急性髓系白血病患者外周血单个核细胞Toll样受体9以及血清肿瘤坏死因子和凋亡基因FAS的表达

背景：Toll样受体9(TLR9)、肿瘤坏死因子a、Fas可能共同参与白血病的发生发展过程。 目的：测定TLR9在急性髓系白血病患者外周血单个核细胞中的表达及血清肿瘤坏死因子α、Fas水平。 方法：从急性髓系白血病患者与正常对照组中分离出外周血单个核细胞,采用反转录-聚合酶链反应法检测外周血单个核细胞中TLR9 mRNA的表达水平,采用酶联免疫吸附试验法检测血清肿瘤坏死因子α、Fas水平。 结果与结论：在急性髓系白血病患者初治组和难治复发组中,外周血单个核细胞中TLR9 mRNA表达高于正常对照组(P < 0.01),化疗后完全缓解组与正常对照组差异无显著性意义(P > 0.05);各病例组血清肿瘤坏死因子α、Fas水平显著高于正常对照组(P < 0.01)。TLR9 mRNA的表达与血清肿瘤坏死因子α、Fas水平均呈正相关。     

CpG寡脱氧核苷酸对外周血单个核细胞功能的影响：1型糖尿病患者与健康者对照

背景：有研究表明CpG寡脱氧核苷酸可增强外周血单个核细胞的功能,但对1型糖尿病患者的影响至今少有报道。 目的：观察CpG寡脱氧核苷酸对1型糖尿患者患者与健康志愿者外周血单个核细胞γ干扰素、白细胞介素12,10表达的影响。 方法：将1型糖尿病患者与健康志愿者的外周血单个核细胞根据刺激物不同分为空白对照组、CpG寡脱氧核苷酸组。用RT-PCR法检测外周血单个核细胞γ干扰素、白细胞介素12 mRNA和白细胞介素10 mRNA的表达。 结果与结论：1型糖尿患者γ干扰素和白细胞介素12 mRNA的表达明显低于健康志愿者(P < 0.01)。1型糖尿患者与健康志愿者外周血单个核细胞经CpG寡脱氧核苷酸组刺激后,γ干扰素和白细胞介素12 mRNA的表达增高(P < 0.01),白细胞介素10 mRNA的表达无差异(P > 0.05)。结果提示,CpG寡脱氧核苷酸可促进1型糖尿患者外周血单个核细胞表达γ干扰素和白细胞介素12。     

急性髓系白血病细胞血管细胞黏附分子1、CD34和CD117的表达

背景：血管细胞黏附分子1与白血病浸润密切相关,白血病细胞本身是否表达血管细胞黏附分子1,以及与疾病难治是否相关尚无定论。 目的：分析血管细胞黏附分子1、CD34、CD117在急性髓系白血病细胞表面的表达,3者之间的相互关系及与难治性急性髓系白血病的相关性。 方法：采用流式细胞技术检测16例急性髓系白血病细胞中血管细胞黏附分子1、CD34、CD117的表达,其中难治组6例,非难治组10例;同时以正常骨髓单个核细胞标本作对照。 结果与结论：急性髓系白血病细胞CD34、CD117表达高于对照组(P < 0.05)。难治组急性髓系白血病细胞CD34表达明显高于非难治组(P < 0.05)。难治组与非难治组CD117表达差异无显著性意义(P > 0.05)。急性髓系白血病细胞血管细胞黏附分子1表达与对照组比较差异无显著性意义(P > 0.05)。难治组与非难治组血管细胞黏附分子1表达差异无显著性意义(P > 0.05)。表明急性髓系白血病细胞伴CD34表达,为不良预后指标之一,CD117、血管细胞黏附分子1表达与其是否难治无明显相关性。     

