Pathophysiology of HIV/AIDS

·         The virus through its envelope proteins attaches to the CD4 receptor and co-receptors found on the surface of T lymphocytes and macrophage to gain entry to the host cells.

·         Following entry of the HIV into a susceptible host cell using the enzyme reverse transcriptase, the viral genome copies itself from RNA to DNA genetic material.
·         The viral DNA copy enters the nucleus of the host cell and becomes intimately incorporated into the host cell’s own DNA using the enzyme integrase.

·         The virus thus becomes a permanent part of an infected person’s nuclear proteins.
·         There follows a latent period during which the provirus in the infected nucleus waits for an external stimulus to start reproducing.

·         CD4+ T lymphocytes, when stimulated by new HIV, other infections and infestations which would normally result in the CD4+ T lymphocyte reproducing itself, now responds to these stimuli by manufacturing HIV.

As more and more viruses are produced and leave the host cell, the cell membrane 

·         weakens leading eventually to the death of the infected CD4+ T lymphocytes

 ·         The multiple steps in replication of HIV provide multiple opportunities for intervention.
·         Therapeutic regimens may be directed at one or several of the following stages essential for viral replication:
o   Attachment of HIV to the host cell;
o   Reverse transcription of viral RNA to DNA;
o   Integration of the pro-viral DNA into the host cells’ DNA; or
o Expression of the viral gene after it has been integrated into host cell DNA, including the transcription of more viral RNA and the translation of viral proteins.


Doctor Pointing X-Ray Result Beside Man Wearing Black Suit
References
Wells BG, DiPiro J, Schwinghammer T (2013), Pharmacotherapy Handbook (6th Ed). New York, NY: McGraw-Hill.

DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey ML, (2008): Pharmacotherapy: A Pathophysiologic Approach (7th ed): New York, NY: McGraw-Hill.

Katz M D., Matthias KR., Chisholm-Burns M A., Pharmacotherapy(2011) Principles & Practice Study Guide: A Case-Based Care Plan Approach: New York, NY: McGraw-Hill.

Schwinghammer TL, Koehler JM (2009) Pharmacotherapy Casebook: A Patient-Focused Approach (7th ed): New York, NY: McGraw-Hill.