小儿急性淋巴细胞白血病血清CD3+ CD4- CD8- T细胞和T细胞亚群的变化及其临床意义

目的 探讨小儿急性淋巴细胞白血病(ALL)外周血CD3+ CD4- CD8- T细胞(DNT细胞)及T淋巴细胞亚群的变化及意义.方法 采用免疫荧光流式细胞术检测30例ALL患儿及24例健康小儿外周血DNT细胞及T淋巴细胞亚群CD3+ T细胞、CD3+ CD4+ T细胞及CD3+ CD8+ T细胞水平.结果 DNT细胞、CD3+ T细胞、CD3+ CD4+ T细胞百分比均明显低于对照组,分别为(4.93±3.75)%比(8.19±3.21)%(t=3.4,P<0.01):(49.99 ±11.70)%比(64.13 ±11.39)%(t=4.1,P<0.01);(28.30 ±7.56)%比(34.61 ±6.43)%(t=3.2,P<0.01);而CD3+ CD8+ T细胞百分比明显高于对照组,为(31.19±9.89)%比(24.33 ±4.24)%(t=3.1,P<0.01).结论 ALL患儿外周血DNT细胞及T亚群的变化提示患儿体内存在免疫功能紊乱,这可能与ALL的发病机制有关.     

外周血中自然杀伤细胞分选纯化方法的比较

目的 比较荧光激活细胞分选技术(FACS)及免疫磁珠分技术(MACS)对外周血自然杀伤(NK)细胞分选纯化的效率,为外周血中低比例细胞的深入研究创造基本条件.方法 选择20名健康志愿者及3例造血干细胞移植(HSCT)后早期(+14 d)患者,通过FACS及MACS各自分选其外周血中NK细胞.结果 分选前健康志愿者外周血NK细胞百分数为(12.86±3.62)%,FACS分选后NK细胞纯度达(96.15±2.03)%,回收率为(95.08±2.16)%;MACS分选后纯度达(93.35±3.61)%,回收率为(94.11±3.01)%.移植后早期患者外周血中NK细胞百分数为(11.01±2.08)%,FACS分选后纯度达(96.22±2.16)%,回收率为(95.27±1.18)%;MACS分选后纯度达(90.98±1.94)%,回收率为(94.54±3.52)%.两种方法分选NK细胞纯度差异有统计学意义(t=5.925,P＜0.05),而回收率差异无统计学意义(t=0.789,P＞0.05).结论 FACS较MACS可以更高效、快速、简便地分离纯化外周血中NK细胞,尤其适于分选移植后早期重建的NK细胞.     

难治性淋巴瘤患者外周血T淋巴细胞亚群与自然杀伤细胞活性的检测及其临床意义

目的 探讨外周血T淋巴细胞亚群及自然杀伤(NK)细胞活性水平与难治性淋巴瘤的相关性.方法 采用流式细胞术(FCM)检测60例初治淋巴瘤患者化疗前外周血T淋巴细胞亚群水平与NK细胞的活性,化疗后随访分为难治组30例、有效组30例,以20名健康者为健康对照组.结果 淋巴瘤患者组化疗前外周血CD+4、CD+4/CD+8、NK细胞数比健康对照组低(30.17±8.63与46.52±1.39,t=12.218,P＜0.05;0.86±0.45与1.64±0.05,t=11.225,P＜0.05;12.39±7.08与19.29±0.84,t=6.365,P＜0.05),CD+3、CD+8细胞数比健康对照组高(76.14±10.71与70.48±1.44,t=-3.439,P＜0.05;40.28±14.03与28.35±0.73,t=-5.625,P＜0.05).难治组化疗前外周血CD+4、CD+4/CD+8、NK细胞数比有效组低(27.70±7.81与33.13±8.82,t=2.163,P=0.036;0.67±0.27与1.10±0.52,t=3.272,P=0.003;9.87±6.60与15.40±6.58,t=2.771,P=0.008),而CD+3、CD+8细胞数比有效组高(79.67±8.18与71.91±12.00,t=-2.540,P=0.015;44.70±13.99与34.98±12.41,t=-2.416,P=0.020).结论 淋巴瘤初治患者化疗前外周血T淋巴细胞亚群水平及NK细胞活性的检测,对判断、预测容易转归为难治的患者可能有一定的参考价值.     

