The lymphatic system consists of lymph fluid, lymphatic vessels, lymph nodes, the spleen, thymus, and lymphatic tissues. It works with the immune and circulatory systems to drain excess interstitial fluid, transport lipids and proteins, and help fight infection through immune responses. Lymphatic vessels begin as tiny blind-ended capillaries that transport lymph through lymph nodes and eventually into the bloodstream via the thoracic duct or right lymphatic duct. The lymph nodes, spleen, thymus, tonsils, and Peyer's patches contain lymphatic tissues that help the immune system respond to pathogens and antigens.

1. Lymphatics:

2. • Lymphatic system:
• 1. fluid called lymph,
• 2. vessels called ‘lymphatic vessels’ that transport the
lymph,
• 3. a no.of structures and organs containing lymphatic
tissue and
• 4. red bone marrow – where stem cells develop into
the various types of blood cells, including
lymphocytes.
• lymph: after interstitial fluid passes into lymphatic
vessels, it is called ‘lymph’.
• diff b/n interstitial and lymph: its location.

4. • Functions:
• 1. draining excess interstitial fluid.
• 2. transporting dietary lipids from GIT.
• 3. carrying out immune responses: initiate highly
specific responses directed against particular microbes
or abnormal cells.
• 2 basic ways: 1. cell mediated immune responses T
cells destroy the intruders by causing them rupture or
by releasing cytotoxic substances.
• 2. antibody mediated immune responses, B cells
differentiate into plasma cells – produce antibodies.

5. • Lymphatic vessels:
• Begin as lymphatic capillaries.
• Tiny vessels are located in the spaces between cells,
are closed at one end.
• Converge to form larger lymphatic vessels.
• Have thin walls and more valves.
• At intervals along the lymphatic vessels, lymph flows
through lymph nodes, encapsulated bean shaped
organs consisting of masses of B cells and T cells.
• Tissues which lack lymphatic capillaries: avascular
tissues, CNS, portions of the spleen, and red bone
marrow.

7. • Lymphatic capillaries:
• Slightly larger in diameter than blood capillaries.
• Permit flow one way – into but not out.
• Ends of endothelial cells overlap.
• Attached to the lymphatic capillaries are ‘anchoring
filaments’, which contain elastic fibers.
• They attach the endothelial cells to surrounding
tissues.
• In small intestine, specialized lymphatic capillaries
called ‘lacteals’ carry dietary lipids into lymphatic
vessels and ultimately into blood.

9. • Presence of these lipids causes the lymph draining
from the small intestine to appear creamy white; such
lymph is referred to as ‘chyle’.
• Elsewhere, lymph is a clear, pale yellow fluid.

10. • Lymphatic trunks and ducts:
• As lymphatic vessels exit lymph nodes in a particular
region of the body, they unite to form ‘lymph trunks’.
• Principal trunks are the lumbar, intestinal,
bronchomediastinal, subclavian, and jugular trunks.
• Lumbar trunks drain lymph from the lower limbs, the
wall, and viscera of the pelvis, the kidneys, the adrenal
glands, and the abdominal wall.
• The intestinal trunk drains lymph from the stomach,
intestines, pancreas, spleen and part of the liver.
• Bronchomediastinal trunks drain lymph from the
thoracic wall, lung, and heart.
• Subclavian trunks drain the upper limbs.
• Jugular trunks drain the head and neck.

11. • Lymph passes from lymph trunks into 2 main
channels, the thoracic duct and the right lymphatic
duct, and then drains into venous blood.
• Thoracic duct: long and begins as a dilation called the
‘cisterna chyli’ anterior to the L2.
• Thoracic duct is the main duct for the return of lymph
to blood.
• Cisterna chyli receives lymph from the right and left
lumbar trunks and from the intestinal trunk.
• In the neck, the thoracic duct also receives lymph from
the left jugular, left subclavian, and left
bronchomediastinal trunks.

