Why do red blood cells lack a nucleus? Alternate theory discussed… 


Nearly all cells in the human body have a nucleus. In circulating red blood cells, the nucleus is conspicuously absent. The nucleus houses cellular DNA and enables cells to replicate and divide. Red blood cells develop as nucleated cells in the bone marrow, but prior to leaving the bone marrow for the peripheral bloodstream, the nucleus is removed. Why does this occur?


Present theories include:



I’m a proponent of a fourth theory.  Given nearly all red blood cell adaptations have occurred in response to infectious disease, the question then arises, what benefit to the immune system is a red blood cell without a nucleus? The answer has to do with viral replication. Viruses cannot replicate without host DNA or RNA from the nucleus. Viruses that unwittingly enter red blood cells through entry proteins in the cell wall enter a prison. Once inside, non-replicating viruses are denatured by time, oxidative stress, and quaternary ammonium compounds. This explains why red blood cells also jettison their mitochondria, as some viruses infect this organelle. Rather than the current notion viruses infect red blood cells, red blood cells quarantine viruses and other pathogens. In fact, there is ongoing research to develop artificially engineered red blood cells to act as viral traps.(1) Will this be our next generation of antibiotics? When viruses “infect” red blood cells, it may be by design.


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