老年初诊急性髓细胞白血病患者CD4+CD25+调节性T细胞的表达

背景：研究证实,很多恶性肿瘤患者体内CD4⁺CD25⁺调节性T细胞存在高表达,近期也有研究发现,急性髓细胞白血病患者外周血CD4⁺CD25⁺调节性T细胞同样表现出高比例表达。 目的：分析老年初诊急性髓细胞白血病患者CD4⁺CD25⁺调节性T细胞的表达特点。 方法：纳入初诊急性髓细胞白血病患者92例,将年龄在60岁以下者设为中青年组(n=22),年龄在60岁以上者设为老年观察组(n=70)。在老年观察组中,32例经规范化疗后完全缓解,设为完全缓解组;将余下38例设为老年组,依据FAB分型标准,分为M2 6例、M3 19例、M4 7例、M5 6例。另选择同期体检健康人群42名作为正常对照组。抽取受试者外周静脉血,检测CD4⁺CD25⁺调节性T细胞表达情况。 结果与结论：老年组、完全缓解组CD4⁺CD25^highFOXP3⁺调节性T细胞比例高于正常对照组(P < 0.01),并且老年组CD4⁺CD25^high FOXP3⁺调节性T细胞比例高于完全缓解组(P < 0.01)。老年组、完全缓解组CD4⁺FOXP3⁺T细胞比例高于正常对照组(P < 0.01),并且老年组CD4⁺ FOXP3⁺T细胞比例高于完全缓解组(P < 0.01)。老年组CD4⁺CD25^high FOXP3⁺调节性T细胞与CD4⁺ FOXP3⁺T细胞比例高于中青年组(P < 0.01)。老年组不同分型间CD4⁺CD25^high FOXP3⁺调节性T细胞和CD4⁺ FOXP3⁺T细胞比例比较差异均无显著性意义(P > 0.05)。Pearson相关性检验结果显示,老年初诊急性髓细胞白血病患者外周血CD4⁺CD25^high FOXP3⁺调节性T细胞比例和CD4⁺ FOXP3⁺T细胞比例呈正相关(r=0.87,P=0.019)。表明老年初诊急性髓细胞白血病患者CD4⁺CD25⁺调节性T细胞比例高于健康人群和中青年急性髓细胞白血病患者。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

流式细胞仪检测急性婴幼儿白血病干细胞

背景：有关儿童急性髓细胞性白血病干细胞含量的测定及急性髓细胞性白血病患儿缓解后白血病干细胞含量与急性白血病微小残留病之间关系的研究国内外未见报道。 目的：通过测定急性髓细胞性白血病干细胞或急性髓细胞性白血病干细胞-IPIC在儿童急性白血病患儿骨髓单个核细胞中的含量,研究急性髓细胞性白血病患儿缓解后白血病干细胞含量与急性白血病微小残留病水平之间的关联。 方法：收集白血病患儿113例次。采用骨髓单个核细胞分离及单细胞悬液制成单细胞悬液,进行单个核细胞染色、急性髓细胞性白血病干细胞分析及根据初诊免疫表型获得白血病相关表型,并采用该白血病相关免疫表型进行单抗组合和流式细胞术测定分析。 结果与结论：①初诊急性髓细胞性白血病组骨髓单个核细胞中急性髓细胞性白血病干细胞含量明显高于初诊急性淋巴细胞性白血病组和非肿瘤对照组(P均< 0.017),初诊急性淋巴细胞性白血病组骨髓单个核细胞中急性髓细胞性白血病干细胞-IPIC含量显著高于非肿瘤对照组(P < 0.017)。②对33例次缓解急性髓细胞性白血病患儿急性髓细胞性白血病干细胞和急性白血病微小残留病相关性分析发现,两者存在显著负相关性。结果提示,①急性髓细胞性白血病干细胞-IPIC也存在于初诊急性淋巴细胞性白血病患儿骨髓细胞中,且当急性淋巴细胞性白血病获完全缓解时急性髓细胞性白血病干细胞-IPIC含量却没有下降,但非肿瘤对照组标本中急性髓细胞性白血病干细胞-IPIC的含量极微。②急性髓细胞性白血病患儿缓解后骨髓中急性髓细胞性白血病干细胞含量和急性白血病微小残留病水平之间存在着明显的负相关。     

