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1. HYPERSENSITIVITY
RATHEESH R.L

2. HYPERSENSITIVITY
• The term hypersensitivity refers to a condition
in which immune system produces a response
against antigen that results in excessive
reactions leading to tissue damage, diseases
or even death.

3. CLASSIFICATION
• BASED ON TIME:
– Immediate hypersensitivity: This type of
hypersensitivity manifests or occurs in few minutes to
few hours.
– Delayed hypersensitivity: This type of hypersensitivity
manifests or occurs after 24 hrs and reaches peaks
after 48-72 hrs.

4. • ACCORDING TO COOMBS AND GEL:
– Type I hypersensitivity: Anaphylaxis
– Type II hypersensitivity: Cytotoxic/ Cytolitic
– Type III hypersensitivity: Immune complex reaction.
– Type IV hypersensitivity: Delayed hypersensitivity
– Type V hypersensitivity: Stimulatory type reaction
– Type VI hypersensitivity: Antibody dependent reaction

5. Type I hypersensitivity
• Type I hypersensitivity (or immediate
hypersensitivity) is an allergic reaction provoked
by re-exposure to a specific type of antigen
referred to as an allergen.

6. MECHANISM
• In type 1 hypersensitivity, B-cells are stimulated to produce IgE
antibodies specific to an antigen.
• The difference between a normal infectious immune response and
a type 1 hypersensitivity response is that in type 1 hypersensitivity
the antibody is IgE instead of IgA, IgG, or IgM.
• During sensitisation, the IgE antibodies bind to Fcε receptors on the
surface of tissue mast cells and blood basophils.
• Mast cells and basophils coated by IgE antibodies are "sensitised."

7. • Later exposure to the same allergen cross-links the
bound IgE on sensitised cells, resulting
in degranulation and the secretion of mediators such
as histamine, leukotriene , and prostaglandin that act
on the surrounding tissues.
• The principal effects of these products
are vasodilation and smooth-muscle contraction.

8. FEATURES OF ANAPHYLAXIS
• Reaction occurs immediately
• IgE produced has an affinity to affect the skin
cells.
• The features occurs due to constriction of
smooth muscles and increased vascular
permeability.
• Duration is short
• It is not a heritable disease.

9. CLINICAL FEATURES
• CUTANEOUS MANIFESTATIONS:
– Wheal and flare reaction ( redness and edema over
tissue)
– Urticaria
– Angio neurotic edema.
• SYSTEMIC MANIFESTATIONS:
– Broncho spasm
– Laryngeal edema
– Respiratory distress
– death

10. Type II hypersensitivity
• In type II hypersensitivity (or cytotoxic
hypersensitivity) the antibodies produced by the immune
response bind to antigens on the patient's own cell
surfaces.
• The antigens recognized in this way may either be
intrinsic ("self" antigen, innately part of the patient's
cells) or extrinsic (adsorbed onto the cells during
exposure to some foreign antigen, possibly as part of
infection with a pathogen).

11. • An example of type II hypersensitivity is the
ABO blood incompatibility where the red
blood cells have different antigens, causing
them to be recognized as different.

12. Type III hypersensitivity
• Type III hypersensitivity occurs when there is
accumulation of immune complexes (antigen-
antibody complexes) that have not been
adequately cleared by innate immune cells,
giving rise to an inflammatory response and
attraction of leukocytes.

13. Type IV hypersensitivity( delayed )
• Type IV hypersensitivity is often called
delayed type hypersensitivity as the reaction
takes two to three days to develop. Unlike the
other types, it is not antibody mediated but
rather is a type of cell-mediated response.

14. MECHANISM
• The cellular events that result in delayed
hypersensitivity reactions primarily involve T
cells and macrophages.
• First, local immune and inflammatory
responses at the site of foreign antigen up-
regulate endothelial cell adhesion molecule
expression, promoting the accumulation of
leukocytes at the tissue site.

15. • molecule expression, promoting the
accumulation of leukocytes at the tissue site.
• The antigen is engulfed by macrophages and
monocytes and is processed and presented to
a T cell that has a specific receptor for that
processed antigen. Macrophages secrete
interleukin (IL)–1, IL-2, IL-6, and other
lymphokines.

16. • Cytotoxic T cells can also be activated.
• The recruited macrophages can form giant
cells. The characteristic histologic appearance
of the macrophage–T-cell infiltrate is a
granuloma.
• This type of infiltrate in the tissue is called
granulomatous inflammation.

17. Type V hypersensitivity Reaction
• Hypersensitivity (also called hypersensitivity
reaction or intolerance) is a set of
undesirable reactions produced by the normal
immune system, including allergies and
autoimmunity.

18. Type VI hypersensitivity
• The difference between a normal infectious
immune response and a type 1 hypersensitivity
response is that in type 1 hypersensitivity the
antibody is IgE instead of IgA, IgG, or IgM.
• During sensitisation, the IgE antibodies bind to Fcε
receptors on the surface of tissue mast cells and
blood basophils.

20. IMMUNOPROPHYLAXIS
• It is defined as prevention of disease by the
production of active or passive immunity.
• Immunoprophylaxis helps to prevent many
infectious disease such as poliomyelitis, yellow
fever, diphtheria, typhoid, dysentry,cholera.

21. IMMUNIZATION
• According to WHO immunization is the
process whereby a person is made immune or
resistant to an infectious disease, typically by
the administration of vaccine.