13. • Thoracic duct receives lymph from the left side of the
head, neck, and chest, the left upper limb, and the
entire body inferior to the ribs.
• Thoracic duct in turn drains lymph into venous blood
at the junction of the left internal jugular and left
subclavian veins.
• Right lymphatic duct:
• long and receives lymph from the right jugular, right
subclavian, and right bronchomediastinal trunks.
• Right lymphatic duct receives lymph from the upper
right side of the body.
• From right lymphatic duct, lymph drains into venous
blood at the junction of right internal jugular and rt.
Subclavian veins.

15. • Formation and flow of lymph:
• Most components of blood plasma filter freely through
the capillary walls to form interstitial fluid, but more
fluid filters out of blood capillaries than returns to
them by reabsorption.
• The excess filtered fluid – about 3 liters per day –
drains into lymphatic vessels and becomes lymph.
• Because most plasma proteins are too large to leave
blood vessels, interstitial fluid contains only a small
amount of protein.
• Proteins that do leave blood plasma cannot return to
the blood by diffusion because the concentration
gradient opposes such movement.

17. • the proteins can move readily through the more
permeable lymphatic capillaries into lymph.
• An important function of lymphatic vessels is to return
the lost plasma proteins to the bloodstream.
• Valves in lymphatic vessels ensure the one way
movement of lymph.
• Lymphatic ducts drain into the junction of the internal
jugular and subclavian veins.
• Same 2 pumps that aid the return of venous blood to
the heart maintain the flow of lymph.
• 1. skeletal pump
• 2. respiratory pump.

18. • Lymphatic organs and tissues:
• 2 groups based on their functions:
• 1. primary lymphatic organs: sites where stem cells
divide and become immunocompetent, that is, capable
of mounting an immune response.
• Red bone marrow and the thymus.
• Pluripotent stem cells in the red bone marrow give rise
to mature, immunocompetent B cells and to pre T
cells, which migrate to and become immunocompetent
T cells in the thymus.
• Secondary lymphatic tissue:
• Where most immune responses occur.
• Include lymph nodes, the spleen, and lymphatic
nodules.

20. • Thymus, lymphnodes, and spleen are considered
organs because each is surrounded by a connective
tissue capsule.
• Thymus:
• Bilobed organ located in the mediastinum between the
sternum and the aorta.
• An enveloping layer of connective tissue holds the 2
lobes closely together, but a connective tissue capsule
separates the two.
• Extensions of the capsule, called ‘trabeculae’ penetrate
inward and divide each lobe into lobules.

22. • Each thymic lobule consists of a deeply staining outer
cortex and a lighter staining central medulla.
• Cortex: large no.of T cells and scattered dendritic cells,
epithelial cells, and macrophages.
• Immature T cells migrate from red bone marrow to
the cortex of the thymus, where they proliferate and
begin to mature.
• Dendritic cells: long branched projections that
resemble the dendrites of a neuron, assist in
maturation process.
• Epithelial cells: several long processes that surround
and serve as a framework for as may as 50 T cells.
• Help educate the pre T cells: positive selection.

23. • Produce thymic hormones that are thought to aid in
the maturation of T cells.
• Macrophages: help clear of the debris of dead and
dying cells.
• Surviving T cells enter the medulla.
• Medulla:
• Widely, scattered, more mature T cells, epithelial cells,
dendritic cells and macrophages.
• Some of the epithelial cells become arranged into
concentric layers of flat cells that degenerate and
become filled with keratohyalin granules and keratin.
• These clusters are called thymic or hassall’s
corpuscles.

25. • Serve as sites of T cell death in the medulla.
• T cells that leave the thymus via the blood migrate to
lymphnodes, the spleen, and other lymphatic tissues
where they colonize parts of these organs and tissues.
• Infants: thymus is large.
• After puberty, adipose and areolar connective tissue
begin to replace the thymic tissue.
• Maturity: gland has atrophied.

