Thymic retention of CD4+CD25+FoxP3+ T regulatory cells is associated with their peripheral deficiency and thrombocytopenia in a murine model of immune thrombocytopenia

Immune thrombocytopenia (ITP) is a bleeding disorder in which antibodies and/or T cells lead to enhanced peripheral platelet destruction and reduced bone marrow platelet production. Several reports have observed that ITP is associated with a peripheral deficiency of tolerance-inducing CD4(+)CD25(+)FoxP3(+) T regulatory cells (Tregs). Using a murine model of ITP, we analyzed Tregs in the spleen and thymus. CD61 knockout mice were immunized against wild-type (CD61(+)) platelets, and their splenocytes were transferred into severe combined immunodeficient (SCID) mice. Compared with SCID mice receiving naive splenocytes, within 2 weeks after transfer, the ITP SCID mice became thrombocytopenic (< 200 × 10(9) platelets/L) and had increased serum anti-CD61 antibodies. The quantity of thymic Tregs by 2 weeks after transfer was significantly elevated, whereas Tregs in the spleens were significantly reduced. Treatment of the ITP mice with 2 g/kg intravenous immunoglobulin raised the platelet counts, reduced antibody production, and normalized the thymic and splenic Treg populations. Compared with thymocytes from ITP mice treated with intravenous immunoglobulin, thymocytes from untreated ITP mice delayed the onset of ITP when administered before engraftment with immune splenocytes. These results suggest that ITP in mice is associated with a peripheral Treg deficiency because of thymic retention and therapy normalizes the Tregs.     

Defective circulating CD25 regulatory T cells in patients with chronic immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is characterized by the presence of antiplatelet autoantibodies as a result of loss of tolerance. CD4+CD25+ regulatory T cells (Tregs) are important for maintenance of peripheral tolerance. Decreased levels of peripheral Tregs in patients with ITP have been reported. To test whether inefficient production or reduced immunosuppressive activity of Tregs contributes to loss of tolerance in patients with chronic ITP, we investigated the frequency and function of their circulating CD4+CD25(hi) Tregs. We found a com-parable frequency of circulating CD4+CD25(hi)Foxp3+ Tregs in patients and controls (n = 16, P > .05). However, sorted CD4+CD25(hi) cells from patients with chronic ITP (n = 13) had a 2-fold reduction of in vitro immunosuppressive activity compared with controls (n = 10, P < .05). The impaired suppression was specific to Tregs as shown by cross-mixing experiments with T cells from controls. These data suggest that functional defects in Tregs contribute to breakdown of self-tolerance in patients with chronic ITP.     

供体CD+4CD+25T细胞及调控基因FOXP3在急性移植物抗宿主病中的作用

目的 探讨供体CD+4CD+25T细胞亚群、FOXP3调控基因的表达与受者移植物抗宿主病(GVHD)的相关性.方法 (1)30例异基因造血干细胞移植(allo-HSCT),采用免疫荧光标记和流式细胞术检测并比较供体粒细胞集落刺激因子(G-CSF)动员前外周血、动员后采集物CD+4CD+25T细胞亚群比例,随访异基因移植后GVHD的发生率和严重程度.(2)应用RT-PCR技术检测供体FOXP3基因表达情况,分析其与GVHD、疾病复发的相关性.结果 (1)所有患者均获造血重建,粒细胞绝对数(ANC)≥0.5×109/L的中位时间为14(12～15)d,PLT≥20×109/L为18(15～25)d.30例allo-HSCT,中位随访时间12.8(8～16)个月,Ⅰ～Ⅳ度急性GVHD分别为3、4、3、5例.慢性GVHD 6例.(2)供体G-CSF动员前外周血、动员后采集物CD+4CD+25T细胞亚群分别为(2.67±0.38)%、(5.01±1.33)%,两者相比差异无统计学意义(P＞0.05).(3)移植后无急性GVHD组、Ⅰ～Ⅱ度急性GVHD组、Ⅲ～Ⅳ度急性GVHD组供体CD+4CD+25T细胞亚群分别为(5.05±1.34)%、(4.17±1.73)%、(1.98±1.10)%.其中Ⅰ～Ⅱ度急性GVHD组与Ⅲ～Ⅳ度急性GVHD组相比差异有统计学意义(P=0.04),无急性GVHD组与Ⅲ～Ⅳ度急性GVHD组相比差异有统计学意义(P=0.002).(4)30例allo-HSCT,7例FOXP3基因表达阳性,5/7例移植后无急性GVHD,其中3例移植后复发,另2/7例移植后Ⅰ度急性GVHD,Ⅱ～Ⅳ度急性GVHD患者FOXP3均不表达.结论 (1)供体CD+4CD+25T细胞亚群比例与受者急性GVHD的发生具有一定的相关性,提高供体CD+4CD+25T细胞数量有望减低移植后急性GVHD发生率.(2)供体移植物FOXP3基因表达阳性,与移植后有无严重急性GVHD发生存在一定相关性.     

