German to English Other General / Conversation / Greetings / Letters Abbreviation

The following is written at the end of a letter inviting someone to take part in a trade congress:

Mit freundlichen Grüßen

1) Wvgl. sofort

name

I haven't been able to gain any clues on what the abbreviation may stand for. My only guesses is that this phrase could be asking the addressee to reply asap or it is an instruction to the secretary to send/distribute the letter immediately. Can't quite make either of these ideas stick though. Thanks in advance for any suggestions.