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Biomedical subjects

X L Zhang

Publications and source records attributed to X L Zhang.

At least 37 records · Page 2Linked to original sources
PubMed2002

Genistein and methoxychlor modulate the activity of natural killer cells and the expression of phenotypic markers by thymocytes and splenocytes in F0 and F1 generations of Sprague-Dawley rats.

The isoflavone genistein (GE) and methoxychlor (MXC) have been shown to be estrogenic in both in vitro and in vivo experimental systems. The objective of the present study was to evaluate the effects of GE and MXC on the immune system in adult and developing rats and the potential interaction between these compounds in their immunomodulatory actions. Timely pregnant Sprague-Dawley rats were exposed to GE (300 or 800 ppm), MXC (800 ppm), or their combinations in feed starting on day 1 of gestation. The offspring were exposed to these chemicals gestationally and lactationally. Immunological evaluation was performed on postnatal day 22. In F0 females, exposure to GE had no effect on the percentages of thymocyte subsets, but caused a significant decrease in the absolute thymus weight at the 800-ppm dose level. In the spleen, GE did not affect the activity of natural killer cells but induced changes in the percentages of splenic T lymphocyte subsets. Exposure to MXC produced no effect on the immune parameters examined except for a decrease in the percentage of CD4+CD8- thymocytes. Additionally, minimal interaction between GE and MXC was observed. In F(1) males, both GE and MXC decreased the percentage of CD4+CD8- thymocytes, but only GE increased spleen natural killer cell activity. MXC in combination with 300 ppm-GE, but not separately, produced significant decreases in the absolute weights of thymus and spleen. In F1 females, GE decreased the percentage of CD4+CD8- thymocytes, increased the percentage of CD4+CD8+ thymocytes, and decreased the activity of spleen natural killer cells. In contrast, MXC increased the percentages of spleen natural killer cells and CD8+ T cells. Overall, the results demonstrate that both GE and MXC can modulate the immune system with greater effects observed in developing rats. Moreover, male and female rats have differential responses to these compounds. A lack of interaction between these two estrogenic chemicals in modulating these immune parameters indicates that their effects on the immune system might involve other mechanisms in addition to the estrogen receptors.

Animals↗
PubMed2001

Primitive deuterostomes from the Chengjiang Lagerstätte (Lower Cambrian, China).

Cambrian fossil-Lagerstätten (sites of exceptional fossil preservation), such as those from Chengjiang (Lower Cambrian) and the Burgess Shale (Middle Cambrian), provide our best window into the Cambrian 'explosion'. Such faunas are known from about 40 localities, and have yielded a widely disparate series of taxa ranging from ctenophores to agnathan fish. Recent excavations of the Chengjiang fossil-Lagerstätte, known from a series of sites near Kunming in Yunnan, south China, have resulted in the discovery of several new forms. In conjunction with material described earlier, these provide evidence for a new group of metazoans, the vetulicolians. Several features, notably a series of gill slits, suggest that this group can throw light on an early stage of deuterostome diversification.

Animals↗
PubMed2001

CD8 expression up to the double-positive CD3(low/intermediate) stage of thymic differentiation is sufficient for development of peripheral functional cytotoxic T lymphocytes.

Control of CD8alpha transcription during development of alpha/beta T cell receptor (TCR) T lymphocytes is mediated by at least two distinct stage-specific cis-acting transcriptional mechanisms (i.e., enhancers). On the CD8alpha(-/-) knockout (KO) background, cis-mechanism I and cis-mechanism II together mediate appropriate stage- and sublineage-specific transgenic (Tg) CD8alpha expression and "rescue" development of peripheral CD8(+) single-positive (SP) cytotoxic T lymphocytes (CTLs). In contrast, on the wild-type (WT)/CD8(+/+) or CD8alpha(-/-)KO backgrounds, a CD8alpha Tg directed by cis-mechanism I alone is activated during the double negative [DN] to double positive [DP] transition and expressed up to the CD3(low/intermediate) DP stage but not in more mature DP or SP thymocytes or peripheral T cells. As loss of cis mechanism I activity occurs around the onset of positive selection, it is possible that events associated with TCR/major histocompatibility complex (MHC) interactions and selection are involved in initiating these changes in CD8alpha transcription. To examine this issue, phenotypic and functional studies were performed for thymocytes and T cells of CD8alpha(-/-) KO mice that expressed a CD8alpha Tg under control of cis-mechanism I only. Despite loss of CD8alpha expression at the DP CD3(low/intermediate) stage, increased populations of mature CD3(hi)CD4(-)CD8(-) thymocytes and CD3(+)CD4(-)CD8(-) peripheral T cells were detected. By several criteria, including MHC class I-restricted antigen recognition, these cells have at least partially undergone positive and negative selection. Therefore, initiation of selection and sublineage commitment are determined before loss of cis-mechanism I-mediated control of CD8alpha transcription. Further, CD8 expression beyond the CD3(low/intermediate) DP thymic stage is not essential for CTL development in vivo or function.

