Lazy-leucocyte syndrome. A new disorder of neutrophil function

The Actin Regulators Involved in the Function and Related Diseases of Lymphocytes

Actin is an important cytoskeletal protein involved in signal transduction, cell structure and motility. Actin regulators include actin-monomer-binding proteins, Wiskott-Aldrich syndrome (WAS) family of proteins, nucleation proteins, actin filament polymerases and severing proteins. This group of proteins regulate the dynamic changes in actin assembly/disassembly, thus playing an important role in cell motility, intracellular transport, cell division and other basic cellular activities. Lymphocytes are important components of the human immune system, consisting of T-lymphocytes (T cells), B-lymphocytes (B cells) and natural killer cells (NK cells). Lymphocytes are indispensable for both innate and adaptive immunity and cannot function normally without various actin regulators. In this review, we first briefly introduce the structure and fundamental functions of a variety of well-known and newly discovered actin regulators, then we highlight the role of actin regulators in T cell, B cell and NK cell, and finally provide a landscape of various diseases associated with them. This review provides new directions in exploring actin regulators and promotes more precise and effective treatments for related diseases.

Molecular Mechanisms of Leukocyte Migration and Its Potential Targeting-Lessons Learned From MKL1/SRF-Related Primary Immunodeficiency Diseases

Megakaryoblastic leukemia 1 (MKL1) deficiency is one of the most recently discovered primary immunodeficiencies (PIDs) caused by cytoskeletal abnormalities. These immunological “actinopathies” primarily affect hematopoietic cells, resulting in defects in both the innate immune system (phagocyte defects) and adaptive immune system (T-cell and B-cell defects). MKL1 is a transcriptional coactivator that operates together with serum response factor (SRF) to regulate gene transcription. The MKL/SRF pathway has been originally described to have important functions in actin regulation in cells. Recent results indicate that MKL1 also has very important roles in immune cells, and that MKL1 deficiency results in an immunodeficiency affecting the migration and function of primarily myeloid cells such as neutrophils. Interestingly, several actinopathies are caused by mutations in genes which are recognized MKL(1/2)-dependent SRF-target genes, namely ACTB, WIPF1, WDR1, and MSN. Here we summarize these and related (ARPC1B) actinopathies and their effects on immune cell function, especially focusing on their effects on leukocyte adhesion and migration. Furthermore, we summarize recent therapeutic efforts targeting the MKL/SRF pathway in disease.

Emerging functions of cytoskeletal proteins in immune diseases

Immune cells are especially dependent on the proper functioning of the actin cytoskeleton, and both innate and adaptive responses rely on it. Leukocytes need to adhere not only to substrates but also to cells in order to form synapses that pass on instructions or kill infected cells. Neutrophils literally squeeze their cell body during blood extravasation and efficiently migrate to the inflammatory focus. Moreover, the development of immune cells requires the remodeling of their cytoskeleton as it depends on, among other processes, adhesive contacts and migration. In recent years, the number of reports describing cytoskeletal defects that compromise the immune system has increased immensely. Furthermore, a new emerging paradigm points toward a role for the cellular actin content as an essential component of the so-called homeostasis-altering molecular processes that induce the activation of innate immune signaling pathways. Here, we review the role of critical actin-cytoskeleton-remodeling proteins, including the Arp2/3 complex, cofilin, coronin and WD40-repeat containing protein 1 (WDR1), in immune pathophysiology, with a special focus on autoimmune and autoinflammatory traits.

MKL1 deficiency results in a severe neutrophil motility defect due to impaired actin polymerization

Megakaryoblastic leukemia 1 (MKL1) promotes the regulation of essential cell processes, including actin cytoskeletal dynamics, by coactivating serum response factor. Recently, the first human with MKL1 deficiency, leading to a novel primary immunodeficiency, was identified. We report a second family with 2 siblings with a homozygous frameshift mutation in MKL1. The index case died as an infant from progressive and severe pneumonia caused by Pseudomonas aeruginosa and poor wound healing. The younger sibling was preemptively transplanted shortly after birth. The immunodeficiency was marked by a pronounced actin polymerization defect and a strongly reduced motility and chemotactic response by MKL1-deficient neutrophils. In addition to the lack of MKL1, subsequent proteomic and transcriptomic analyses of patient neutrophils revealed actin and several actin-related proteins to be downregulated, confirming a role for MKL1 as a transcriptional coregulator. Degranulation was enhanced upon suboptimal neutrophil activation, whereas production of reactive oxygen species was normal. Neutrophil adhesion was intact but without proper spreading. The latter could explain the observed failure in firm adherence and transendothelial migration under flow conditions. No apparent defect in phagocytosis or bacterial killing was found. Also, monocyte-derived macrophages showed intact phagocytosis, and lymphocyte counts and proliferative capacity were normal. Nonhematopoietic primary fibroblasts demonstrated defective differentiation into myofibroblasts but normal migration and F-actin content, most likely as a result of compensatory mechanisms of MKL2, which is not expressed in neutrophils. Our findings extend current insight into the severe immune dysfunction in MKL1 deficiency, with cytoskeletal dysfunction and defective extravasation of neutrophils as the most prominent features.

Bleeding tendency and ascorbic acid requirements: systematic review and meta-analysis of clinical trials

CONTEXT

The World Health Organization set the recommended daily vitamin C intake, henceforth referred to as ascorbic acid (AA), on the basis of scurvy prevention. Double-blind AA depletion-repletion studies suggest that this recommended AA dose may be too low to prevent microvascular fragility.

