Abstract: Method of treating or ameliorating symptoms of T-cell mediated disease wherein a composition comprising a therapeutically effective amount of a polyunsaturated fatty acid and a pharmaceutically acceptable carrier is administered to the patient. The polyunsaturated fatty acid contains 18-25 carbon atoms, 1-6 double bonds and has 1 or 2 substitutions selected from &bgr; oxa, &ggr; oxa, &bgr; thia and &ggr; thia, based on the fatty acid acyl carbon atom, or the polyunsaturated fatty acid contains 16-26 carbon atoms, 3-double bonds and is covalently coupled at the carboxylic acid group to an amino acid.

Abstract: The present invention provides a method of stimulating macrophage, neutrophil and/or monocyte function in a subject. The method involves the administration of an effective amount of a free fatty acid having a 18-24 carbon chain length with 2-6 double bonds. Preferred polyunsaturated fatty acids are 20:4(n-6), 20:3(n-6), 20:5(n-3), 22:6(n-3), 19:2(n-6), 18:3.gamma.(n-6), 23:4(n-6) and 24:4(n-6).

Abstract: Methods for treating melanoma or a disease caused by bacteria, fungi, Chlamydia, Mycoplasma, Rickettsia or Plasmodium falciparum are disclosed wherein a fatty acid having a carbon length up to 30 carbon atoms and two or more double and/or triple bonds, derivatives or oxidation products thereof is administered.