26. • Lymphnodes:
• Located along lymphatic vessels are about 600 bean
shaped lymph nodes.
• Scattered throughout the body, both superficially and
deep, and usually occur in groups.
• Large groups of lymph nodes are present near the
mammary glands and in the axillae and groin.
• Covered with capsule of dense connective tissue that
extends into the node.
• Capsular extensions, trabeculae, divide the node into
compartments, provide support, and provide a route
for blood vessels into the interior of a node.
• Internal to the capsule is a supporting network of
reticular fibers and fibroblasts.

27. • Capsule, trabeculae, reticular fibers, and fibroblasts
constitute the stroma of a lymphnode.
• Parenchyma: superficial cortex and deep medulla.
• Cortex: Outer and inner
• Outer cortex: egg shaped aggregates of B cells called
‘lymphatic nodules’.
• Lymphatic nodule consisting chiefly of B cells –
primary lymphatic nodule.
• Secondary nodules – formed in response to an
antigenic challenge and are sites of plasma cell and
memory B cell formation.

29. • After B cells in a primary lymphatic nodule recognize
an antigen, the primary lymphatic nodule develops
into a secondary lymphatic nodule.
• Center of a secondary nodule contains a region of light
staining cells called a ‘germinal center’ – contains B
cells, follicular dendritic cells and macrophages.
• Follicular dendritic cells present an antigen – B cells
proliferate and develop into antibody-producing
plasma cells or develop into memory B cells.
• Memory B cells persist after an initial immune
response and ‘remember’ having encountered a
specific antigen.
• B cells that don’t develop properly undergo apoptosis
and are destroyed by macrophages.

30. • Inner cortex:
• Doesn’t contain lymphatic nodules.
• Consists mainly of T cells and dendritic cells that enter
a lymphnode from other tissues.
• Dendritic cells present antigens to T cells, causing
their proliferation.
• Newly formed T cells then migrate from the
lymphnode to areas of the body where there is
antigenic activity.
• Medulla:
• Contains B cells, antibody-producing plasma cells that
have migrated out of the cortex into the medulla, and
macrophages.

31. • Lymph flows through a node in one direction only.
• Enters through afferent lymphatic vessels, which
penetrate the convex surface of the node at several
points.
• Afferent vessels contain valves that open toward the
center of the node, directing lymph inwards.
• Within the node, lymph enters sinuses, series of
irregular channels that contain branching reticular
fibers, lymphocytes, and macrophages.
• Afferent  subcapsular sinus(imm. Beneath the
capsule)  trabecular sinuses (extend through cortex
parallel to the trabeculae)  medullary sinuses
(extend through the medulla)  ½ efferent lymphatic
vessels.

32. • Efferent vessels – convey lymph, antibodies secreted
by plasma cells, and activated T cells out of the node.
• Emerge from slight depression ‘hilum’.
• Blood vessels also enter and leave the node at the
hilum.
• Function as a type of filter.
• As lymph enters one end of a lymphnode, foreign
substances are trapped by the reticular fibers within
the sinuses of the lymphnode.
• Macrophages then destroy some foreign substances by
phagocytosis while lymphocytes destroy others by
immune responses.
• Filtered lymph then leaves the other end of the lymph
node.

34. Metastasis through lymphatic vessels:
• Metastasis – spread of a disease from one part of the
body to another, can occur via lymphatic vessels.
• All malignant tumors eventually metastasize.
• Cancer cells may travel in the blood or lymph and
establish new tumors where they lodge.
• When metastasis occurs via lymphatic vessels,
secondary tumor sites can be predicted according to
the direction of lymph flow from the primary tumor
site.
• Cancerous lymphnodes feel enlarged, firm, nontender,
and fixed to underlying structures.
• Most times, its coz of infection – soft, tender n mobile.

