung complications. Immunosuppressive agents were initially beneficial on the lung complications, but the patients later showed no response to therapy, and all died from respiratory failure 7-195 days (median, 28 days) after the development of ME and BP. The results suggest that these complications progress rapidly, are resistant to treatment, and have a poor prognosis. It is therefore important to start prophylaxis and treatment as early as possible.