4. INTRODUCTION
Periodontal disease involves
1) Local infection
2) A host response
That may results in connective tissue alteration.
The immune system plays a key role in limiting the infection to the
gingival crevice or to the tissue with immediate vicinity of the gingival
crevice
There are 3 general hypotheses for possible etiological mechanism causing
periodontal disease have been proposed
1) infection of one or more virulent bacteria within the normal host
2) Deficiency in the host response to the bacterial infection
3) A combination of both
5. Periodontal diseases are infectious in origin but the extent and the
severity of the disease depends on the interaction between the
bacterial challenge and the host response.
The immune response also orchestrate the alteration of connective
tissue in a complex remodeling process involving cycles of
destruction and reconstruction.
Leukocytes are critical to periodontal defense as most potential
periodontal pathogens are known to be resistant to the anti microbial
mechanism of serum.
6. Leukocytes that are involved in the acute inflammation
1) Neutrophils
Leukocytes that involved in the chronic inflammation
1) Monocytes
2) Marcophages
7. Functions of leukocytes
These leukocytes constitutes the main phagocytic cell system in the
mammalian host defense against the infecting agents.
They perform variety of functions such as
Engulfment of the bacteria
Secretion of the lytic enzymes
Release of the mediators which are responsible for the coordination
of the inflammatory response as well as tissue repair and
remodelling.
8. NEUTROPHILS
Neutrophils are so called
polymorphonuclear leukocytes
These are the most abundant population
of circulating white blood cells.
These are spherical cells about 12 to 15
µm in diameter with numerous
membranous projections
They contain nucleus which is
segmented into 3 to 5 connected lobules
9. Neutrophils represents about 70% of all the leukocytes and more
than 10^11 cells are produce every day in bone marrow
(Darcy et al 1976)
Neutrophils are the initials leukocytes that are recruited in the
gingiva
They exit the circulation and migrates into junctional epithelium and
gingival crevices where they provide protection against the
periodontal bacteria .
Once neutrophils reach the end of their lifespan within tissues, they
are cleared mostly by macrophages through the process of
phagocytosis
(Bratton and Henson, 2011)
11. Neutrophil Exit from the Bone Marrow
Only 1 or 2% of all neutrophils in the body are found in the blood
under normal homeostatic conditions.
Mature neutrophils are kept in the bone marrow through the action
of two chemokine receptors, CXCR2 and CXCR4.
Osteoblasts and other bone marrow stromal cells produce CXCL12
and keep CXCR4-expressing neutrophils in the bone marrow.
G-CSF induces neutrophil exit from the bone marrow by interfering
with the CXCR4-CXCL12 interaction
(Summers et al., 2010)
12. In addition, ligands for CXCR2, such as CXCL1, CXCL2, CXCL5,
and CXCL8 (in humans) are expressed by endothelial cells outside
the bone marrow when neutrophils need to be mobilized into the
blood
(Eash et al., 2010; Köhler et al., 2011)
G-CSF prompts the release of neutrophils by inducing upregulation
of CXCR2 ligands on megakaryocytes, reduced expression of
CXCL12 by bone marrow stroma cells.
(Köhler et al., 2011)
13. Normal Neutrophil Functions
Neutrophils are the initial leukocytes that are recruited into the
gingiva
Neutrophils are well adapted to function in hypoxic environments,
because virtually all of their energy is derived from fermentation of
stored glycogen rather than oxidative phosphorylation.
The primary role of the neutrophil is the destruction of pathogens
that threaten tissues outside of the blood.
14. For this reason, leaving the blood, finding targets, and killing targets
are important phagocyte functions in the defense of the
periodontium.
15. Margination and Diapedesis
Neutrophils adhere to the luminal surface of the vascular
endothelium (rolling, margination) and migrate across the
endothelium ( diapedesis, inter-endothelial transmigration).
There are two phases of leukocyte--endothelium adherence
the selectin-dependent phase (primarily involved in rolling)
the integrin-dependent phase (primarily involved in diapedesis).
