The enriched V_H replacement products identified in different strains of autoim<i>m</i>une prone mice or IgH genes encoding aut<i>o</i>antibodies have been positively selected during autoimmune responses.

<p>(A) Analysis of the frequencies of positively charged versus negatively charged amino acids encoded by the 3′ end V_H genes and the identified V_H replacement footprints from different strains of mice or IgH genes encoding autoantibodies. Statistical significance was determined using a two-tailed Chi square test with Yate’s correction. <i>p</i><0.05 (*) is considered significant. (B) Comparison of the amino acids encoded by the identified V_H replacement footprints in <i>MRL/lpr</i> mice. <i>n</i>, numbers of amino acids encoded by the identified V_H replacement footprints. (C) Mutation status analysis of identified V_H replacement products and non-V_H replacement products from different subgroups of IgH genes.