How to no follow the paginated comments

There are two special filters for that:

add_filter( 'previous_comments_link_attributes', 'wpse_77217_comment_nofollow' );
add_filter( 'next_comments_link_attributes', 'wpse_77217_comment_nofollow' );

function wpse_77217_comment_nofollow()
{
    return ' rel="nofollow"';
}