急性淋巴细胞白血病的免疫分型及CD4+CD25+T调节细胞检测

背景：在急性淋巴细胞白血病发病过程中,CD4⁺CD25⁺T调节细胞对机体免疫反应可能起着一定的调节作用。 目的：观察急性淋巴细胞白血病患者的免疫分型及外周血CD4+CD25+T调节细胞的变化情况。 方法：采用流式细胞仪对35例急性淋巴细胞白血病患者进行免疫分型,并检测外周血CD4⁺CD25⁺T调节细胞的数目,与18名健康对照作比较。 结果与结论：急性B细胞淋巴细胞白血病22例,急性T细胞淋巴细胞白血病13例;22例急性B细胞淋巴细胞白血病中CD19的阳性表达率最高(100%),而13例急性T细胞淋巴细胞白血病中CD7阳性表达率最高(100%)。急性B细胞淋巴细胞白血病患者外周血CD4⁺CD25⁺T调节细胞和急性T细胞淋巴细胞白血病患者差异无显著性意义(P > 0.05),但均高于健康对照(P < 0.05)。表明急性B细胞淋巴细胞白血病中CD19阳性表达率最高,急性T细胞淋巴细胞白血病中CD7阳性表达率最高,同时急性淋巴细胞白血病患者外周血CD4⁺CD25⁺T调节细胞水平显著增高。     

AML-M5患者外周血naive T细胞水平和TCR Vβ谱系利用特点

目的了解急性髓性白血病M5亚型(AML-M5)患者 T细胞受体重排删除DNA环(TRECs)的含量和TCR Vβ基因谱系利用和克隆性,从而了解AML患者的胸腺近期输出功能和TCR Vβ亚家族T细胞增殖特点.方法利用实时定量PCR(TaqMan)方法检测5例M5患者外周血单个核细胞TRECs的水平,并根据外周血中CD3阳性率计算CD3细胞中TRECs水平.利用RT-PCR和基因扫描分析患者外周血单个核细胞的TCR Vβ24个亚家族基因表达和克隆性.9例正常人外周血作为对照.结果 M5患者外周血中TRECs含量为0.76±1.21/1000 CD3+细胞,明显低于正常人TRECs水平(6.84±4.71/1000 CD3+细胞,p<0.05).5例患者外周血T细胞表达不同数量Vβ亚家族(2-16个).基因扫描分析显示4例病人外周血中的一些Vβ亚家族出现克隆性T细胞, Vβ1,Vβ15和Vβ21克隆性T细胞均分别见于3例病人中.结论率先报道了AML-M5型患者胸腺近期输出naive T细胞功能明显降低,尽管整体T细胞免疫功能低下,患者仍存在优势利用和克隆性增殖Vβ亚家族T细胞,提示其具有一定地对白血病细胞相关抗原产生特异性免疫反应的能力.     

急性淋巴细胞白血病患者骨髓单个核细胞TAp63基因的表达

背景：据作者查新检索,国内外有关急性白血病患者骨髓单个核细胞TAp63基因表达的报道罕见。 目的：观察急性淋巴细胞白血病患者骨髓单个核细胞TAp63基因的表达及其意义。 方法：50例急性淋巴细胞白血病患者,其中32例急性B淋巴细胞白血病,18例急性T淋巴细胞白血病。同期选择27例非恶性血液病患者作为对照。取肝素抗凝的骨髓液2~4 mL,用Ficoll液分离骨髓单个核细胞,半定量反转录聚合酶链反应法检测TAp63的表达。 结果与结论：50例急性淋巴细胞白血病患者有49例表达TAp63,急性淋巴细胞白血病组明显高于非恶性血液病组(P < 0.05),急性B淋巴细胞白血病表达水平显著高于急性T淋巴细胞白血病(P < 0.05)。动态观察了5例初治急性淋巴细胞白血病化疗后不同阶段TAp63的表达变化,发现初治时TAp63表达,缓解后低表达或不表达,复发后又表达。结果表明TAp63在急性淋巴细胞白血病患者骨髓单个核细胞的表达明显高于非恶性血液病患者,尤其在急性B淋巴细胞白血病患者中高表达。     

