Hello all, especially @jonyb, hope your wife is hanging in there. I got diagnosed about 10 years ago with both IgM (WM) and IgG kappa LPL. (and elevated kappa FLC) No symptoms to speak of and never needed treatment for them. Two years ago a third mutation, also IgG kappa, and more kappa FLC, showed up diagnosed in the end as CLL. Still no symptoms but started zanu treatment 4 months ago due to ever increasing new IgG/FLC and it's working well. I've been tracking the original LPLs at the IWMF forum https://groups.io/g/iwmfconnect/and suggest that you do likewise as the best source of relevant Ig LPL. So, here is what I have gleaned and my opinions. The rarity of non-IgM is a problem since only 75 cases per year are diagnosed in the USA compared to 1500 per year of WM.

First, solo Rituximab is not commonly prescribed to treat these conditions. Treatment options deserve their own posting, except to say that since both Ig types are similar B cell lymphomas, WM treatments are the first choice. And only treat due to symptoms that might include anemia. What symptoms led to your treatment?Bone marrow per cent is not the best way to keep track. Percentages don't track well with blood tests or symptoms.

The best way to track the LPL is testing total IgG and FLC, but supplement IgG number with SPEP and immunofixation which will give an M spike number representing the level of monoclonal IgG which is the culprit. For years my total IgG fluctuated between 1400 and 1900, upper normal range around 1500. But M spike ran around 1100-1300 indicating that most of it was monoclonal IgG kappa consistent with FLC kappa. IgM numbers ran 600-1200. BTW, in general kappa anything seems to be better than lambda.

Every WM expert I consulted formally or at educational forums were candid about the rarity problems of IgG LPL and scarcity of data but in the end all had success treating it like WM with anemia due to cancer cells in the marrow out competing normal cells for space. None had significant experience with elevated IgG causing significant problems. Jonyb's wife has unique, complicated issues compared to my uneventful journey. Never got into researching FLC much since they were only slightly elevated during my LPL days but really took off when the CLL IgG kappa clone showed up.

Enough for now.