Ronit Gavrieli

Chronic granulomatous disease in Israel : Clinical, functional and molecular studies of 38 patients

Chronic granulomatous disease (CGD) is an innate immunodeficiency due to a genetic defect in one of the NADPH-oxidase components. In the course of 21 years, 38 Israeli CGD patients were diagnosed with 17 gene mutations, seven of which were new. Clinical, functional, and molecular studies were accomplished. Although X-linked recessive (XLR)-CGD is worldwide the most common genotype of the disease (~70%), in our study only 11 patients (29%) suffered from XLR-CGD. In Israel, the higher incidence of the autosomal recessive (AR) form of CGD (63%) may be related to consanguineous marriages. In three patients (8%), all four proteins of the NADPH oxidase were present. Severe clinical expression was found both in the XLR and AR forms, but in general a milder disease was evident in AR-CGD, particularly in patients with p47(phox) deficiency. Despite early and aggressive therapy, a mortality rate of 26% was noted. Given that bone-marrow transplantation was successful in five of seven patients, it is recommended to perform it as early as possible before tissue damage is irreversible.

A congenital neutrophil defect syndrome associated with mutations in VPS45

BACKGROUND Neutrophils are the predominant phagocytes that provide protection against bacterial and fungal infections. Genetically determined neutrophil disorders confer a predisposition to severe infections and reveal novel mechanisms that control vesicular trafficking, hematopoiesis, and innate immunity. METHODS We clinically evaluated seven children from five families who had neutropenia, neutrophil dysfunction, bone marrow fibrosis, and nephromegaly. To identify the causative gene, we performed homozygosity mapping using single-nucleotide polymorphism arrays, whole-exome sequencing, immunoblotting, immunofluorescence, electron microscopy, a real-time quantitative polymerase-chain-reaction assay, immunohistochemistry, flow cytometry, fibroblast motility assays, measurements of apoptosis, and zebrafish models. Correction experiments were performed by transfecting mutant fibroblasts with the nonmutated gene. RESULTS All seven affected children had homozygous mutations (Thr224Asn or Glu238Lys, depending on the childs ethnic origin) in VPS45, which encodes a protein that regulates membrane trafficking through the endosomal system. The level of VPS45 protein was reduced, as were the VPS45 binding partners rabenosyn-5 and syntaxin-16. The level of β1 integrin was reduced on the surface of VPS45-deficient neutrophils and fibroblasts. VPS45-deficient fibroblasts were characterized by impaired motility and increased apoptosis. A zebrafish model of vps45 deficiency showed a marked paucity of myeloperoxidase-positive cells (i.e., neutrophils). Transfection of patient cells with nonmutated VPS45 corrected the migration defect and decreased apoptosis. CONCLUSIONS Defective endosomal intracellular protein trafficking due to biallelic mutations in VPS45 underlies a new immunodeficiency syndrome involving impaired neutrophil function. (Funded by the National Human Genome Research Institute and others.).

Infections associated with chronic granulomatous disease: linking genetics to phenotypic expression

Chronic granulomatous disease (CGD) is an inherited primary immunodeficiency characterized by the absence or malfunction of the NADPH oxidase in phagocytic cells. As a result, there is an impaired ability to generate superoxide anions and the subsequent reactive oxygen intermediates. Consequently, CGD patients suffer from two clinical manifestations: recurrent, life-threatening bacterial and fungal infections and excessive inflammatory reactions leading to granulomatous lesions. Although the genotype of CGD was linked to the phenotypic expression of the disease, this connection is still controversial and poorly understood. Certain correlations were reported, but the clinical expression of the disease is usually unpredictable, regardless of the pattern of inheritance. CGD mainly affects the lungs, lymph nodes, skin, GI tract and liver. Patients are particularly susceptible to catalase-positive microorganisms, including Staphyloccocus aureus, Nocardia spp. and Gram-negative bacteria, such as Serratia marcescens, Burkholderia cepacea and Salmonella spp. Unusually, catalase-negative microorganisms were reported as well. New antibacterial and antimycotic agents considerably improved the prognosis of CGD. Therapy with IFN-γ is still controversial. Bone marrow stem cell transplantation is currently the only curative treatment and gene therapy needs further development. In this article, the authors discuss the genetic, functional and molecular aspects of CGD and their impact on the clinical expression, infectious complications and the hyperinflammatory state.