AML-M5患者外周血naive T细胞水平和TCR Vβ谱系利用特点

目的　了解急性髓性白血病M5亚型 (AML -M5 )患者T细胞受体重排删除DNA环 (TRECs)的含量和TCRVβ基因谱系利用和克隆性 ,从而了解AML患者的胸腺近期输出功能和TCRVβ亚家族T细胞增殖特点 .方法　利用实时定量PCR(TaqMan)方法检测 5例M5患者外周血单个核细胞TRECs的水平 ,并根据外周血中CD3阳性率计算CD3细胞中TRECs水平 .利用RT -PCR和基因扫描分析患者外周血单个核细胞的TCRVβ2 4个亚家族基因表达和克隆性 .9例正常人外周血作为对照 .结果　M5患者外周血中TRECs含量为 0 .76± 1.2 1/ 10 0 0CD3 细胞 ,明显低于正常人TRECs水平 (6 .84± 4 .71/ 10 0 0CD3 细胞 ,p <0 .0 5 ) .5例患者外周血T细胞表达不同数量Vβ亚家族 (2 - 16个 ) .基因扫描分析显示 4例病人外周血中的一些Vβ亚家族出现克隆性T细胞 ,Vβ1,Vβ15和Vβ2 1克隆性T细胞均分别见于 3例病人中 .结论　率先报道了AML -M5型患者胸腺近期输出naiveT细胞功能明显降低 ,尽管整体T细胞免疫功能低下 ,患者仍存在优势利用和克隆性增殖Vβ亚家族T细胞 ,提示其具有一定地对白血病细胞相关抗原产生特异性免疫反应的能力     

胚胎骨髓来源间充质干细胞对人Th17细胞的免疫调节

背景：众多研究表明间充质干细胞能发挥免疫调节功能,抑制T细胞增殖。 目的：观察胚胎骨髓来源间充质干细胞对人Th17细胞的调节作用。 方法：将人胚胎骨髓间充质干细胞与正常人外周血单个核细胞或CD4⁺ T细胞以1∶10比例共培养4 d,以单个核细胞或CD4⁺T细胞单独培养为对照。应用实时定量PCR检测细胞白细胞介素17 mRNA表达,酶联免疫吸附试验检测细胞上清中白细胞介素17蛋白水平,流式细胞术检测Th17细胞数量。 结果与结论：胚胎骨髓来源间充质干细胞与单个核细胞共培养组白细胞介素17 mRNA表达水平明显高于单个核细胞组(P < 0.01)。与此一致的是,胚胎骨髓来源间充质干细胞与单个核细胞或CD4⁺T细胞共培养组细胞上清中白细胞介素17蛋白水平明显高于单个核细胞组、CD4⁺ T细胞组(P < 0.05,P < 0.01)。胚胎骨髓来源间充质干细胞与CD4⁺ T细胞共培养组Th17细胞数量明显高于CD4⁺ T细胞组(P < 0.01),但胚胎骨髓来源间充质干细胞本身并不表达白细胞介素17。表明胚胎骨髓来源间充质干细胞可促进人Th17细胞增殖。     

CD4+CD25+Treg在急性淋巴细胞白血病患者外周血中的表达及其体外实验研究

目的初步探讨CD4 CD25 调节性T细胞(CD4 CD25 regulatory T cells,CD4 CD25 Treg)在急性淋巴细胞白血病(acute lymphocytic leukemia,ALL)患者化疗前及化疗缓解后外周血中的表达水平,并研究患者血清能否诱导外周血CD4 CD25-T细胞转化为CD4 CD25 Treg。方法①采用流式细胞术分别检测ALL初诊组、化疗完全缓解或部分缓解组及正常对照组外周血中CD4 CD25 T细胞所占比例,然后通过荧光定量RT-PCR检测各组外周血中转录因子Foxp3mRNA的表达水平,并逐层分析比较。②采集正常人外周血单个核细胞后,对照组用正常人血清,实验组用患者血清并分别设浓度梯度进行培养,72h后采用流式细胞术、荧光定量RT-PCR分别检测CD4 CD25 T细胞和Foxp3mRNA表达。结果ALL化疗缓解组CD4 CD25 T细胞及Foxp3mRNA表达水平均明显高于ALL初诊组和正常对照组(P<0.05),后两者之间CD4 CD25 T细胞水平无统计学差异(P>0.05),但ALL初诊组Foxp3mRNA含量较正常对照组明显升高(P<0.01),差异具有统计学意义;并且血清培养对照组CD4 CD25 T细胞水平及Foxp3mRNA含量均明显低于实验组(P<0.05),且其表达并不随血清浓度的增加而升高。结论CD4 CD25 Foxp3 Treg在ALL初诊组及化疗缓解组患者外周血中比例明显升高,且初步表明患者血清中的可溶性物质可诱导外周血CD4 CD25 T细胞转化为CD4 CD25 Treg,提示CD4 CD25 Treg可能是ALL免疫抑制的一个重要原因。     

