Altered effector CD4+ T cell function in IL-21R-/- CD4+ T cell-mediated graft-versus-host disease.

We previously showed that transplantation with IL-21R gene-deficient splenocytes resulted in less severe graft-versus-host disease (GVHD) than was observed with wild type splenocytes. In this study, we sought to find mechanism(s) explaining this observation. Recipients of donor CD4(+) T cells lacking IL-21R exhibited diminished GVHD symptoms, with reduced inflammatory cell infiltration into the liver and intestine, leading to prolonged survival. After transplantation, CD4(+) T cell numbers in the spleen were reduced, and MLR and cytokine production by CD4(+) T cells were impaired. These results suggest that IL-21 might promote GVHD through enhanced production of effector CD4(+) T cells. Moreover, we found that CD25 depletion altered neither the impaired MLR in vitro nor the ameliorated GVHD symptoms in vivo. Thus, the attenuated GVHD might be caused by an impairment of effector T cell differentiation itself, rather than by an increase in regulatory T cells and suppression of effector T cells.

Mesenchymal stromal cells inhibit Th17 but not regulatory T-cell differentiation.

BACKGROUND AIMS: A previous study has demonstrated that mouse mesenchymal stromal cells (MSC) produce nitric oxide (NO), which suppresses signal transducer and activator of transcription (STAT) 5 phosphorylation and T-cell proliferation under neutral and T helper 1 cells (Th1) conditions. We aimed to determine the effects of MSC on T helper 17 cells (Th17) and regulatory T-cell (T-reg) differentiation. METHODS: CD4 T cells obtained from mouse spleen were cultured in conditions for Th17 or Treg differentiation with or without mouse MSC. Th17 and Treg differentiation was assessed by flow cytometry using antibodies against interleukin (IL)-17 and forkhead box P3 (Foxp3), a master regulator of Treg cells. RESULTS: MSC inhibited Th17 but not Treg differentiation. Under Th17 conditions, MSC did not produce NO, and inhibitors of indoleamine-2,3-dioxygenase (IDO) and prostaglandin E(2) (PGE2) both restored MSC suppression of differentiation, suggesting that MSC suppress Th17 differentiation at least in part through PGE2 and IDO. CONCLUSIONS: Our results suggest that MSC regulate CD4 differentiation through different mechanisms depending on the culture conditions.

Prognostic impact of serum soluble interleukin-2 receptor level at diagnosis in elderly patients with diffuse large B-cell lymphoma treated with R-CHOP.

Diffuse large B-cell lymphoma (DLBCL) is a clinically heterogeneous disease. To evaluate the clinical relevance of the serum soluble interleukin-2 receptor (sIL-2R) level, we retrospectively analyzed 178 patients aged ≥60 years who were newly diagnosed with DLBCL. We determined the cutoff value of the sIL-2R level to be 1280 U/mL using the area under the receiver operating characteristic curve. The high sIL-2R group exhibited significantly inferior 5-year progression-free survival (PFS) (36.2% vs. 86.1%, p < .001) and 5-year overall survival (OS) (49.7% s. 83.8%, p < .001) than the low sIL-2R group. Multivariate analysis revealed that a high sIL-2R level was a significant prognostic factor for PFS and OS (hazard ratio [HR]: 5.65, p < .001 and HR: 2.99, p = .001, respectively). This study showed that measurement of the sIL-2R level at diagnosis is clinically beneficial for identifying elderly patients with DLBCL who have a poor prognosis.

Mechanisms of immunomodulation by mesenchymal stem cells.

Mesenchymal stem cells (MSCs) have been identified in animals, especially in bone marrow. As stem cells, they have the ability to differentiate into multiple cell types. This potential raises exciting therapeutic possibilities. A recent report described the successful use of MSCs for the treatment of graft-versus-host disease; however, the scientific community has yet to define the molecular mechanisms of immunomodulation by MSCs. This review summarizes what is known and discusses the conflicting data with regard to the mechanisms of immunomodulation by MSCs.

Pleocytosis after hemopoietic stem cell transplantation.

Frequency and clinical significance of cerebrospinal fluid (CSF) pleocytosis in hemopoietic stem cell (HSC) transplantation were surveyed. Cyclosporine (CSA)- or tacrolimus (FK506)-based regimens were used as graft-vs-host disease (GVHD) prophylaxis in allogeneic HSC transplantation. CSF pleocytosis with or without neurologic symptoms was detected in 12 of 25 patients receiving allogeneic HSC transplants but in none of 11 patients receiving autologous HSC transplants. Of the 12 patients with CSF pleocytosis, only one patient developed leukoencephalopathy later. There was a correlation between CSF cell numbers and trough levels of CSA but not with those of FK506. In patients receiving allogeneic HSC transplants, CSF pleocytosis may be relatively common and may reflect neurologic damage associated with calcineurin inhibitors.

Distribution of serum erythropoietin levels in Japanese patients with myelodysplastic syndromes.

Erythropoiesis-stimulating agents (ESAs) are used to ameliorate anemia in lower-risk myelodysplastic syndromes (MDS). Serum erythropoietin (EPO) level <500 IU/L is widely accepted as a major predictive factor for response to ESAs. However, few data about EPO levels in the Japanese population are available. We therefore evaluated distribution of serum EPO levels in Japanese patients with MDS. Forty-three cases were analyzed; 30 were classified as lower-risk MDS (low or intermediate-1 by the international prognostic scoring system). Twenty-two cases were transfusion dependent. The overall median hemoglobin level was 7.7 g/dL. The median value of serum EPO was 254 IU/L (range: 16.4-23,000). Serum EPO levels had a strong inverse correlation with hemoglobin levels, and a significantly larger proportion of patients showed high EPO levels (>500 IU/L) in the transfusion-dependent group. In the higher-risk group, no significant correlation between EPO and hemoglobin was observed. Regression analyses showed that serum EPO of 500 IU/L corresponds to 8.29 g/dL of hemoglobin in lower-risk MDS. The results indicate that patients with hemoglobin levels of 8.0 g/dL or more, who are still transfusion independent, may be good candidates for ESA treatment.