Animals↗
PubMed2001

Caveolin-1 null mice are viable but show evidence of hyperproliferative and vascular abnormalities.

Caveolin-1 is the principal structural protein of caveolae membranes in fibroblasts and endothelia. Recently, we have shown that the human CAV-1 gene is localized to a suspected tumor suppressor locus, and mutations in Cav-1 have been implicated in human cancer. Here, we created a caveolin-1 null (CAV-1 -/-) mouse model, using standard homologous recombination techniques, to assess the role of caveolin-1 in caveolae biogenesis, endocytosis, cell proliferation, and endothelial nitric-oxide synthase (eNOS) signaling. Surprisingly, Cav-1 null mice are viable. We show that these mice lack caveolin-1 protein expression and plasmalemmal caveolae. In addition, analysis of cultured fibroblasts from Cav-1 null embryos reveals the following: (i) a loss of caveolin-2 protein expression; (ii) defects in the endocytosis of a known caveolar ligand, i.e. fluorescein isothiocyanate-albumin; and (iii) a hyperproliferative phenotype. Importantly, these phenotypic changes are reversed by recombinant expression of the caveolin-1 cDNA. Furthermore, examination of the lung parenchyma (an endothelial-rich tissue) shows hypercellularity with thickened alveolar septa and an increase in the number of vascular endothelial growth factor receptor (Flk-1)-positive endothelial cells. As predicted, endothelial cells from Cav-1 null mice lack caveolae membranes. Finally, we examined eNOS signaling by measuring the physiological response of aortic rings to various stimuli. Our results indicate that eNOS activity is up-regulated in Cav-1 null animals, and this activity can be blunted by using a specific NOS inhibitor, nitro-l-arginine methyl ester. These findings are in accordance with previous in vitro studies showing that caveolin-1 is an endogenous inhibitor of eNOS. Thus, caveolin-1 expression is required to stabilize the caveolin-2 protein product, to mediate the caveolar endocytosis of specific ligands, to negatively regulate the proliferation of certain cell types, and to provide tonic inhibition of eNOS activity in endothelial cells.

Albumins↗
PubMed2001

Increased expression of the Zn-finger transcription factor BTEB1 in human endometrial cells is correlated with distinct cell phenotype, gene expression patterns, and proliferative responsiveness to serum and TGF-beta1.

Basic transcription element binding (BTEB, also designated BTEB1) protein is a member of the Sp-family of GC-box binding transcription factors that exhibit distinct patterns of expression in many cell types and tissues. A role for BTEB1 in the regulation of cell growth and gene transcription has been invoked, but little is known about the molecular mechanisms underlying these activities. The present study examined the functional consequences of high and low BTEB1 expression in the human endometrial carcinoma cell line Hec-1-A, by deriving stable clonal lines that expressed sense (S) and anti-sense (As) rat BTEB1 constructs. Clonal S lines, with BTEB1 mRNA and protein levels higher than in corresponding parent (N) and As lines, displayed enhanced DNA synthesis upon 3[H]-thymidine incorporation, in serum-containing but not in serum-free medium, and increased cell cycle kinetics, concomitant with the induction in expression of the genes for the cell cycle-associated components cyclin D1, PCNA, cyclin-dependent kinase (Cdk) inhibitor p21, and Cdk2. Compared to N and As lines, S lines also had diminished ability to grow in multi-layers and exhibited increased mRNA levels for plasminogen activator inhibitor-1 (PAI-1), secretory leukocyte protease inhibitor (SLPI), and tissue inhibitor of metalloproteinases (TIMP)-2. In serum-free medium, S, but not N nor As lines, had enhanced DNA synthesis with transforming growth factor (TGF)-beta1, albeit all lines demonstrated similar responses to insulin-like growth factor-I and to epidermal growth factor, respectively. The higher DNA synthesis in S relative to N and As, lines upon exogenous TGF-beta1 addition, was observed in concert with increased expression of cyclins D1 and E and p21, genes. Moreover, S and As lines had increased mRNA levels for TIMP-1, TIMP-2, PAI-1, and beta-catenin, and diminished SLPI, and to a lesser extent, Cdk4 mRNA levels, with TGF-beta1 treatment. These results suggest that BTEB1 may mediate cell growth, in part, by modulating gene expression levels of distinct cell cycle and growth-associated proteins. The correlation between serum- and TGF-beta1 induction of DNA synthesis with increased BTEB1 expression further suggests that BTEB1 may constitute an important downstream regulatory component of various signaling pathways utilized by serum-associated and other growth factors in endometrial epithelial cells.