初发急性髓性白血病患者外周血中高表达TAL1基因及其意义

目的:分析调控造血分化的重要转录因子TAL1在急性髓性白血病(AML)细胞株及原代AML细胞中的表达特点。方法:利用real-time PCR法分别检测47例初发急性髓性白血病患者外周血单个核细胞以及急性白血病细胞株(Jurkat、CCRF-CEM、HL-60和NB4细胞株)中TAL1 mRNA的水平,并以12例健康志愿者外周血样本作为对照组。结果:TAL1 mRNA在AML细胞株(HL-60和NB4)、T细胞急性淋巴细胞白血病(T-ALL)细胞株(Jurkat和CCRF-CEM)和原代AML细胞中的水平均显著高于健康对照组(P0.05)。各AML亚型中TAL1的mRNA表达水平均较对照组显著升高,并以AML-M1和AML-M5 2个亚型升高最为明显(P0.05)。结论:AML细胞中TAL1异常高表达可能与其影响粒系的分化发育有关,其能否作为AML发病相关分子标志物有待进一步研究。     

Aberrant expression of CD7, CD56, and CD79a antigens in acute myeloid leukemias

The prognostic significance of selected markers of leukemic cells is well known. CD7 and CD56 expression at diagnosis has been associated with low remission rates and biological aggressiveness in a significant proportion of acute leukemias. Among 46 patients with acute myeloid leukemia, we found CD7 expression in 15 cases (32.6%) and CD56 positivity in 10 patients (21.7%). Six of these myeloid leukemia cases (13%) showed expression of both CD7 and CD56. Four of 46 (8.7%) patients expressed CD79a. Among the 10 that were acute myeloblastic leukemia, 8 expressed CD7, 4 expressed CD56, and 4 were positive for CD79a. Thus, these markers were expressed early in hemopoietic ontogeny in the lesser-differentiated acute myeloid leukemia subtypes, including FAB M0, M1, and M2. Whereas CD7 and CD56 were each positive in 4 cases of acute myelomonocytic leukemia (FAB M4 subtype), there was no CD79a expression in the M4 cases. CD7 is expressed by mature T cells, NK cells, and an immature myeloid cell subset. NK cells and a T cell subset express CD56. By contrast, CD79a is a B cell marker that is assigned a high score of 2.0 in the differentiation of acute leukemias of ambiguous lineage in the WHO classification. The aberrant expression of CD7, CD56, and CD79a, representing the capacity of these leukemias for trilineal expression of leukocyte differentiation antigens, portends a poor prognosis.     

Tim-3 is highly expressed in T cells in acute myeloid leukemia and associated with clinicopathological prognostic stratification

T cells immunoglobulin mucin 3 (Tim-3) is an important inhibitory stimulatory molecule, which has been reported to play a vital role in the tumor immune escape and be correlated with clinicopathological prognostic stratification in solid tumor. However, the related research is rare of Tim-3 in non-solid tumor, such as acute myeloid leukemia (AML). In this study, we investigated the expression characteristics of Tim-3 on the peripheral blood T cells of newly diagnosed AML patients and its clinical significance. Peripheral blood was obtained from 36 patients with newly diagnosed AML before intervention, with peripheral blood from 20 cases of healthy volunteers collected as normal control. Expression levels of Tim-3 on the peripheral blood T cells were assayed with flow cytometry. We found that Tim-3 expression on the peripheral blood CD4+ T cells and CD8+ T cells in newly diagnosed AML patients were significantly increased compared with that of normal control. CD4+ T cells/CD8+ T cell ratio (CD4/CD8) of peripheral blood in AML patients was significantly correlated with NCCN high risk group. The higher expression level of Tim-3 on CD4+ T cells in the peripheral blood of AML patients had significant correlation with FLT3-ITD mutation, the higher expression level of Tim-3 on CD8+ T cells in AML patients was significantly correlated with NCCN high risk group. To conclude, our results support the concept that Tim-3 is highly expressed on the peripheral blood T cells of AML patients, and Tim-3 expression significantly correlates with clinicopathological prognostic stratification in AMLTim-3, T cell, acute myeloid leukemia, tumor immune escape, clinicopathological prognostic stratification     

Role of CD28/B7 costimulation in the dexamethasone-induced suppression of IFN-gamma.

