A compound of formula (I) R-L-CO-X (I) (wherein R is a C10-24 unsaturatedhydrocarbon group optionally interruptedby one or more heteroatoms or groups of heteroatoms selected from S, O, N, SO,SO2, said hydrocarbon group comprisingat least 4 non-conjugated double bonds； L is a linking group forming a bridgeof 1 to 5 atoms between the R group and thecarbonyl CO； and X is an electron withdrawing group) or a salt thereof for usein the treatment of glomerulonephritis.
