Veggienft, I am puzzled by your post.

RA is an autoimmune disease with a strong inflammatory component - that is why anti-inflammatory agents are often effective in management of it.

Lectins are proteins which bind oligosaccharides with high specificity - each lectin has a different specificity. Exogenous lectins (mainly found in plant foods) can have local effects in the GI tract if the plant food has not been adequately cooked. If the food has been cooked exogenous lectins will not have local effects and (in just the same way as any other protein) will be broken down into their amino acids by digestive enzymes. I don't know of any evidence that intact exogenous lectins can pass across the gut mucosal boundary and enter the blood stream, where they (potentially) might interact with immune system proteins - do you have evidence which suggests that this is the case?

There are also endogenous lectins, naturally made in the human body. Mannan-binding lectin is an example - it, and others, play important roles in the innate immune system.

"The old medical saw which says autoimmune diseases happen when the immune system attacks "self" tissue by mistaking it for "not-self" antigens is simply false."

This statement will come as a considerable surprise to people (like me) whose professional knowledge includes immunology.

Would you like to justify it, ideally with referenced data?