FAMILY CENTER FOR ALLERGY AND ASTHMA
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Stiehm’s: Polymorphonuclear leukocytes include Neutrophils, Eosinophils and Basophils Until the last decade N main fxn was to kill bacterial pathogens by oxidative and secretory capabilities. Now we know they play a major role in the overall immune response to a variety of pathogens by their traditional role of phagocytosis and by the production of a number of cytokines ie. interleukins (IL1-6), TNF - a. N Maturation Arise from the BM stem cells which eventually commit to granulocyte differentiation. , CFU-G (colony forming unit - granulocyte.) This pool of cells differentiate into the myeloid cells. Granule Differentiation 1:Primary or Azurophilic cytyoplasmic granules: myeloperoxidase, lysozyme, acid hydrolases, neutral proteases (elastase), sialidase 2:Secondary or Specific granules: lactoferrin, lysosome, B12 binding protein, phospholipase A2, collagenase, plasminogen activator, Cytochrome b, sialidase. N. granules are generated in the Gogi complex and bud off from the endoplasmic reticulum. Abnormalities of budding occur in Chediak-Higashi with the formation of giant coalesced granules. Cytokines involved in Differentiation: G-CSF, IL-3, IL-6, SCF - most derived from T cells Membrane Receptors on Mature Cell CR1, CR3, FcRIII Blood pool is made up of Marginated and Circulating equal in size Half life of granulocyte after leaves BM = 6-10hrs. In infants the storage of n is very small and so can be exhausted quickly in infection resulting in neutropenia. Have decreased chemotaxis and adherence until about 5 years old. Neonates also have decreased adherence proteins Activation: First step is binding of a ligand to a receptor. Adhesion receptorsTable 5-2 Within 1 minute of ligand-receptor binding, a transmembrane signal is generated and the end-stage activity is initiated. Killing: Oxidative Bursts - oxygen radicals, NADPH Nonoxidative Bursts (CGD) - granule contentsCHAPTER 15: Functional activities include adherence, migration, phagocytosis, secretion, respiratory burst, and intracellular killing, Most common lesions in patients with deficient numbers or defective function of N are soft tissue inflammation and abscess Common pathogens - S.aureus, Psudomonas, Serratia , Enterobacteriaccae, Aspergillus and Candida. Labs: Numbers of circulating N, functional tests are performed in most medical centers. Oxidative burst measured by NBT (nitroblue tetrazolium), flow cytometry to evaluate receptors, chemotaxis.DISORDERS of N Quanitiy !. Neuetropenia = ciruclating n <500/mm3 from decreased production or release of mature neutrophils from the BM congenital or secondary to infections ie parvovirus, drugs(lithium, certain antibiotics), toxins, neoplasia, antineutrophil antibodies, autoimmune disorders. ( 50% of infants whose mothers have hypertension during pregnancy have transient neutropenia due to reduced production (KoenigJL, Christensen, RD. Incidence, neutrophil kinetics, and natural history of neonatal neutropenia associated with maternal hypertension. NEJM 321:557-562, 1989) a. Congenital Neutropenia (Kostmann’s Syndrome) P444 persistent, severe absolute neutropenia and maturation arrest at the promyelocyte in the BM. During the first months of life - pneumonia, OM gingivitis and perineal or UTI. Until recently only 30 % survival to 5yrs, now improved prognosis with recombinant human granulocyte colony-stimulating factor.rhG-CSF. results in normalization in 1-2 weeks. Common in Scandinavians. ANC<500 b. Cyclic Neutropenia have regular cyclic fluctuations usually every 21 days, but range of 14-36 days with periods of severe neutropenia (<200cells/mm3) lasting 3-10 days, alternanting with periods of normal neutrophil counts. BM evaluation reveals cyclic oscillations of hematopoietic progenitors. The defect in this disorder may be the inabilitly of