利妥昔单抗治疗糖皮质激素无效的特发性血小板减少性紫癜疗效观察

目的 探讨利妥昔单抗治疗特发性血小板减少性紫癜(ITP)的疗效、安全性及治疗前后B细胞、血小板膜糖蛋白(GP)特异性自身抗体的变化.方法 利妥昔单抗(375 mg/m2,每周1次,连用4周)治疗12例糖皮质激素治疗无效的ITP患者,监测治疗前后的血常规、血清免疫球蛋白定量(IgG、IgM、IgA)、血小板GPⅡb/Ⅲa和(或)GP Ⅰ b/Ⅸ特异性自身抗体、CD+3、CD+4、CD+8、CD+19、CD+20细胞数.结果 4例完全有效,3例部分有效,2例微效,3例无效.随访中位时间5(0.5～12)个月,疗效均维持较好.有效患者治疗后血小板自身抗体均转阴.治疗前后血清IgG、IgM、IgA无明显变化,CD+3、CD+4、CD+8细胞数无明显变化.治疗后CD+19/CD+20细胞数(4.1±2.2)×106/L与治疗前(295.0±86.4)×106/L比较明显下降(P＜0.01).无严重不良反应.结论 利妥昔单抗治疗糖皮质激素无效的ITP患者安全、有效.     

原发性肝细胞癌患者CD4+CD25+调节性T淋巴细胞的频率、表型及功能

目的探讨CD4^＋CD25^＋调节性T淋巴细胞（CD4^＋CD25^＋Treg）在HCC患者外周血及肿瘤组织中的频率、抑制功能及临床意义。方法收集18例原发性HCC患者的PBMC、肝癌组织及相应的癌旁组织标本,以及10例CHB患者和15名健康对照的外周血标本,以三色与四色流式分析法分析PBMC以及肿瘤浸润的淋巴细胞中CD4^＋CD25^＋Treg的频率及表型,并同时分析其与HBV持续感染、肿瘤TNM分期和其他临床指标的关系,用BrdU掺入法评价CD4^＋CD25^＋Treg的免疫抑制功能。结果与健康对照组相比HCC患者、慢性HBV感染者外周血中CD4^＋CD25^＋Treg频率明显上升（P＜0．01）,且HCC患者肿瘤浸润的淋巴细胞中CD4^＋CD25^＋Treg的频率也明显上调（P＜0．01）;随着肿瘤的进展HCC患者外周血中CD4^＋CD25^＋Treg呈上升趋势（P＜0．05）; HCC患者CD4^＋CD25^＋Treg可非特异性地抑制自身活化的CD4^＋CD25^- T淋巴细胞,并呈剂量依赖性,且抑制能力与健康对照组相比差异无统计学意义。结论HCC患者外周血中及肿瘤组织中CD4^＋CD25^＋Treg的频率升高,增多的CD4^＋CD25^＋Treg可能参与抑制抗HCC的免疫应答,从而使肝癌细胞逃脱机体的“免疫监视”作用。     

Reduced transforming growth factor-beta1 production by mononuclear cells from patients with active chronic idiopathic thrombocytopenic purpura

