Adenosine Deaminase Deficiency and Purine Nucleoside Phosphorylase Deficiency in Common Variable Immunodeficiency

The clinical presentations of adenosine deaminase deficiency and purine nucleoside phosphorylase deficiency are widely variable and include clinical and immunologic findings compatible with common variable immunodeficiency. The screening of 44 patients with common variable immunodeficiency failed to identify any individuals with deficiencies of these enzymes.     

The First Purine Nucleoside Phosphorylase Deficiency Patient Resembling IgA Deficiency and a Review of the Literature

Purine nucleoside phosphorylase (PNP) deficiency is a rare autosomal recessive primary immunodeficiency disorder characterized by decreased numbers of T-cells, variable B-cell abnormalities, decreased amount of serum uric acid and PNP enzyme activity. The affected patients usually present with recurrent infections, neurological dysfunction and autoimmune phenomena. In this study, whole-exome sequencing was used to detect mutation in the case suspected of having primary immunodeficiency. We found a homozygous mutation in PNP gene in a girl who is the third case from the national Iranian registry. She had combined immunodeficiency, autoimmune hemolytic anemia and a history of recurrent infections. She developed no neurological dysfunction. She died at the age of 11 after a severe chicken pox infection. PNP deficiency should be considered in late-onset children with recurrent infections, autoimmune disorders without typical neurologic impairment.     

大肠埃希菌嘌呤核苷磷酸化酶基因载体的构建及对胰腺癌细胞的作用

目的 构建大肠埃希菌(Escherichia coli)嘌呤核苷磷酸化酶(purine nucleoside phosphorylase,PNP)基因表达载体,研究其生物活性,为肿瘤的基因治疗奠定基础.方法 PCR扩增大肠埃希菌K12的PNP基因,T4连接酶将PNP连接入pMSCV逆转录病毒载体,构建重组逆转录病毒载体...     

Evidence for a Pathway Independent from 2'-Deoxyguanosine and Reversible by IL-2 by which Purine Nucleoside Phosphorylase Inhibitors Block T-Cell Proliferation

Patients with homozygous deficiency of purine nucleoside phosphorylase (PNP) present with a T-cell selective immune deficiency. To elucidate the potential use of PNP inhibitors in the therapy of cutaneous T-cell lymphomas (CTCLs) the authors studied the effects of CI-1000 (formerly PD 141955-2) and CI-972 on a T-cell line My La established from a patient with mycosis fungoides. Both PNP inhibitors had significant, dose-dependent, inhibitory effects on the proliferation of the T-cell line. CI-1000 (ED₅₀: 3.7 μM) was approximately six-fold more potent in blocking ³H-thymidine uptake than CI-972 (ED₅₀: 22.5 μM). The inhibitory effect of either substance could not be increased by addition of deoxyguanosine. Flow cytometric analysis revealed that both PNP inhibitors caused a block in the S-phase of the cell cycle. The inhibitory effect on proliferation was reversible partially by addition of IL-2. When testing proliferation inhibition of both substances on an IL-2-dependent T-cell line (SeAx), their inhibitory effects were reduced significantly. These data document a mechanism of action of the PNP inhibitors independent of deoxyguanosine and partially reversible by IL-2. The authors' observations suggest the potential use of PNP inhibitors in the therapy of cutaneous T-cell lymphomas and provide evidence for a pathway independent from deoxyguanosine by which PNP inhibitors might function in T cells.     

慢性乙型肝炎患者B细胞功能的研究

对24例乙型慢迁肝患者进行体外B细胞功能研究.结果显示慢性迁延性肝炎(慢迁肝)患者外周血单个核细胞自发产生或经美洲商陆(PWM)刺激后产生的IgG、IgM量与正常人相比无显著差异.乙型慢活肝患者自发产生的IgG、IgM量比正常人明显升高,但经PWM刺激后,IgG、IgM的产生量反而比对照组明显减低.慢活肝患者血清IgG量与B细胞体外培养产生的IgG量有较明显的相关性.     

CD72, a Coreceptor with Both Positive and Negative Effects on B Lymphocyte Development and Function

Introduction  B lymphocytes remain in a resting state until activated by antigenic stimuli through interaction with the B cell receptor (BCR). Coreceptors on B cells can modulate the thresholds for signaling through the BCR for growth and differentiation. CD72 is a B cell coreceptor that has been shown to interact with CD100, a semaphorin, and to enhance BCR signaling. Discussion  CD72 ligation induces a variety of early signaling events such as activation of the Src kinases Blk and Lyn and the non-src kinase Btk leading to activation of the mitogen-activated protein (MAP) kinases, events usually associated with positive signaling. CD72 signals can enable Btk-deficient B cells to overcome their unresponsiveness to BCR signaling. On the other hand, BCR-mediated signals are enhanced in CD72-deficient cells but are reduced in CD100 null cells. The dual effects of CD72 on B cells can be explained by its association with positive and negative signaling molecules. Thus, CD72 interacts with SHP-1, an SH2-domain containing protein tyrosine phosphatase, a negative regulator of signaling, and Grb2, an adaptor protein associated with the Ras/MAPK pathway. Ligation of CD72 also triggered its association with CD19, a positive modulator of B cell receptor signaling. We propose a dual signaling hypothesis to explain the growth and differentiation promoting properties of CD72. Deficiency in either CD72 or CD100 leads to autoimmunity in mouse models. CD72 expression and polymorphisms exhibit some association with autoimmune diseases such as lupus, Sjogren’s syndrome, and type 1 diabetes.     