OBJECTIVES

(1) To conduct a systematic review and meta-analysis of controlled clinical trials on whether AA supplementation leads to a reduced gingival bleeding tendency, a manifestation of microvascular fragility; and (2) to relate AA plasma levels to retinal hemorrhaging, another manifestation of microvascular fragility.

DATA SOURCES

Data were reviewed from 15 trials conducted in 6 countries with 1140 predominantly healthy participants with measures of gingival bleeding tendency, and from the National Health and Nutrition Examination Survey (NHANES) III of 8210 US residents with measures of retinal hemorrhaging.

RESULTS

In clinical trials, AA supplementation reduced gingival bleeding tendency when estimated baseline AA plasma levels were < 28 μmol/L (standardized mean difference [SMD], -0.83; 95%CI, -1.16 to -0.49; P < 0.002). Supplementation with AA did not unequivocally reduce gingival bleeding tendency when baseline estimated AA plasma levels were >48  μmol/L or unknown (respective standardized mean differences: -0.23, 95%CI, -0.45 to -0.01, P < 0.05; and -0.56; 95%CI: -1.19 to 0.06, P < 0.08). In NHANES III, prevalence of both retinal hemorrhaging and gingival bleeding tendency increased when AA plasma levels were within the range that protects against scurvy (11-28 μmol/L; respective prevalence ratios adjusted for age and sex: 1.47; 95%CI: 1.22-1.77; and 1.64; 95%CI: 1.32-2.03; P < 0.001 for both).

CONCLUSION

Consistent evidence from controlled clinical trials indicates that setting human AA requirements based on scurvy prevention leads to AA plasma levels that may be too low to prevent an increased gingival bleeding tendency. Gingival bleeding tendency and retinal hemorrhaging coincide with low AA plasma levels and thus may be reflective of a systemic microvascular pathology that is reversible with an increased daily AA intake.

When Actin is Not Actin' Like It Should: A New Category of Distinct Primary Immunodeficiency Disorders

An increasing number of primary immunodeficiencies (PIDs) have been identified over the last decade, which are caused by deleterious mutations in genes encoding for proteins involved in actin cytoskeleton regulation. These mutations primarily affect hematopoietic cells and lead to defective function of immune cells, such as impaired motility, signaling, proliferative capacity, and defective antimicrobial host defense. Here, we review several of these immunological "actinopathies" and cover both clinical aspects, as well as cellular mechanisms of these PIDs. We focus in particular on the effect of these mutations on human neutrophil function.

Coronin 1A depletion restores the nuclear stability and viability of Aip1/Wdr1-deficient neutrophils

Bowes et al. show that in zebrafish embryos deficient in the cofilin cofactor AIP1/Wdr1, neutrophils display F-actin as cytoplasmic aggregates, spatially uncoupled from active myosin, then undergo a progressive unwinding of their nucleus followed by eruptive cell death. This adverse phenotype is fully rescued by depletion of another cofilin cofactor, coronin 1A.

Actin dynamics is central for cells, and especially for the fast-moving leukocytes. The severing of actin filaments is mainly achieved by cofilin, assisted by Aip1/Wdr1 and coronins. We found that in Wdr1-deficient zebrafish embryos, neutrophils display F-actin cytoplasmic aggregates and a complete spatial uncoupling of phospho-myosin from F-actin. They then undergo an unprecedented gradual disorganization of their nucleus followed by eruptive cell death. Their cofilin is mostly unphosphorylated and associated with F-actin, thus likely outcompeting myosin for F-actin binding. Myosin inhibition reproduces in WT embryos the nuclear instability and eruptive death of neutrophils seen in Wdr1-deficient embryos. Strikingly, depletion of the main coronin of leukocytes, coronin 1A, fully restores the cortical location of F-actin, nuclear integrity, viability, and mobility of Wdr1-deficient neutrophils in vivo. Our study points to an essential role of actomyosin contractility in maintaining the integrity of the nucleus of neutrophils and a new twist in the interplay of cofilin, Wdr1, and coronin in regulating F-actin dynamics.

Lessons learned from the study of human inborn errors of innate immunity

Innate immunity contributes to host defense through all cell types and relies on their shared germline genetic background, whereas adaptive immunity operates through only 3 main cell types, αβ T cells, γδ T cells, and B cells, and relies on their somatic genetic diversification of antigen-specific responses. Human inborn errors of innate immunity often underlie infectious diseases. The range and nature of infections depend on the mutated gene, the deleteriousness of the mutation, and other ill-defined factors. Most known inborn errors of innate immunity to infection disrupt the development or function of leukocytes other than T and B cells, but a growing number of inborn errors affect cells other than circulating and tissue leukocytes. Here we review inborn errors of innate immunity that have been recently discovered or clarified. We highlight the immunologic implications of these errors.

Sequential Evaluation of Immunoreactivity in Patients with Melanoma Undergoing Surgery and Adjuvant Therapy