Chronic idiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder in which activated T-helper (Th) cells and different Th-cell cytokines might play an important role. We have recently reported that chronic ITP patients in remission had elevated plasma levels of the Th3 cytokine transforming growth factor-beta1 (TGF-beta1), possibly as a part of a bystander immune suppression. In the present study we found that, in ITP patients with active disease [platelet count (plc) < 50 x 10(9)/l], mitogen-stimulated peripheral blood mononuclear cells (PBMC) had a significantly reduced production of TGF-beta1 (444 +/- 178 pg/ml; n = 6) compared with patients with plc 50-150 x 10(9)/l (1293 +/- 374 pg/ml; n = 9; P < 0.05), patients with plc >150 x 10(9)/l (1894 +/- 244 pg/ml; n =12; P <0.005) and healthy controls (1698 +/- 241 pg/ml; n = 10; P < 0.01). Nineteen per cent of ITP patients expressed a platelet-induced PBMC proliferation. Surprisingly, 22% of the ITP patients had a PBMC proliferation below the normal range, i.e. a suppressed proliferation in the presence of platelets; five of these six patients had active disease. In summary, this study demonstrated that chronic ITP patients with active disease had reduced PBMC production of the Th3 cytokine TGF-beta1. This result gives further support to the theory that chronic ITP in active phase is associated with a downregulated Th3-response.     

Rituximab chimeric anti-CD20 monoclonal antibody treatment for adults with chronic idiopathic thrombocytopenic purpura

The role of rituximab, a chimeric monoclonal antibody directed against the CD20 antigen, in the treatment of patients with chronic idiopathic thrombocytopenic purpura (ITP) has not been determined. The effectiveness and side effects of this therapeutic modality were investigated in a cohort of 25 individuals with chronic ITP. All patients had ITP that had been resistant to between 2 and 5 different therapeutic regimens, including 8 patients who had already failed splenectomy. Patients were scheduled to receive intravenous rituximab at the dose of 375 mg/m(2) once weekly for 4 weeks. Rituximab infusion-related side effects were observed in 18 patients, but were of modest intensity and did not require discontinuation of treatment. A complete response (platelet count greater than 100 x 10(9)/L) was observed in 5 cases, a partial response (platelet count between 50 and 100 x 10(9)/L) in 5 cases, and a minor response (platelet count below 50 x 10(9)/L, with no need for continued treatment) in 3 cases, with an overall response rate of 52%. In 7 cases, responses were sustained (6 months or longer). In 2 patients with relapsed disease, repeat challenge with rituximab induced a new response. In patients with a complete or partial response, a significant rise in platelet concentrations was observed early during the course of treatment, usually 1 week after the first rituximab infusion. No clinical or laboratory parameter was found to predict treatment outcome, although there was a suggestion that women and younger patients have a better chance of response. In conclusion, rituximab therapy has a limited but valuable effect in patients with chronic ITP. In view of its mild toxicity and the lack of effective alternative treatments, its use in the setting of chronic refractory ITP is warranted. (Blood. 2001;98:952-957)     

TNF downmodulates the function of human CD4+CD25hi T-regulatory cells

CD4+CD25+ T-regulatory cells (Tregs) play an essential role in maintaining immunologic homeostasis and preventing autoimmunity. However, little is known about the exogenous factors that regulate their differentiation and function. Here, we report that TNF inhibits the suppressive function of both naturally occurring CD4+CD25+ Tregs and TGFbeta1-induced CD4+CD25+ T-regulatory cells. The mechanism of this inhibition involves signaling through TNFRII that is constitutively expressed selectively on unstimulated Tregs and that is up-regulated by TNF. TNF-mediated inhibition of suppressive function is related to a decrease in FoxP3 mRNA and protein expression by the Tregs. Notably, CD4+CD25hi Tregs isolated from patients with active rheumatoid arthritis (RA) expressed reduced levels of FoxP3 mRNA and protein and poorly suppressed the proliferation and cytokine secretion of CD4+ effector T cells in vitro. Treatment with anti-TNF antibody (infliximab) increased FOXP3 mRNA and protein expression by CD4+CD25hi Tregs and restored their suppressive function. Thus, TNF has a novel action in modulating autoimmunity, by inhibiting CD4+CD25+ Treg activity.     

