Leukemic target susceptibility to natural killer cytotoxicity: relationship with BCR-ABL expression

Blood ◽  
2002 ◽  
Vol 99 (6) ◽  
pp. 2107-2113 ◽  
Author(s):  
Frédéric Baron ◽  
Ali G. Turhan ◽  
Julien Giron-Michel ◽  
Bruno Azzarone ◽  
Mohamed Bentires-Alj ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Specific Inhibitor ◽  
Intercellular Adhesion Molecule ◽  
Target Cells ◽  
Intercellular Adhesion Molecule 1 ◽  
Down Regulation ◽  
Subsequent Decrease

Abstract Chronic myeloid leukemia is a clonal myeloproliferative expansion of transformed primitive hematopoietic progenitor cells characterized by high-level expression of BCR-ABL chimeric gene, which induces growth factor independence. However, the influence of BCR-ABL expression on cell-mediated cytotoxicity is poorly understood. In the present study, we asked whether BCR-ABL expression interferes with leukemic target sensitivity to natural killer (NK) cell cytolysis. Our approach was based on the use of 2 BCR-ABL transfectants of the pluripotent hematopoietic cell line UT-7 expressing low (UT-7/E8, UT-7/G6) and high (UT-7/9) levels of BCR-ABL. As effector cells, we used CD56bright, CD16−, CD2− NK cells differentiated in vitro from CD34 cord blood progenitors. We demonstrated that BCR-ABL transfectants UT-7/9 were lysed by NK cells with a higher efficiency than parental and low UT-7/E8.1 and UT-7/G6 transfectants. This enhanced susceptibility to lysis correlated with an increase in expression of intercellular adhesion molecule 1 (ICAM-1) by target cells. Treatment of UT-7/9 cells by STI571 (a specific inhibitor of the abl kinase) resulted in a decrease in NK susceptibility to lysis and ICAM-1 down-regulation in target cells. Furthermore, the constitutive activation of nuclear factor-κB (NF-κB) detected in BCR-ABL transfectant UT-7/9, was significantly attenuated when cells were treated by STI571. Interestingly, inhibition of NF-κB activation by BAY11-67082 (a specific NF-κB inhibitor) resulted in down-regulation of ICAM-1 expression and a subsequent decrease in NK-induced killing of UT-7/9 transfectants. Our results show that oncogenic transformation by BCR-ABL may increase susceptibility of leukemic progenitors to NK cell cytotoxicity by a mechanism involving overexpression of ICAM-1 as a consequence of NF-κB activation.

scholarly journals Molecules and structures involved in the adhesion of natural killer cells to vascular endothelium.

1991 ◽  
Vol 173 (2) ◽  
pp. 439-448 ◽  
Author(s):  
P Allavena ◽  
C Paganin ◽  
I Martin-Padura ◽  
G Peri ◽  
M Gaboli ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Adhesion Molecule ◽  
Vascular Endothelium ◽  
Nk Cell ◽  
Leukocyte Adhesion ◽  
Umbilical Vein ◽  
Interleukin 2 ◽  
Intercellular Adhesion Molecule

The present study was designed to define molecules and structures involved in the interaction of natural killer (NK) cells with the vascular endothelium in vitro. Resting and interleukin 2 (IL-2)-activated NK cells were studied for their capacity to adhere to resting and IL-1-treated human umbilical vein endothelial cells (EC). In the absence of stimuli, NK cells showed appreciable adhesion to EC, with levels of binding intermediate between polymorphs and monocytes. The binding ability was increased by pretreatment of NK cells with IL-2. Using the appropriate monoclonal antibody, the beta 2 leukocyte integrin CD18/CD11a was identified as the major adhesion pathway of NK cells to unstimulated EC. Activation of EC with IL-1 increased the binding of NK cells. In addition to the CD18-CD11a/intercellular adhesion molecule pathway, the interaction of resting or IL-2-activated NK cells to IL-1-activated EC involved the VLA-4 (alpha 4 beta 1)-vascular cell adhesion molecule 1 receptor/counter-receptor pair. No evidence for appreciable involvement of endothelial-leukocyte adhesion molecule was obtained. Often, NK cells interacted either with the culture substrate or with the EC surface via dot-shaped adhesion structures (podosomes) protruding from the ventral surface and consisting of a core of F-actin surrounded by a ring of vinculin and talin. The identification of molecules and microanatomical structures involved in the interaction of NK cells with EC may provide a better understanding of the regulation of NK cell recruitment from blood, their extravasation, and their migration to tissues.