The immunologic profile of 15 patients undergoing surgery and adjuvant chemoimmunotherapy for cutaneous melanoma was studied for a mean period of 18 months. In vivo cellular immunity was assayed by evaluation of delayed hypersensitivity response (DHR) to primary antigen and a panel of recall antigens. In vitro cellular immunity was evaluated by means of total and T-lymphocyte counts in peripheral blood and by the lymphocyte blastogenic response to phytohemagglutinin stimulation. Humoral immunity was assayed by determining the serum levels of IgG, IgA and IgM and of complement components C3c, C4 and Factor B. Phagocytic activity was studied by testing leukocyte chemotaxis, neutrophil phagocytosis and leukocyte random migration. The in vitro parameters were determined preoperatively at diagnosis, 6 times during the first 2 postoperative weeks, and then every month during adjuvant therapy. No correlation was found between DHR and clinico-pathologic stage of tumor, or with subsequent clinical course. Significant depression of total lymphocyte and T-lymphocyte count and blastogenic response of lymphocytes was found at diagnosis. The lymphocyte response to PHA decreased significantly in the early postoperative period but returned to preoperative levels one week after surgery. Periodic fluctuations of lymphocyte blastogenic response and progressive decrease of total lymphocyte counts and T-lymphocyte counts were observed during the 18-month follow-up. No significant alterations of immunoglobulin levels were recorded at diagnosis or during the postoperative period. Complement levels were within normal values preoperatively; in the early postoperative period a transient increase of C3c, C4 and Factor B was recorded, then complement levels progressively decreased. Parameters of phagocytic activity were normal at diagnosis and fluctuated within the normal range throughout the whole period of study.

Cytoskeletal abnormalities and neutrophil dysfunction in WDR1 deficiency

Cell motility, division, and structural integrity depend on dynamic remodeling of the cellular cytoskeleton, which is regulated in part by actin polymerization and depolymerization. In 3 families, we identified 4 children with recurrent infections and varying clinical manifestations including mild neutropenia, impaired wound healing, severe stomatitis with oral stenosis, and death. All patients studied had similar distinctive neutrophil herniation of the nuclear lobes and agranular regions within the cytosol. Chemotaxis and chemokinesis were markedly impaired, but staphylococcal killing was normal, and neutrophil oxidative burst was increased both basally and on stimulation. Neutrophil spreading on glass and cell polarization were also impaired. Neutrophil F-actin was elevated fourfold, suggesting an abnormality in F-actin regulation. Two-dimensional differential in-gel electrophoresis identified abnormal actin-interacting protein 1 (Aip1), encoded by WDR1, in patient samples. Biallelic mutations in WDR1 affecting distinct antiparallel β-strands of Aip1 were identified in all patients. It has been previously reported that Aip1 regulates cofilin-mediated actin depolymerization, which is required for normal neutrophil function. Heterozygous mutations in clinically normal relatives confirmed that WDR1 deficiency is autosomal recessive. Allogeneic stem cell transplantation corrected the immunologic defect in 1 patient. Mutations in WDR1 affect neutrophil morphology, motility, and function, causing a novel primary immunodeficiency.

Analysis of neutrophil polarization and chemotaxis

Neutrophil polarization and directed migration (chemotaxis) are critical for the inflammatory response. Neutrophil chemotaxis is achieved by the sensing of narrow gradients of chemoattractant and the subsequent polarization and directed migration toward the chemotactic source. Despite recent progress, the signaling mechanisms that regulate neutrophil polarization during chemotaxis have not been clearly defined. Here, we describe methods to analyze neutrophil polarization and asymmetric redistribution of signaling components induced by chemoattractant using immunofluorescence. Further, methods are described to dissect the role of specific signaling pathways during chemotaxis by the use of murine neutrophils from transgenic mouse models. Finally, methods for time-lapse microscopy and transwell assay for the analysis of neutrophil chemotaxis will also be discussed.

Identification of mRNAs for the various diacylglycerol kinase isoforms in neutrophils from patients with localized aggressive periodontitis

BACKGROUND

Diacylglycerol kinase (DGK) metabolizes diacylglycerol (DAG), an endogenous activator of protein kinase C, to phosphatidic acid. We have previously reported increased DAG in neutrophils from patients with localized aggressive periodontitis (LAP) associated with reduced DGK activity. This reduction could be related to a mutation, post-translational modification, differential expression, or lack of expression of a particular isoform(s).

OBJECTIVE

The aim of this study was to identify the mRNAs for DGK isoforms in normal and LAP neutrophils.

METHODS

The alpha-, gamma-, and delta-isoforms of DGK were identified by polymerase chain reaction (PCR) using specific oligonucleotide primers for each isoform. The PCR products were isolated and sequenced for comparison to published sequences to confirm the validity of the PCR reaction. Total RNA was isolated from LAP and normal neutrophils, and northern blotting and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to examine the level of mRNA for each isoform.

RESULTS

No major differences were found in the isoform pattern between resting normal and LAP neutrophils. However, the levels of mRNA for the alpha- and gamma-isoforms of DGK were increased in normal neutrophils while slightly decreased in LAP cells upon stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP).

CONCLUSION

These data suggest that alterations in the mRNAs for the various isoforms of DGK during cell stimulation and the involvement of DGK that is expressed in multiple forms are subject to a variety of regulatory/control mechanisms and these mechanisms may explain the role of the 'primed' neutrophil phenotype associated with LAP.

A practical approach to neutrophil disorders

This review discusses disorders of altered neutrophil number and function and provide a basic framework for patient evaluation and management. The sections begin with neutropenia, neutrophilia and neutrophil dysfunction with a general screening approach to differentiate common, more benign syndromes from rare, often more serious disorders. Also included is a detailed discussion of some specific primary neutrophil syndromes at the end of each section. Focus is placed on specific disorders that are clinically common or particularly instructive.