Low percentages of regulatory T cells in common variable immunodeficiency (CVID) patients with autoimmune diseases and its association with increased numbers of CD4+CD45RO+ T and CD21low B cells

BackgroundCommon variable immunodeficiency (CVID) is a heterogeneous group of primary antibody deficiencies defined by marked reductions in serum IgG, IgA and/or IgM levels and recurrent bacterial infections. Some patients are associated with defects in T cells and regulatory T cells (Tregs), resulting in recurrent viral infections and early-onset autoimmune disease.MethodsWe analyzed whether there is an association between Tregs cells (CD4+CD25+CD127^low and CD4+CD25+FoxP3+); memory T cells (CD4+CD45RO+); memory B cells (CD19+CD27-IgD-); and CD21^low B cells (CD19+CD38^lowCD21^low); as well as autoimmune manifestations in 36 patients with CVID (25 women and 11 men, mean age 24 years), all by flow cytometry.ResultsFourteen patients presented with autoimmune diseases (AI) (39%), including 11 with autoimmune thrombocytopenia (ITP) (31%); two with vitiligo (6%); one with systemic lupus erythematosus (LES) (3%); and one with multiple sclerosis (MS) (3%). CVID patients with AI had a reduced proportion of Tregs (both CD4+CD25+CD127^low and FoxP3+ cells) compared with healthy controls. CVID patients with AI had expanded CD21^low B cell populations compared with patients who did not have AI. A correlation between increased CD4+CD45RO T cell populations and reduced Tregs was also observed.ConclusionsOur results showed that 39% of patients with CVID had AI and reduced Tregs populations. Research in this area might provide noteworthy data to better understand immune dysfunction and dysregulation related to CVID.     

Circulating dendritic cells subsets and CD4+Foxp3+ regulatory T cells in adult patients with chronic ITP before and after treatment with high-dose dexamethasome

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder, and high-dose dexamethasome (HD-DXM) has been used as a first-line therapy for patients with ITP. However, little is known about the role of dendritic cells (DCs) and CD4(+)Foxp3(+) regulatory T (Treg) cells in the pathogenesis of chronic ITP and the effects of HD-DXM on DCs and Treg cells. In this study, we investigated the amounts of circulating myeloid DCs (mDCs), plasmacytoid DCs (pDCs), and CD4(+)Foxp3(+) Treg cells in 26 untreated adult patients with chronic ITP. All patients had thrombocytopenia (platelet count <50 x 10(9)/L) for more than 6 months. We also observed short-time changes of DCs and Treg cells after treatment with HD-DXM in these patients. Both mDCs and pDCs numbers in patients were comparable with that of healthy controls. In contrast, the percentage of Treg cells was significantly reduced in patients when compared with healthy controls (P < 0.0001). After 4-days treatment with HD-DXM, Treg cells and mDCs were increased (P < 0.0001 and P < 0.05), while pDCs decreased (P < 0.0001), and CD11c expression level in mDCs was downregulated (P < 0.0001). These results suggest that Treg cells are deficient in ITP and the immunosuppressive therapy of glucocorticoids could cause the short-time changes of these cells.     

The CD34+90+ cell dose does not predict early engraftment of autologous blood stem cells as well as the total CD34+ cell dose

CD90 or Thy-1 is an antigen co-expressed with CD34+ on putative immature hematopoietic stem cells. Peak mobilization of CD34+90+ cells into the blood occurs a few days earlier than peak mobilization of total CD34+ cells. Because it is not known which cell type best correlates with engraftment, the optimal timing of apheresis remains unclear. The purpose of the study was to determine if the CD34+90+ cell dose predicts engraftment of autologous blood stem cells independent of the total CD34+ cell dose/kg, the dose of other CD34+ cell subsets (CD34+33-, CD34+38-, CD34+41+), or various clinical factors. Data were analyzed on 125 consecutive patients ranging in age from 19 to 66 years (median 46) who underwent autologous blood stem cell transplantation (ABSCT) for breast cancer (54), lymphoma (59), or other malignancies (12). By univariate analysis, neutrophil (> or = 0.5 x 10(9)/l) and platelet (> or = 20 x 10(9)/l or > or = 100 x 10(9)/l) engraftment correlated better with the total CD34+ cell dose than with the CD34+90+ cell subset. Using Cox proportional hazards models, factors independently associated with both neutrophil engraftment (> or = 0.5 x 10(9)/l) and platelet engraftment (> or = 20 x 10(9)/l and > or = 100 x 10(9)/l) were higher total CD34+ dose/kg and high-dose regimen (melphalan-containing slower than other regimens). In conclusion, the total CD34+ dose/kg was a better predictor of hematopoietic engraftment following ABSCT than the dose of any CD34+ subset, including CD34+90+ cells. Apheresis should continue to be timed according to peak CD34+ levels.     

