Yes non-neutralizing antibodies were observe in some patients in different diseases , but majority time they are neutralizing..

" February 13 , Chinese senior health officer called on people who had recovered from the new coronavirus to donate blood plazma , because it might contain valuable protein that could be use to treat sick patients " according to New York Times..

Some critically ill patients now in China , were helped by plazma transfusion , their inflammation reduced within 12 to 24 hrs.