36. • Spleen:
• Largest single mass of lymphatic tissue in the body.
• Located in the left hypochondriac region between the
stomach and diaphragm.
• Has a hilum – through which splenic artery, splenic
vein, and efferent lymphatic vessels enter.
• Capsule - +. Extends inwards forming ‘trabeculae’.
• Parenchyma: white pulp and red pulp.
• White pulp: lymphatic tissue – consists mostly of
lymphocytes and macrophages arranged around
branches of splenic artery called ‘central arteries’.
• Red pulp: blood filled venous sinuses and cords of
splenic tissue called ‘splenic (bilroth’s) cords’.

38. • Splenic cords consists of RBC, macrophages,
lymphocytes, plasma cells and granulocytes.
• Blood flowing into the spleen through the splenic
artery enters central arteries of the white pulp.
• Within the white pulp, B cells and T cells carry out
immune functions, similar to lymphnodes;
macrophages destroy blood-borne pathogens by
phagocytosis.
• Within red pulp, spleen performs 3 functions:
• 1. removal by macrophages or ruptured, worn out, or
defective blood cells and platelets.
• 2. storage of platelets, upto 1/3rd of the body’s supply.
• 3. production of blood cells during fetal life.

39. • Ruptured spleen:
• Most often damaged in cases of abdominal trauma.
• Severe blows over the inferior left chest or superior
abdomen can fracture the protecting ribs.
• Crushing injuries  ruptured spleen  hgge and
shock.
• Prompt removal of spleen – splenectomy – needed to
prevent death due to bleeding.
• Immune functions decrease in the absence of spleen.
• Spleen’s absence also places the pt. at higher risk for
‘sepsis’ due to loss of the filtering and phagocytic
functions of the spleen.
• To reduce risk – pts. Take prophylactic antibiotics
before any invasive procedures.

40. • Lymphatic nodules:
• Masses of lymphatic tissue that arent surrounded by a
capsule.
• Scattered throughout the lamina propria of mucous
membranes lining the GI, UT and reproductive tracts
and the respiratory airways – aka ‘mucous associated
lymphatic tissue (MALT)’.
• Some occur in multiple large aggregations in specific
parts of the body.
• E.g: pharyngeal tonsils.
• Peyer’s patches – ileum of the SI.

42. • 5 tonsils – form a ring at the junction of the oral cavity
and oropharynx and at the junction of the nasal cavity
and nasopharynx.
• 1. single ‘pharyngeal tonsil’ or ‘adenoid’ – posterior
wall of the nasopharynx.
• 2. 2 ‘palatine tonsils’ – posterior region of the oral
cavity; one on either side.
• Removed during tonsillectomy.
• 3. paired ‘lingual tonsil’ – at the base of the tongue.
• WALDEYER’S RING.

44. Development of lymphatic tissues:
• Lymphatic tissues begin to develop by the end of 5th
week of embryonic life.
• Lymphatic vessels –develop from ‘lymph sacs’ – arise
from developing veins – derived from ‘mesoderm’.
• 1. first lymph sacs to appear – jugular lymph sacs –
lymphatic capillary plexuses spread to the thorax,
upper limbs, neck and head.
• 2. retroperitoneal lymph sac – spread to the
abdominal viscera and diaphragm.
• 3. cisterna chyli – gives rise to inferior portion of the
thoracic duct and the cisterna chyli of the thoracic
duct.

45. • 4. posterior lymph sacs – produce capillary plexus and
vessels of the abdominal wall, pelvic region, and lower
limbs.
• All the lymph sacs become invaded by mesenchymal
cells and are converted into groups of lymphnodes.
• Spleen develops from ‘mesenchymal cells.
• Thymus – outgrowth of the 3rd pharngeal pouch.

46. Aging:
• Most people become more susceptible to all types of
infections and malignancies.
• Response to vaccines is decreased, and they tend to
produce more autoantibodies.
• Age related atrophy of thymus or decreased
production of thymic hormoes.
• T cells become more responsive to antigens, and fewer
T cells respond to infections.
• T cells no. decreases with age – B cells are also less
responsive  decreased antibody levels.
• Increased susceptibility to infections.