Animals↗
PubMed2001

An Early Cambrian tunicate from China.

Like the Burgess Shales of Canada, the Chengjiang Lagerstätte from the Lower Cambrian of China is renowned for the detailed preservation as fossils of delicate, soft-bodied creatures, providing an insight into the Cambrian explosion. The fossils of possible hemichordate chordates and vertebrates have attracted particular attention. Tunicates, or urochordates, comprise the most basal chordate clade, and details of their evolution could be important in understanding the sequence of character acquisition that led to the emergence of chordates and vertebrates. However, definitive fossils of tunicates from the Cambrian are scarce or debatable. Here we report a probable tunicate Cheungkongella ancestralis from the Chengjiang fauna. It resembles the extant ascidian tunicate genus Styela whose morphology could be useful in understanding the origin of the vertebrates.

Animals↗
PubMed2001

Caveolin-3 null mice show a loss of caveolae, changes in the microdomain distribution of the dystrophin-glycoprotein complex, and t-tubule abnormalities.

Caveolin-3, a muscle-specific caveolin-related protein, is the principal structural protein of caveolae membrane domains in striated muscle cells. Recently, we identified a novel autosomal dominant form of limb-girdle muscular dystrophy (LGMD-1C) in humans that is due to mutations within the coding sequence of the human caveolin-3 gene (3p25). These LGMD-1C mutations lead to an approximately 95% reduction in caveolin-3 protein expression, i.e. a caveolin-3 deficiency. Here, we created a caveolin-3 null (CAV3 -/-) mouse model, using standard homologous recombination techniques, to mimic a caveolin-3 deficiency. We show that these mice lack caveolin-3 protein expression and sarcolemmal caveolae membranes. In addition, analysis of skeletal muscle tissue from these caveolin-3 null mice reveals: (i) mild myopathic changes; (ii) an exclusion of the dystrophin-glycoprotein complex from lipid raft domains; and (iii) abnormalities in the organization of the T-tubule system, with dilated and longitudinally oriented T-tubules. These results have clear mechanistic implications for understanding the pathogenesis of LGMD-1C at a molecular level.

Animals↗
PubMed2001

Selenium geochemistry of paddy soils in Yangtze River Delta.

Selenium (Se) content both in total and bioavailable forms were very low (25-35 and 9.5 micrograms/kg, respectively) in waterlogged paddy soils in the central Yangtze River Delta. This was due to changes in geochemistry and the inherent properties of the parent materials of these lowland paddy soils. The very low Se content (23 micrograms/kg) in the parent material resulted in low total Se content in the soil. The main chemical changes under long-term waterlogged conditions are depletion of molecular oxygen, decrease of redox potential, and reduction of Fe (III) to Fe (II) and SeO3(2-) to Se0. This led to low availability of Se in soils, and subsequently low Se content (29 micrograms/kg) in brown rice grain produced in this region. It has been suspected that low Se content in staple food might be one of the major reasons for a high infection rate of the intestine and stomach cancers and the higher death rate caused by these diseases in the region. Foliage spray of Na2SeO3 at early heading stage of rice plant growth improved the Se content of brown rice grain, hull, and straw, and would improve human and animal health.

Biological Availability↗
PubMed2001

Mismatch negativity in subjects at high risk for alcoholism.

