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Objectives Patients with acquired aplastic anemia (AA) without HLA-matched sibling donors or aged >40 years receive immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG). We investigated the relationship between plasma rabbit ATG (r-ATG) concentration and IST response. Methods From May 2012 to October 2017, 81 patients with severe AA who required initial IST were included. A 1:1 block randomization was employed for 2.5 and 3.5 mg/kg doses of r-ATG. Results No significant difference in response rates was observed between the 2.5 and 3.5 mg/kg groups (63% vs. 58%, P = .894). Median r-ATG concentrations on days 14 and 28 after IST were 15.2 (0.0-97.7) and 1.8 (0.0-74.9 µg/mL), respectively. According to r-ATG concentration, response rates were significantly higher in the group with higher r-ATG concentration than in those with lower r-ATG concentration (day 14, 88% vs. 52%; P = .006 and day 28, 79% vs. 46%; P = .005). In multivariate analysis, higher r-ATG concentrations at day 28 were independent predictors of favorable response to IST at 6 months (odds ratio, 0.29; 95% confidence interval, 0.09-0.93; P = .037). Conclusions The present data indicate that higher r-ATG concentration at day 28 resulted in improved IST response.

Trisomy 8 (+8), one of the most common chromosomal abnormalities found in patients with myelodysplastic syndromes (MDS), is occasionally seen in patients with otherwise typical aplastic anemia (AA). Although some studies have indicated that the presence of +8 is associated with the immune pathophysiology of bone marrow (BM) failure, its pathophysiology may be heterogeneous. We studied 53 patients (22 with AA and 31 with low-risk MDS) with +8 for the presence of increased glycosylphosphatidylinositol-anchored protein-deficient (GPI-AP-) cells, their response to immunosuppressive therapy (IST), and their prognosis. A significant increase in the percentage of GPI-AP- cells was found in 14 (26%) of the 53 patients. Of the 26 patients who received IST, including nine with increased GPI-AP- cells and 17 without increased GPI-AP- cells, 14 (88% with increased GPI-AP- cells and 41% without increased GPI-AP- cells) improved. The overall and event-free survival rates of the +8 patients with and without increased GPI-AP- cells at 5 yr were 100% and 100% and 59% and 57%, respectively. Examining the peripheral blood for the presence of increased GPI-AP- cells may thus be helpful for choosing the optimal treatment for +8 patients with AA or low-risk MDS. © 2014 John Wiley & Sons A/S.

A 1-yr-old Japanese male infant developed hepatitis-associated aplastic anemia (AA), and anti-thymocyte globulin (ATG) plus cyclosporine A (CsA) was administered without any appreciable effects. Laboratory examination of the patient's serum obtained before therapy revealed various autoantibodies, such as PA-IgG, anti-platelets, anti-single-stranded DNA (ssDNA), and anti-double-stranded DNA (dsDNA) antibodies (Abs) in addition to anti-DRS-1 Abs and anti-moesin Abs, both of which are known to be detectable in approximately 40% of all patients presenting with AA. He was therefore treated with 17.5 mg/kg/d rituximab 5.5 months after ATG/CsA therapy. The same rituximab therapy was repeated three times once a month thereafter. His neutrophil counts started to increase 50 d after the first rituximab therapy and he achieved a complete remission at 16 months after the last rituximab administration. All of the autoantibodies including anti-ssDNA, dsDNA, DRS-1, and moesin became undetectable when he attained the remission. Anti-CD20 monoclonal antibody therapy may be effective in a subset of patients with AA characterized by the presence of autoantibodies.