the myeloid precursors to respond to physiologic concentrations of G-CSF. May be familial, AD with variable expression of X-linked with HyperIgM. RX: G-CSF. recurrent bouts of oral ulcers, stomatitis, fevers and soft tissue infections. Etiology unknown C. Gylcogen Storage Disease Type 1B 2. Disorders of Neutrophil ChemotaxisPrompt accumulation of phagocytic cells in tissues invaded by bacteria is essential. Miles and associates (1957) provided graphic experimental evidence by demonstrating that as little as a two hour delay of migration of neutrophil leukocytes enabled bacteria to produce severe lesions by as much as 10,000 fold. a. primary b. secondary to circulating hinhibiotry factors 3.complement abnl. A. Leuckocyte Adhesion Deficiency Defect Type 1. 1. Autosomal Recessive characterized by recurrent, life threatening bacterial infections with impaired pud formation and wound healing. Neutrophils don not accumulate at extravascular inflammatory despite marked peripheral blood leukocytosis do to the absence of adhesion molecules called the integrins - CD11a-c/CD18. These molecules are essential for adherence and to transverse the capillary endothelium. Basically it is the CD18 that is missing. This maps to Chromosome 21. ie. Neonatal period - septicemia or extension of the infection into the abdominal cavity may occur as a complication of omphalitis and separation of the umbilical cord may be delayed. Childhood - gingivitis, periodontitis, recurrent OM, sinusitis,and pneumonia, perirectal abscess, cellulitis, etc. Most common organisms, S.aureus, enterobacteria, Psuedomonas, Candida albicans. Diagnosis - Extreme neutrophilia (>15,000cells/mm3), confirmed by flow cytometry analyis using monoclonal antibodies for CD11 or CD18. B. Hyperimmunoglobulin E SyndromeThe bibilical medical eponym Job’Syndrome origoinated with the initial description of two patients with multiple cutaneous abscesses, severe eczema and liver and pulmonary infections.Additonal signs include high levels of serum IgE and a neutrophil chemotactic defect. Triad: Severe eczematoid dematitis, recurrent infections and high levels of IgE Auotosomal dominant with incomplete penetrance. Serum IgE range from 2150 -90,000 IU/ml, a large amount directed against S. Aureus. often peripheral eosinophilia Usually don’t experience allergy Dermatities, coarse facies, osteoporosis, recurrent pneumonias with pneumatoceles and empyema, chronic OM, mastoiditis The chemotactic inhibition may be due to IgG-IgE complexesDisorders of Oxidation A.. Chronic Granulomatous Disease B. MyeloperoixdaseAutoimmune Neutropenia There are two types of leukocyted antigens 1. those shared with other tissues ie. HLA 2. those present only on the neutrophil (NA1, NA2, NB1) A. Isoimmune Neonatal neutropenia Analogous to Rh disease. Severe neutropenia in infants ANC 1-1900, relative monocytosis, BM showed arreds at hte metamyelocyte or band stage. Nuetrophil count usually improves in 2-17 weeks. Secondary to infants having a different NA type to mothers. Maternal ab to foreigh fetal antigen causes the neutropenia. B. Autoimmune Neutropenia - presents in infancy or childhood. Probably the most connon cause of chronic neutroeonia of infnacy and early childhood. Usually a primary process when neutropenia is the only hematological abnormality. Secondary is usually in adults - SLE, Evans, Cancer. Neutrophil ab may be deteected by agglultination or flurescence. Mean age of recovery is 30m and 95% recover by 4y. Threatment with steroids or IVG is usually successful although many will relapse. Complications can include permanent gingival hypertrophpyo and hearing loss. Mechanism of triggering autoab is unknow. Controversial association to later develpment of collagen vascular disaease. Usually a benign process In infancy afetao-maternal incompatibility has been shown involving neutrophil alloantigens b. transitory