BACKGROUND: Evidence from P300 studies in both alcohol-dependent and high-risk (HR) individuals suggests that the reduced P300 amplitudes that often characterize these individuals may reflect a deficit in inhibition (hyperexcitability) in the central nervous system. In this context, the mismatch negativity (MMN) was investigated in the male and female HR offspring of alcohol-dependent fathers and a mixed-sex, low-risk (LR) control group. METHODS: As subjects read popular materials, they received a random sequence of 500 binaurally presented tones of 600 Hz and 1600 Hz. The designation of the rare stimulus (n = 60 trials) and frequent stimulus (n = 440 trials) was alternated across subjects. Recordings of MMN were made from 61 electrodes; risk group comparisons were restricted to the five frontal midline electrodes: Fpz, Afz, Fz, Fcz, and Cz. The MMN was obtained by calculating the integral of the area under the curve for both the frequent and rare waveforms over an interval from 100 to 190 msec and then subtracting the former from the latter. RESULTS: The primary observation was that MMN responses in the HR group were significantly larger than those in the LR group. In addition, both LR and HR individuals manifested differential responses to the rare and frequent stimuli, and MMN responses in both groups were largest at Fcz and smallest at Fpz. DISCUSSION: The results indicate that individuals at high risk for alcoholism differ electrophysiologically from LR controls. These differences were manifested as larger magnitudes of the MMN. The findings suggest the possibility that as measured by the MMN, individuals at high risk for alcoholism may be characterized by a deficit in inhibition (excessive neural excitation). The presence of these preexisting central nervous system states may lead to ethanol use for self-medication, which then may facilitate the development of both tolerance to and dependence on ethanol.

Adolescent↗
PubMed2001

[Genetic diversity evaluation of cultivars (G. hirsumtum L.) from the Changjiang river valley and Tellow river valley by RAPD markers].

Forty-one polymorphic decamer primers with clear and repeated band pattern, which were screened out from 300 randomly selected primers, were applied to assess genetic diversity of cultivars (G. hirsumtum L.) from the Changjiang river valley and the Yellow river valley by RAPD analysis. Eighty-four polymorphic loci were obtained from 84 cultivars from the Changjiang river valley and 96 polymorphic loci were obtained from 68 cultivars from the Yellow river valley. Jaccard's genetic similarity coefficients were calculated using the software of NTSYS-pc version 1.80, and two dendrograms were constructed by the unweighted pair group method of arithmetic average (UPGMA). Mean similarity coefficient among cultivars from the Changjiang river valley was up to 0.631. And cultivars from the Yellow river valley had an average similarity coefficient of 0.632. Compared similarity coefficient matrices and frequency distribution of pairwise similarity coefficients, a conclusion was drawn that cultivars from the two areas had nearly the same level of genetic diversity. Same base germplasm, breeding objectives, breeding methods and strategy could be attributed to similar genetic diversity between the two areas.

China↗
PubMed2001

[Analysis of chlorogenic acid in sunflower cake by thin-layer chromatography].

The analytical method of chlorogenic acid in sunflower cake by thin-layer chromatography(TLC) was developed. With 36% acetic acid as mobile phase and on the polyamide film plate, the Rf value of chlorogenic acid was 0.61. The calibration curve was linear in the range of 0.05 microgram-0.6 microgram of chlorogenic acid with the detection limit of 0.025 microgram and the average recovery of 97.53%. The inter-plate accuracy of chlorogenic acid was 2.57%. With 70% ethyl alcohol as extracting solvent and 30 min of extraction time, the amount of chlorogenic acid in the extract, the residue amount of chlorogenic acid in the sunflower cake and the extraction rate were determined and calculated by applying this method. The optimal time of extraction was found.

Calibration↗
PubMed2001

[The effect of stress-relaxation plate fixation on the remodeling of the cortex under plate].

OBJECTIVE: To explore the influence of stress-relaxation plate(SRP) fixation on the remodeling of cortex under plate. METHODS: Twenty-eight New Zealand rabbits were used in this study, the bilateral tibia were osteotomized in the middle and fixed with SRP (experimental group) and rigid plate (control group) respectively. The scanning electron microscopy was used to observe the bone remodeling process from 2 to 48 weeks after operation. RESULTS: There was cortex osteoporosis beneath plate in different degree in both experimental and control groups before 8 weeks, it showed as the disorganization of collagen fiber structure and formation of resorption cavities. In comparison, the osteoporosis degree in experimental group showed milder than that of the control group. After 12 weeks, the resorption cavities became smaller, and the structure of collagen fibers became regular with the alignment parallel to the long axis of cortex. In contrast to the experimental group, the bone osteoporosis under plate of control group exacerbated continuously. CONCLUSION: Without removal of the bone plate, SRP fixation not only reduce the degree of plated bone osteoporosis, but also make the osteoporosic bone return to normal.

Animals↗
PubMed2000

Caveolin-1 regulates transforming growth factor (TGF)-beta/SMAD signaling through an interaction with the TGF-beta type I receptor.

