Looking on the internet deeply has found these results:

following up with is the most popular phrase on the web.

following with 15,130,000 results on the web	following up with 110,200,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	I thought I was following up with Felix this morning. I'm following up with Mr Wong's case. I got a message from Divya ripping into me for not following up with a patient. I look forward to following up with you. Wick, I'm following up with everybody who had access to Nirvana. Say the police are following up with some solid leads. We're following up with Mr. Ross and Ms. Thorne... I'm just following up with this patient between surgeries.

following with

15,130,000 results on the web

following up with

110,200,000 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

I thought I was following up with Felix this morning.
I'm following up with Mr Wong's case.
I got a message from Divya ripping into me for not following up with a patient.
I look forward to following up with you.
Wick, I'm following up with everybody who had access to Nirvana.
Say the police are following up with some solid leads.
We're following up with Mr. Ross and Ms. Thorne...
I'm just following up with this patient between surgeries.