复方参鹿颗粒干预肾阳虚型骨髓增生异常综合征造血调控的临床观察

目的 评判复方参鹿颗粒对肾阳虚型骨髓增生异常综合征(MDS)(难治性贫血/难治性血细胞减少伴多系造血异常)(RA/RCMD)造血调控情况.方法 30例MDS-RA/RCMD患者随机分成复方参鹿颗粒组(简称参鹿组)(15例)和十一酸睾酮组(15例),测评治疗前后外周血象、T细胞亚群+自然杀伤(NK)细胞、骨髓细胞免疫表型.结果 参鹿组与治疗前相比,红细胞、血色素、血小板有明显上升,治疗前分别为(2.39±0.99)×1012/L、(84.47±28.68)g/L、(81.13±96.85)×109/L,治疗后分别为(2.80±0.98)×1012/L、(94.87±25.63)g/L、(98.67±107.9)×109/L,差异均有统计学意义(t=4.0359、t=2.7009、t=2.2573,均P<0.05),十一酸睾酮组仅有血红蛋白数量上升,治疗前为(71.93±27.53)g/L,治疗后为(80.07±26.03)g/L,差异有统计学意义(t=2.3125,P=0.0365);参鹿组治疗后CD+4、CD+8、CD+4/CD+8、NK细胞均达到或接近正常值,分别为(37.9±5.9)%、(24.0±5.8)%、1.75±0.83、(13.0±6.9)%,与治疗前的(29.3±11.7)%、(29.6±5.8)%、1.12±0.59、(8.8±5.7)%相比差异有统计学意义(t=2.6194、t=2.6595、t=2.6581、t=2.2288,均P<0.05),十一酸睾酮组治疗后仅CD+8、CD+4/CD+8接近正常值,分别为(22.1±7.5)%、1.50±0.74,与治疗前(26.6±7.5)%、1.18±0.55相比差异有统计学意义(t=2.2377,P=0.0420;t=2.9352,P=0.0109),治疗后,参鹿组CD+4表达率为(37.9±5.9)%,十一酸睾酮组为(30.5±12.6)%,差异有统计学意义(t=2.1738,P=0.0474);参鹿组对骨髓细胞CD+13、CD+33、CD+34、CD+64、CD+117的异常阳性表达调控能力强于安雄组(前三者u=2.76、u=3.39、u=2.85,均P<0.01,后两者u=2.17、u=2.46,均P<0.05).结论 复方参鹿颗粒能有效调控肾阳虚型MDS-RA/RCMD正常造血功能.     

CD+4CD+25调节性T细胞在小儿急性白血病发病中的作用

目的 观察CD+4 CD+25调节性T(Treg)细胞在急性白血病患儿及非白血病患儿外周血中的变化,研究CD+4 CD+25 Treg细胞在小儿急性白血病发病中的作用.方法 采用流式细胞术检测急性白血病初诊患儿组20例及非白血病患儿对照组20例外周血CD+4 CD+25 Treg细胞的数量及比例.结果 初诊患儿组及对照组外周血CD+4 CD+25 CD-127 Treg细胞占CD+4 T细胞的比例分别为(11.57±1.04)%和(6.75±0.75)%,在初诊患儿组高于对照组(t=16.808,P<0.001).结论 急性白血病患儿外周血中CD+4 CD+25 CD-127 Treg细胞数量升高,提示CD+4 CD+25 Treg细胞可能在白血病的发生、发展中起一定作用.     