Relationship of frequency of CD4+CD25+Foxp3+ regulatory T cells with disease progression in antiretroviral-naive HIV-1 infected Chinese

Forty-five antiretroviral-naive HIV-1 infected patients and 14 healthy controls in North China were enrolled in this study. The frequency of CD4+CD25+Foxp3+ regulatory T cells (Tregs) and levels of expression of CD95, HLA-DR and CD38 in T cells were detected by flow cytometry. We found that the frequency of Tregs was higher in AIDS patients than in asymptomatic HIV-1 infected patients (P=0.004). The frequency of Tregs was significantly correlated with absolute CD4 count, viral load, CD4+CD95+ T cells and CD8+CD95+ T cells (P<0.05). The relationship between the frequency of Tregs and immune activation was not found in HIV-infected patients. We concluded that the frequency of Tregs in HIV-infected Chinese patients was significantly correlated with disease progression.     

Rituximab efficacy and safety in adult splenectomy candidates with chronic immune thrombocytopenic purpura: results of a prospective multicenter phase 2 study

Whether rituximab could effectively and safely avoid splenectomy for adults with chronic immune thrombocytopenic purpura (ITP) remains unresolved. A multicenter, prospective, open-label, single-arm, phase 2 trial was conducted to assess rituximab safety and efficacy in adult splenectomy candidates with chronic ITP. Sixty patients with chronic (>or= 6 months) ITP and platelet counts less than 30 x 10(9)/L received a weekly intravenous infusion of rituximab (375 mg/m(2)) for 4 weeks. All other ITP treatments were stopped. A good response was defined as a platelet count 50 x 10(9)/L or more, with at least a doubling of the initial value at 1 and 2 years after the first rituximab infusion. Patients who required another treatment during follow up were considered nonresponders. Sixteen patients experienced transient side effects that necessitated treatment discontinuation for only 1. Good 1-year responses were obtained in 40% of the patients (24/60 [95% confidence interval: 28%-52%]). At 2 years, 33.3% (20/60 patients) had good responses and 6.7% (4/60) had sustained platelet counts of 30 x 10(9)/L or more without treatment. Thirty-six (60%) patients failed to respond; 25 underwent splenectomy. Based on these results, rituximab was an apparently safe and effective splenectomy-avoiding option in some adults with chronic ITP. This trial is registered at http://clinicaltrials.gov as NCT00225875.     

High-dose intravenous gammaglobulin (IVG) in neonatal immune thrombocytopenia

Recent reports suggest that intravenous gammaglobulin (IVG) may be an effective treatment modality in patients with immune thrombocytopenia (ITP). Two newborns with isoimmune thrombocytopenia secondary to HLA-A2 and PLA1 platelet antigen incompatibilities with their respective mothers and two newborns with thrombocytopenia secondary to maternal ITP were treated with IVG 400 mg/kg/day x 5 days. One patient was exposed to steroids in utero; only one mother was thrombocytopenic at the time of delivery. All patients were severely thrombocytopenic on day 1 of treatment with mean platelet count of 5.7 x 10(9)/L. All had petechiae and positive quaiac stools, and patients with isoimmune thrombocytopenia had CT scan evidence of intracranial bleeds. The mean platelet count after 24 hr was 26.7 x 10(9)/L and the average platelet increase was 21 x 10(9)/L and 33 x 10(9)/L at 24 and 48 hr, respectively. The two cases with isoimmune thrombocytopenia had sustained platelet increases; the two cases secondary to maternal ITP had transient platelet elevations. IVG can rapidly elevate the platelet count in these patients, especially those with severe bleeding manifestations.     