neutropenia in infants born to mothers with autoimmuune neutropenia. Destruction occurs by opsonization , intravascular lysis, Antibody depentent cell mediated cytotoxicityDrug therapy - nitrogen mustard, chlorambucil, azathioprine, 6-mercaptopurine, phenothiazine, zidovudine. Sulfonamides, methicillin and cephaloridine, penicillin,may produce transient neutropenia RA, Cirrhosis, Lups and malaria causes neutropenia by abnormal cytophilic immunoglobulinemlia resulting in trappin of granulocytes in the spleen.,Neutropenia 1. reduced production - severe congenital neutropenia, cycli, Schwachman, leukemia 2. abnormal distribution or enhanced peripheral consumption - immune mediated, septicemia.DDX: rapidly reversible neutropenia associated with infections, durg induce, cyclilc netropoenia, those associated with immunoglobulin abnormalites.CASE PRESENTATIONS 1. S. G. - XLA 2. S.P - Cyclic NeutropeniaOverview: Immune system has 4 major components:*Pediatrics in Review 1993 Pie shape 1. Antibody , humoral or B cell - 50 % of all primary immunodeficiencie 2. Cell-mediated, T cell 7% 3. Phagocytosis - Polymorphonuclear and Mononuclear - 20% 4. complement - 2%Prevalence of known primary immunodeficeincy is 1/100,000 excluding IgA and IgG subclass deficiency2. Clinical Case3. Neutrophil4. Ddx of Neutrophil Disorder5. Immunodeficiencies in General6.. XLA, CGD, Hyper Ige, Cylcic neutropenia Case Presentation S.G.Neutrophils One of the polymorphonuclear leukocytes - others include Eosinophils and Basophils. Until the last 10 years the main function of neutrophils was though to kill bacterial pathogens by phagocytosis, oxidative and secretory capabilities. Recently we have been introduced to others roles in the immune system secondary to their cytokine production ie. Interleukins 1, 8, 12, TNF - a and B , and GM-CSF, which are involved in the inflammatory response. The neutrophil is important in the earlyl stages of infection, especially before an antibody response has occurred. Origin and Tissue Distribution Bone Marrow derived and arise from the pluripotential stem cells. (SEE ALEX”S CHART) IL-1, IL-3, IL-6 and SCF are needed to produce the G-M progenitor cell, the IL-3, GM-CSF and G-CSF leard to the production of the Neutrophil. The mature cell stays in the marrow storage compartment for 5 days, then ciruclates for 10 hours until it enters the tissue at sites of infection. It has been estimated that more than 100 billion neutrophils enter and leave the circulation of a 70kg person daily under normal conditions. In infants the storage of neutrophils in the bone marrow is very small and so can be exhausted quickly in infection. resulting in neutropenia. The blood pool is made up of a marginated and circulating pool of roughly equal size. With stress and in response to beta-agonists and IL-6 neutrophlils shift from the marginated area into cirulation. Ultrastructure - Histology pg 38 Neutrophils have a multilobe nucleus and the cytoplasm contains two types of granules - the Primary or Azurophil granules and the Secondary or Specific granules. Of note the granules are generated in the Golgi complex and then bud off from the endoplasmic reticulum. Abnormalities of budding occur in Chediak-Higashi with the formation of giant colaesced granules. Steihms p 461. Membrane receptors are very important in the function of the neutrophil in terms of chemotaxis, diapedesis and phagocytosis. Other antigens include the HGA or human granulocyte antigens that are very polymorphic ie. NA1 and NA2 that are responsible for immune neutropenias. Stiehms p.97 N surface proteins. Neutrophil function in the Neonate The bone marrow storage the neonate is very small compared to the adult and exhausts quickly and may result in neutropenia. Neonate function is also poorer than in adults. Most studies agree there is a decrease in chemotaxis and adherence until approximately age 5yrs. Killing by the Neutrophil can be Nonoxidative or Oxidative. 