47. AIDS:
• Acquired immunodeficiency syndrome.
• Progressive destruction of immune system cells by the
‘human immunodeficiency virus’  infections.
• Symptom free for many years.
• AIDS represents end stage of infection by HIV.
• HIV transmission:
• HIV is present in the blood and some body fluids, it is
most effectively transmitted by actions or practices
that involve the exchange of blood or body fluids
between people.
• Transmitted in semen or vaginal fluid during
unprotected anal, vaginal or oral intercourse.

48. • Also is transmitted by direct blood-to-blood contact –
as occurs in IV drug abusers who share needles.
• Can be transmitted from mother to baby during birth
or during breast feeding.
• Not transmitted by physical contact such as hugging
or sharing house hold items.
• Virus can be eliminated from personal care items and
medical equipment by exposing them to heat or
cleaning them with common disinfectants such as
H2O2, betadine etc.

49. • Structure:
• Inner core of RNA covered by a protein coat (capsid).
• Retrovirus since its genetic material is carried in RNA
instead of DNA.
• Surrounding capsid is an envelope of a lipid layer that
is penetrated by glycoproteins.
• Outside living host cell, virus cannot replicate.
• After infecting and entering a host cell, it uses host’s
enzymes and ribosomes to make thousands of copies
of the virus.
• New virus eventually leave and then infect other cells.
• Begins with binding of HIV glycoproteins to receptors
in the host cell’s plasma membrane  transports virus
into its cytoplasm via receptor mediated endocytosis.

51. • Once inside the host cell, HIV sheds its protein coat
and viral enzyme called ‘reverse transcriptase’ reads
the viral RNA strand and makes a DNA copy.
• Viral DNA copy then becomes integrated into the host
cell’s DNA.
• Viral DNA is duplicated along with the host cells’s
DNA during normal cell division.
• In addition, the viral DNA can cause the infected cell
to begin producing millions of copies of viral RNA and
to assemble new protein coats for each copy.
• New HIV copies bud off from the cell’s plasma
membrane and circulate in the blood to infect other
cells.

53. • Mainly damages T helper cells.
• Initially they are replaced as fast as they are destroyed.
But eventually body’s ability to replace is slowly
exhauts and the no.of helper T cells in circulation
progressively declines.
• Signs, symptoms and diagnosis:
• Initial – experience brief flu-like illness.
• Fever, fatigue, rash, headache, joint pains, sore throat,
and swollen lymphnodes, night sweats.
• 3-4 weeks after HIV infection – plasma cells begin
secreting antibodies against HIV.
• Detectable in blood plasma and is basis for some of the
screening tests for HIV.

54. • When people are tested: HIV positive – means they
have antibodies to HIV antigen in their bloodstream.
• Progression to AIDS:
• After a period of 2-10 years – HIV destroys enough
helper T cells  begin to experience
immunodeficiency.
• Have enlarged lymphnodes, and experience persistent
fatigue, involuntary weight loss, night sweats, skin
rashes, diarrhea, and various lesions of mouth and
gums.
• Infection to neurons  affects memory and visual
disturbance.

55. • As the immune system slowly collapses, person
becomes susceptible to opportunistic infections.
• AIDS is diagnosed when the helper T cell count drops
below 200 cells per microliter of blood or when
opportunistic infections arise, whichever occurs first.
• Opportunistic infections usually are the cause of
death.
• Treatment of HIV:
• Cannot be cured.
• Drugs that extend life:
• 1. reverse transcriptase inhibitors: interfere with the
action of the reverse transcriptase enzyme.
• Zidovudine, didanosine and stavudine.

56. • 2. protease inhibitors:
• Interfere with the action of protease, a viral enzyme
that cuts proteins into pieces to assemble the protein
coat of newly produced HIV particles.
• Nelfinavir, saquinavir, ritonavir, and indinavir.
• HAART therapy: combination of 2 differently acting
reverse transcriptase inhibitors and one protease
inhibitor.
• Drastic reduction in viral load and an increase in the
no.of helper T cells.
• Delays progression of HIV infection to AIDS.
• Remission or disappearance of opportunistic
infections.

