HIV Pathophysiology, by Dr. Vishnu

This powerpoint, deals with HIV pathophysiology, signs and symptoms, mode of transmission and diagnostic parameters.
Purely based on clinical pharmacist perspective.

1. HIVPATHOPHYSIOLOGY :ALL
YOUNEEDTOKNOW
Dr. Vishnu R Nair, Pharm-D, RPh,
Dip. (Nutrition),
Assistant Professor (Dept. of
Pharmacy Practice),
NIMS Institute of Pharmacy.
HIV: THE SILENT KILLER

2. DEFINITIONS:
HIV (Human Immunodeficiency Virus): Virus, that
attacks cells which help in fighting infections 
reduces immunity of the affected person
Refer:https://www.hiv.gov/hiv-
basics/overview/about-hiv-and-aids/what-are-hiv-
and-aids
AIDS(AcquiredImmunodeficiencySyndrome):Late
stageofHIVinfection,thatoccurswhenthebody’s
immunesystemisbadlydamagedduetoHIV.
EPIDEMIOLOGICAL STATISTICS:
38 million people are living with HIV worldwide
African region remains worst affected (1 out of
every 25 people have HIV)
Refer:https://www.who.int/gho/hiv/en/
In India:
a.2.1 million people living with HIV
b.Third largest HIV epidemic in the world
c.Prevalence age of disease: 15-49 years

3. d.50% of HIV cases in India concentrated in
Maharashtra, Tamil Nadu & Andhra Pradesh
(mostly contracted heterosexually)
e.8% of HIV cases in India concentrated in
North-East (Manipur) [among intravenous drug
abusers].
f.Refer:https://www.avert.org/professionals/hiv-
around-world/asia-pacific/india
ETIOLOGIC AGENT:
STRUCTURE OF HIV VIRUS.

4. AIDS caused by a HIV virus
RNA virus in nature (retrovirus)
ROUTES OF TRANSMISSION:
1.Sexual transmission:
Constitutes 75% of all HIV transmissions
Other STDs (gonorrhea, chlamydial infections) 
help in HIV spreading
Transmission from male-to-male & male-to-female
more potent than female-to-male.
2.Transmission via blood & blood products:
Occurs due to:
a.Intravenous drug abusers (sharing needles,
syringes)
b.Haemophiliacpatients receive large
amounts of blood from multiple donors high
risk!
c.Blood transfusions (if blood/ blood product is
infected with HIV)

5. 3.Vertical transmission:
Also known as perinatal transmission
Occurs either via:
a.Mother to fetus transmission
b.Through breast milk.
4. Occupational transmission:
Improper disposal of biological wastes 
renders health-care professionals at high risk of
HIV!
5. Transmission by other body fluids:
Saliva, tears, sweat, urine, breast milk, CSF, etc...

6. PATHOGENESIS:
Major principle: Depletion of CD4+ T-cells
(Helper T-cells) results in profound
immunosuppression!!
Explained via the following steps:
A.Selective tropism for CD4+ molecule
receptor
B.Internalisation
C.Uncoating & viral DNA formation
D.Viral integration
E.Viral replication
F.Latent period & immune attack
G.CD4+ T-cell destruction
H.Viral dissemination
I.Impact of HIV infection on other immune
cells.

7. 1.Selective tropism for CD4+ molecule receptor:
HIV enters into body uses its gp120
envelope to bind to CD4+ T-cell
Tropism means affinity
In other words, HIV has affinity for
CD4+ T-cell binds to it.
2. Internalization:
HIV binds to CD4+ T-cell receptor surface
For entering into cell membrane HIV uses
CCR (Chemokine coreceptor)
3. Uncoating & viral DNA formation:
Once virus enters into T-cell cytoplasm
Viral RNA gets converted into DNA, using
enzyme reverse transcriptase

8. ss-DNA formed
ss-DNA forms ds-DNA using enzyme DNA
polymerase
This viral DNA undergoes frequent mutations
Thus, HIV is incurable (less response to anti-
retroviral therapy)!!
4.Viral integration:
Viral DNA in cytoplasm
Enters into nucleus of host T-cell, using
enzyme integrase
Viral particle at this stage provirus (stage of
virus, where it enters into T-cell DNA, and
becomes part of host cell DNA).

