I never had a specific interest in institutional interaction, but
Anna Lindström's interest in interactions between elderly and their home help carers somehow rubbed of on me. A substantial amount of the research I have done on interaction has been based on a corpus of home help interactions that I collected while working with Anna.
I find the home help visits particularly interesting because they have a hybrid-like nature and are not as such purely "institutional": they take place in the old person's home, so she is sometimes acting as a host, sometimes as a customer/client, just as the home help is sometimes acting like a visitor, sometimes as service provider and caregiver.
I have also worked on a corpus of audiology consultations, mostly as a collaboration with Ben Matthews - we have looked, for instance, at the way in which hearing problems are described and how treatment is negotiated.
Heinemann, T. & Matthews, B. 2015. Concessions in audiology.