Transforming growth factor-beta (TGF-beta) signaling proceeds from the cell membrane to the nucleus through the cooperation of the type I and II serine/threonine kinase receptors and their downstream SMAD effectors. Although various regulatory proteins affecting TGF-beta-mediated events have been described, relatively little is known about receptor interactions at the level of the plasma membrane. Caveolae are cholesterol-rich membrane microdomains that, along with their marker protein caveolin-1 (Cav-1), have been implicated in the compartmentalization and regulation of certain signaling events. Here, we demonstrate that specific components of the TGF-beta cascade are associated with caveolin-1 in caveolae and that Cav-1 interacts with the Type I TGF-beta receptor. Additionally, Cav-1 is able to suppress TGF-beta-mediated phosphorylation of Smad-2 and subsequent downstream events. We localize the Type I TGF-beta receptor interaction to the scaffolding domain of Cav-1 and show that it occurs in a physiologically relevant time frame, acting to rapidly dampen signaling initiated by the TGF-beta receptor complex.

3T3 Cells↗
PubMed2000

Neonatal (cord blood) T cells can competently raise type 1 and 2 immune responses upon polyclonal activation.

In the neonate, cellular immunity has generally been hypothesized as being incompetent. Accumulating evidence from several recent studies, together with our present report, contradicts this hypothesis. T-helper cell and T cytotoxic type 1 and 2 (Th1/Th2 and Tc1/Tc2, respectively) cytokine responses to polyclonal T cell receptor (TCR) activation were assessed in medium-term cultures of human cord blood T cells using intracellular cytokine staining, which could measure the frequencies of cytokine-producing cells. In this study, we examined the responses of cord blood CD4(+) and CD8(+) T cells in regard to the production of interferon (IFN)-gamma and interleukin (IL)-4 and compared the responses with those obtained from T cells of healthy adults. We found that the responses in cord blood T cells activated with TCR stimulation were comparable to those of their adult counterparts. Moreover, the Th/Tc cells that developed in cord blood were as competent as adult cells for both IFN-gamma and IL-4 secretion. In addition, IL-12 production, which is critical for both Th1 and Tc1 responses, was equally comparable in the two groups. The production of two major cross-regulatory cytokines, tumor necrosis factor-alpha and IL-10, was similarly comparable and not significantly different between the two groups. Taken together, these results indicate that, though naive, the neonatal T cell is competent to respond to TCR-mediated stimulation and to produce both type 1 and type 2 cytokines.

Adult↗
PubMed2000

CD8+ T cells are necessary for recognition of allelic, but not locus-mismatched or xeno-, HLA class I transplantation antigens.

Although HLA transgenic mice (HLA TgM) could provide a powerful approach to investigate human MHC-specific T cell responsiveness, the extent to which these molecules are recognized by the mouse immune system remains unclear. We established TgM expressing HLA class I alleles A2, B7, or B27 in their fully native form (HLAnat) or as hybrid molecules (HLAhyb) of the HLA alpha1/alpha2 domains linked to the H-2Kb alpha3, transmembrane, and cytoplasmic domains (i.e., to maintain possible species-specific interactions). Comparison of each as xeno- (i.e., by non-TgM) vs allo- (i.e., by TgM carrying an alternate HLA allele) transplantation Ags revealed the following: 1) Although HLAhyb molecules induced stronger xeno-CD8+ T cell responses in vitro, additional effector mechanisms must be active in vivo because HLAnat skin grafts were rejected faster by non-TgM; 2) gene knockout recipients showed that xenorejection of HLAnat and, unexpectedly, HLAhyb grafts doesn't depend on CD8+ or CD4+ T cells or B cells; 3) each HLAhyb strain developed tolerance to "self" but rejected allele- (-B27 vs -B7) and locus- (-B vs -A) mismatched grafts, the former requiring CD8+ T cells, the latter by CD8+ T cell-independent mechanisms. The finding that recognition of xeno-HLAhyb does not require CD8+ T cells while recognition of the identical molecule in a strictly allo context does, demonstrates an alpha1/alpha2 domain-dependent difference in effector mechanism(s). Furthermore, the CD8+ T cell-independence of locus-mismatched rejection suggests the degree of similarity between self and non-self alpha1/alpha2 determines the effector mechanism(s) activated. The HLA Tg model provides a unique approach to characterize these mechanisms and develop tolerance protocols in the context of human transplantation Ags.

Alleles↗
PubMed2000

Expression and regulatory function of the transcription factor Sp1 in the uterine endometrium at early pregnancy: implications for epithelial phenotype.

