Following antibody treatment, the patient experienced a good clinical response lasting over 1 year. Before therapy, the overall VH gene usage of the RA patient was largely similar to the distributions expected from published data for normal individuals, except for certain genes (4-34, 1-69, 3-07), which have already been reported with a biased distribution in autoimmune disorders. In addition, several clonally related sequences were found in the VH5 family.
B-cell regeneration occurred 7 months after anti-CD20 antibody therapy. Significant changes in the distribution of different genes could be observed: 4-34 and 1-69 decreased to a proportion that would be expected in healthy individuals. Clonally related sequences were not found anymore. A greater overall variety of the VH gene segments used was observed, in particular in the larger families like VH3 and VH4. Interestingly, somatic hypermutation was significantly enhanced at the time point of B-cell regeneration.
Seventeen months after therapy, the general distribution of the VH genes was comparable with that observed before treatment, except for some genes (4-34 remained at the level found after therapy). No clonally related sequences were found. Somatic hypermutation was significantly reduced to the frequency determined before therapy.