Some people's cells don't have receptors on their cells that HIV can link on to. This means their body thinks that HIV proteins are its own proteins, and it doesn't react to them. I've seen beautiful pictures of HIV with knobs on that Hans Gelderblom of the Koch Institute in Berlin took. Most viral copies are defective. It's like seeds - plants produce many more seeds than the ones which grow.
Oxidative stress is a real phenomenon.
Immune and other cells which are highly stimulated produce increased amounts of free oxygen atoms and other oxidising compounds. In small amounts NO is a neurotransmitter, enabling the nervous system to function. In larger amounts it damages brain cells and causes dementia. In the US at least, I think it's pretty dead. They can disrupt but they're no real influence any more.