What is the importance of the 427 suitcases discovered at Willard Asylum in the novel, What She Left Behind?

There are precisely 427 suitcases left at Willard by the former, mostly deceased patients. The number is quite large and specific in order to represent the 50,000 patients who wound their way through the asylum over its historical existence. While only 427 suitcases remain, each suitcase is filled with personal effects from former owners who never had a chance to reclaim the suitcases, or their private lives, once they went inside Willard. So the impact of each lost soul from the asylum becomes large in impact (especially on the volunteers who unlock them and catalog the contents) because of the unusual intimacy of their left-behind personal effects.