Upregulation of CD72 expression on CD19+CD27+ memory B cells by CD40L in primary immune thrombocytopenia

CD72 is a co‐receptor of B cells and regulates B cell activation. Although aberrant expression of CD72 has been reported in primary immune thrombocytopenia (ITP), it is uncertain whether this aberrant expression is restricted to specific B cell subsets. Furthermore, the mechanisms that regulate CD72 expression are unknown. In this study, we found higher frequency of CD19⁺ B cells, CD19⁺CD27⁺ memory B cells and lower frequency of CD19⁺CD27⁻ naive B cells in active ITP patients compared with controls and patients in remission. CD72 expression on CD19⁺CD27⁺ cells was upregulated in active ITP patients and correlated with platelet count and anti‐platelet autoantibodies. In vitro, CD40L could specifically induce CD72 upregulation on CD19⁺CD27⁺ B cells. In combination with CD40L, interleukin (IL) 10 and BAFF (also termed TNFSF13B) further enhanced CD72 expression on CD19⁺CD27⁺ B cells, whereas IL21 reduced CD72 upregulation. CD72mRNA expression after CD40L stimulation was increased in ITP patients and controls. Significant increase of CD40L on CD4⁺ T cells was correlated with CD72 expression on CD19⁺CD27⁺ B cells in ITP patients. In conclusion, upregulation of CD72 expression on CD27⁺memory B cells might take part in the pathogenesis of ITP. Elevated CD40L on CD4⁺ cells combined with cytokines might contribute to the upregulation of CD72 expression on CD27⁺memory B cells.     

Autologous stem cell transplantation for autoimmunity induces immunologic self-tolerance by reprogramming autoreactive T cells and restoring the CD4+CD25+ immune regulatory network

Despite a rapidly accumulating clinical experience with autologous stem cell transplantation (ASCT) as a treatment for severe refractory autoimmune disease, data on the mechanisms by which ASCT induces immune tolerance are still very scarce. In this study it is shown that ASCT restores immunologic self-tolerance in juvenile idiopathic arthritis (JIA) via 2 mechanisms. First, ASCT induces a restoration of the frequency of FoxP3 expressing CD4+CD25bright regulatory T cells (Tregs) from severely reduced numbers before ASCT to normal levels after ASCT. This recovery is due to a preferential homeostatic expansion of CD4+CD25+ Tregs during the lymphopenic phase of immunereconstitution, as measured by Ki67 and CD44 expression, and to a renewed thymopoiesis of naive mRNA FoxP3 expressing CD4+CD25+ Tregs after ASCT. Second, using artificial antigen-presenting cells to specifically isolate self-reactive T cells, we demonstrate that ASCT induces autoimmune cells to deviate from a proinflammatory phenotype (mRNA interferon-gamma [IFN-gamma] and T-bet high) to a tolerant phenotype (mRNA interleukin-10 [IL-10] and GATA-3 high). These data are the first to demonstrate the qualitative immunologic changes that are responsible for the induction of immune tolerance by ASCT for JIA: the restoration of the CD4+CD25+ immune regulatory network and reprogramming of autoreactive T cells.     

Measurement of natural (CD4+CD25high) and inducible (CD4+IL-10+) regulatory T cells in patients with systemic lupus erythematosus