9. 5.Viral replication:
HIVprovirus
PartofhostcellDNA
HostcellDNAtranscriptsforviralRNA,usingtat
gene
Viralparticlesmultiply,withthehelpof:
RNA viral particles fill cytoplasm of CD4+ T-
cell 
acquire protein coating
Released cytokines cause spread of infection
to other body sites (e.g., CNS infection caused
by TNF-α)
IL-4, IL-5, IL-6,
IL-10
(produced by
TH2 cells)
IL-2, Interferon-
alpha (produced
by TH1 cells)

10. 6.Latent period & immune attack:
Virusmayremaininactiveinthe
infectedT-cellforlongtimeperiods
(knownaslatentperiod)
Duringlatentperiodimmune
systemgetsactivated
Antibodies,macrophages,CD4+&
CD8+T-cellstrytoeliminatevirus
invain!!!
7. CD4+ T-cell destruction:
Viral particles inside cell form buds
on the cell-wall of host cell
Through buds virus detaches from
host cell causes damage to cell
membrane death of host cell!

11. 8.Viral dissemination:
Once host cell is killed (broken up) viral
particles get released into blood spread to
all body parts & infect more CD4+ T-cells!
Causes viraemia!
HIV through circulation enters lymphoid
tissues (lymph nodes, spleen) multiplies
further
Finally, lymphoid tissues become
reservoir of virus!
9. Impact of HIV infection on other immune cells:
Effects include:
Immune system
parameter
Impact of HIV infection
Macrophages Become reservoir of HIV
Infection
Dendritic
follicular cells of
lymph node
HIV causes massive
enlargement of follicle centres
causes lymphadenopathy

12. B-cells
CD4+ T-cells activate B-
cells
Reduction in T-cells (due to
HIV infection)
causes reduction in B-
cells
NK cells Reduced Helper T-cells 
reduced cytokine production
reduces NK cells
CD8+ T-cellsIncreased.
Net effect of HIV on immune system: Profound
immunosuppression!!!
Severe immunosuppression makes victim
vulnerable to opportunistic infections &
tumours eventual death!!!

13. CLINICAL MANIFESTATIONS
OF HIV INFECTION:
ManifestationImportant catchpoints
Wasting syndrome
Involuntary loss of body weight
(>10%)
Reasons include:
1.Malnutrition
2.Hyper-metabolism
3.Malabsorption
4.Anorexia
5.Complications of multiple
opportunistic infections.
Persistent
generalized
lymphadenopathy
Enlarged lymph nodes
Damage to lymph nodes 
increased risk of opportunistic
infections
GI system
Due to opportunistic infections:
a)Chronic watery/bloody diarrhoea
b)Oral candidiasis
c)Anorexia
d)Mucosal ulcers
e)Abdominal pain
In advanced stage/AIDS:
a) GI tumors (Kaposi’s sarcoma)

14. Pulmonary system
Due to opportunistic infections:
a)Pneumonia
b)Lung abscess
c)ARDS
d)Secondary tumors.
Mucocutaneous
Erythematous rashes
Infections
Skin cancers
Hematologic
Anemia
Leukopenia
Thrombocytopenia
CNS
Encephalopathy
Dementia
Meningitis
Peripheral neuropathy
Gynaecologic
Vaginitis
Cervix carcinoma
Renal system
Nephropathy
UTI
Liver
Steatosis (fatty liver)
Hepatitis B/C co-infection
CVS
Cardiomyopathy
Pericardial effusion
Secondary tumors
Ophthalmic
lesions
Retinopathy
Retinitis
Secondary tumors

15. Musculoskeletal
System
Osteoporosis
Osteopenia
Osteomyelitis
Endocrine system
Hyperinsulinemia
Dyslipidemia
Lipodystrophy (buffalo hump)
Thyroid dysfunction.
DIAGNOSIS:
Parameter Description
Antibody tests
•ELISA
•Western blot
Direct detection of HIV
•PCR
•HIV culture
Tests to detect defects
in immunity
•CD4+ T-cell count:
reduced
•CD8+ T-cell count:
•Increased
Lymphopenia
Platelet count:
Thrombocytopenia

16. IMAGE GALLERY:

18. For further reference check on the
following links:
1.https://www.youtube.com/watch?v=5g1ijp
BI6Dk
2.https://www.youtube.com/watch?v=Qm2
wV-wCCOI
3.https://www.youtube.com/watch?v=8sipX8
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THANK YOU!!!