Can antibiotics alter CD8 (Cluster of Differentiation 8) cell absolute count results?

From the Guidelines

Antibiotics can alter the efficacy of immunotherapy by disrupting the gut microbiome, which in turn can affect CD8 cell counts, and it is recommended to avoid antibiotic use before immunotherapy treatment whenever possible. When considering the impact of antibiotics on CD8 cell counts, it's essential to understand the complex relationship between the gut microbiome and the immune system. Studies have shown that antibiotics can impair the balance between the gut microbiome and the host, leading to poor clinical outcomes during immunotherapy 1. The use of antibiotics has been associated with decreased progression-free survival (PFS) and overall survival (OS) in patients with non-small cell lung cancer (NSCLC) undergoing PD-1/PD-L1 blockade 1. Some key points to consider include:

• The gut microbiome plays a crucial role in maintaining intestinal homeostasis and immune function 1
• Antibiotics can disrupt the balance of the gut microbiome, leading to changes in immune cell populations, including CD8 T cells 1
• The effect of antibiotics on CD8 cell counts is typically indirect, and the primary concern is the impact of antibiotics on the efficacy of immunotherapy 1
• Certain bacteria, such as Akkermansia muciniphila, have been shown to correlate with clinical responses to immunotherapy, and oral administration of these bacteria may improve treatment outcomes 1.

From the Research

CD8 Cells Absolute and Antibiotics

• The use of broad-spectrum antibiotics can alter the gut microbiome, which in turn can affect CD8+ T cell counts and immune function 2, 3, 4.
• Studies have shown that broad-spectrum antibiotics can impair T cell immune function, including CD8+ T cells, and promote lung cancer metastasis 2.
• The administration of broad-spectrum antibiotics can lead to a significant dysbiosis of the composition and diversity of gut microbiota, which can affect CD8+ T cell counts and immune function 2, 3, 5.
• Fecal microbiota transplantation (FMT) can restore the intestinal microbiota composition and improve immune function, including CD8+ T cell counts, after broad-spectrum antibiotic treatment 3.
• The impact of antibiotics on CD8+ T cell counts can vary depending on the type of antibiotic, dosage, and duration of treatment, as well as individual factors such as health status and diet 5.

Clinical Significance of CD8+ T Cell Counts

• CD8+ T cell counts can be elevated during HIV infection and may not normalize despite long-term combination antiretroviral therapy (cART) 6.
• Low CD8+ T cell counts have been associated with increased AIDS-related mortality, while marked elevations in CD8+ T cell counts after long-term cART have been associated with increased non-AIDS-related mortality 6.
• The clinical significance of CD8+ T cell counts can vary depending on the individual's health status, disease progression, and treatment regimen 6.

Mechanisms and Implications

• The gut-microbiota-spleen-brain axis may play a role in the impact of broad-spectrum antibiotics on CD8+ T cell counts and immune function 4.
• The use of broad-spectrum antibiotics can have profound effects on the immune system, including alterations in splenic functions, neutrophils, NK cells, macrophages, and CD8+ T cells 4.
• Further studies are needed to unravel the distinct molecular mechanisms underlying microbiota-driven changes in immune homeostasis and to provide novel therapeutic or preventive approaches in human immunopathologies 3.