scholarly journals Human natural killer cells can inhibit clonogenic growth of fresh leukemic cells

Blood ◽  
1983 ◽  
Vol 61 (3) ◽  
pp. 596-599 ◽  
Author(s):  
M Beran ◽  
M Hansson ◽  
R Kiessling
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Colony Growth ◽  
Inhibitory Effect ◽  
Leukemic Cells ◽  
Target Cells ◽  
Human Natural Killer Cells ◽  
Release Assay

Abstract The effect of allogenic human natural killer (NK) cells on fresh leukemic cells from three patients was investigated. The low levels of leukemic target cell lysis in the conventional 51Cr-release assay contrasted with a pronounced inhibitory effect on the colony growth of the clonogeneic leukemic target cells (L-CFC). The ability of allogeneic lymphocytes to inhibit L-CFC increased if they were pretreated with interferon (IFN), which also increased their NK activity, monitored in parallel cytotoxicity assay, against K562. Furthermore, cell separation procedures, based on differences in density among nonadherent lymphocytes, revealed that only NK cell containing fractions were inhibitory. We have also compared the susceptibility to NK-mediated L-CFC inhibition of IFN pretreated leukemic target cells with that of nontreated target cells. As in the case of NK lysis in general, this pretreatment of target cells abolished the presumably NK-mediated L-CFC inhibition. In conclusion, these data provide the first indication that NK cells can inhibit the in vitro growth of fresh clonogenic leukemia cells from patients with nonlymphocytic leukemia. The identity of NK cells as effector is strongly suggested by Percoll separation and responsiveness to interferon; the final proof awaits more sophisticated purification of these cells.

scholarly journals Human natural killer cells can inhibit clonogenic growth of fresh leukemic cells

Blood ◽  
1983 ◽  
Vol 61 (3) ◽  
pp. 596-599
Author(s):  
M Beran ◽  
M Hansson ◽  
R Kiessling
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Colony Growth ◽  
Inhibitory Effect ◽  
Leukemic Cells ◽  
Target Cells ◽  
Human Natural Killer Cells ◽  
Release Assay

The effect of allogenic human natural killer (NK) cells on fresh leukemic cells from three patients was investigated. The low levels of leukemic target cell lysis in the conventional 51Cr-release assay contrasted with a pronounced inhibitory effect on the colony growth of the clonogeneic leukemic target cells (L-CFC). The ability of allogeneic lymphocytes to inhibit L-CFC increased if they were pretreated with interferon (IFN), which also increased their NK activity, monitored in parallel cytotoxicity assay, against K562. Furthermore, cell separation procedures, based on differences in density among nonadherent lymphocytes, revealed that only NK cell containing fractions were inhibitory. We have also compared the susceptibility to NK-mediated L-CFC inhibition of IFN pretreated leukemic target cells with that of nontreated target cells. As in the case of NK lysis in general, this pretreatment of target cells abolished the presumably NK-mediated L-CFC inhibition. In conclusion, these data provide the first indication that NK cells can inhibit the in vitro growth of fresh clonogenic leukemia cells from patients with nonlymphocytic leukemia. The identity of NK cells as effector is strongly suggested by Percoll separation and responsiveness to interferon; the final proof awaits more sophisticated purification of these cells.

scholarly journals Differential natural killer cell–mediated inhibition of HIV-1 replication based on distinct KIR/HLA subtypes

2007 ◽  
Vol 204 (12) ◽  
pp. 3027-3036 ◽  
Author(s):  
Galit Alter ◽  
Maureen P. Martin ◽  
Nickolas Teigen ◽  
William H. Carr ◽  
Todd J. Suscovich ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Cell Activity ◽  
Cell Contact ◽  
Target Cells ◽  
Dependent Manner ◽  
Hiv 1

Decline of peak viremia during acute HIV-1 infection occurs before the development of vigorous adaptive immunity, and the level of decline correlates inversely with the rate of AIDS progression, implicating a potential role for the innate immune response in determining disease outcome. The combined expression of an activating natural killer (NK) cell receptor, the killer immunoglobulin-like receptor (KIR) 3DS1, and its presumed ligand, human leukocyte antigen (HLA)–B Bw4-80I, has been associated in epidemiological studies with a slow progression to AIDS. We examined the functional ability of NK cells to differentially control HIV-1 replication in vitro based on their KIR and HLA types. NK cells expressing KIR3DS1 showed strong, significant dose- and cell contact–dependent inhibition of HIV-1 replication in target cells expressing HLA-B Bw4-80I compared with NK cells that did not express KIR3DS1. Furthermore, KIR3DS1+ NK cells and NKLs were preferentially activated, and lysed HIV-1 infected target cells in an HLA-B Bw4-80I–dependent manner. These data provide the first functional evidence that variation at the KIR locus influences the effectiveness of NK cell activity in the containment of viral replication.