急性白血病患者造血干细胞P-选择素表达的研究

目的 研究急性白血病(AL)患者骨髓白血病干细胞表面分子P-选择素(CD62P)的表达情况及其临床意义.方法 采用流式细胞术(FCM)检测56例初治AL患者骨髓CD62P的表达情况,以15例健康成年人骨髓标本为对照.结果 38例急性髓系白血病(AML)患者干细胞(CD+45CD+34CD-38)中CD62P平均表达水平为(6.72±7.64)%,12例急性B淋巴细胞白血病(B-ALL)患者干细胞(CD+45CD+34CD+19)为(3.46±2.51)%,6例急性T淋巴细胞白血病(T-ALL)患者干细胞(CD+45 CD+34CD+7)为(6.23±4.95)%,均明显高于健康对照组[(1.04±1.23)%](t值分别为2.847、3.284、3.091,P＜0.01).经过正规方案治疗后,完全缓解组患者CD62P表达与健康对照差异无统计学意义(t=0.397,P＞0.05).另外CD+62P的AML及T-ALL患者白细胞计数、血红蛋白及血小板计数均明显高于CD-62P患者(t值分别为4.153、8.095、8.289、7.235、8.692、9.832,P＜0.05);而CD+62P与CD-62P的B-ALL患者无明显差异(t值分别为0.340、1.142、0.019,P＞0.05).结论 CD62P是血小板活化的标志物之一,在不同类型的AL中有不同程度的表达.AL骨髓造血干细胞中CD62P可能作为白血病造血干细胞的标志,以及临床疗效观察预后判断的指标之一.     

成年人伴CD2表达B系急性淋巴细胞白血病免疫表型特征分析

目的 了解成年人伴CD2表达B系急性淋巴细胞白血病(CD+2 B-ALL)的免疫表型特征,为临床诊断、治疗及预后判断提供依据.方法 应用流式细胞术及多种单克降抗体检测18例成年人CD+2B-ALL及68例CD-2 B-ALL患者的免疫表型,并对其结果进行分析比较.结果 CD+2 B-ALL的发病年龄明显小于CD-2 B-ALL,18例成年人CD+2 B-ALL的大部分表面标志物与CD-2 B-ALL相似,其中CD10表达水平[(73.78±26.67)%]高于CD-2 B-ALL[(52.84±35.25)%],差异有统计学意义(t=2.35,P<0.05),CD33表达水平[(15.46±27.41)%]则低于CD-2 B-ALL[(31.15±27.72)%],差异有统计学意义(t=2.16,P<0.05);所有B-ALL患者都高表达CD34,阳性表达率分别为72.2%(13/18)和80.9%(55/68),差异无统计学意义(χ2=0.64,P>0.05).CD+2 B-ALL的CD20阳性率明显低于CD-2 B-ALL,差异有统计学意义(χ2=11.38,P<0.05).CD+2 B-ALL伴髓系抗原(CD13或CD33)表达率为44.4%(8/18),明显低于CD-2 B-ALL的72.1%(49/68),差异有统计学意义(χ2=4.86,P<0.05).结论 成年人CD+2 B-ALL与CD-2 B-ALL具有相似的免疫表型,主要来源于造血干细胞的恶性转化,CD+2 B-ALL伴髓系抗原(CD13、CD33)及CD20表达明显低于CD2 B-ALL,提示成年人CD+2 B-ALL可能有较好的预后.     

鼻腔自然杀伤/T细胞淋巴瘤放射治疗的疗效和影响因素

目的 回顾分析鼻腔自然杀伤(NK)/T细胞淋巴瘤的放射治疗效果,并分析其预后因素.方法 回顾分析9年间接受放射治疗的62例鼻腔NK/T细胞淋巴瘤的临床资料和疗效,单因素分析采用Kaplan-Meier法,多因素分析用COX比例风险模型.结果 全组中位生存时间69.7个月(95%CI为63.0～78.0个月),3、5年总生存率分别为66.1%和46.8%,远处转移导致治疗失败占61.8%.T淋巴细胞CD3升高组和降低组的中位生存时间分别为72.6个月和39.6个月,两组比较差异有统计学意义(x2=4.9309,P=0.0264).多因素分析表明,修正后国际预后指数(IPI)为0～1(x2=7.5266,P=0.0061)、CD3升高(x2=9.0912,P=0.0266)和治疗结束达到CR(x2=9.0912,P=0.0106)是影响鼻腔NK/T细胞淋巴瘤放疗总生存的有利预后因素.结论 放射治疗鼻腔NK/T细胞淋巴瘤疗效肯定,但远处转移治疗失败率高,全身治疗仍具有重要地位;修正后IPI为0～1、CD3升高、治疗结束达到CR是影响鼻腔NK/T细胞淋巴瘤放疗总生存的有利预后因素.     