57. • Blood test may be negative – but the virus still
lurks in the lymphatic tissues.
• Infected person can still transmit the virus to
another person.

58. Allergic reactions:
• A person who is overly reactive to a substance that is
tolerated by most other people is said to be ‘allergic’ or
‘hypersensitive’.
• Antigens that induce an allergic reaction are called
‘allergens’.
• Common allergens: food, antibiotics, vaccines,
venoms, cosmetics, chemicals in plants, pollen, dust,
molds, dyes etc.,
• 4 basic types of hypersensitivity reactions:
• 1. type I (anaphylactic reactions):
• Most common and occur within a few minutes after a
person sensitized to an allergen is reexposed to it.

59. • In response to the first exposure to certain allergen,
some people produce IgE antibodies that bind to the
surface of mast cells and basophils.
• Next time same allergen enters the body, it attaches to
the IgE antibodies already present.
• In response, the mast cells and basophils release
histamine, prostaglandins, leukotrienes, and kinins.
• These mediators cause vasodilation, increased blood
capillary permeability, increased mucus secretion,
increased smooth muscle contraction in the airways of
the lungs.
• Person experiences difficulty in breathing, a runny
nose.

62. • Anaphylactic shock: occur in a susceptible individual
who has just received a triggering dose – wheezing
and shortness of breath as airways constrict are
usually accompanied by shock due to vasodilation and
fluid loss from blood.
• This life threatening emergency is usually treated by
injecting epinephrine to dilate the airways and
strengthen the heartbeat.
• Type II (cytotoxic) reactions:
• Caused by antibodies directed against antigens on a
person’s blood cells or tissue cells.
• Reaction of antibodies and antigens usually leads to
activation of complement.

63. • Eg: incompatible blood transfusion.
• Type III (immune complex) reactions:
• Involve antigens, antibodies, and complement.
• When certain ratios of antigen to antibody react, the
immune complexes are small enough to escape
phagocytosis, but they become trapped in the
basement membrane under the endothelium of blood
vessels, where they activate complement and cause
inflammation.
• E.g: GN and RA.
• Type IV (cell mediated) reactions or delayed
hypersensitivity reactions:
• Appear 12-72 hrs after exposure to an allergen.

65. • Occur when allergens are taken up by antigen-
presenting cells that migrate to lymphnodes and
present the allergen to T cells, which then proliferate.
• Some of the new T cells return to the site of allergen
entry into the body, where they produce gamma
interferon, which activates the macrophages, and
tumor necrosis factor, which stimulates an
inflammatory response.
• Intracellular bacteria such as mycobacterium
tuberculosis trigger this type of cell mediated immune
response.
• Skin test for TB also is a delayed hypersensitivity
reaction.

66. • Abscesses and ulcers:
• If pus cannot drain out of an inflamed region, the
result is an ‘abscess’ – an excessive accumulation of
pus in a confined space.
• Common examples: pimples and boils.
• When superficial inflamed tissue sloughs off the
surface of an organ or tissue, the resulting open sore is
called an ‘ulcer’.
• People with poor circulation are susceptible to ulcers
in their legs – stasis ulcers.
• PUS – collection of dead cells (phagocytes and tissue)
and fluid.

68. • Graft rejection:
• Organ transplantation involves the replacement of an
injured or diseased organ, such as the heart, liver,
kidney, lungs, or pancreas, with organ donated by
another individual.
• Immune system recognizes the proteins in the
transplanted organ as foreign and mounts both cell
mediated and antibody mediated immune response.
• Success of an organ or tissue transplant depends on
histocompatibility.
• More MHC antigens, greater the histocompatibility,
and thus the greater the probability that the tranplant
will not be rejected.