Spatiotemporal regulation of moesin phosphorylation and rear release by Rho and serine/threonine phosphatase during neutrophil migration

Neutrophil motility is crucial to effective host defenses against microorganisms. While uropod retraction is a critical step in the migration of neutrophils, the underlying molecular mechanism is not well understood. Here, we show that inhibition of the Rho small GTPase with C3 exoenzyme prevented the retraction of trailing uropods, indicating that the process of rear release is mediated by a Rho signaling pathway. C3 exoenzyme caused marked elongation of directionally migrating neutrophils, suggesting an additional role for Rho in the maintenance of functional polarized cell shape. We also show that phosphorylation and dephosphorylation of the plasma membrane-actin filament cross-linker moesin are spatiotemporally controlled in migrating neutrophils. In particular, phosphorylation of moesin at threonine 558 depended on Rho activity. Videomicroscopy showed that dephosphorylation of this carboxy-terminal threonine preceded uropod retraction. Calyculin A, an inhibitor of type 1 and type 2A serine/threonine phosphatases, suppressed the moesin dephosphorylation and impaired uropod retraction in a dose-dependent manner. Cypermethrin, an inhibitor of type 2B serine/threonine phosphatase, had no such effects. The finding that Rho small GTPase and type 1/type 2A phosphatases are involved in rear release yields novel insights into the biochemical mechanisms of neutrophil migration.

Dizygotic twin sisters with myelokathexis: mechanism of its neutropenia

Dizygotic twin sisters were first found to have neutropenia at 1 year of age when evaluated for recurrent pulmonary infections. Since then they have remained neutropenic (0.05 approximately 0.5 x 10(9)/l). Despite of their neutropenia, myeloid hyperplasia was evident on a marrow smear examination, and a number of cells were hypersegmented with fine interlobular bridging with chromatin strands and cytoplasmic vacuolation. Electron microscopy showed apoptotic cells with condensed nuclei and apoptotic bodies in the cytoplasm. Although life span, hydrogen peroxide production, phagocytosis, spreading, and chemotaxis of peripheral neutrophils were normal, the survival of bone marrow neutrophils in both infants was markedly decreased when compared with that of normal bone marrow neutrophils. During the bone marrow culture apoptotic neutrophils were observed at an earlier stage in both patients than in normal controls, biochemically and morphologically. Morphology of bone marrow neutrophils in both patients resembled that of cultured control bone marrow neutrophils. Peripheral neutropenia and appearance of characteristic neutrophils in the bone marrow in myelokathexis are considered to be an expression of apoptosis of bone marrow neutrophils.

The pathogenesis of periodontal diseases

This informational paper was prepared by the Research, Science, and Therapy Committee of The American Academy of Periodontology, and is intended for the information of the dental profession. The purpose of the paper is to provide an overview of current knowledge relating to the pathogenesis of periodontal diseases. The paper will review biological processes thought to provide protection against periodontal infections. It will further discuss the mechanisms thought to be responsible for both overcoming and subverting such protective mechanisms and those that lead to destruction of periodontal tissues. Since an understanding of pathogenic mechanisms of disease is one foundation upon which new diagnostic and therapeutic modalities are based, the practitioner can use this information to help make decisions regarding the appropriate application of such new modalities in patient care settings.

Neutrophil defects as risk factors for periodontal diseases

There are several hypotheses proposed for the etiologic mechanisms causing periodontal diseases. These include a paradigm in which all individuals are equally susceptible to one or several pathogenic bacteria; a second paradigm that holds that all bacteria are equally virulent and that host susceptibility determines onset of disease; or a combination of the above. In this review, we analyze the role of neutrophil dysfunction as a risk factor for the onset of periodontitis. Both intrinsic or genetically inherited abnormalities of neutrophils and acquired neutrophil abnormalities are considered. While a large body of data implicates neutrophil dysfunction, either intrinsic or acquired (bacterially or extrinsically induced), as a significant risk factor for the periodontal diseases, clear, prospective, longitudinal epidemiologic studies to evaluate this association remain to be performed.

Defective chemotaxis and calcium response in localized juvenile periodontitis neutrophils

Localized juvenile periodontitis (ljp) is an early onset form of periodontal disease characterized by unique localization to first molars and incisors and a high prevalence of neutrophil abnormalities, particularly chemotaxis. The intracellular transduction mechanisms that follow receptor-ligand coupling on the neutrophil surface and lead to chemotaxis are not clearly established. Chemotaxis and phagocytosis are modulated by a variety of receptors and involve several activation pathways; the role of intracellular calcium as a presumptive second messenger and mediator of these events is well established. The putative effector mechanisms for the chemotactic receptor of neutrophils also include the possible activation of a phospholipase, protein kinase C, methyltransferase, or adenylate cyclase. In normal neutrophils, a phosphoinositide pathway initiated by phospholipase C, which results in the activation of protein kinase C via diacylglycerol and the generation of IP3, has been implicated. In order to better understand the stages of neutrophil transduction, fluorescent probes were used to monitor neutrophil calcium changes. Chlorotetracycline (CTC) was used as an indirect probe of intracellular membrane-bound pool of calcium stores, and Quin-2 was used to monitor cytosolic free calcium levels of FMLP stimulated normal and LJP neutrophils. The results indicate that the early phase of the calcium response affiliated with the release of intracellularly sequestered calcium appears intact in LJP neutrophils, as the CTC fluorescence changes were similar to control values. The second phase of the calcium response, associated with membrane channel activation and an influx of extracellular calcium, appeared compromised in the neutrophils of the LJP population.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased oxidative product formation by peripheral blood polymorphonuclear leukocytes in human periodontal diseases

We examined the oxidative burst (hydrogen peroxide-dependent oxidative product formation) of polymorphonuclear leukocytes (PMNL) in the peripheral blood from the patients with various types of periodontal diseases including localized juvenile (LJP), generalized juvenile (GJP) and adult periodontitis (AP). Heparinized peripheral blood was obtained from 15 LJP, 13 GJP and 52 AP patients and from 30 healthy control subjects. The oxidative product (2',7'-dichlorofluorescein; DCF) formation of PMNL by stimulation with phorbol myristate acetate myristate acetate was evaluated by a rapid quantitative assay using flow cytometry. The results indicated that all patient groups contained variable populations with normal or increased DCF formation, while the control subjects exhibited DCF formation as a single population. No significant differences in average DCF formation were found among the three patient groups. Although individual patients gave various values, the average DCF formation of the three patient groups was much higher than that of the control group. Statistical analysis revealed a significant positive correlation between DCF formation and the clinical periodontal parameters on an individual basis. Furthermore, after initial periodontal treatment, DCF formation decreased to normal levels. These results suggest that the capacity of peripheral blood PMNL to mount oxidative burst reactions might reflect the inflammatory status of periodontal disease.