骨髓间充质干细胞静脉输注对猕猴细胞免疫功能的影响

目的 评价猕猴间充质干细胞( MSC)静脉异体输注后对细胞免疫功能的影响。方法分离培养MSC;不做其他处理,将异体MSC静脉输注给受者猴,通过定期监测外周血象、混合淋巴细胞反应( MLR)、T细胞亚群来判断MSC输注后受者细胞免疫功能的变化。结果成功培养了猕猴的MSC。异体MSC输注后,受者无明显毒性反应、排异表现及血象变化。可以在一定时间内（2周左右）抑制受者T细胞在MLR中的增殖活性,受者猴A2、A3及A4输注MSC的数量分别为4.0×105/kg、1.0×106/kg、2.0×106/kg,在输注后第14天时,MLR的相对反应值(RR)与输注前比较均明显降低,分别从(46.0±2.6)％、( 40.9±2.3)％、(48.3±2.0)％降至(40.4±1.73)％、(33.0±2.1)％、(39.0±1.0)％(F=1O.19,P=0.023;F=2.593,P= 0.013;F= 28.431,P=0.003),输注后第30天时RR均恢复到输注前水平;统计结果显示,抑制程度(△RR)与输注MSC数量呈正相关(F=27.413,P=0.038)。A4是输注MSC数量最多的受者,输注后第14天开始,外周血CD3+、CD3+ CD4+、CD3+CD8+细胞的百分比与输注前相比有所降低,在输注后第30天左右恢复至输注前水平。结论单纯体内输注异体MSC,可以在一定时间内抑制受者T细胞的免疫活性;免疫抑制程度与输注MSC数量呈正相关。MSC特殊的免疫学特性使其具有深远的临床应用价值。     

粒细胞集落刺激因子对供体造血干细胞移植物中树突状细胞的影响

目的 探讨粒细胞集落刺激因子(G-CSF)对正常异基因造血干细胞移植供者外周血与骨髓移植物中Ⅰ型树突状细胞(DC1)、Ⅱ型树突状细胞(DC2)的数量及DC2/DC1比例的影响.方法 以G-CSF每天10μg/kg动员5 d后,以流式细胞术(FCM)检测11例G-CSF动员的异基因外周血造血干细胞移植物及20例G-CSF动员的异基因骨髓移植物中的DC1、DC2数量及DC2/DC1比例,并与8例正常供者动员前外周血及10例健康者动员前骨髓进行比较.结果 动员前后骨髓DC2由14.37×106/L增至29.68×106/L(t=2.433,P=0.022),而骨髓DC1分别为13.77×10a/L和18.88×106/L(t=0.625,P=0.541);DC2/DC1比例在动员后为1.83±0.81,较动员前的1.12±0.32明显升高(t=2.685,P=0.013).正常供者以G-CSF动员前、后移植物中外周血DC2数量分别为14.92×106/L和26.76×106/L(t=2.390,P=0.029),DC2/DC1比例分别为1.00±0.37和2.02±1.43(t=2.158,P=0.044),但外周血DC1分别为14.21×106/L和18.02×106/L(t=0.625,P=0.541).结论 移植前以G-CSF动员正常异基因干细胞移植供者,可选择性提高外周血及骨髓移植物中DC2的数量,而DC1数量无明显增加.     

Immune reconstitution after autologous progenitor hemopoietic cell transplantation. A study comparing autologous bone marrow and autologous peripheral blood transplantation