Glycosylphosphatidylinositol-anchored protein-deficient (GPI-AP−) T cells can be detected in some patients with bone marrow failure (BMF), but the link between these cells and BMF pathophysiology remains to be elucidated. To clarify the significance of GPI-AP− T cells in BMF, peripheral blood from 562 patients was examined for the presence of CD48−CD59−CD3+ cells using high-resolution flow cytometry (FCM), and the GPI-AP− T cells were characterized with regard to their phenotype and sensitivity to inhibitory molecules, including herpesvirus entry mediator (HVEM) and a myelosuppressive cytokine, TGF-β. A multi-lineage FCM analysis detected CD48−CD59−CD3+ T cells in 72 (12.8%) of the patients, together with GPI-AP− myeloid cells. Unexpectedly, 12 patients (10 with aplastic anemia and 2 with myelodysplastic syndrome-refractory anemia, 2.1%), who showed clinical features similar to those of other BMF patients with GPI-AP− myeloid cells, such as a good response to immunosuppressive therapy, displayed 0.01–0.3% GPI-AP− cells exclusively in T cells. The CD48−CD59− T cells consisted of predominantly effector memory (EM) and terminal effector cells, while CD48−CD59− T cells from non-BMF patients who had received anti-CD52 antibody only showed EM and central memory phenotypes. TGF-β and HVEM capable of inhibiting T-cell proliferation via its GPI-AP CD160 ligation suppressed the in vitro proliferation of GPI-AP+ T cells more potently than that of GPI-AP− T cells from the same patients. The presence of GPI-AP− T cells, as well as GPI-AP− myeloid cells, may therefore reflect the immunopathophysiology of BMF in which cytokine-mediated suppression of hematopoietic stem cells via GPI-AP-type receptors takes place.

Objectives: Some patients with myelodysplastic syndrome (MDS) show a marked increase in the percentage of immature platelet fraction (IPF%) despite the absence of severe thrombocytopenia. To determine the significance of such an unbalanced increase in the IPF%, we investigated the IPF% and other laboratory findings of 51 patients recently diagnosed with MDS. Method: Subjects consisted of 80 healthy males, 90 healthy females, and 51 patients with MDS and 20 patients with idiopathic thrombocytopenic purpura (ITP). The IPF and IPF% were determined using a Sysmex XE-2100 system loaded with IPF Master software (XE IPF Master, Sysmex). Platelet counts were measured simultaneously. Results: IPF% and platelet counts of these patients ranged from 1.1% to 25.1% (median, 5.3%) and from 6 to 260 × 109/L (median, 71 × 109/L), respectively. Twelve patients showed platelet counts more than 50 × 109/L with 10% or more IPF%. All of the 12 patients had chromosome abnormalities including monosomy 7 and complex abnormalities involving 7 or 5q. In the other 39 patients who did not show the aberrant IPF% increase, chromosomal abnormalities were seen only in seven patients and none of them had chromosome 7 abnormalities. The IPF% of two patients increased to more than 10% in association with the appearance of monosomy 7. Conclusions: These findings suggest that a high IPF% in MDS patient may be a marker for karyotypic abnormalities with a poor prognosis, including chromosome 7 abnormalities.

Human leukocyte antigen (HLA)-mismatched stem cell transplantation from non-inherited maternal antigen (NIMA)-complementary donors is known to produce stable engraftment without inducing severe graft-versus-host disease (GVHD). We treated two patients with acute myeloid leukemia (AML) and one patient with severe aplastic anemia (SAA) with HLA-mismatched stem cell transplantation (SCT) from NIMA-complementary donors (NIMA-mismatched SCT). The presence of donor and recipient-derived blood cells in the peripheral blood of recipient (donor microchimerism) and donor was documented respectively by amplifying NIMA-derived DNA in two of the three patients. Graft rejection occurred in the SAA patient who was conditioned with a fludarabine-based regimen. Grade III and grade IV acute GVHD developed in patients with AML on day 8 and day 11 respectively, and became a direct cause of death in one patient. The findings suggest that intensive conditioning and immunosuppression after stem cell transplantation are needed in NIMA-mismatched SCT even if donor and recipient microchimerisms is detectable in the donor and recipient before SCT.

