Immunoglobulin levels in serum during 24 months follow-up, for patients included in the KTS-2-2010 trial with rituximab maintenance therapy, and shown as grams per liter (g/L). In panels A, B and C are shown serum levels for IgG, IgA, and IgM, respectively, with corresponding values at baseline and at 24-months, for each of 23 patients included in KTS-2-2010. P-values from paired t-tests. Panel D: Baseline levels of serum IgG (g/L), shown for patients with subsequent clinical response to B-cell depletion therapy during follow-up, or patients with no response. P-value from unpaired Mann-Whitney U test. The dotted lines indicate normal reference values as established by Haukeland University Hospital.