In vitro exposure of peripheral blood mononuclear cells (PBMC) to glucocorticoids (GC), at concentrations observed during psychologic stress, induces a shift in the human type 1/type 2 cytokine balance toward a type 2 cytokine response. The mechanisms involved in these cytokine alterations are unknown but likely include modulation of regulatory cytokines or the interaction between the antigen-presenting cell (APC) and T lymphocyte or both. The CD28/B7 costimulation pathway has been reported to modulate the type 1/type 2 cytokine balance and may contribute to the GC-associated cytokine alterations. Therefore, we sought to determine the effect of dexamethasone (Dex) on the expression and function of the human CD28/B7 costimulatory pathway and whether these alterations contribute to the Dex-induced type 1/type 2 cytokine alterations. Dex inhibited the expression of both CD80 and CD86 on THP-1 cells, a human acute monocytic leukemia cell line, as determined by flow cytometry. Dex also inhibited the expression of CD28 and CTLA-4 on phytohemagglutinin (PHA)-stimulated CD3+ T lymphocytes, which was attenuated by the addition of interleukin-12 (IL-12). Lastly, activation of CD28 with anti-CD28 antibody attenuated the Dex-induced decrease in interferon-gamma (IFN-gamma) production by anti-CD3 antibody-stimulated PBMC. These data suggest that Dex induces a modulation of the CD28/B7 costimulatory pathway that contributes to the shift in the type 1/type 2 cytokine balance toward a predominant type 2 cytokine response.     

CD66c antigen expression is myeloid restricted in normal bone marrow but is a common feature of CD10+ early-B-cell malignancies

Abstract: CD66c is a surface (and intracellular) molecule bound to the membrane by a glycosyl-phosphatidylinositol anchor. While its expression on peripheral granulocytes is well recognized, less is known about its distribution in early steps of normal and neoplastic hematopoiesis. We analyzed by flow cytometry cell surface expression of CD66c on bone marrow cells from 4 healthy subjects and on bone marrow or peripheral blood cells from 127 patients with newly diagnosed hematologic malignancies: 70 de novo acute myeloid leukemias (AML), 6 refractory anemias with excess of blasts in transformation, 3 myeloid and 3 lymphoid blastic phases of chronic mye-logenous leukemia, 33 B-lineage and 6 T-lineage acute lymphoblastic leukemias (B- and T-ALL), and 3 B-cell and 3 T-cell non-Hodgkin's lymphomas in the leukemic phase. We found that in normal bone marrow CD66c expression was myeloid restricted, reaching its highest level on promyelocytes. As for de novo AML, slight expression of CD66c was found on 6/25 (24%) AML-M4 and only occasionally in other subgroups. In 9 out of 10 cases of acute promyelocytic leukemia, CD66c was totally absent, but antigen expression was easily detectable following in vitro exposure to all- trans retinoic add. Among lymphoid malignancies, CD10⁺ early-B-ALL consistently expressed the molecule (20/23 cases, or 87%) whereas both CD10^- early-B ALL and Smlg⁺ B-ALL completely lacked it. Finally, dual staining with CD66c and CD10 proved to be a suitable tool for distinguishing even low percentages of residual leukemic cells (CD10⁺/CD66c⁺) from normal regenerating early-B cells (CD10⁺/CD66c^-) in CD10⁺ early-B-ALL induced into remission.     

Impaired expression of CD28 on T cells in hairy cell leukemia

T cells from patients with active hairy cell leukemia (HCL), a chronic B cell malignancy, show poor proliferation in response to allogeneic peripheral blood mononuclear cells (PBMC). In order to study the T cell dysfunction, the expression of several adhesion and costimulatory molecules was analyzed by flow cytometry. Circulating T cells from HCL patients showed increased percentages of CD28(-) in all T cell subsets. In some patients the percentage of CD28(-) T cells within the CD4(+) subset was increased up to 80%. These CD4(+)CD28(-) T cells did not proliferate in a mixed lymphocyte culture (MLC) against allogeneic PBMC. After enrichment for CD4(+)CD28(+) T cells, the proliferative response in the MLC was recovered, but this response was still lower than the proliferative response from control T cells. In conclusion, lack of CD28 on T cells and a restricted T cell repertoire may contribute to immune deficiency in patients with HCL.