Interesting reading about the "helper class" as an anti-pattern.  Basically this is saying that functions/static methods are an anti-pattern in Java and C#.

* http://blogs.msdn.com/b/nickmalik/archive/2005/09/06/461404.aspx
* http://blogs.msdn.com/b/nickmalik/archive/2005/09/07/462054.aspx

The recommendation is to replace a helper class with static methods, with a helper object which you get by dependency injection.  Or in an even more extreme case replace the function with a new object that performs the operation.