Depression's SSRIs, the flu, and autism...can cross-targeting explain why only 50% get autism?

Autoimmune cross-targeting hypothesis: a virus marks the inside of a cell while a larger infection marks the outside and the combination triggers autoimmune disease.  The immune system is instructed to destroy both the inside and the outside of the target.

Low serotonin causes depression

Autism increased by 50% when antidepressant drugs are taken during pregnancy: Selective serotonin reuptake inhibitors specifically
http://www.sciencedaily.com/releases/2015/12/151214130227.htm

SSRIs bound to the outside of the frontal lobe nerves at the serotonin transporters

Testosterone increases the number of serotonin transporters
http://www.sciencedaily.com/releases/2015/01/150126083816.htm

This means more bound to the outside of the frontal lobe nerves increasing the change of the immune system attacking.

If we say that autism is an autoimmune disease caused by cross-targeting.

Autism and autoimmune antibodies to fetal brain
https://spectrumnews.org/news/researchers-flag-targets-of-autism-linked-antibodies/

 The flu virus which infects inside the frontal lobe nerves and RA which causes antibodies against the outside of frontal lobe nerves had been considered as the cause of birth autism on this blog.

Flu and autism
http://www.webmd.com/brain/autism/news/20121109/flu-pregnancy-autism

Frontal lobe and the flu
http://www.sciencedirect.com/science/article/pii/S0887899499001502

RA in mothers and autism
https://spectrumnews.org/news/large-study-links-autism-to-autoimmune-disease-in-mothers/

 (the vaccine triggered form of autism occurs on different parts of the brain according to this blog)

 However the amount of RA diagnosed has been decreasing and the amount of antidepressants prescribed has been increasing.

Could it be that SSRIs replace the outer infections of RA (mycoplasmas)? Did these babies born with autism from mothers taking SSRI get exposed to the flu? Is that why it is only 50% and not all?

Note that penicillin triggers autoimmune hemolytic anemia much the same way by coating the outside of the red blood cells.