BACKGROUND: In order to find out the effect of peripheral blood (PB) hematopoietic progenitor cells on immune reconstitution the present study compares, through a randomized trial, some lymphoid subsets after peripheral blood (PBT) or bone marrow (BMT) autologous transplantation. MATERIAL AND METHODS: Twelve patients suffering from malignant hematological disorders were included (6 BMT and 6 PBT). From these patients 14 lymphoid and natural killer (NK) subsets were sequentially analyzed using appropriate dual staining. NK activity was analyzed by measuring Cr51 release from the K562 cell line. Studies were done in days and -6, +10, +17, +24, +31, +38, +52, +66, +90, +120, +180 and +360 after transplantation. RESULTS: The CD8+ cell regeneration was produced mainly by activated cells (CD38+), and no differences were observed between BMT and PBT, but CD8+ HLADR+ cells were higher in the PBT group. During the first year after transplantation CD4+ lymphoid cells were never within normal range, and its recovery was due to the memory subset (CD4+/CD45RO+). The CD19+ lymphocytes began their regeneration after the first month and it was produced mainly by by the CD19+/CD5+ subset. NK cells recovered faster in patients who underwent PBT, but NK activity was similar in both subgroups of patients and it was within normal range from day +17 until the end of the study. CONCLUSION: T, B and NK lymphoid reconstitution do not differ significantly between patients that receive BM or PB as hemathopoietic rescue, but PB seems influence a faster reconstitution of cytotoxic subsets (CD8+/HLADR+ and NK lymphoid cells).     

Rationalizing infection control in the dental office

We performed a prospective study in 17 consecutive patients following Autologous bone marrow (BM) or rhG-CSF primed peripheral blood item cell (PBSC) transplantation, with the objective of comparing immune recovery between both procedures and to evaluate results in rhG-CSF mobilized peripheral blood stem cell transplantation (PBSCT). Kinetics of immune reconstitution showed differences, with a faster recovery of CD3+ and CD8+ T cells, and a more rapid and sustained recovery of CD8+/-/CD56+ natural killer (NK) cells in the PBCSCT group. Autologous bone marrow transplantation (ABMT) was associated with a improved reconstitution of the CD19+/CD5+/-subpopulation. Moreover, rhG-CSF mobilized PBSCT generated a greater recovery of CD8+/-/CD56+ cells than previous data concerning transplantation with peripheral blood (PB) progenitors collected after myelosuppressive chemotherapy or myelosuppressive therapy plus rhG-CSF. Our results show differences in the rate and pattern of B and T lymphocytes reconstitution after ABMT and PBSCT. Additionally, we state an enhancement of CD56+ cells in patients undergoing PBSCT mobilized solely using rhG-CSF.     

Changes of immunological markers after autologous peripheral blood stem cell transplantation

PURPOSE: Recently high-dose chemotherapy with peripheral blood stem cell transplantation (PBSCT) has become an important treatment for hematological and solid tumors. METHODS: Immunological parameters were examined before and after PBSCT in 9 patients with lung cancer and 13 patients with malignant lymphoma. Findings were compared with those for bone marrow transplantation (BMT). Peripheral blood cells were analyzed for phenotype and the levels of cytokines and soluble factors were measured. RESULTS: After PBSCT, activated T cells (CD3+HLA-DR+ cells, CD8+HLA-DR+ cells) and suppressor/cytotoxic T cells (CD8+CD11b- cells) were significantly higher in the patients with lung cancer than in those with malignant lymphoma. Serum levels of interleukin-4 and soluble interleukin-2 receptor were also significantly higher in the patients with lung cancer than in those with lymphoma. On the other hand, the serum levels of interferon gamma, tumor necrosis factor alpha, interleukin-6, soluble human leukocyte antigen class 1, and soluble thrombomodulin were significantly increased after bone marrow transplantation. The transfused peripheral stem cells of lung cancer and lymphoma patients had a similar number of granulocyte/macrophage-colony-forming units, but lung cancer patients had significantly more CD34-positive cells. CONCLUSION: By reinfusing large numbers of autologous immune cells, PBSCT may accelerate immune reconstitution, with T cells being likely to have a marked therapeutic potential. The changes after PBSCT were greater in patients with lung cancer than in lymphoma patients. These blood cells are potent mediators of anticancer activity and could play an important role in the elimination of autologous malignant cells.     