We investigated whether depressed plasma antithrombin and protein C activity, considered as a specific finding of disseminated intravascular coagulation (DIC), is due to consumption coagulopathy in septic patients with DIC. An analysis of hemostatic parameters was performed in 139 septic patients (68 with DIC and 71 without DIC). Plasma activity of antithrombin and protein C tended to be significantly decreased in septic patients with DIC but not in those without DIC (p < 0.001). However, when the septic patients were classified into three groups according to the albumin (or choline esterase) level, no significant differences in antithrombin activity or protein C activity were observed between the patients with and without DIC in any of the subgroups. Notably, neither the plasma activity of antithrombin nor protein C was decreased even in septic patients with DIC who had normal plasma levels of albumin (or choline esterase). No significant correlation was observed between plasma levels of thrombin-antithrombin complex (TAT) and antithrombin activity, or between plasma levels of TAT and protein C activity either in septic patients with DIC or without DIC. It is reasonable to conclude that the markedly reduced plasma activity of antithrombin and protein C is not due to consumption coagulopathy in septic patients with DIC.

To clarify the pathologic significance of granulocytes exhibiting the paroxysmal nocturnal haemoglobinuria (PNH) phenotype in patients with aplastic anaemia (AA), we examined peripheral blood from 100 patients with AA for the presence of granulocytes deficient in glycosylphosphatidylinositol (GPI)-anchored proteins using a sensitive flow cytometric assay. A significant increase in the frequency of CD55 + CD59 + CD11b + granulocytes (>0.003%) compared to normal individuals was observed in 31 of 35 (88.6%) patients with untreated AA at diagnosis. The proportions of patients showing increased PNH granulocytes in treated AA patients with a short ( 5 yr) disease duration were 68.6% (11/16) and 20.4% (10/49), respectively. When 19 patients showing increased frequency of PNH granulocytes before therapy were studied 6-12 months after antithymocyte globulin plus cyclosporin A therapy, the frequency decreased to 0.01-90% of pretreatment values in 15 recovering patients. These findings suggest that a relative increase in the number of PNH granulocytes is a common feature of AA at diagnosis, and that it may represent the presence of immunologic pressure to normal haematopoietic stem cells as a cause of AA.

A 1-yr-old Japanese male infant developed hepatitis-associated aplastic anemia (AA), and anti-thymocyte globulin (ATG) plus cyclosporine A (CsA) was administered without any appreciable effects. Laboratory examination of the patient's serum obtained before therapy revealed various autoantibodies, such as PA-IgG, anti-platelets, anti-single-stranded DNA (ssDNA), and anti-double-stranded DNA (dsDNA) antibodies (Abs) in addition to anti-DRS-1 Abs and anti-moesin Abs, both of which are known to be detectable in approximately 40% of all patients presenting with AA. He was therefore treated with 17.5 mg/kg/d rituximab 5.5 months after ATG/CsA therapy. The same rituximab therapy was repeated three times once a month thereafter. His neutrophil counts started to increase 50 d after the first rituximab therapy and he achieved a complete remission at 16 months after the last rituximab administration. All of the autoantibodies including anti-ssDNA, dsDNA, DRS-1, and moesin became undetectable when he attained the remission. Anti-CD20 monoclonal antibody therapy may be effective in a subset of patients with AA characterized by the presence of autoantibodies.

A marked increase in CD16+ CD56- NK cells in the peripheral blood (PB) was observed in a cord blood transplant (CBT) recipient with refractory acute myeloid leukaemia (AML) in association with attaining molecular remission. CD16+ CD56- NK cells isolated from the patient became CD16+CD56+NKG2D+ when they were cultured in the presence of IL-2. Although cultured CD16+CD56- NK cells retained the killer-cell immunoglobulin receptor (KIR)-ligand (KIR-L) specificity and the patient's leukemic cells expressed corresponding KIR ligands, they killed patient's leukemic cells expressing ULBP2. The cytotoxicity by cultured CD16+CD56- NK cells was abrogated by anti-ULBP2 antibodies. When leukemic cells obtained at relapse after CBT were examined, both the ULBP2 expression and susceptibility to the cultured NK cells decreased in comparison to leukemic cells obtained before CBT. An increase in the CD16+CD56- NK cell count (0.5 x 10(9)/L or more) in PB was observed in seven of 11 (64%) CBT recipients but in none of 13 bone marrow (BM) and eight peripheral blood stem cell (PBSC) transplant recipients examined during the similar period after transplantation. These findings suggest an increase in CD16+CD56- NK cells to be a phenomenon unique to CBT recipients and that mature NK cells derived from this NK cell subset may contribute to the killing of leukemic cells expressing NKG2D ligands in vivo.