Overproduction of neutrophil radical oxygen species correlates with negative symptoms in schizophrenic patients: parallel studies on neutrophil chemotaxis, superoxide production and bactericidal activity

Defective neutrophil function in schizophrenic patients has recently been reported. There are several lines of evidence to support the contribution of oxygen free radicals in schizophrenia, including increased lipid peroxidation, fatty acids and alterations in blood levels of anti-oxidant enzymes. Eighteen schizophrenic patients (DSM-IV) and 15 healthy controls were studied. Neutrophil chemotaxis, superoxide production and bactericidal activity were investigated. A statistically significant increase of superoxide anion release was found in schizophrenic patients compared with controls (mean+/-S.E.M., patients: 6.89+/-0.30 nmol O2-/10(6) cells/min, controls: 5.13+/-0.55 nmol O2-/10(6) cells/min). Moreover, a significant positive correlation between superoxide production and negative symptoms as assessed by the Positive and Negative Syndrome Scale was demonstrated. No differences were detected in chemotaxis and phagocytosis between schizophrenic patients and healthy controls. The present findings of a positive correlation between superoxide generation and negative symptoms in schizophrenic patients support the hypothesis that superoxide anion may participate in the pathogenesis of schizophrenia, as an excess of free radicals could contribute to the deterioration phase of the disease. Further studies are required to establish the role of oxidative stress in the ethiopathogenesis of schizophrenia.

Neutrophil function response to aerobic and anaerobic exercise in female judoka and untrained subjects

Objectives—Recent studies have indicated reduced immunity in trained athletes. Aim—To assess the effects of aerobic and anaerobic exercise on the phagocytic process in 18–26 year old trained female judoka (n = 8) and untrained controls (n = 7). Methods—Each subject participated randomly in two different testing sessions (aerobic, 20 minutes of treadmill running at 70–80% of maximal heart rate; anaerobic, Wingate anaerobic test). Venous blood samples were drawn before, immediately after, and 24 hours after each session. Results—There were no significant differences in basal values of net chemotaxis (chemotaxis − random migration), bactericidal activity, and superoxide anion release between the judoka and the untrained women. There was a significant decrease in net chemotaxis 24 hours after the aerobic exercise in both the judoka (from 64 (19) to 39 (13) cells/field, p<0.02) and the untrained controls (from 60 (7) to 47 (12) cells/field, p<0.05). Bactericidal activity and superoxide anion release did not change significantly after aerobic exercise in either group. There were no significant changes in net chemotaxis, bactericidal activity, and superoxide anion release after anaerobic exercise in either the judoka or untrained women. Conclusions—The decrease in net chemotaxis after aerobic, but not after anaerobic, exercise, suggests that net chemotaxis is affected by the combination of exercise intensity and duration, and not by the exercise intensity itself. Similar effects of both exercise sessions in the judoka and the untrained women suggest that training had no effect on neutrophil function response to aerobic and anaerobic exercises.