Therapeutic Effects of ALT-803, an IL-15 Superagonist, in Combination with Anti-CD20 Chimeric Antigen Receptor Modified Expanded Natural Killer CELLS Against Pediatric Burkitt Lymphoma (BL)

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3085-3085 ◽  
Author(s):  
Yaya Chu ◽  
Fangyu Lee ◽  
Janet Ayello ◽  
Brian Hang ◽  
Melanie Zhang ◽  
...  
Keyword(s):  
Natural Killer Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Peripheral Blood ◽  
Burkitt Lymphoma ◽  
Nk Cell ◽  
Target Cells ◽  
Killer Cells ◽  
Anti Cd20

Abstract Background: The outcome for children with Burkitt lymphoma (BL)has improved significantly but for patients who relapse, the prognosis is dismal due to chemo-immunotherapy resistance (Cairo et al, JCO, 2012, Cairo et al, Blood, 2007). NK cells are bone marrow-derived cytotoxic lymphocytes that play a major role in the rejection of tumors. A variety of activating and inhibitory receptors on the NK cell surface are engaged to regulate NK cell activities and to discriminate target cells from other healthy 'self' cells. However, NK therapy is limited by several factors, including small numbers of active NK cells in unmodified peripheral blood, lack of tumor targeting specificity, and multiple mechanisms of tumor escape of NK cell immunosurveillance. Our group has successfully modified expanded peripheral blood Natural Killer cells (exPBNK) with an anti-CD20 CAR to target rituximab sensitive/resistant CD20+ BL cells in vitro and in NSG mice (Chu/Cairo, et al, Can Imm Res 2015). However, the short lifespan/persistence of adoptively transferred NK cells has limited the therapeutic efficacy. ALT-803 (Altor BioScience Corporation) is a superagonist of an IL-15 variant bound to an IL-15Rα-Fc fusion with enhanced IL-15 biological activity (Zhu et al. 2009 J Immunol), longer half-life and increased potency (Han, et al. Cytokine. 2011). It is currently in several clinical trials in patients with variety of cancers such as refractory indolent non-Hodgkin's lymphoma (NCT02384954). Objective: We hypothesize that ALT-803, IL-15 superagonist complex, promotes exPBNK persistence and significantly enhances the cytotoxicity of anti-CD20 CAR exPBNK against CD20+ BL. Method: PBMCs were expanded with lethally irradiated K562-mbIL21-41BBL cells (Dean Lee et al, PLoS One, 2012). CD56+ CD3- exPBNK cells were isolated using Miltenyi NK cell isolation kit. Anti-CD20-4-1BB-CD3 ζ mRNA (CAR mRNA) was producedin vitro and nucleofected into exPBNK as we have previously described (Chu/Cairo, et al, Can Imm Res 2015). ALT-803 was provided by Altor BioScience Corporation. ExPBNK cells were cultured with 0.35ng/ml or 3.5ng/ml ALT-803. NK proliferation was monitored with MTS assays. NK receptors expression and cytotoxicity were examined by flow cytometry (Chu/Cairo, et al, ASH 2014). NK resistant BL cells Raji and Daudi were used as target cells. Results: % CD56+ CD3- PBNK cells were significantly increased compared to media alone at day 14 (mean 81.85% vs 14.91%, n=3, p<0.001) when co-cultured with the irradiated feeder cell K562-mbIL21-41BBL. The absolute NK numbers were enhanced with irradiated K562-mbIL21-41BBL cells as feeders compared to IL-2 alone after normalized to the INPUT NK cell numbers (mean 2247 fold±293.7 vs 0.516 fold±0.225, n=3, p<0.001) at day 14. Different doses of ALT-803 or IgG were added to the culture medium of purified expanded exPBNK. Proliferation assays were performed at day 3, 7,11, and 17. ALT-803 significantly promoted exPBNK proliferation and persistence compared to IgG in vitro in a dose-dependent manner (A490 reading at 3.5ng/ml dose: ALT803 vs IgG=0.3383+0.009 vs 0.0987+0.0007, P<0.0001 at d17). And ALT-803 significantly enhanced exPBNK cytotoxicity against NK resistant BL cells: Raji (ALT803 vs IgG= 49.54%+2.7% vs 5.99+0.34%, p<0.001, E:T=10:1) and Daudi (ALT803 vs IgG= 63.73%+3.09% vs 2.58+1.96%, p<0.001, E:T=10:1). It also maintained the highcytoxicity of exPBNK at d4, d10 and d18 against Raji (E:T=10:1, d4 vs d10 vs d18=62.07% vs 49.54% vs 61.47%) and against Daudi (E:T=10:1, d4 vs d10 vs d18=76.02% vs 63.73% vs 55%) by maintaining the activating receptors expression such as NKp30, NKp44, and NKp46. Further-more, we demonstrated ALT-803 significantly enhanced the cytotoxicity of anti-CD20 CAR modified exPBNK against Raji (CAR vs MOCK= 81.19%+0.35% vs 66.19+0.94%, p<0.001, E:T=10:1) and Daudi (CAR vs MOCK= 91.41%+0.45% vs 80.56+1.07%, p<0.001, E:T=10:1) compared to mock modified exPBNK. ALT-803 also significantly enhanced the cytotoxicity of anti-CD20 CAR modified exPBNK against NK resistant BL cells: Raji and Daudi compared to anti-CD20 CAR modified exPBNK maintained in medium without ALT803 (Fig.1). Conclusions: ALT-803 maintained the cytotoxicity of exPBNK and in vitro persistence and significantly enhanced anti-CD20 CAR exPBNK cytotoxicity against pediatric NK resistant BL. The in vivo effect of ALT-803 on CAR exPBNK using humanized NSG models is under investigation. Disclosures Wong: Altor BioScience Corporation: Employment, Other: stockholder of Altor Bioscience Corporation. Lee:Intrexon, Ziopharm, Cyto-Sen: Equity Ownership.

