Here is an explanation of how ketamine affects the immune system, with cited sources:
Ketamine has been shown to have several immunosuppressive effects:
- Reduces natural killer cell activity: Natural killer (NK) cells are a type of lymphocyte that plays a vital role in innate immunity against viruses and tumors. Studies have found that ketamine suppresses the cytotoxic activity of NK cells in a dose-dependent manner.[1]
- Reduces lymphocyte proliferation: Lymphocytes are white blood cells vital for adaptive immune responses. Research shows ketamine inhibits the proliferation of lymphocytes in response to mitogens (substances that stimulate cell division).[2]
- Decreases pro-inflammatory cytokines: Cytokines are small proteins secreted by immune cells that regulate inflammatory responses. Ketamine has decreased levels of specific pro-inflammatory cytokines like IL-6, IL-1β, and TNF-α.[3]
- Induces apoptosis in lymphocytes: Apoptosis is programmed cell death. Some studies indicate ketamine may trigger apoptosis in lymphocytes through mitochondrial dysfunction.[4]
The immunosuppressive effects appear most pronounced during acute intoxication stages. One study found NK cell function normalized 72 hours after ketamine administration.[1]
However, human data still lacks the long-term immunological impact of repeated ketamine use. Those with compromised immune systems should avoid recreational use due to added infection risks.[5]
Overall, current evidence suggests ketamine negatively modulates both innate and adaptive immunity through multiple mechanisms. However, these effects seem transient once the drug is eliminated from the body.
Sources:
[1] https://www.ncbi.nlm.nih.gov/pubmed/1033742
[2] https://www.ncbi.nlm.nih.gov/pubmed/6152589
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3132252/
[4] https://www.ncbi.nlm.nih.gov/pubmed/15964647
[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3713393/