22. TYPES OF IMMUNIZATION
• ACTIVE IMMUNIZATION
• PASSIVE IMMUNIZATION
• COMBINE ACTIVE AND PASSIVE IMMUNIZATION

23. • ACTIVE IMMUNIZATION:
– Active immunization is the induction of immunity
after exposure to an antigen.
– Antibodies are created by the recipient and may
be stored permanently.
• PASSIVE IMMUNIZATION
– Passive immunity is the transfer of active
humoral immunity in the form of ready-made
antibodies.

24. • COMBINE ACTIVE AND PASSIVE IMMUNIZATION:
– Both the active and passive type of immunization
will be provided to the patients.

25. ACTIVE IMMUNIZATION
• Vaccines
– Vaccines are the preparations of live attenuated or
dead organisms which when introduced the body
produce artificially active immunity.

26. TYPES
• Live attenuated vaccine:
– These are the suspensions of living organisms with
reduced virulence but are able to produce
antibodies.
– Eg: BCG vaccine, oral typhoid vaccine
• Inactivated or killed vaccines:
– In such vaccines, the organisms will be present
which are killed with heat, formalin, phenol,
alcohol or UV radiation.
– Eg: pertusis vaccine, plague vaccine

27. • Toxoids:
– These are modified toxins that have lost
toxigenicity but retain antigenicity.
– Eg: TT
• Subunit vaccines:
– A sub unit vaccine or acellular vaccine is one that
uses antigenic portions of a pathogen, rather than
using the whole pathogen.
– Eg: vaccine for Hepatitis B

28. • Conjugate vaccine:
– These are the vaccines made by conjugating bacterial
capsular antigens to molecules that stimulate the
immune system to produce antibodies.
– Eg: pneumococcal vaccines
• DNA vaccine
– In such vaccines a particular gene from a pathogen is
inserted into the plasmid of bacteria and these
plasmids are then injected to the skin or muscle.
– Eg: tried against malaria

29. • Autogenous vaccines:
– These are the vaccines prepared from the bacteria
isolated from the localized infection such as
staphylococcal boil.
– The pathogens are killed and then injected into the
same person to induce production of more antibodies
against the pathogen.

30. • Combined vaccines:
– These are the mixture of two or more types of
vaccines.
– Eg: DPT, DT

31. PASSIVE IMMUNIZATION
• It involves the injection of exogenous antibody
present in human or animal serum to provide
immediate protection of an infection.
• The immunity will be produced for a limited
period of time.
• There are three types,
– Pooled immunoglobin
– Specific immunoglobin/ specific human immunoglobin
– Homologous and heterologous sera

32. • Pooled immunoglobin
– It is prepared from pooled normal human serum
containing high levels of appropriate antibody.
• Specific immunoglobin
– It is prepared from the serum of the patients who are
recovering from infection or from persons who have
been actively immunized against a specific infection.

33. • Homologous and heterologous sera
– Anti bacterial, anti-viral antibodies in human or
animals serum are injected to provide temporary
protection against infection.

34. COMBINED PASSIVE & ACTIVE
IMMUNIZATION
• In some disease passive immunization is
undertaken in conjugation with inactivated
vaccine products in order to provide both
immediate passive immunity which is temporary
and slowly developing active immunity which
lasts for longer period of time.

35. IMMUNIZATION SCHEDULE
• At birth - BCG
- OPV-0
• At 6 weeks - DPT-1
- OPV-1
• At 10 weeks - DPT-2
- OPV-2
- Hib-1
• At 14 weeks - DPT-3
- OPV-3
- Hib-2
• At 9 months - MMR

36. • At 12-18 months - Hib(B)
• At 16-24 months - DPT(B)
-OPV(B)
• At 5-6 years -DT
• At 10-16 years - TT-0
- TT-1
- TT-2

37. COLD CHAIN
• The cold chain includes all the materials,
equipments and procedures used to maintain
vaccines in required temperature range of +2 -
+8 degree C from the time of manufacture
until the vaccines are administered.

38. COLD CHAIN EQUIPMENTS
• COLD BOX:
• It is used for transport of large quantities of vaccine by
vehicle to out reach sites. It can keep vaccine cold for
periods up to one week without electricity supply.
• VACCINE CARRIER:
• It is used to transport small quantities of vaccine by
vehicle, by bicycle or by foot to outreach the sites by
primary health care workers. It can help vaccine at safe
temperature upto 2-3 days.

39. • FLASKS:
• They are used only if the vaccine carriers are not
available.
• ICE PACKS:
• They can be made in freezer and keep vaccines cool in
cold boxes, carriers and flasks.
• REFRIGERATOR:
• It is the most important component of vaccine storage.
Vaccines for polio, measels, BCG are stored in freezer
compartment.
• However, vaccines for typhoid, DPT, TT are stored in
refrigerator, but they should not be allowed to freeze.

40. GENERAL PRACTICES OF VACCINE
STORAGE AND HANDLING
• To retain the patency of vaccine, it should
keep between +2 - +8 degree C.
• Domestic refrigerator/ ice lined refrigerator
are used for short term storage.
• For long time storage, -20 degree C is
preferred for BCG, OPV & Measles. Do not
freeze other vaccines.
• Always store vaccines on middle shelves of
refrigerator

41. • Leave space between the packages in the
refrigerator to allow air to circulate.
• Check the expiry date of vaccine frequently.
• Take the vaccine out of the refrigerator only
when ready to administer.
• Return un used vaccine to refrigerator
immediately after the required dose has been
drawn.
• Protect vaccines from the sun light.

42. TRANSPORT OF VACCINES
• Vaccines must be protected in insulated and
monitored containers so that they stay
between +2 - +8 degree celcious.
• Vaccines must be protected from heat, cold,
sunlight and flurocent lights.

43. GOOD BYE…