Mortgage-related litigation hit a three-year high during this year’s first quarter according to a recent report. The increase was fueled partly by a jump in cases involving companies suing each other, as opposed to cases between lenders and homeowners.

There were 155 active state and federal cases during the first quarter of 2010, according to the Mortgage Litigation Index, a study issued jointly by Washington, D.C.-based Patton Boggs and MortgageDaily.com on Wednesday. That compares with 134 in 2009′s fourth quarter and 81 cases during last year’s first quarter.