16. Selectins
Selectins are closely related to the regulators of complement
activation (RCA) gene region products.
They are encoded on chromosome I and possess complement
regulatory (CR) that may be important in binding C3, C4, and C5
metabolites.
Inflammation causes endothelium to immediately express P-selectin,
which it stores in granules and also induces the biosynthesis of E-
selectin.
17. Both P- and E-selectin strengthen the binding between the leukocyte
and the endothelial cell and increase the number of leukocytes
"rolling" in the inflamed postcapillary venule.
Inflammation also induces endothelium to produce the chemokine
(intercrine), endothelial interleukin-8 (IL-8).
Cytokines are dissipated rapidly by hemodynamic flow, and thus it
is important that the leukocyte be temporarily immobilized by the
selectins
18. Leukocyte ß2-lntegrins
IL-8 causes the leukocyte to shed L-selectin and to express the ß2-
integrins.
The leukocyte ß2 integrins include three related transmembranous
glycoproteins consisting of a noncovalently associated heteroduplex
structure.
19. The three leukocyte integrins are
leukocyte function-associated antigen- I (LFA-l)
Mac-I
p l50,95
20. The distribution of LFA-1 is greater than that of the other two
leukocyte ß2-integrins, found on all leukocytes except some tissue
macrophages.
Both LFA-1 and Mac-I are important in diapedesis. LFA-1 and Mac-
I interact with intercellular adhesion molecules (lCAMs), ICAM- 1
and ICAM-2.
The leukocyte ß2-integrins present as the molecular mediators of
binding with endothelial cells.
21. At the beginning of transendothelial migration, neutrophils show
distinct polarization, extending a pseudopod between the endothelial
cells while maintaining the nuclei and granules on the luminal side.
The neutrophil eventually works its way to the serosal side of the
endothelium, where it pauses briefly between the basement
membrane and the endothelial cell before entering the connective
tissues.
22. Chemotaxis
Chemotaxis is the directed movement of a cell along a chemical
gradient.
The neutrophil is attracted by chemical signals (chemotoxins) from
multiple sources.
23. This muitiplicity permits the neutrophil to respond to different
insults and also provides a system that enables the neutrophil to
respond to insult even if one receptor is defective
Both C5a and formyl peptides are likely to play a major role in
attracting neutrophils into the gingival crevice.
The gingival crevice contains 23% to 85% of the major complement
components and activation has also been demonstrated in crevicular
fluid
24. Chemotaxin Receptors
Chemotaxis requires that the phagocyte possess specific chemotaxin
receptors for all of the molecules
The most well-studied chemotaxin receptor is the receptor for
formylmethionyl peptides, known as the formylmethionyl peptide
receptor (FPR).
The FPR is a transmembrane glycoprotein (about 32 kd) and binds
to formylated hydrophobic peptides derived from bacteria.
The affinity of the FPR is regulated by guanosine
triphosphate/guanosine diphosphate (GTP/GDP)-binding G protein.
25. Chemotaxin receptors and their relatives in the G protein-
coupled receptor superfamily, G protein receptor
superfamily.
27. Opsonization : Binding of Neutrophils to
Targets
Opsonization refers to the process of coating a particle with
recognizable molecules to enable phagocytic ingestion.
There are two types of opsonins that should be considered
the complement metabolite, iC3b
Immunoglobulin G (lgG).
The main function of the iC3b is the endocytosis
28. Phagocytic adhesion to targets may also be mediated by antibody
using surface receptors collectively known as Fc receptors
these Fc receptors are basically of 3 types
FcyRI – high affinity receptors found mainly on macrophages
FcyRII
FcyRIII low affinity receptors found mainly on macrophage and
neutrophil
29. The mechanism of phagocyte adhesion to targets may vary with
disease states. Both gingivitis and adult periodontitis (AP) have been
characterized primarily as involving alternative pathway activation
In localized juvenile periodontitis (LJP) observed greater classic
pathway activation, which suggests a higher degree of opsonic
antibody interacting with target antigen
30. Antimicrobial Systems
Neutrophils have oxidative and nonoxidative mechanisms for
exerting antimicrobial effects.
