Bartonellosis bacteria persist in which cells to evade the immune system?

• A. Hepatocytes
• B. Adipose tissue
• C. Neurons
• D. Red blood cells and endothelial cells lining blood vessels

Answer: (D)

Bartonella persists predominantly inside red blood cells and in endothelial cells lining blood vessels. This intracellular niche helps the bacteria hide from the immune system and maintain long-lasting bacteremia.

Red blood cells are enucleated and lack MHC molecules, so they don’t present antigens or recruit phagocytes effectively. Bacteria inside RBCs are shielded from antibodies and many immune defenses. Endothelial cells, while capable of presenting some immune signals, can harbor the bacteria as well, enabling ongoing infection and contributing to vascular lesions seen with Bacillary angiomatosis.

Hepatocytes, adipose tissue, and neurons are not the primary reservoirs for Bartonella in the classic sense, so they’re less associated with the immune evasion that persistence in red blood cells and endothelial cells provides.