1. Nonoxidative - phagocytosis and then utilization of the microbes own microbial waste ie. Steptococcus pneumoniae or by the granule contents 2. Oxidative via the NADPH oxidase enzyme system - invovles an electron cascade for the production of superoxide.The most common lesion in patients with either a deficient number or defedtive function of neutrophils are soft tissue inflammation and abscess. The most common pathogens include S.aureus, Pseudomonas, Serratia, Enterobacteriaccae, Aspergillus and Candida. NEUTROPENIADefinition of Neutropenia in Childhood 2 weeks - 1year = ANC<2500 > 1 year = ANC<1500 in the strictest sense some use ANC<500 *African American children have 100-200/mm3 fewer neutrophilsMechanisms Leading to Neutropenia 1. Proliferation Defects - Bone Marrow failure either at progenitor cell or regulatory level 2. Maturation Defects - Intrinsic defect in granulocytic elements 3. Survival Defects - Ususally due to antineutrophil ab or infection 4. Distribution Abnormalities - Defective BM release or increased margination - rare Acquired - See Alex’s Chart 1. Autoimmune Neonatal Neutropenia 2. Alloimmune Neonatal Neutropenia 3. Transient Neonatal Neutropenia 4. Secondary Autoimmune Neutropenia 5. Miscellaneous Causes - Drugs, Bacterial Infection, Viral Infections Nutritional Deficiencies, Metabolic DiseasesCongenital - 1. Chronic Idiopathic Neutropenia of Childhood 2. Kostamann’s Syndrome 3. Cyclic Neutropenia 4. Familial Benign Chronic NeutropeniaFamilial 1. Schwachman Syndrome 2. Cartilage Hair Hypoplasia 3. Dyskeratosis Congenita 4. MyelokathexisAssociations with other Immunodeficiencies 1. XLA 2. HyperIgM 3. Fanconi’s Anemia 4. Chediak-Higashi SyndromeEvaluation of Neutropenia 1. History 2. PE 3. Laboratory Data with morphologic review of blood smear 4. BM examTreatments 1. Antibiotics 2. Steroids 3. IVIG 4. Recombinant human CSFXLA Underlying defect is limited to the B cell lineage. Characterized by profound deficiency of B cells resulting in hypogammaglobulinemia. This disease was first discovered by Bruton’s in 1952. ABBAs pg 412 schematic of B cell development Defect is a mutation in the Btk or B cell specific tyrosine kinase. This is believed to be involved in the formation of the light chain of immunoglobulins. This gene maps to the long arm of the X chromosome at Xq22. This gene is used in the differentiation of pre - B cells to mature B cells. Therefore there is a lack of mature B cells such as plasma cells in the body such as the GALT , lymph nodes - there are no germinal centers and bone marrow. Sometimes the block is incomplete and some antibodies are produced. Mutations from family to family are variable. Clinical manifestations” Because IgG is transported across the placenta, symptoms from this immunodeficiency usaually begin between 4-12mos. Some studies in the United Kingdom describe symptoms beginning in 20% between 3-5 yrs old. Increased susceptiblility to Bacterial Infections and Viral infections - ie. Sterptococcus pneumoniae, Haemophilius influenze, Staphylococcus aureus, and Psuedomonas due to the need for opsonization, whereas intracellular microbes and fungi are handled normally. Otitis, sinusitis, pneumonia, pyoderma, diarrhea, sepsis, menigitis, septic arthritis There is particular vulnerability to the Enterovirus - echovirus, coxsackie, and polio. A number of children with XLA have vaccine-related poliomyelitis with the live virus. Several children develop a chronic meningoencephalitis. Other less common manifestations 1. Neutropenia - Hermaszewski and Webster 1993, Alopecia totalis, Protein losing enteropathy, and amyloidosis. PE: Hypoplastic or absent tonsils Labs: Reduced IgG, IgA, IgM, IgE Inability to make antibody responses. Few if any B cells in periphery as detected by flow cytometry with monoclonal ab to CD19 and CD20