Aspects of leukocyte function and the complement system following aeeorbic exercise in young female gymnasts

Recent studies have reported reduced immunity in trained athletes. Scant information exists on changes in the immune function among trained children. The purpose of this study was to assess the effect of aerobic exercise on the phagocytic process of neutrophils and the complement system in young athletes. Subjects included prepubertal elite female gymnasts (n=7) and untrained girls (n=6) aged 10–12 years. Venous blood was withdrawn before, immediately post and 24 h following a 20‐min run at a heart rate of 170–180 beats · min−1. Neutrophil random migration, chemotactic activity, bactericidal function and PMA/FMLP‐stimulated superoxide anion release as well as various complement components were assessed. Net chemotaxis was found reduced (P<0.05) 24 h following exercise (58±11 vs. 36±11 cells/field in gymnasts and 47±7 vs. 42±8 cells/field in untrained girls pre and 24 h post‐exercise, respectively). The basal values, as well as post‐exercise values of bactericidal activity were lower ((P<0.05) in gymnasts as compared with the control group (0.8±0.3, 0.8±0.2 and 0.8±0.2 log decrease of colonies in gymnasts at pre−, immediately post−, and 24 h post‐exercise, respectively and 11±0.1, 1.1±0.1 and 1.0±0.2 log decrease of colonies in controls, respectively). No significant effect on the bactericidal activity was observed in either group following exercise. The addition of homologous sera did not correct the bactericidal activity. PMA‐stimulated superoxide anion release decreased (P<0.05) among gymnasts immediately following exercise (5.7±0.4 vs. 4.4± 1.0 mmol 02/106 PMN · min) and remained low 24 h later. The same trend was observed in FMLP‐stimulated neutrophils but the data were not significant. Significantly decreased levels (P<0.05) of the early complement components (ClQ, C1R) were also found following exercise (1±0.64 vs. 1.27±0.28 and 1.09±0.07 vs. 1.02±0.06 pre‐ and postexercise in gymnasts and untrained, respectively). Furthermore, consistently lower C2 and C3 were observed in gymnasts compared with controls. Neutrophil dysfunction as well as impairment of the complement system seem to occur following exercise.

Neonatal neutrophil inflammatory responses: Parallel studies of light scattering, cell polarization, chemotaxis, superoxide release, and bactericidal activity

Neutrophil dysfunction among newborn infants, especially those born prematurely, is well recognized, but the mechanism responsible for this phenomenon is yet to be clarified. In this study, we evaluated the stimulus response coupling in neutrophils from 90 healthy newborns and 96 healthy adults in an effort to establish whether defective neonatal neutrophil function is a result of impaired signal perception or immature responsiveness. Measurement of rapid‐ and slow‐light scattering responses (LSR) to 1 μM FMLP stimulation revealed that neonatal neutrophils have about one‐half the corresponding responsiveness of adult cells (rapid‐LSR: 6.1 ± 3.1 arbitrary light intensity units vs. 12.0 ± 2.8, P < .001; and slow‐LSR: 5.0 ± 2.5 vs. 9.1 ± 2.0; P < .001). The same markedly reduced activity was observed in newborn neutrophil chemotaxis and bactericidal activity in comparison with adult cells. Nevertheless, low FMLP concentrations (less than 1 nM) induced no difference in cell polarization between newborn and adult neutrophils, yet at higher FMLP concentrations, the newborn revealed significantly reduced cell polarization. Our data suggest that newborn infants bear a fully functional FMLP signal perception but lack the full capacity of inflammatory responsiveness. Am. J. Hematol. 58:8–15, 1998.

Chronic Granulomatous Disease: Clinical, Functional, Molecular and Genetic Studies. The Israeli Experience with 84 patients

