Sandoz, which manufactures cyclosporin A, the drug used to help organ transplants "take", has applied to license the drug to treat recalcitrant cases of psoriasis.

According to trials, the drug showed that 92 per cent of psoriasis patients have marked and sustained improvement on cyclosporin.

Recently at the Second Congress on Immunotherapy in Auto immune Diseases in Paris, the drug, tradenamed Sandimmun, was also applauded to treat rheumatoid arthritis, nephrotic syndrome, Crohn's disease, lupus and even allergic asthma.

Before you jump on the immunosuppressive drug bandwagon, it's wise to heed the cautionary note sounded by Richard Horton in The Lancet (June 1, 1991).

"Cyclosporin . . . might be an effective therapeutic agent for rheumatoid arthritis, as indicated in short term open studies," he said, although in one double blind study of 70 patients in Italy, it proved no more effective than azathioprine and on stopping treatment the relapse rate was 80 per cent a year later. "Nephrotoxicity (liver poisoning) and hypertension, which occurred in up to 30 per cent of patients, continues to be the most serious side effect, although these changes were usually reversible on stopping treatment."

Similar lack of prolonged success was found with nephrotic syndrome and Crohn's disease. "On the basis of data presented in Paris, it may be difficult to justify prescription of cyclosporin for these extended indications outside controlled clinical trials," he said.

Furthermore, a group of French doctors wrote in the New England Journal of Medicine (June 13, l991) that cyclosporin therapy results in frequent neurologic complications. Following a liver transplant, a child being given cyclosporin developed an "unexplained" coma and convulsions on two occasions.