Altered diacylglycerol level and metabolism in neutrophils from patients with localized juvenile periodontitis

Diacylglycerol, a physiological activator of protein kinase C, was elevated nearly twofold in unstimulated peripheral blood neutrophils from patients with localized juvenile periodontitis compared with cells from normal individuals. These cells also showed an enhanced and prolonged elevation of diglyceride in response to N-formylmethionylleucylphenylalanine. The metabolism of a cell-permeant diacylglycerol by diglyceride kinase was significantly decreased, because of a fivefold or higher elevation in the apparent Km of cellular diglyceride kinase.

Flow cytometric evaluation of phagocytosis by peripheral blood polymorphonuclear leucocytes in human periodontal diseases

The complement-dependent phagocytic functions of polymorphonuclear leucocytes (PMNL) in peripheral blood from 15 patients with localized juvenile periodontitis (LJP), 13 with generalized juvenile periodontitis (GJP) and 52 with adult periodontitis (AP), and from 30 normal subjects as controls were measured by flow cytometry. Heparinized blood was collected and incubated with fluorescent microspheres, and erythrocytes were removed. By means of single-cell analysis the percentage of phagocytosing cells (% phagocytosis) and the mean number of microspheres phagocytosed by one PMNL (degree of phagocytosis; d-phagocytosis) were measured. Some but not all patients with LJP (53%) and GJP (46%) showed consistently low % phagocytosis and d-phagocytosis. On the other hand, only 6% of AP patients and no healthy subjects showed a reduction of PMNL phagocytosis. Phagocytosis was unchanged after initial periodontal treatment in all subjects, suggesting the depression of PMNL phagocytosis may not be a transient phenomenon associated with periodontal status. Furthermore, PMNLs from the LJP patients that showed depressed phagocytic function exhibited depressed phagocytic responses with either autologous or normal plasma, while control PMNLs with either normal or the patients' plasma showed normal responses. These results suggested that the depressed phagocytic responses in LJP patients could be due to cell-associated defect(s) on the PMNL.

Effect of aztreonam upon human polymorphonuclear leukocyte functions

Aztreonam (SQ 26,776), a new synthetic monobactam with an excellent antibacterial spectrum was analyzed in vitro. In this paper, the effect of aztreonam on the phagocytic process of human neutrophils isolated from fifteen healthy volunteers was studied. Chemotaxis was not modified with aztreonam at any of the doses used (10, 20, 40, 60, 80 and 100 micrograms/ml). On the other hand, this antibiotic at 100 micrograms/ml significantly increases (P less than 0.05) Candida albicans ingestion as well as their digestion by neutrophils at 10 and 100 micrograms/ml.

Phagocytosis of virulent Porphyromonas gingivalis by human polymorphonuclear leukocytes requires specific immunoglobulin G

No studies to date clearly define the interactions between Porphyromonas gingivalis and human peripheral blood polymorphonuclear leukocytes (PMN), nor has a protective role for antibody to P. gingivalis been defined. Using a fluorochrome phagocytosis microassay, we investigated PMN phagocytosis and killing of P. gingivalis as a function of P. gingivalis-specific antibody. Sera from a nonimmune rabbit and a healthy human subject were not opsonic for virulent P. gingivalis A7436, W83, and HG405; phagocytosis of these strains (but not 33277) required opsonization with hyperimmune antiserum (RaPg). Diluting RaPg with a constant complement source decreased proportionally the number of P. gingivalis A7436 cells phagocytosed per phagocytic PMN. Enriching for the immunoglobulin G fraction of RAPg A7436 enriched for opsonic activity toward A7436. An opsonic evaluation of 18 serum samples from adult periodontitis patients revealed that only 3 adult periodontitis sera of 17 with elevated immunoglobulin G to P. gingivalis A7436 were opsonic for A7436 and, moreover, that the serum sample with the highest enzyme-linked immunosorbent assay titer was most opsonic (patient 1). However, the opsonic activity of serum from patient 1 was qualitatively and not just quantitatively different from that of the nonopsonic human sera (but was less effective opsonin than RaPg). Strain variability was observed in resistance of P. gingivalis to phagocytosis, and opsonization was strain specific for some, but not all, strains tested. An evaluation of killing of A7436 revealed that serum killing and extracellular killing of P. gingivalis were less effective alone when compared with intracellular PMN killing alone.

Chronic omphalitis in a 4-month-old girl

A case of chronic omphalitis present for birth in a 4-month-old girl is presented. The biopsy of the bud-like lesion failed to reveal a local malformation or remnants of umbilical cord but showed a common loose edematous tissue in which the inflammatory cells appeated remarkably scanty. The contrast existing between this poorly cellular local infiltrate and the high level of peripheral blood leucocytes (over 30,000/microliters) was in fact the most striking feature that allowed to evoke the diagnosis of Deficiency Leucocyte Adhesion molecules. Immunocytochemical investigations using anti CD11a, CD11b and CD18 monoclonal antibodies on fresh tissue or, better, peripheral leucocytes are necessary to confirm the diagnosis of this uncommon immunological autosomic recessive inherited disorder.