Abnormalities of regulatory T cells may play an important role in the loss of self-tolerance, which is a major characteristic of lupus. The objective of this study was to determine the ratio and the number of natural CD4+CD25highFoxp3+ and inducible CD4+IL-10+ regulatory T cells in lupus patients and to search correlation with disease activity. Seventy-two Hungarian lupus patients were enrolled in the study. Fourty-one age- and sex matched healthy donors served as controls. Flow cytometry was used for the quantification of CD4+CD25high Foxp3+ (nTreg) and CD4+IL-10+ (iTreg) cells. The ratio (3.06 +/- 1.45%) and the number (0.019 +/- 0.012 x 10(9)/L) of nTreg cells decreased in lupus significantly (P < 0.001 in both) as compared to normal controls (4.26 +/- 1.01% and 0.039 +/- 0.017 x 10(9)/L). The ratio of iTreg cells were significantly higher in patients than in controls (20.92 +/- 14.02% versus 15.49 +/- 11.65%, P < 0.03), but the number of these cell type did not differ in significant manner (0.314 +/- 0.236 x 10(9)/L versus 0.259 +/- 0.183 x 10(9)/L). The 19 active patients were characterised by significantly higher disease activity index (SLEDAI 8.63 +/- 2.95 versus 1.74 +/- 1.68, P < 0.001) and anti-DNA concentration (117.85 +/- 145.89 versus 37.36 +/- 68.85 IU/mL, P = 0.001) as compered to the 52 inactive patients. Furthermore, active patients required higher dose of methylprednisolon than inactive ones (14.8 +/- 10.6 versus 4.8 +/- 3.4 mg/day, P < 0.001). However, we did not find statistical significant difference in the number and ratio of the examined cell populations regarding to disease activity. Altered ratio and number of both natural and inducible regulatory T cells may play a role in the pathogenesis of lupus. There are small but appreciable difference in the number of regulatory T cells between inactive patients and healthy controls. It suggests that immunoregulatory deficiencies are present in the inactive stage of the disease also.     

CD34+/CD90+ cells infused best predict late haematopoietic reconstitution following autologous peripheral blood stem cell transplantation

This study aimed to identify which graft product subset of cells might be the most predictive of late haematopoietic recovery (three to 12 months) following autologous peripheral blood stem cell transplantation (PBSCT). The relationships between the numbers of reinfused CD34+ cells and their immature subsets such as CD34+/CD90+, CD34+/AC133+, CD34+/CD38- and CD34+/HLA-DR- cells, and haemoglobin, white blood cell (WBC) and platelet counts at 3, 6, 9 and 12 months after PBSCT, were studied in 25 patients with haematological and solid malignancies. The total CD34+ cell number, as well as CD34+/CD90+ and CD34+/AC133+ cell numbers, correlated with platelet counts at 3, 6, 9 and 12 months after PBSCT, but the CD34+/CD90+ cells infused best predicted platelet recovery during the first 12 months after PBSCT (P < 0.0238 at any time-point). The CD34+/AC133+ cell dose also correlated with WBC counts at 3 months post PBSCT. In addition, all patients receiving more than 80 x 10(4) CD34+/CD90+ cells/kg showed platelet counts greater than 100 x 10(9)/l at all points after PBSCT, suggesting that this value of the CD34+/CD90+ cells infused was a threshold dose for durable haematopoietic engraftment after PBSCT.     

IL-5 promotes induction of antigen-specific CD4+CD25+ T regulatory cells that suppress autoimmunity

Immune responses to foreign and self-Ags can be controlled by regulatory T cells (Tregs) expressing CD4 and IL-2Rα chain (CD25). Defects in Tregs lead to autoimmunity, whereas induction of Ag-specific CD4+CD25+ Tregs restores tolerance. Ag-specific CD4+CD25+ FOXP3+Tregs activated by the T helper type 2 (Th2) cytokine, IL-4, and specific alloantigen promote allograft tolerance. These Tregs expressed the specific IL-5Rα and in the presence of IL-5 proliferate to specific but not third-party Ag. These findings suggest that recombinant IL-5 (rIL-5) therapy may promote Ag-specific Tregs to mediate tolerance. This study showed normal CD4+CD25+ Tregs cultured with IL-4 and an autoantigen expressed Il-5rα. Treatment of experimental autoimmune neuritis with rIL-5 markedly reduced clinical paralysis, weight loss, demyelination, and infiltration of CD4+ (Th1 and Th17) CD8+ T cells and macrophages in nerves. Clinical improvement was associated with expansion of CD4+CD25+FOXP3+ Tregs that expressed Il-5rα and proliferated only to specific autoantigen that was enhanced by rIL-5. Depletion of CD25+ Tregs or blocking of IL-4 abolished the benefits of rIL-5. Thus, rIL-5 promoted Ag-specific Tregs, activated by autoantigen and IL-4, to control autoimmunity. These findings may explain how Th2 responses, especially to parasitic infestation, induce immune tolerance. rIL-5 therapy may be able to induce Ag-specific tolerance in autoimmunity.     

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.