scholarly journals Exploitation of natural killer cells for the treatment of acute leukemia

Blood ◽  
2016 ◽  
Vol 127 (26) ◽  
pp. 3341-3349 ◽  
Author(s):  
Rupert Handgretinger ◽  
Peter Lang ◽  
Maya C. André
Keyword(s):  
Cell Therapy ◽  
Nk Cells ◽  
Natural Killer ◽  
Adoptive Transfer ◽  
Nk Cell ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Target Cells

Abstract Natural killer (NK) cells play an important role in surveillance and elimination of malignant cells. Their spontaneous cytotoxicity was first demonstrated in vitro against leukemia cell lines, and NK cells might play a crucial role in the therapy of leukemia. NK cell activity is controlled by an array of germ line–encoded activating and inhibitory receptors, as well as modulating coreceptors. This biologic feature can be exploited in allogeneic cell therapy, and the recognition of “missing-self” on target cells is crucial for promoting NK cell–mediated graft-versus-leukemia effects. In this regard, NK cells that express an inhibitory killer immunoglobulin-like receptor (iKIR) for which the respective major histocompatibility complex class I ligand is absent on leukemic target cells can exert alloreactivity in vitro and in vivo. Several models regarding potential donor–patient constellations have been described that have demonstrated the clinical benefit of such alloreactivity of the donor-derived NK cell system in patients with adult acute myeloid leukemia and pediatric B-cell precursor acute lymphoblastic leukemia after allogeneic stem cell transplantation. Moreover, adoptive transfer of mature allogeneic NK cells in the nontransplant or transplant setting has been shown to be safe and feasible, whereas its effectivity needs further evaluation. NK cell therapy can be further improved by optimal donor selection based on phenotypic and genotypic properties, by adoptive transfer of NK cells with ex vivo or in vivo cytokine stimulation, by the use of antibodies to induce antibody-dependent cellular cytotoxicity or to block iKIRs, or by transduction of chimeric antigen receptors.

