Affected by a tinge of nostalgia in middle of poem (5)
I believe the answer is:
tween
'nostalgia in middle of poem' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'affected by a tinge' is the wordplay.
'affected' becomes 'twee' (I've seen this before).
'by' says to put letters next to each other.
'a tinge' becomes 'n' (I can't justify this - if you can you should give a lot more credence to this answer).
'twee'+'n'='TWEEN'
'of' acts as a link.
Can you help me to learn more?
(Another definition for tween that I've seen is " In middle of abridged".)