Lymphocyte Subpopulation Number and Function in Infancy

Normal values for percentages of lymphocyte subpopulations and functional responses to mitogen stimulation in infancy are not well established. In the present study, lymphocyte subpopulations were examined in umbilical cord blood samples and in peripheral blood samples drawn before 7 and 24 months of age (mean age 10.4 months) from a healthy population of infants born in Tucson, Arizona. Results indicate significant increases occurred from birth to later infancy in the percentages of total T cells (CD3), T-cell subsets (CD4, CD8) and B cells (CD20). The CD4/CD8 ratio and the functional responses to ConA and PWM mitogens significantly decreased from birth to later infancy. PHA responsiveness did not show a significant change. Results from cross-sectional analyses (n=271) were supported in a smaller longitudinal subset (n=37). There were no detectable ethnic- or gender-related differences in cord blood or samples obtained in later infancy. The normal values established in this study will be useful in studies of immune-system maturation and in the clinical evaluation of newborns, infants, and toddlers suspected of either acquired or congenital immune-deficiency states.     

Changes in T,B, and NK Lymphocyte Subsets During and After Normal Pregnancy

PROBLEM: Pregnancy affects the maternal immune system and the clinical course of maternal diseases. Here we report the changes in the detailed lymphocyte subsets of helper T cells, suppressor T cells, CD5⁺ B cells, T cell receptor (TCR) αβ-positive T cells (Tαβ cells), TCRαβ-negative T cell (Tγδ cells), and others during and after pregnancy through to one year postpartum, and discuss the significance of the changes. METHOD: The absolute numbers of helper T cells, suppressor T cells, cytotoxic T cells, TCRαβ-negative T cells (Tγδ cells), CD5^— B cells, CD5⁺ B cells, and NK cell subsets were examined by two-color flow cytometry in peripheral blood from 51 healthy non-pregnant women, 106 healthy pregnant women, and 148 healthy postpartum women. RESULTS: In early pregnancy, the numbers of suppressor T cells and NK cells with strong cytotoxicity (NK⁺⁺⁺ cells) increased, and the number of cytotoxic T cells decreased. In late pregnancy, the helper T cell and NK⁺⁺⁺ cell numbers decreased. Tαβ, CD5^— B and CD5⁺ B cells decreased during pregnancy. After delivery, helper T cells and cytotoxic T cells increased from 1 to 4 months postpartum, and suppressor T cells increased at 7 months postpartum. TCRαβ-negative T cells increased at 4 to 10 months postpartum. Both CD5^— and CD5⁺ B cells decreased further at 1 month postpartum, but CD5⁺ B cells increased markedly at 7 to 10 months postpartum. CONCLUSIONS: These data indicate that 1) early increases of suppressor T cells and NK⁺⁺⁺ cells during pregnancy may be related to the mechanism to accept or reject the fetus in early pregnancy, respectively; 2) late decreases of helper T cells and NK⁺⁺⁺ cells may be related to the maintenance of pregnancy: 3) postpartum increases of helper T cells, cytotoxic T cells, TCRαβ-negative T cells (Tγδ cells), and CD5⁺ B cells may be related to the postpartum aggravation of autoimmune diseases; and 4) the immunological effects of pregnancy remains until about 1 year after delivery.     

B Lymphocyte Fibronectin Receptors: Expression and Utilization

Lymphocytes adhere to fibronectin (FN) via multiple receptors of the VLA (beta 1, CD29 integrin) family. The cellular requirement for the variety of FN receptors (FNR) which have been described is unclear, but they may be associated with differential signalling processes, cooperative effects which may stabilize cellular attachment, or cell homing and retention processes. The present study was undertaken to examine the FN adherence properties and receptor utilization patterns of human B cells. Of ten B-cell culture lines which were studied, six demonstrated a significant adherence to FN. Among these, four employed alpha 4 beta 1, (CD49d/29) and two employed alpha 4 beta 1/alpha 5 beta 1, (CD49d/29, CD49e/29). There was no apparent correlation between the differentiation status of the lines and their FNR utilization patterns. Furthermore, expression of FNR alone was not sufficient to confer FN binding potential. Freshly isolated tonsil B cells did not display significant adherence to FN. Following stimulation, a marked increase in VLA antigens was observed, and the capacity to attach to FN-coated surfaces was co-acquired. Analysis of the induced bulk B-cell population demonstrated that both alpha 4 beta 1 and alpha 5 beta 1 were used for adherence. These results clearly indicate that activated B cells, similar to T cells, may express and utilize alpha 5 beta 1 as a FNR.     

小鼠B细胞趋化因子原核表达与纯化

用多聚酶链反应 (PCR)扩增小鼠 B细胞趋化因子 (BL C)基因片断并导入 Bam H1和 Pst1两个酶切位点 ,插入到原核表达载体 PQE30中 ,构建重组质粒 p BL C- PQE30 ,并诱导相对分子量为 10 Kda的重组目的蛋白r BL C的表达 ,通过 Ni柱亲和层析纯化目的蛋白。双酶切和测序分析显示小鼠 B细胞趋化因子片断正确插入原核表达载体 PQE30中 ,重组蛋白 Western blot分析显示出特异性条带。提示已通过基因工程方法获得并纯化了小鼠B细胞趋化因子重组蛋白。