Oxidative mechanisms are based on reduction of oxygen with
resultant formation of toxic oxygen metabolites.
Nonoxidative mechanisms in general appear to be based on
membrane-disruptive antibiotic activities of peptides or peptide
domains within larger proteins
31. NEUTROPHIL ABNORMALITIES
Primary neutrophil defects are often associated with severe forms of periodontal
disease and pyogenic infection of the host.
32. Neutropenia and Agranulocytosis
Neutropenia and agranulocytosis are signs of diseases or disease
processes
An individual is said to be neutropenic if neutrophil counts are
below 1500 mm3
Agranulocytosis if counts drop below 500 mm3
The decreased number of neutrophils can result from either a
decreased production of cells, or an increased peripheral destruction
of cells.
Decreased production is usually due to bone marrow hypoplasia,
although drugs, chemicals, ionizing radiation, infection, vitamin
deficiencies and bone marrow tumors can cause similar effects
33. Oral manifestations –
Generalized, painful stomatitis,
spontaneous bleeding and necrotic tissue.
Radiographs generally reveal a progressive pattern of bone loss at an
early age.
34. Leukocyte Adhesion Deficiency
Leukocyte adhesion deficiency (LAD) is a defect of cellular
adhesion molecules resulting in a clinical syndromes
These are of 2 types
Type 1
Type 2
35. TYPE 1
type 1 (LAD-I) is an autosomal disorder which is localized to
chromosome 21 q22.3.
It characterized by the inability of individuals to express the ß2
subunit which is common to the leukocyte integrins LFA-1, Mac-1,
and p 150,95.
Periodontal disease is related to whether one or two defective alleles
are present.
Homozygotes exhibit generalized prepubertal periodontitis (GPP),
which affects both the deciduous and the permanent dentition.
Heterozygotes appear to have normal prepubartal periodontal status
36. Clinical Features:
These patients also have frequent respiratory tract infections and
sometimes otitis media
Oral manifestation:
The children may present with acute gingival inflammation of both
primary and permanent dentitions, as well as gingival proliferation,
recession, tooth mobility, and pathologic migration. Both primary
and permanent teeth may be affected, often resulting in early tooth
loss
37. Type II
It is also an autosomal disorder which is caused by the changes in
the gene at the chromosomes 21q3
This condition is characterized by the deficiency of receptors for the
selectins on the endothelial membrane
In this the neutrophil rolling does not increase in response to the
inflammation.
Individual with this deficiency suffer from recurrent bacterial
infections, neutrophilia and severe periodontitis
38. Hyperimmunoglobulinemia E
Hyperimmunoglobulinemia HIE; also known as job’s syndrome
It is a rare, complex autosomal recessive disorder localized to
chromosome 7q21
Characterized by marked elevation of immunoglobulin E (IgE),
variable defects in neutrophil chemotaxis,
Chronic dermatitis (eczematoid rash),
"coarse facies," and
Serious, life-long bouts of recurrent infections with opportunistic
organisms (staphylococcus aureus and candida albicans) that result
in skin abscesses with lack of erythema.
39. The cause of HIE is unclear, but it has been suggested that the
balance between the T-cell elaboration of IL-4 and interferon-y
(INF-y) is defective.
40. Chediak-Higashi Syndrome
Chediak-Higashi syndrome (CHS) is a rare disease with an autosomal
recessive inheritance which is localized to chromosome lq43.
In this Azurophils and Specific granules fuses into a giant granules which
are called as Megabodies leading defective granules formation.
Neutrophil defects include decreased chemotaxis, degranulation, and
microbicidal activity.
Neutropenia and depressed inflammation are also observed.
