Figure 1. Neutrophils migrate toward a target from which C5a is being released. Neutrophils in the venule stick to the wall of the vessel in response to C5a, then move into the tissues by migrating between the endothelial cells that line the vessel and travel up the C5a gradient toward the target. Reproduced with permission from Babior BM (1988). Function of neutrophils and mononuclear phagocytes. In: Wyngaarden JB, Smith LH and Bennett JC (eds) Cecil Textbook of Medicine (19th edn), pp. 899–904. Philadelphia: WB Saunders.

Figure 2. The mechanism of an inflammatory attack in familial Mediterranean fever (FMF). Pyrin/marenostrin, the product of the gene for FMF, is postulated to activate the biosynthesis of a protein that inactivates C5a and other polypeptides with similar properties. Failure to produce the inactivator leads to attacks of FMF. PMN denotes neutrophil. Reproduced with permission from Babior BM and Matzner Y (1997) The familial Mediterranean fever gene – cloned at last. New England Journal of Medicine 337(21): 1548–1549. ©Copyright 1997 Massachusetts Medical Society. All rights reserved.

Figure 3. The mode of inheritance of familial Mediterranean fever (FMF). In the genetic chart shown here, the parents are FMF carriers, each with one normal chromosome 16 (white) and one chromosome 16 that carries the defective FMF gene (blue). Since the offspring inherit one chromosome 16 from each parent, and the chromosome they inherit is selected at random, the chances are 1 in 4 that they will receive 2 normal chromosomes, 1 in 2 that they will become carriers by receiving one normal and one defective chromosome, and 1 in 4 that they will receive 2 defective chromosomes and therefore develop FMF. The genders of the offspring were assigned arbitrarily, with circles indicating males, squares females. The incidence of FMF is unrelated to the gender of the offspring.