Yes, I was fortunate to have low total IgG as well as low subclasses 1 and 3. I also needed to do a Pneumovax challenge to meet my insurance companies guidelines. There were several ways of qualifying. Due to my diagnosis, which says I'll need it forever, they approved an initial year of treatment, every 3 weeks.
I started antivirals in June, IVIG in August, and IV azithromycin/doxycycline/rifampin in October. It's been a steady trend of improvement over time, though the IVIG gives me symptoms for 4-5 days each time. After that, I do ok until a couple days before the next IVIG.
My brain fog cleared, I don't feel as sick and fatigued, my lymph nodes aren't as swollen all the time, I'm not taking naps hardly at all now, when I was taking 2-3 a day, my POTS is improving, I can focus better and tolerate more exercise, and I almost feel normal at times, though I still have a long way to go to have a normal life.
But feeling normal even in little bits is amazing, given how I felt for 3 years.
So, for me, its been worth it, even though there have been significant side effects at times. And the foundational nutrition and endocrine support had been helpful, too.