T-cell infiltration of primary CNS lymphoma

We stained 13 primary CNS lymphomas (PCNSLs) (six from patients with AIDS, seven from immunocompetent patients) with a panel of antibodies to T cells (pan T cell [CD3], T helper cell [CD4], T suppressor cell [CD8], delta/delta cell [CD4-8-]), B cells (CD20), hematopoietic cells (T200), and NK cell (CD56). We estimated the percentage of tumor cells staining with each antibody. All tumors were B-cell lymphomas. The non-AIDS tumors showed a significant infiltration with CD3+ cells (mean of 10.82% of total cells). The AIDS patients' tumors showed a smaller percentage of CD3+ infiltrating cells (mean, 4.88% of total cells) (p<0.01). CD4+ cells were 9.11% of the total hematopoietic cells in the non-AIDS patients and 3.13% in AIDS patients (p<0.01). AIDS patients showed some CD8+ cells (0.3%), which was significantly higher than in immunocompetent patients (0%) (p<0.05). Very few tumor cells stained with the NK cell and delta/delta cell markers. Both immunocompetent and AIDS patients with PCNSL exhibit significant CD3+ and CD4+ cell infiltration of their tumors; this infiltration is significantly lower in AIDS patients. AIDS patients show a minor CD8+ cell infiltration of their tumors. These results on PCNSL are different from systemic lymphomas, which show a higher CD4 and CD8 cell infiltration, and may offer insights into the more aggressive nature of AIDS-related PCNSL.     

Successful engraftment of allogeneic CD34-enriched marrow cell transplantation from HLA-mismatched parental donors

The CD34 antigen is expressed on pluripotent stem cells and the CD34+ cell has been shown to be capable of hematopoietic reconstitution in animal and human autologous grafts. We asked if CD34+ cells could reconstitute hematopoiesis in human allogeneic transplantation from a HLA-mismatched donor. Three pediatric patients with advanced leukemia received allogeneic CD34-enriched marrow cell graft from HLA two (two patients) or three (one patient) loci-mismatched parental donors. CD34+ cell selection was performed with mouse anti-CD34 antibody 9C5 and magnetic beads coated sheep anti-mouse IgG1. 1.53 to 2.48 x 10(9) marrow cells were processed and 2.53 to 7.89 x 10(7) positively selected cells were recovered. The selected population showed 93.7 to 99.0% CD34+ cells and total recovery of CD34+ cells from the starting population was 54.6 to 62.3%. CD34+ cell selection resulted in more than 99.9% depletion of CD5+ cells from the bone marrow. The patients received 2.53 to 7.25 x 10(6) CD34-enriched cells/kg after myeloablative therapy. All patients achieved trilineage engraftment that was confirmed by various genetic markers. Acute graft-versus-host disease (GVHD) was grade 0 (two patients) or grade I (one patient), and hematological recovery was successfully achieved as follows; the days to reach granulocytes over 0.5 x 10(9)/I were 11 to 13 days, reticulocytes over 2% was 18 to 28 days, platelets over 50 x 10(9)/I was 33 to 58 days. One patient is surviving without relapse of leukemia and two patients died after either mixed hematopoietic chimerism or leukemia relapse was observed. These studies suggest that CD34+ marrow cells are capable of hematopoietic reconstitution from HLA two or three loci-mismatched donors even with the lowest dose of mature T cells.     

Difference in the expression of Fas/Fas-ligand and the lymphocyte subset reconstitution according to the occurrence of acute GVHD

Acute graft-versus-host disease (aGVHD) remains a major barrier to a wider application of allogeneic bone marrow transplantation (BMT). Although this complication is mainly dependent on donor-derived T lymphocytes, very little information is available concerning the mechanism of lethality. In this study, we investigated both the expression of Fas/Fas-ligand (FasL) and lymphocyte subset reconstitution in patients who underwent HLA-matched related allogeneic BMT (n = 16) and normal donors (n = 10), and several distinct features were observed. First, the reconstitutions of CD3+ and CD56+ cells were different between the aGVHD+ and aGVHD- group. In particular, the percentage of CD3-CD56+ cells was significantly decreased in patients with aGVHD (P < 0.01). Second, the expansion of CD8+ (P = 0.01) and CD8+ CD28- T cells (P = 0.03) was a characteristic finding in patients with aGVHD. Finally, we found that the percentages of Fas+CD8+, Fas+HLA-DR+ and FasL+ CD8+ cells were significantly increased. Fas antigen was highly coexpressed on most of the lymphocyte subsets, especially on CD8+ cells (P < 0.01), and also, significantly higher coexpression of FasL on CD8+ cells was found in patients with aGVHD (P < 0.01). In summary, an increase in the percentage of CD8+ cells which express Fas and its ligand in patients with aGVHD after BMT points to a possible role for the Fas/FasL pathway in the effector phase of aGVHD.     

