REUTERS : http://www.reuters.com/article/bankingfinancial-SP/idUSN2139741320070822 (Adds comment from Grant Thornton) By Paritosh Bansal NEW YORK, Aug 21 (Reuters) - Trusts representing Refco Inc creditors on Tuesday sued the now-defunct futures and commodities broker's legal, accounting and financial advisers for more than $2 billion over Refco's collapse. The Refco Litigation Trusts said they sued Banc of America Securities (BAC.N: Quote, Profile, Research), Credit Suisse Securities (USA) (CSGN.VX: Quote, Profile, Research) and Deutsche Bank Securities (DBKGn.DE: Quote, Profile, Research) in the circuit court of Cook County, Illinois. The 155-page complaint also names accounting firms Ernst & Young [ERNY.UL], PricewaterhouseCoopers [PWC.UL] and Grant Thornton; law firm Mayer, Brown, Rowe & Maw LLP; certain loan participants, including Ingram Micro Inc (IM.N: Quote, Profile, Research); and Refco executives, including former Chief Executive Philip Bennett.[...] The lawsuit, the latest in a series of cases stemming from the collapse, alleges that Refco's fraudulent scheme "only could have worked with the active assistance of Refco's cadre of outside auditors, professionals and advisers."