Chronic granulomatous disease (CGD) is an innate immunodeficiency with a genetic defect of the nicotinamide adenosine dinucleotide phosphate, reduced, oxidase components. This leads to decreased reactive oxygen species (ROS) production, which renders patients susceptible to life‐threatening infections. Over the course of 30 years, we diagnosed CGD in 84 patients from 61 families using functional, molecular, and genetic studies. The incidence of CGD in Israel is 1.05 per 100,000 live‐births in the Jewish population and 1.49 in the Israeli Arab population. We diagnosed 52 patients (62%) with autosomal recessive inheritance (AR‐CGD) and 32 (38%) with X‐linked recessive inheritance (XLR‐CGD). Consanguinity was detected in 64% of AR‐CGD families (14% in Jews and 50% in Israeli Arabs). We found 36 different mutations (23 in XLR‐CGD and 13 in AR‐CGD patients), 15 of which were new. The clinical spectrum of CGD varied from mild to severe disease in both XLR and AR forms, although the AR subtype is generally milder. Further, residual ROS production correlated with milder clinical expression, better prognosis and improved overall survival. Patients with recurrent pyogenic infections developed fibrosis and hyperinflammatory states with granuloma formation. The management of CGD has progressed substantially in recent years, evolving from a fatal disease of early childhood to one of long‐term survival. Our present cohort displays an encouraging 81% overall long term survival. Early hematopoietic stem cell transplantation is advisable before tissue damage is irreversible. Successful transplantation was performed in 18/21 patients. Therapeutic gene modification could become an alternative cure for CGD. Am. J. Hematol. 92:28–36, 2017.

Lessons Learned from Phagocytic Function Studies in a Large Cohort of Patients with Recurrent Infections

BackgroundThere is a paucity of data on the relationship between demographic characteristics, specific clinical manifestations, and neutrophil dysfunction, guiding physicians to decide which clinical signs and symptoms are a code for an underlying phagocytic disorder.MethodsThe data over a 21-year period of all adult and pediatric patients referred to our Laboratory for Leukocyte Functions with recurrent pyogenic infections were analyzed. Neutrophil function studies included chemotaxis, superoxide production (SOP), bactericidal activity (BA), and specific studies in case of suspected primary phagocytic disorder (PPD).ResultsNeutrophil dysfunction was found in 33.6% of 998 patients; chemotaxis in 16.6%, SOP in 6%, and BA in 24.5%. The younger the patient and the more organ systems involved, the greater the probability of finding phagocytic impairment. Impaired chemotaxis correlated with recurrent aphthous stomatitis, infections associated with elevated IgE, and purulent upper respiratory tract infections. Impaired SOP and BA correlated with deep-seated abscesses, recurrent lymphadenitis, sepsis, and bone and joint and central nervous system infections. PPDs were identified in 5.7%, chronic granulomatous disease in 4.8%, neutrophil glucose-6-phosphate dehydrogenase deficiency in 0.3%, leukocyte adhesion deficiency type 1 in 0.4%, and myeloperoxidase deficiency in 0.2%. Phagocytic evaluation contributed to the diagnosis of hyperimmunoglobulin-E syndrome (n = 21) and Chediak-Higashi syndrome (n = 3).ConclusionsPPDs are identified in 5.7% of patients with recurrent pyogenic infections; in the remainder, phagocytic dysfunction may be related to deleterious effects of persistent infection, drug consumption, or disorders not yet established.

The Effect of Aerobic Exercise on Neutrophil Functions

PURPOSE Intense exercise bouts are associated with a reduction of immune function and increased susceptibility to infections. Neutrophils act as a first line of defense to eliminate infectious agents and are also involved in muscle tissue inflammatory response to exercise. Intensive exercise suppresses several neutrophil functions including chemotaxis. The study investigates the pathophysiological mechanisms of impaired chemotaxis after submaximal aerobic exercise. METHODS Twenty-three healthy physically active adult males were tested before and 24 h after 30 min of treadmill running at 75% VO2max. N-formyl-Met-Leu-Phe (fMLP)-stimulated neutrophil migration, polarization, adherence, expression of adhesion molecules (CD11b/CD18), and chemotactic receptor (C5aR) were assessed preexercise and postexercise. RESULTS Neutrophil chemotaxis and polarization were found to be impaired 24 h postexercise. Adherence was impaired 24 h postexercise as well, but the expression of the adhesion molecule CD11b/CD18 was not affected. Further, the availability of the C5aR was found to be unaffected 24 h postaerobic exercise. CONCLUSIONS The pathophysiological mechanism of the impaired chemotaxis is likely related to the impaired postexercise neutrophil adherence and polarization but not to changes in the chemotactic receptor availability.