Objective: Myelodysplastic syndromes (MDS) and aplastic anemia (AA) are the most common anemias that require transfusion therapy in Japan. This retrospective survey investigated relationships between iron overload, chelation practices, and morbidity/mortality in patients with these diseases. Method: Medical histories of transfusion-dependent patients were assessed at transfusion onset, chelation onset, and study end. Results: Data were collected from 292 patients with MDS, AA, pure red cell aplasia, myelofibrosis, and other conditions. Patients received a mean of 61.5 red blood cell units during the previous year. Fewer than half (43%) of patients had previously received deferoxamine (DFO) therapy. Only 8.6% received daily/continuous DFO. In all, 75 deaths were reported, with cardiac and liver failure noted in 24.0 and 6.7% of cases. Of these, 97% had ferritin levels >1000 ng/mL. Abnormal cardiac and liver function was observed in 21.9% (14/64) and 84.6% (11/13) of all patients assessed. Effective chelation with DFO resulted in improved serum ferritin, liver enzymes, and fasting blood sugar. Conclusions: Mortality is higher in heavily iron-overloaded patients, with liver and cardiac dysfunction being the primary cause. Daily/continuous chelation therapy was effective at reducing iron burden and improving organ function. Chelation therapy should be initiated once serum ferritin levels exceed 1000 ng/mL.

Human leukocyte antigen (HLA)-mismatched stem cell transplantation from non-inherited maternal antigen (NIMA)-complementary donors is known to produce stable engraftment without inducing severe graft-versus-host disease (GVHD). We treated two patients with acute myeloid leukemia (AML) and one patient with severe aplastic anemia (SAA) with HLA-mismatched stem cell transplantation (SCT) from NIMA-complementary donors (NIMA-mismatched SCT). The presence of donor and recipient-derived blood cells in the peripheral blood of recipient (donor microchimerism) and donor was documented respectively by amplifying NIMA-derived DNA in two of the three patients. Graft rejection occurred in the SAA patient who was conditioned with a fludarabine-based regimen. Grade III and grade IV acute GVHD developed in patients with AML on day 8 and day 11 respectively, and became a direct cause of death in one patient. The findings suggest that intensive conditioning and immunosuppression after stem cell transplantation are needed in NIMA-mismatched SCT even if donor and recipient microchimerisms is detectable in the donor and recipient before SCT.

In an attempt to characterize host-derived haemopoietic cells in mixed haemopoietic chimeras, we studied bone marrow cells from male patients with chronic myelocytic leukaemia (CML) transplanted with marrow grafts from female donors. Amplification of a Y chromosome-specific sequence (YDNA) in DNA from marrow mononuclear cells using polymerase chain reaction (PCR) revealed persistence of host cells in 2 of 3 patients studied. On the other hand, persistence of Ph1-positive cells was unable to be demonstrated in the marrow cells from these patients using reverse transcription PCR (RT-PCR) for detecting bcr-abl chimeric messenger RNA. RT-PCR sensitivity for detecting minimal Ph1-positive cells in a background of Ph1-negative cells proved better than that of the PCR for detecting male cells among female cells. When bone marrow progenitor cells from one of the documented mixed chimeras were analyzed after an in vitro colony assay using PCR, 2 of 12 erythroid burst-forming units (BFU-E) proved to be YDNA-positive, i.e., of host origin, whereas none of them was shown to be Ph1-positive, although 12 BFU-E analyzed in the marrow cells obtained pretransplant from the same patient were all YDNA- and Ph1-positive. These findings indicate that, in some marrow transplant recipients with CML, a small number of host-derived normal haemopoietic progenitor cells may persist following lethal chemoradiotherapy and allogeneic bone marrow transplantation despite the fact that Ph1-positive clones can be eradicated.