PATHOPHYSIOLOGY OF HYPERSENSITIVITY 3 AND 4

1. Vignan pharmacy college , vadlamudi
By
B.Nom Kumar Naik
17AB1T0005

2. Type - III or immune - complex
mediated Hypersensitivity
• Large amount of antigen and
antibodies form complexs in blood.
• They are normally removed by
reticuloendothelial system.
• If not eliminated can deposit in
capillaries or joints and trigger
inflammation and immune - complex
diseases.

4. • A few of these have been mentioned below :
-
• Eg : - 1. serum sickness (foreign antigen
+anti bodied -----> immune complexes at
different tissues )
• Characterised by fever , urticaria (hives or
nettle rash) , arthralgia , splenomegaly ,
lymphadenopathy and eosinophilia.
• Some drugs associated with this type of
reactions are allopurinol , barbiturates ,
captopril , griseofulvin , phenytoin ,
Quinidine and sulphonamides

6. • 2.Glomerulonephritis : -
characterized by inflammation of
glomeruli of kidney and that leads to
impairment in the kidney 's ability to
filter urine.
• 3.systemic lupus erythematous : - It
is an autoimmune disease , where
antibodies are formed against DNA ,
histones and nuclear proteins.

8. • 4.Rheumatoid arthritis : -
Deposition of immune complexes
at synovial membrane causes
rheumatoid arthritis.
• Treatment : - NSAIDs ,
Immunosuppressive drugs or
corticosteroids.

10. • Delayed type hypersensitivity is a
function of T - Lymphocytes , not an
antibodies.
• As the name suggests, the response is
often Delayed.
• When the T - helper cells binds to the
APC , gets activated.
• And releases of cytokines and
macrophage activation
• Type - IV or Delayed type
hypersensitivity

12. • And T - cell mediated cytotoxicity
.
• It can be transferred by
immunologically committed T-
cells , not by serum .
• Eg : - 1.contact hypersensitivity : -
usually maximal at 48 hours.
Predominantly an epidermal
reaction.A small molecule's act as
"HAPTENS "
• Langerhans cells are the antigen
presenting cells.

14. • 2. Tuberculin type hypersensitivity :
Maximum at 48 - 72 hours. It is
due to infiltration of macrophages.
Reddish swollen skin lesions at the
site of injection ( intradermally -
bacterial protein, tuberculin which
is derived from cell Wall of tubercle
bacterium , mycobacterium
tuberculosis )