1. A method of attenuating severity of exogenous protein inhibitor syndrome, comprising the step of administering an effective amount of a CD40:CD154 binding interruptor to a subject afflicted with, or at risk of, said syndrome, where said CD40:CD154 binding interruptor is an antibody specifically bound with CD154, its antigen-binding fragment or a derivative thereof and where said protein inhibitor syndrome is produced by exogenous protein which is therapeutical protein. 2. A method of suppressing adverse effects of exogenous protein inhibitor syndrome, comprising the step of administering an effective amount of a CD40:CD154 binding interruptor to a subject afflicted with, or at risk of, said syndrome, where said CD40:CD154 binding interruptor is an antibody specifically bound with CD154, its antigen-binding fragment or a derivative thereof and where said protein inhibitor syndrome is produced by exogenous protein which is therapeutical protein. 3. A method of preventing development of exogenous protein inhibitor syndrome, comprising the step of administering an effective amount of a CD40:CD154 binding interruptor to a subject afflicted with, or at risk of, said syndrome, where said CD40:CD154 binding interruptor is an antibody specifically bound with CD154, its antigen-binding fragment or a derivative thereof and where said protein inhibitor syndrome is produced by exogenous protein which is therapeutical protein. 4. A method of delaying onset of exogenous protein inhibitor syndrome, comprising the step of administering an effective amount of a CD40:CD154 binding interruptor to a subject afflicted with, or at risk of, said syndrome, where said CD40:CD154 binding interruptor is an antibody specifically bound with CD154, its antigen-binding fragment or a derivative thereof and where said protein inhibitor syndrome is produced by exogenous protein which is therapeutical protein. 5. A method of inhibiting development of exogenous protein inhibitor syndrome, comprising the step of administering an effective amount of a CD40:CD154 binding interruptor to a subject afflicted with, or at risk of, said syndrome, where said CD40:CD154 binding interruptor is an antibody specifically bound with CD154, its antigen-binding fragment or a derivative thereof and where said protein inhibitor syndrome is produced by exogenous protein which is therapeutical protein. 6. A method of reversing exogenous protein inhibitor syndrome, comprising the step of administering an effective amount of a CD40:CD154 binding interruptor to a subject afflicted with, or at risk of, said syndrome, where said CD40:CD154 binding interruptor is an antibody specifically bound with CD154, its antigen-binding fragment or a derivative thereof and where said protein inhibitor syndrome is produced by exogenous protein which is therapeutical protein. 7. A method of preserving therapeutic activity of an exogenous protein, comprising the step of administering an effective amount of a CD40:CD154 binding interruptor to a subject being treated with said exogenous protein, where said CD40:CD154 binding interruptor is an antibody specifically bound with CD154, its antigen-binding fragment or a derivative thereof and where said protein inhibitor syndrome is produced by exogenous protein which is therapeutical protein. 8. A method of restoring therapeutic activity of an exogenous protein, comprising the step of administering an effective amount of a CD40:CD154 binding interruptor to a subject being treated with said exogenous protein, to which the subject has developed an immune response, where said CD40:CD154 binding interruptor is an antibody specifically bound with CD154, its antigen-binding fragment or a derivative thereof and where said protein inhibitor syndrome is produced by exogenous protein which is therapeutical protein. 9. A method according to claim 8, wherein said antibody is a monoclonal antibody. 10. A method according to claim 9, wherein the monoclonal antibody has the antigen specific binding characteristics of the 5c8 antibody produced by ATCC Accession No. HB 10916. 11. A method according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the exogenous protein is administered to replace an endogenous, but defective protein. 12. A method according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the exogenous protein has substantially the same as primary structure as a corresponding, endogenous protein, and is produced from an isolated host cell harboring expressible, recombinant nucleic acid encoding said exogenous protein. 13. A method according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the exogenous protein is of bacterial origin. 14. A method according to claim 11, wherein the exogenous protein is a clotting factor. 15. A method according to claim 14, wherein the clotting factor is Factor Vffi or Factor Df. 16. A method according to claim 12, wherein the exogenous protein is a growth hormone, wound healing factor, growth factor, cytokine, lymphokine, enzyme, clotting factor, or plasma component. 17. A method according to claim 13, wherein the exogenous protein is streptokinase. 18. A method according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the subject is human. 19. A method according to claim 19, wherein the human is a hemophiliac. 20. A method according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein said therapeutical protein is an allergen.