Phagocytic function and antibody-dependent cellular cytotoxicity of human neutrophils in the presence of N-formimidoyl thienamycin

The efficacy of an antibiotic in the treatment of bacterial infections depends upon the interactions of the drug, bacteria and phagocytes. We have studied "in vitro" the effect of N-formimidoyl thienamycin (Imipenem), a novel beta-lactamic antibiotic, on the phagocytic function and antibody-dependent cellular cytotoxicity of human neutrophil leukocytes. The incubation of these cells with 50 micrograms/ml of Imipenem similar to the therapeutic levels reached in plasma results in an increase of their adherence capacity to nylon fiber and to substrate, induced mobility or chemotaxis, opsonization, phagocytosis of Candida albicans (with serum, with decomplementarized serum and without serum) and latex beads, candidicidal power and the capacity of NBT reduction. Imipenem at this dose also presents chemoattractant power for neutrophils and enhances the antibody-dependent cellular cytotoxicity (ADCC).

Effect of benign familial neutropenia on the periodontium of Yemenite Jews

The purpose of this study was to compare the periodontal status of Yemenite Jews with and without benign familial neutropenia (BFN). Thirty-four volunteers were examined at baseline and after 3 years. Plaque index (PlI), bleeding index (BI) probing depth (PD), and attachment levels (AL) were recorded. Differential blood counts were done on at least three occasions during the study. Volunteers with at least one count of less than 2000 neutrophils were considered neutropenic. The majority of patients received oral hygiene instructions and scaling at the initial visit. During the study there was a significant drop in PlI (P less than 0.01) and BI (P less than 0.05). At baseline the BFN and non-BFN volunteers had similar PlI, but the BI was significantly greater in the BFN group. At follow-up, there was a significantly greater number of teeth with pockets greater than or equal to 6 mm in the BFN group (P less than 0.05). These results indicate that volunteers with BFN, a phenomenon that has not previously been associated with any pathology, are more susceptible to gingival inflammation and attachment loss than unaffected volunteers and that they respond more favorably to an improvement in oral hygiene.

Chemiluminescence of peripheral polymorphonuclear leukocytes from adult periodontitis patients

Polymorphonuclear leukocytes (PMN's) constitute a primary host resistance factor against infection. This study investigated the chemiluminescent (CL) response of peripheral blood PMN's isolated from human subjects with adult periodontitis. 32 subjects were categorized on the basis of age and periodontal disease status into 4 equal groups--young healthy, young diseased, old healthy and old diseased. PMN CL was stimulated using heat-killed, serum-opsonized Fusobacterium nucleatum--a specific periodontopathic gram-negative anaerobe, and Escherichia coli as a gram-negative control organism. The results showed a statistically significant enhancement (p less than 0.05) in the CL response, which was cell associated, in the young diseased subjects. This was not seen in the old subjects (p greater than 0.05), suggesting that in periodontal disease in young subjects the peripheral blood PMNs may be in a metabolically activated state. There was nevertheless a degree of variability between individual subjects within each of the 4 clinical groups.

Effects of acetylsalicylic acid on the phagocytic function of human polymorphonuclear leukocytes in vitro

1. In this paper acetylsalicylic acid (aspirin), an anti inflammatory drug, was studied in vitro at doses of 50, 100, 200 and 500 mg/l to see its effects on adherence, chemotaxis, spontaneous mobility, phagocytosis, candidicide power, nitrobule tetrazolium (NBT) reduction as well as the incorporation and metabolism of arachidonic acid in human polymorphonuclear neutrophils (PMNns). 2. Aspirin significantly stimulated neutrophil adherence to nylon fiber at all the doses used, with a correlation between the doses used and the adherence indices found. 3. At the therapeutic dose (100 mg/l) aspirin brings about a significant increase of chemotaxis, but reduces this property at the highest dose (500 mg/l). On the other hand, spontaneous mobility is not altered except with the 500 mg/l dose of aspirin which produces a significative decrease. 4. The ingestion of Cándida albicans by PMNns is significant at the therapeutic dose; the candidicide power is not modified with any of the doses used with 100 mg/l of aspirin nitroblue tetrazolium (NBT) reduction is significantly increased. 5. No changes are observed in the incorporation of arachidonic acid or in the release of its metabolites.

Effect of plaque removal on patients with acute leukemia

The aim of the present investigation was to study the effect of daily plaque removal on gingival inflammation and the occurrence of oral mucosal ulcers in granulocytopenic patients with acute myeloid leukemia. Eleven patients were analyzed prospectively and consecutively during a period of 28 days, in which the patients were treated with antineoplastic drugs. The patients had their teeth scaled, and plaque was removed daily. On Day 1 all had gingival inflammation, and two had profound periodontitis with pocket depths and loss of attachment greater than 5 mm. During the treatment period plaque scores were reduced in all patients and a corresponding decrease in gingival inflammation was seen. It was possible to obtain healthy gingiva during treatment with cytotoxic drugs. In addition, the development of oral mucosal lesions was low compared with other studies. This study demonstrates that daily plaque removal from the teeth resolves gingival inflammation also in severely granulocytopenic patients.