Elucidation of the integrin LFA-1–mediated signaling pathway of actin polarization in natural killer cells

Blood ◽  
2010 ◽  
Vol 116 (8) ◽  
pp. 1272-1279 ◽  
Author(s):  
Emily M. Mace ◽  
Jinyi Zhang ◽  
Katherine A. Siminovitch ◽  
Fumio Takei
Keyword(s):  
Signaling Pathways ◽  
Natural Killer ◽  
Signaling Pathway ◽  
Actin Polymerization ◽  
Nk Cell ◽  
Intercellular Adhesion Molecule ◽  
Target Cells ◽  
Type I ◽  
Intercellular Adhesion Molecule 1 ◽  
Associated Proteins

Abstract The leukocyte integrin LFA-1 is critical for natural killer (NK) cell cytotoxicity as it mediates NK-cell adhesion to target cells and generates activating signals that lead to polarization of the actin cytoskeleton. However, the LFA-1–mediated signaling pathway is not fully understood. Here, we examined the subcellular localization of actin-associated proteins in wild-type, talin-deficient, and Wiskott-Aldrich Syndrome protein (WASP)–deficient NK cells bound to beads coated with the LFA-1 ligand intercellular adhesion molecule-1 (ICAM-1). In addition, we carried out coimmunoprecipitation analyses and also used a pharmacologic reagent to reduce the level of phosphatidylinositol-4,5-bisphosphate (PIP2). The results revealed the following signaling pathways. Upon ICAM-1 binding to LFA-1, talin redistributes to the site of LFA-1 ligation and initiates 2 signaling pathways. First, talin recruits the actin nucleating protein complex Arp2/3 via constitutive association of vinculin with talin and Arp2/3. Second, talin also associates with type I phosphatidylinositol 4-phosphate 5-kinase (PIPKI) and binding of LFA-1 to ICAM-1 results in localized increase in PIP2. This increase in PIP2 recruits WASP to the site of LFA-1 ligation where WASP promotes Arp2/3-mediated actin polymerization. These processes are critical for the initiation of NK cell–mediated cytotoxicity.

scholarly journals Vav1 Phosphorylation Is Induced by β2 Integrin Engagement on Natural Killer Cells Upstream of Actin Cytoskeleton and Lipid Raft Reorganization

2003 ◽  
Vol 198 (3) ◽  
pp. 469-474 ◽  
Author(s):  
Béatrice Riteau ◽  
Domingo F. Barber ◽  
Eric O. Long
Keyword(s):  
Actin Cytoskeleton ◽  
Nk Cells ◽  
Natural Killer ◽  
Actin Polymerization ◽  
Nk Cell ◽  
Intercellular Adhesion Molecule ◽  
Cell Contact ◽  
Target Cells ◽  
Cholesterol Depletion ◽  
Β2 Integrin

The guanine nucleotide exchange factor Vav1 regulates actin polymerization and contributes to cytotoxicity by natural killer (NK) cells. An open question is how Vav1 becomes activated and what receptor can signal upstream of actin cytoskeleton rearrangement upon NK cell contact with target cells. Using transfected insect cells that express ligands of human NK cell receptors, we show that engagement of the β2 integrin LFA-1 on NK cells by intercellular adhesion molecule (ICAM)-1 led to a tyrosine phosphorylation of Vav1 that was not sensitive to cholesterol depletion and to inhibition of actin polymerization. Vav1 phosphorylation was blocked by an inhibitor of Src-family kinases, and correlated with activation of its downstream effector PAK. Binding of activation receptor 2B4 to its ligand CD48 was not sufficient for Vav1 phosphorylation. However, coengagement of 2B4 with LFA-1 resulted in an enhancement of Vav1 phosphorylation that was sensitive to cholesterol depletion and to inhibition of actin polymerization. Vav1 was recruited to a detergent-resistant membrane (DRM) fraction only when 2B4 and LFA-1 were coengaged, but not after LFA-1 engagement. Therefore, binding of LFA-1 to ICAM-1 on target cells may initiate an early signaling cascade in NK cells through activation of Vav1, leading to cytoskeleton reorganization and amplification of signals from other activation receptors.

scholarly journals Sostdc1 regulates natural killer cell maturation and cytotoxicity

2018 ◽  
Author(s):  
Alberto J. Millan ◽  
Sonny R. Elizaldi ◽  
Eric M. Lee ◽  
Jeffrey O. Aceves ◽  
Deepa Murugesh ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Cell Development ◽  
Cell Maturation ◽  
Target Cells ◽  
List Type