69. • Histocompatibility testing:
• Tissue typing – done before any organ transplant.
• Closer the match between the major histocompatibility
complex proteins of the donor and recipient, the
weaker is the graft rejection response.
• Cytokine therapy:
• Use of cytokines to treat medical conditions.
• Interferons – first cytokines shown to have effects
against some human cancers.
• Alpha interferon – approved to treat kaposi sarcoma
(occurs in HIV infected persons)

70. • Also used for treating genital herpes, hepatitis B and
C, hairy cell leukemia.
• Beta interferons – slows progression of multiple
sclerosis, reduces frequency and severity of MS
attacks.
• Most widely used interferons in cancer: interleukin-2.
• Adv. Effects: high fever, severe weakness, difficulty
breathing due to pul. Edema, and hypotension leading
to shock.

71. • Monoclonal antibodies:
• Antibodies produced against a given antigen by
plasma cells can be harvested from an individual’s
blood.
• An antigen typically has many epitopes (part of
antigen that is recognized by immune system), several
different clones of plasma cells produce different
antibodies against the antigen.
• If a single plasma cell could be isolated and induced to
proliferate into a clone of identical plasma cells, then a
large quantity of identical antibodies could be
produced.
• Lymphocytes and plasma cells are difficult to grow in
culture.

72. • So, B cells are fused with tumor cells – HYBRIDOMA
– grows easily and proliferate endlessely.
• Long term sources of large quantities of pure, identical
antibodies – MONOCLONAL ANTIBODIES coz they
come from a single clone of identical cells.
• Used in preparing vaccines to counteract the rejection
associated with transplants, to treat autoimmune
diseases, and perhaps to treat AIDS.

74. • Cancer immunology:
• The study of ways to use immune responses for
detecting, monitoring, and treating cancer.
• Ex: colon releases CEA – carcinoembryonic antigen
into the blood and prostate cancer cells release
prostate specific antigen (PSA).
• Detecting these antigens in blood doesn’t provide
definitive diagnosis of cancer, because both antigens
are also released in certain noncancerous conditions.
• High levels of cancer related antigens in the blood
often do indicate the presence of a malignant tumor.
• One method – inactive lymphocytes are removed in a
blood sample and cultured with IL-2.

75. • Resulting ‘lymphokine-activated killer’ cells (LAK) are
then transfused back into the patient’s blood.
• Another method: lymphocytes procured from a small
biopsy sample of a tumor are cultured with IL-2.
• After their proliferation in culture, such tumor-
infiltrating lymphocytes (TILs) are reinjected.

76. • Adenitis:
• Enlarged, tender, and inflamed lymphnodes resulting
from an infection.
• Allograft:
• A transplant between genetically distinct individuals
of the same species.
• Skin transplants from other people and blood
transfusions are allografts.
• Autografts:
• Transplant in which one’s own tissue is grafted to
another part of the body.

77. • Chronic fatigue syndrome:
• Disorder, usually occurring in young adults and
primarily in females, characterized by:
• 1. extreme fatigue that impairs normal activities for
atleast 6 months and
• 2. the absence of other known diseases (cancer,
infections, drug abuse, toxicity or psychiatric
disorders) that might produce similar symptoms.
• Congenital thymic hypoplasia: aka Digeorge anomaly.
• Congenital immunodeficiency characterized by
abnormal facies; congenital heart defects;
hypoparathyroidism with hypocalcemia; cognitive,
behavioral, and psychiatric problems; and increased
susceptibility to infections.

78. • Abnormal facies: characterized by hypertelorism,
micrognathia, short philtrum with fish-mouth
appearance, antimongoloid slant, and telecanthus with
short palpebral fissures.
• Congenital heart diseases:
• included tetralogy of Fallot, VSD, ASD, pulmonary
atresia and TGA etc.,
• Immunologic:
• Thymic hypoplasia or aplasia leading to defective T-
cell function is the hallmark.
• Increased susceptibility to infections +.