Paleopathology in Australopithecus africanus: a suggested case of a 3-million-year-old prepubertal periodontitis

The fossil remains of a juvenile Australopithecus africanus specimen from Sterkfontein Member 4 temporally confined on faunal grounds to 2.5-3.0 million years before the present (Myr B.P.) show pathological alterations of the periodontal alveolar process consistent with a case of prepubertal periodontitis. This diagnosis is based on macroscopic features of alveolar bone loss distribution, pattern of periodontal bone destruction, migration of the affected deciduous molars, and on stereomicroscopic and scanning electron microscopic evidence of alveolar bone destruction. Differential diagnoses and pathological exclusions are discussed in terms of localized patterns of periodontal bone destruction and presumptive survival rate. The reported case appears to be the first detailed description of a recognized disease in early hominid evolution.

Neutrophil function disorders

The polymorphonuclear leukocyte (neutrophil) is the most important phagocytic cell that defends the host against acute bacterial infection. Disorders of neutrophil function are suggested by recurrent cutaneous, periodontal, respiratory, or soft tissue infections. Staphylococcus aureus, gram-negative bacilli, and less commonly, Candida albicans, are the causative organisms. Treatment is supportive involving surgical drainage and antibiotics. Bone marrow transplantation offers hope to some patients. The biochemical and molecular defects have been identified for some of these disorders. Identification of these defects and their physiologic consequences have improved our understanding of how the activated neutrophil is attracted and adheres to inflammatory sites, and produces toxic products that destroy bacteria. However, the activated neutrophil may also damage normal tissue and participate in diseases such as rheumatoid arthritis and the adult respiratory distress syndrome (ARDS).

Periodontal manifestations of the heritable Mac-1, LFA-1, deficiency syndrome. Clinical, histopathologic and molecular characteristics

The clinical, histopathologic and functional consequences of the genetic deficiency of leukocyte Mac-1, LFA-1 and p150,95 were assessed among three affected patients, heterozygotes and unaffected individuals among two generations of a single kindred. Longitudinal assessments of this family afforded the unique opportunity to characterize the natural history of severe periodontal manifestations associated with this disorder. Features uniformly observed among each patient included recurrent, necrotic soft tissue infections, impaired pus formation, delayed wound healing, constant granulocytosis, severe abnormalities of adhesion-dependent granulocyte functions and a profound deficiency (3%-6% of normal) of Mac-1 glycoproteins on granulocyte surfaces. Characteristic features of generalized prepubertal periodontitis including rapidly progressive alveolar bone loss affecting the primary and permanent dentitions (leading to premature tooth loss), recession, clefting and migration in association with intense gingival inflammation were uniformly observed. Biopsies of inflamed periodontal tissues in these individuals demonstrated dense infiltrates of mononuclear leukocytes but a striking absence of extravascular neutrophil granulocytes. Heterozygous family members demonstrated approximately half normal Mac-1 protein expression but no susceptibility to systemic infections and normal, adhesion-dependent leukocyte functions. Prepubescent heterozygotes demonstrated no periodontal manifestations but a 31-year-old heterozygous female exhibited clinical and radiographic features typical of postjuvenile periodontitis. The profound periodontal manifestations recognized in this clinical-pathologic model emphasize the physiologic importance of leukocyte adhesion reactions in defense of the periodontium and further suggest a possible pathologic role for Mac-1 proteins in other forms of early-onset periodontitis.

Decreased numbers of chemotactic factor receptors in chronic neutropenia with defective chemotaxis: spontaneous recovery from the neutrophil abnormalities during early childhood

Childhood chronic neutropenia with decreased numbers of chemotactic factor receptors as well as defective chemotaxis was first demonstrated in an 8-month-old girl. Chemotactic factor receptors on neutrophils were assayed using tritiated N-formyl-methionyl-leucyl-phenylalanine (3H-FMLP). The patient's neutrophils had decreased numbers of the receptors: numbers of the receptors were 20,000 (less than 3 SD) as compared with those of control cells of 52,000 +/- 6,000 (mean +/- SD) (n = 10). The neutropenia disappeared spontaneously by 28 months of age parallel with the improvement of chemotaxis and increase in numbers of chemotactic factor receptors. These results demonstrate a transient decrease of neutrophil chemotactic factor receptors as one of the pathophysiological bases of a transient defect of neutrophil chemotaxis in this disorder.

The autologous mixed lymphocyte reaction (AMLR) as a possible indicator of immunoregulation in chronic inflammatory periodontal disease

Immunoregulatory control at both a local and systemic level is likely to be an important factor in the control of chronic inflammatory periodontal disease, explaining, at least in part, the individual variations between patients as well as the cyclical nature of the disease process. The autologous mixed lymphocyte reaction (AMLR), which is due to the stimulation of T cells by autologous HLA-DR positive non-T cells in the absence of specific antigen, is thought to be an in vitro correlate of immunoregulation. It is possible therefore, that the AMLR may detect systemic immunoregulatory phenomena in chronic inflammatory periodontal disease and that aberrations in the AMLR may be a manifestation of the disease and in turn reflect disease activity. Recent evidence does in fact suggest that the peripheral blood AMLR may identify particular disease groups, provided age and time of peak responsiveness are taken into account and hence may have an epidemiological application. It remains to be determined, however, that when used in a longitudinal fashion, the AMLR does reflect individual disease activity. These results are reviewed and areas of future research discussed.

Inflammatory bowel disease in glycogen storage disease type Ib

We have observed the development of chronic inflammatory bowel disease, indistinguishable from Crohn disease, in two boys with glycogen storage disease type Ib (GSD-Ib). A chance association of these diseases in two patients is unlikely. Studies of their neutrophils showed severe chronic neutropenia (mean absolute granulocyte counts of less than 500 cells/microliter) and markedly deficient chemotactic response (less than 5% of reference values) in the patients with GSD-Ib and normal neutrophil values in four patients with glycogen storage disease type Ia (GSD-Ia). Monocyte counts and responses to chemotactic stimulation were normal in both GSD-Ia and GSD-Ib. Chronic inflammatory bowel disease appears to be associated with GSD-Ib, and neutrophil abnormalities may be involved in the pathogenesis of the bowel inflammation.