Human natural killer cell committed thymocytes and their relation to the T cell lineage

Recent studies have demonstrated that mature natural killer (NK) cells can be grown from human triple negative (TN; CD3-, CD4-, CD8-) thymocytes, suggesting that a common NK/T cell precursor exists within the thymus that can give rise to both NK cells and T cells under appropriate conditions. In the present study, we have investigated human fetal and postnatal thymus to determine whether NK cells and their precursors exist within this tissue and whether NK cells can be distinguished from T cell progenitors. Based on the surface expression of CD56 (an NK cell-associated antigen) and CD5 (a T cell-associated antigen), three phenotypically distinctive populations of TN thymocytes were identified. CD56+, CD5-; CD56-, CD5-, and CD56-, CD5+. The CD56+, CD5- population of TN thymocytes, although displaying a low cytolytic function against NK sensitive tumor cell targets, were similar in antigenic phenotype to fetal liver NK cells, gave rise to NK cell clones, and were unable to generate T cells in mouse fetal thymic organ cultures (mFTOC). This population of thymocytes represents a relatively mature population of lineage-committed NK cells. The CD56-, CD5- population of TN thymocytes were similar to thymic NK cells in antigenic phenotype and NK cell clonogenic potential. Clones derived from this population of TN thymocytes acquired CD56 surface expression and NK cell cytolytic function. CD56-, CD5- TN thymocytes thus contain a novel population of NK cell-committed precursors. The CD56-, CD5- population of TN thymocytes also contains a small percentage of CD34+ cells, which demonstrate no in vitro clonogenic potential, but possess T cell reconstituting capabilities in mFTOC. The majority of TN thymocytes do not express CD56, but coexpress CD34 and CD5. These CD56-, CD5+, CD34+ cells demonstrate no NK or T cell clonogenic potential, but are extremely efficient in repopulating mFTOC and differentiating into CD3+, CD4+, CD8+ T cells. The results of this investigation have identified NK cells and NK cell precursors in the human thymus and have shown that these cell types are unable to differentiate along the T cell lineage pathway. Thus, while a common NK/T cell progenitor likely exists, once committed to the NK cell lineage these cells no longer have the capacity to develop along the T cell developmental pathway.     

Evaluation of a dual-color flow cytometry immunophenotyping panel in a multicenter quality assurance program

A basic immunophenotyping panel that employed dual-color combinations of fluorescein isothiocyanate (FITC) and phycoerythrin (PE) conjugated monoclonal antibodies (mAb; FITC-CD45/PE-CD14, FITC-IgG1/PE-IgG2, FITC-CD3/PE-CD8, FITC-CD3/PE-CD4, FITC-CD3/PE-CD16 + PE-CD56, and PE-CD19) was utilized in a quality assurance program to determine whether the 4 laboratories participating in a multicenter AIDS study obtained similar lymphocyte subset percentage values for T cells, B cells, NK cells, and CD4+ and CD8+ T cells. Over a 1 1/2 year period, 78 shared peripheral blood specimens were prepared and analyzed in each laboratory. The CD45bright CD14- percentage for each specimen was used to correct that individual's lymphocyte subset values. Interlaboratory coefficients of variation (CV) for the human immunodeficiency virus type I (HIV) seronegative (n = 38) and HIV-seropositive (n = 40) specimens using this panel were < 3% for total T cells; < 5% for CD4+ T cells and CD8+ T cells; < or = 17% for B and NK cells; and < 8% for CD4T/CD8T ratios. The 6-tube basic immunophenotyping panel has several notable features: a) for clinical studies, it permits comprehensive evaluation of an individual's major lymphocyte subsets, i.e., T, B, NK, and CD4+ and CD8+ T cells; b) for interlaboratory proficiency testing programs, it allows the detection of differences among laboratories in measurements of several functionally distinct cell populations; and c) for within-sample quality assurance, it provides several quality control checks, including the lymphosum, i.e., the sum of an individual's corrected T+B+NK values, a sum that was generally 100 +/- 5% on the HIV-seronegative specimens analyzed in this study.