The uterus during early pregnancy synthesizes a complex array of signaling molecules with specific spatial and temporal modes of expression and which are critical for embryo implantation and subsequent development. The mechanism(s) underlying the differential pattern of synthesis of these pregnancy-associated proteins is not understood very well. The present study evaluated the expression and trans-activation potential of the transcription factor Sp1 in the early pregnancy porcine endometrium to determine its temporal and functional association with the endometrial epithelial-specific genes encoding the transplacental iron-transport protein uteroferrin (UF) and an Sp-family member, basic transcription element-binding (BTEB) protein. Two identical Sp1 clones (717 bp) were isolated from a porcine endometrial cDNA library by polymerase chain reaction (PCR). The nucleotide sequence of these clones encodes a partial protein sequence of 238 amino acids encompassing the Zn-finger region and had significant identities with the corresponding regions in the rat and human proteins. By using a specific antibody raised against human Sp1, porcine endometrial Sp1 was found to exhibit a molecular weight of 110 kDa, was localized predominantly in the nuclei of glandular and luminal epithelial cells, and appeared to exist as a phosphorylated protein. Northern blot analysis demonstrated three distinct size transcripts of approximately 3.5, 5, and 8 kb for endometrial Sp1. The expression of Sp1 mRNA and protein, determined by RT-PCR and by its ability to bind Sp1 consensus motif in gel mobility shift assays, respectively, overlapped with, but did not parallel that of UF mRNA during early pregnancy. The effect of increased Sp1 expression on UF gene promoter activity was examined using a human Sp1 expression vector that was transiently transfected into primary cultures of pig endometrial glandular epithelial cells. Sp1 increased (P < 0.05) the promoter activities of various UF promoter-Luciferase reporter constructs by 2 to 4-fold, over those transfected with empty expression vector. Co-transfection of a BTEB expression vector with the Sp1 expression vector modified the effect of Sp1 on UF promoter activity in the shortest construct. These results suggest that Sp1 mediates the regulation of endometrial epithelial gene expression during pregnancy, and that this function is likely altered in vivo by co-expression of other family members, including BTEB.

Acid Phosphatase↗
PubMed2000

Intracellular cytokine profile of T cells from children with acute lymphoblastic leukemia.

PURPOSE: During an ongoing immune response, cytokines produced by T helper types 1 (Th1) and 2 (Th2) together with T cytotoxic types 1 (Tc1) and 2 (Tc2) are critical to the effectiveness of that response. Dysregulated expansion of one or the other subset may contribute to the impaired function of the T-cell-mediated immune system in cancer patients. In the present study we have investigated whether such dysregulation might exist in children with acute lymphoblastic leukemia (ALL). METHODS: We analyzed 61 blood samples from 45 children with B cell precursor ALL and 16 healthy children. Interleukin(IL)-2, IL-4, and interferon gamma (IFN gamma) production of their respective purified CD4+ and CD8+ T cells were assessed at the single-cell level by intracellular-cytokine-staining flow cytometry. RESULTS: At the time of diagnosis, IL-2-producing cell populations in CD4+ and CD8+ T cells were reduced below the normal range in 31 of 44 (70.5%) and 23 of 38 (60.5%) cases respectively. Similarly, IFN gamma-producing cell populations in CD4+ and CD8+ T cells decreased in 17 of 44 (38.6%) and 18 of 38 (47.4%) cases respectively. Conversely cell populations capable of IL-4 production in CD4+ and CD8+ T cell subsets were increased in 13 of 30 (43.3%) and 15 of 30 (50.0%) cases respectively. Therefore, the Th1-to-Th2 and Tc1-to-Tc2 ratios (1.6 +/- 2.2 and 7.7 +/- 6.7 respectively) were significantly lower in peripheral blood T cells of ALL patients (n = 30) than those (6.0 +/- 2.9 and 20.1 +/- 10.3 respectively) in 15 healthy controls (P < 0.0001). Although both CD45RA+/CD4+ and CD45RA+/CD8+ cells significantly increased in 43 ALL patients (P < 0.05), there existed no apparent correlation between CD45 isoform expression and cytokine (IL-2 and IFN gamma) production. Interestingly, the ability to produce both IL-2 and IFN gamma was recovered in 8 cases examined, after complete remission had been achieved. CONCLUSION: These observations suggest that, in both CD4+ and CD8+ T cells of ALL patients, there is a dysregulation in the functionality of Th1 (Tc1) and Th2 (Tc2) cells with a gross reduction of Th1 (Tc1) cell populations and an expansion in Th2 (Tc2).

Adolescent↗