AbstractNatural killer (NK) cells are specialized lymphocytes with the innate ability to eliminate virally infected and cancerous cells, but the mechanisms that control NK cell development and cytotoxicity are incompletely understood. We identified novel roles for Sclerostin domain containing-1 (Sostdc1) in NK cell development and function. Sostdc1-knockout (Sostdc1-/-) mice display a progressive accumulation of transitional NK cells (CD27+CD11b+, tNK) with age, indicating a partial developmental block. The Ly49 repertoire on NK cells in Sostdc1-/- mice is also changed. Lower frequencies of Sostdc1-/- splenic tNKs express inhibitory Ly49G2 receptors, but higher frequencies express activating Ly49H and Ly49D receptors. However, the frequencies of Ly49I+, G2+, H+ and D+ populations were universally decreased at the most mature (CD27-CD11b+, mNK) stage. We hypothesized that the Ly49 repertoire in Sostdc1-/- mice would correlate with NK killing ability, and observed that Sostdc1-/- NK cells are hyporesponsive against MHC-I-deficient cell targets in vitro and in vivo, despite higher CD107a surface levels and similar IFNγ expression to controls. Consistent with Sostdc1’s known role in the regulation of Wnt signaling, high levels of Wnt coactivators Tcf7 and Lef1 were observed in Sostdc1-/- NK cells. Expression of the NK development gene Id2 was decreased in Sostdc1-/- iNK and tNK cells, but we observed no changes in Eomes and Tbx21 expression. Reciprocal bone marrow transplant experiments showed that Sostdc1 regulates NK cell maturation and expression of Ly49 receptors in a cell-extrinsic fashion from both non-hematopoietic and hematopoietic sources. Taken together, these data support a role for Sostdc1 in the regulation of NK cell maturation, and NK cell cytotoxicity, and identify potential NK cell niches.Summary of ResultsSostdc1-/- mice display a partial block between the tNK and mNK developmental stages.Sostdc1 influences the Ly49 receptor repertoire on NK cells.NK cells in Sostdc1-/- mice display impaired ability to kill β2m-/- target cells.Sostdc1-/- NK cell subsets express high levels of Wnt coactivators Tcf7 and Lef1.Id2 expression is decreased in iNK and tNK cells in the absence of Sostdc1.Bone marrow transplantation experiments demonstrate cell-extrinsic regulation of NK cell maturation by Sostdc1 in both non-hematopoietic (stromal) and hematopoietic cells.

scholarly journals Identification of an unusual Fc gamma receptor IIIa (CD16) on natural killer cells in a patient with recurrent infections

Blood ◽  
1996 ◽  
Vol 88 (8) ◽  
pp. 3022-3027 ◽  
Author(s):  
E de Vries ◽  
HR Koene ◽  
JM Vossen ◽  
JW Gratama ◽  
AE von dem Borne ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Function ◽  
Nk Cell ◽  
Peripheral Blood Lymphocytes ◽  
Target Cells ◽  
Fc Gamma Receptor ◽  
Gamma Receptor ◽  
Tract Infections

We found an unusual fc gamma receptor IIIa (CD16) phenotype on the natural killer (NK) cells of a 3-year-old boy, who suffered from recurrent viral respiratory tract infections since birth. He also had severe clinical problems after Bacille Calmette-Geerin (BCG) vaccination and following Epstein-Barr virus and Varicella Zoster virus infections. His peripheral blood lymphocytes contained a normal percentage and absolute number of CD3-CD7+ cells, which were positively stained with the CD16 monoclonal antibodies (MoAbs) 3G8 and CLBFcRgran1, but did marginally stain with the CD16 MoAb Lau11c/B73.1. Fc gamma RillIb expression on granulocytes appeared to be normal. NK cell function, analyzed in vitro by direct cytotoxicity on K562 target cells and ADCC-activity on P815 target cells, was normal compared with an age-matched healthy control. Sequence analysis of the Fc gamma RIIIA gene, encoding CD16 on NK cells and macrophages, showed a T to A nucleotide substitution at position 230 on both alleles, predicting a leucine (L) to histidine (H) amino acid change position 48 in the first extracellular lg-like domain of Fc gamma RIIIa, which contains the Leu11c/B73.1 epitope. The combined use of CD16 and CD56 MoAbs labeled with the same fluorescent dye, as often applied in routine immunophenotyping procedures, will leave these homozygotes undiagnosed. The pattern of infections in this patient is in agreement with the postulated function of NK cells in the immunological defense against viruses and other intracellular microorganisms. Further analysis of the NK cell function in vitro and follow-up of the clinical course of Fc gamma RIIIA-48H/H homozygotes is required to ascertain whether this genotype is causally related to an NK cell immunodeficiency.

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