[Minor bcr/abl positive acute lymphoblastic leukemia preceded by knee joint pain due to bone marrow necrosis].

A 16-year-old male was referred to our hospital in April 2003 due to severe knee joint pain from five months previously. Lymphoblasts were identified in his peripheral blood, resulting in a diagnosis of acute lymphoblastic leukemia (ALL). Bone marrow examination revealed massive necrosis with clusters of lymphoblasts and the bcr/abl fusion gene. Magnetic resonance imaging (MRI) of the knee joint showed low signal intensity on T1-weighted images, and peripheral rim enhancement on Gd-DTPA enhanced fat suppression images, which was compatible with bone marrow necrosis. After the patient achieved complete remission (CR), the knee joint pain has disappeared. He was treated with an allogeneic bone marrow transplantation (BMT) from an HLA-identical unrelated donor and has been in CR for 26 months after the diagnosis of ALL. In the knee joint, the replacement of fatty marrow after BMT has been confirmed with MRI. Hematological malignancies including ALL should be considered in the cases of bone marrow necrosis and adequate treatment may improve necrosis.

CD56 expression in normal immature granulocytes after allogeneic hematopoietic stem cell transplantation.

Bone marrow mononuclear cells from 93 patients with hematological malignancies after allogeneic hematopoietic stem cell transplantation (AHSCT) were analyzed using flow cytometry (FCM). The disease was acute myeloblastic leukemia (50 patients), acute lymphoblastic leukemia, and others. Conditioning was myeloablative (80 patients) or reduced intensity. The stem cell source was bone marrow (75 patients), peripheral blood stem cells, or cord blood. After AHSCT, granulocyte colony-stimulating factor was given to all patients. All patients showed engraftment of the donor cells. FCM was conducted on a median of 22 days after AHSCT. The gate was set around a granulocytic region consisting of immature granulocytes. The positivity rates of CD13, CD14, CD15, CD33, CD34, CD56, and HLA-DR in the cells were 59.9 ± 27.4%, 5.8 ± 8.8%, 98.3 ± 1.9%, 92.3 ± 12.4%, 2.6 ± 5.8%, 24.3 ± 16.7%, and 9.1 ± 6.6%, respectively. The greatest value of CD56 positivity was 73.1%. On the basis of CD56 expression, cases of more than 24% CD56 positivity were assigned to the CD56-high group (39 patients), while the rest were assigned to the CD56-low/negative group. There were no significant differences between the two groups in terms of disease status, sex, donor, hematopoietic stem cells, days of FCM analysis, or peripheral blood cell counts around the days of performing FCM. These results indicate that CD56 can be expressed in normal immature granulocytes at a variety of expression levels in regenerative bone marrow. Attention should be paid when evaluating aberrant antigen expression of CD56 in granulocytes.

Rituximab plus 70% cyclophosphamide, doxorubicin, vincristine and prednisone for Japanese patients with diffuse large B-cell lymphoma aged 70 years and older.

In the rituximab era, several large studies have suggested that full-dose rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) might be the best treatment for patients with diffuse large B-cell lymphoma (DLBCL) aged 60 years and older. However, it remains unclear whether this is also the case for those aged 70 years and older. Previously untreated patients with DLBCL aged 70 years and older (elderly) were treated with R-70%CHOP, and patients younger than 70 years (younger) were treated with full-dose R-CHOP every 3 weeks, for a total of 6-8 cycles. Complete remission (CR) rates in elderly versus younger patients were 75 vs. 78% (p = 0.7), respectively. The 3-year overall survival, event-free survival and progression-free survival of elderly versus younger patients were 58 vs. 78% (p < 0.05), 45 vs. 70% (p < 0.05) and 64 vs. 72% (p = 0.43), respectively. Severe adverse events were more frequent in the elderly, even with the dose reduction in that age group. Three-year PFS with R-70%CHOP for patients aged 70 years and older was not significantly worse than that with full-dose R-CHOP for younger patients, suggesting that R-70% CHOP might be a reasonable choice for patients with DLBCL aged 70 years and older, especially for those with comorbidities.

Nitric oxide plays a critical role in suppression of T-cell proliferation by mesenchymal stem cells.

The molecular mechanisms by which mesenchymal stem cells (MSCs) suppress T-cell proliferation are poorly understood, and whether a soluble factor plays a major role remains controversial. Here we demonstrate that the T-cell-receptor complex is not a target for the suppression, suggesting that downstream signals mediate the suppression. We found that Stat5 phosphorylation in T cells is suppressed in the presence of MSCs and that nitric oxide (NO) is involved in the suppression of Stat5 phosphorylation and T-cell proliferation. The induction of inducible NO synthase (NOS) was readily detected in MSCs but not T cells, and a specific inhibitor of NOS reversed the suppression of Stat5 phosphorylation and T-cell proliferation. This production of NO in the presence of MSCs was mediated by CD4 or CD8 T cells but not by CD19 B cells. Furthermore, inhibitors of prostaglandin synthase or NOS restored the proliferation of T cells, whereas an inhibitor of indoleamine 2,3-dioxygenase and a transforming growth factor-beta-neutralizing antibody had no effect. Finally, MSCs from inducible NOS-/- mice had a reduced ability to suppress T-cell proliferation. Taken together, these results suggest that NO produced by MSCs is one of the major mediators of T-cell suppression by MSCs.