The depressed inflammation is thought to be due to decreased chemotaxis
and secretion.
41. Clinical features:
The syndrome may present as abnormalities of pigmentation,
Recurrent infections, and bleeding tendencies.
Oculocutaneous albinism can affect the skin, eyes, and hair.
Ocular abnormalities can include nystagmus, photophobia and
reduced visual acuity.
Infections are commonly skin abscesses, pneumonias, otitis media
and sinusitis.
42. Oral manifestations of this disease include severe periodontitis and
oral ulceration .
Charon 1985
43. Specific Granule Deficiency
Specific granule deficiency (SGD) is a rare disease, probably
autosomal recessive disorder.
In this neutrophils are lacked of specific granules
In SGD there is defect in packaging of both specific and azurophilic
granules.
Specific granules proteins that are missing include lactoferrin,
cytochrome B, C5a receptors and CR3.
44. The deficiency of these components results in depressed repiratory
burst activity, diminished ability to respond to chemotoxins and poor
phagoicytosis.
There is also decreased in inflammation due to deficiency of
chemotoxin receptors and cells are less responsive chemotactically.
Oral manifestation of this disease includes severe periodontitis and
oral ulcer.
45. Papillon-Lefevre Syndrome
Papillon-Lefevre syndrome (PLS) features rapid generalized
destruction of alveolar bone (affecting both the primary and
secondary dentition) and palmar-plantar hyperkeratosis.
The exact immunologic abnormality that contributes to this
condition is unknown.
But one report indicates that PLS may be associated with diminished
neutrophil activity.
Van Dayk 1984
Neutrophils from an individual with PLS had decreased receptor
affinity for chemotaxin ligands such as formyl peptides
46. Clinical Features:
Ectopic calcifications of the falx cerebri and choroid plexus,
increased susceptibility to infection, mental retardation, and
endocrine disorders have been reported in this syndrome.
Oral manifestations:
It is characterised by a diffuse palmoplantar keratosis associated
with aggressive periodontitis of both primary and permanent
dentitions and in some cases, calcification of the dura matar.
47. Chronic Granulomatous Disease
Chronic granulomatous disease (CGD) is clinically diagnosed by the
presence of recurrent, indolent, pyogenic infections with certain
bacteria.
The cause of this problem is the inability of host phagocytes to
mount a normal respiratory burst.
This lead to inability of rapidly killing the bacteria, which then gain
access to the connective tissues, leads to the formation of
granulomas by the chronic immune cells.
The X-linked form involves a mutation in the gene encoding the
heavy subunit of cytochrome b
48. An autosomal recessive form of CGD that mimics the X-linked
form (i.e., the absence of cytochrome b) involves the mutation of the
small subunit of cytochrome b and is encoded on chromosome
16q24.20
Individuals with CGD exhibit greater than normal oral ulceration
and gingivitis, but CGD has not been strongly associated with
severe periodontitis
Charon 1985
49. CONCLUSION
Certain periodontal diseases may represent the failure of specific
neutrophil immune mechanisms which control specific
periodontopathic bacteria and specific subsequent chronic
inflammatory responses. Impaired neutrophil functions as well as
impaired functions of other cells of the host response are a central
mechanism in the progression of chronic and aggressive forms of
periodontitis. The knowledge of these syndromes is essential as they
can influence the prognosis and management of periodontal disease.
Hence it is important to know the functions of these cellular
sentinels and their role on periodontal disease.
50. References
Carranza 8th edition
Neutrophil: A Cell with Many Roles in Inflammation or Several Cell
Types? Rosales, C. (2018),Frontiers in Physiology,
9. doi:10.3389/fphys.2018.00113
Neutrophil associated syndromes and periodontitis Journal of
Chemical and Pharmaceutical Research, 2016, 8(2):421-427
The Neutrophil: Mechanisms of Controlling Periodontal Bacteria
Kenneth T. Miyasaki J Periodontol 1991; 62:761-774
