CORRECTED - UPDATE 2-Bayer unit sues Abbott over Humira arthritis drug

(Corrects last paragraph to delete reference to long-range forecast for Humira sales)

* Bayer sues Abbott for patent infringement

* Seeks damages for past and future infringements (Adds Abbott comment)

BANGALORE/FRANKFURT, Dec 31 (Reuters) - Bayer Healthcare LLC, a unit of Bayer AG (BAYG.DE), is suing Abbott Laboratories (ABT.N) in a patent infringement case relating to Humira, Abbott's top-selling drug.

In a suit filed on Dec. 24 in the U.S. district court for the Eastern District of Texas, Bayer Healthcare said Abbott's drug infringes a 1997 Bayer patent "Human Anti-TNF Antibodies."

A Bayer spokeswoman confirmed on Wednesday that the company had filed a lawsuit but declined to elaborate.

An Abbott spokesman said Humira does not infringe Bayer's patent and Abbott believes that Bayer's patent is invalid.

"We will vigorously defend against this lawsuit," he said.

Bayer Healthcare asked the court to determine that Abbott infringed the patent and to award damages for past and future infringements as well attorney fees, the court filing showed.

Bayer chose to file in Texas because Abbott and subsidiaries Abbott Bioresearch Center Inc. and Abbott Biotechnology Ltd. sell and advertise Humira there, the documents showed.

The patent covers antibodies that fight a protein called "tumor necrosis factor" (TNF) that causes inflammation.

Humira is used to treat patients with arthritis, psoriasis, Crohn's disease and a form of arthritis called ankylosing spondylitis.

Humira competes with the drug Remicade, made by Johnson & Johnson's (JNJ.N) Centocor unit, and Wyeth's (WYE.N) Enbrel.

Abbott forecast 2008 Humira sales of more than $4.4 billion. (Reporting by Ajay Kamalakaran in Bangalore and Nicola Leske in Frankfurt; Editing by David Cowell and Steve Orlofsky)