Topical immunotherapy for pseudomonas keratitis in rabbits: use of antilipopolysaccharide plasma.

Pseudomonas keratitis is currently treated with antibiotics with a variable success rate. Part of the morbidity caused by pseudomonas is due to the action of lipopolysaccharide (LPS) present on the surface membrane of the bacteria. Specific IgG present in equine anti-LPS hyper-immune plasma has been found to bind to the LPS from a range of Gram-negative bacteria, including pseudomonas, and by activating complement it destroys these bacteria. Anti-LPS plasma was therefore used as a therapeutic agent in experimentally induced pseudomonas keratitis in rabbits. Thirteen out of 15 (86.7%) anti-LPS treated eyes improved, whereas four out of 17 (23.5%) saline treated control eyes improved (chi 2 = 12.76 p less than 0.001) No ill effects were noted when anti-LPS was administered to healthy rabbit or baboon eyes. Anti-LPS thus was protective in pseudomonas keratitis, and clinical trials appear to be warranted.