Chemiluminescence in the assessment of polymorphonuclear leukocyte function in chronic inflammatory periodontal disease

Polymorphonuclear neutrophils (PMN's) constitute the primary host resistance factor against infection. They are prominent cells in both the gingival tissue and gingival sulcus in most forms of periodontal disease. Although defective PMN function has been implicated in the pathogenesis of localized juvenile periodontitis (LJP) and rapidly progressive periodontitis (RPP), this may not necessarily be the case in adult periodontitis (AP). A number of studies have failed to detect PMN dysfunction in AP. However, it may be that in this form of chronic inflammatory periodontal disease (CIPD) the defects in peripheral blood PMN function are subtle and the methods used may lack the necessary sensitivity. Chemiluminescence (CL) is the light energy produced by the PMN during its interaction with bacteria or other particles and has been demonstrated to correlate well with antibacterial integrity. Measurement of CL produced by phagocytically challenged PMN's may provide a very sensitive assay of the functional ability of these cells, and, hence, may be useful in assessing PMN activity in CIPD. Recent studies using PMN's obtained from periodontal diseased patients challenged with the periodontopathic organism Fusobacterium nucleatum have revealed an elevated CL response compared to non-diseased controls. These results are reviewed and areas for future research discussed.

Host factors in juvenile periodontitis

This study was undertaken to determine whether defects in leukocyte function or in genes at the MHC play a role in the etiology of either localized (LJP) or generalized (GJP) juvenile periodontitis. Thirteen LJP and five GJP patients (ranging in age from 13 to 22 years) and their matched controls were compared with respect to selected leukocyte functions and HLA phenotypic frequencies. The results of these studies indicated that there were significant decreases in the phagocytic and chemotactic abilities of polymorphonuclear leukocytes (PMN) in both LJP and GJP. All JP patients displayed intrinsic cell defects in chemotaxis compared with controls; in addition, some patients displayed multiple defects, including those which were serum-associated. Also, there appeared to be a significant association between JP and HLA-DR2 and HLA-A33 phenotypes. Fifty percent of the JP patients were HLA-DR2-positive, whereas only six percent of the matched controls were positive. Thirty-six percent of JP patients were HLA-A33-positive, whereas none of the controls was positive. The association seen with DR2 may be due to sampling, since there were no significant differences between the JP cases and a larger unmatched control sample which was not evaluated for periodontal disease. We conclude from these data that increased susceptibility of some patients to a very aggressive and destructive form of periodontal disease (JP) is based on defects in PMN responsiveness. Further investigations are necessary to determine whether these defects are under genetic control.

Morphology of polymorphonuclear neutrophils during periodontal disease in the cynomolgus monkey

The polymorphonuclear neutrophil (PMN) appears to be an important cell in the protection of the host from pathogenic periodontal micro-organisms. The purpose of the present histological studies was to observe the emigration of the PMN from the gingival vessels to the periodontal pocket during gingivitis and ligature-induced periodontitis in the cynomolgus monkey. 2 adult female monkeys were treated by application of a silk ligature around selected posterior teeth. After 9 weeks, the monkeys were perfused and block sections of both ligated (early periodontitis) and non-ligated (gingivitis) sites were obtained, cut into smaller blocks containing a single interdental area (N = 15 for periodontitis, N = 5 for gingivitis) and processed for light and electron microscopic observations. Morphologically, no differences in PMNs between gingivitis and periodontitis were observed and therefore the following description applies to both disease states. In the vessels, the endothelial cells appeared to be actively involved in PMN emigration, maintaining long processes which surrounded the PMNs. Within the connective tissue, the PMNs maintained their typical morphology which included polylobated nuclei and numerous lysosomal granules. Many intact PMNs were observed intercellularly within the connective tissue and the epithelium. Within the periodontal pocket, a multilayer of PMNs surrounded the plaque mass. Cells with numerous bacteria-containing phagolysosomes were observed with increasing frequency as they approached the plaque. Deeper within the bacterial deposit, PMNs were seen in varying stages of degeneration. These histologic studies, when interpreted in the light of reports of severe, rapidly-progressive periodontitis in patients with PMN disorders, suggest that the interaction of PMNs with bacterial plaque may serve to maintain a defensive boundary which protects the host tissues from irreversible destruction.

Modification of neutrophil chemotactic responsiveness during various inflammatory reactions

Various inflammatory reactions have been induced in order to examine the chemotactic response of polymorphonuclear leucocytes (PMN) collected under various experimental conditions. Cells were harvested from the pleural cavity of rats after the induction of three acute non specific inflammatory reactions and two immune reactions. The results obtained with two techniques of chemotactic assessment (agarose assay and Boyden chamber technique) demonstrated a variation of chemotactic response depending on the cell source and the chemoattractants used. Using agarose assay, we distinguished locomotor reactivity of PMN harvested after immune inflammatory reactions from that of PMN harvested after non immune inflammatory reactions. Chemokinetic and chemotactic responses to various chemoattractants were inhibited in the first case and not affected in the second. Using the Boyden chamber technique, inhibition of random or oriented migration of PMN harvested after immune inflammatory reactions after the injection of a non antigenic irritant such as calcium pyrophosphate crystals (CaPP) was also observed.