Restoration of complement function by plasma infusion in factor I (C3b inactivator) deficiency

EDITORIAL C O R R E S P O N D E N C E

Editorial correspondence is subject to critical review and to current editorial policy in respect to publication in part or in full. Preference is given to letters related to articles published in The Journal, but letters on topics of current interest may be accepted if space is available. Letters are restricted to 300 words or less and three supporting references.

Erratum: Renal clearance of gentamicin in cystic fibrosis To the Editor." We are grateful to Dr. M. Spino and colleagues for identifying an error in our paper?. In Fig. 2, r 2 should be r, as indicated correctly in the text. The open circles represent another patient group not used in these analyses. Noni E. MacDonald, M.D., M.Sc., F.R.C.P.(C) Head, Infectious Disease Service Department o f Pediatrics University o f Ottawa Children's Hospital o f Eastern Ontario Ottawa, Ont. K1H 8L1, Canada REFERENCE

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MacDonald NE, Arias NG, Peterson RG et al: Renal clearance of gentamicin in cystic fibrosis. J PEDZATR103:985, 1983.

Restoration of complement function by plasma infusion in factor I (CJb inactivator) deficiency To the Editor: Recently Barrett and Boyle 1 reported the effective treatment of factor I (C3b inactivator) deficiency by plasma infusions. This kind of replacement therapy fias already been performed and reported 2'3 and implies more potential risks than sensitization against factor I and transfusion-associated hepatitis. We have observed two moderate anaphylacfic reactions during plasma infusions during a 2-year treatment period. W e did not find any evidence of antibodies to factor I. However, by infusing plasma native C3 is also infused, which in the presence of circulating activated convertase of the alternate pathway C3-b--ff~is rapidly cleaved to C3a and CJb. C3a, of course, is a potent anaphylotoxin. If the generation of C3a exceeds the inactivation process of C3bBb by the control proteins of the alternate pathway, the patient is at considerable risk to develop anaphylaxis. We think that this problem can be managed and that long-term treatment by plasma infusions can be effective. However, any physician performing this

kind of treatment should be aware of this third risk. The more appropriate way to treat this inherited deficiency is replacement of purified factor I, as shown by Ziegler et at. 4 We agree that factor H levels are low in factor I deficiency. The authors propose factor H consumption by binding to C3b, which is continuously generated by C3bBb. We have looked for this possible mechanism but did not find any experimental support. We found that factor H exists in at least tWO different molecular forms, which We termed H~ and H a. H~ is not identical with C3bH because its sedimentation coefficient on analytical ultracentrifugation is close to 7s (Wahn and Day, unpublished data). As plasma infusions change the electrophoretic mobility of factor H, w e think that the two molecular forms of H can be converted to each other and that factor I may be involved in the control of the metabolic steps. Volker Wahn, M.D. Ulrich G~bel, M.D. Universithts-Kinderklinik D 4000 D~sseldorf Federal Republic o f Germany Noorbibi K. Day, Ph.D. Oklahoma Medical Research Foundation Oklahoma City, OK

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Barrett D J, Boyle MDP: Restoration of complement function in vivo by plasma infusion in factor I (C3b inactivator) deficiency. J PEDIATR 104:76, 1984. Wahn V, G6bel U, Rauterberg EW, Rother U, Laurell AB: Long-term treatment of a ~atient with C3b inactivator deficiency (abstract). A!lergol Immunopathol 8:422, 1980. Wahn V, Rother U, Rauterberg EW, Day NK, Laurell AB: C3b inactivator deficiency: Association with an alpha migrating factor H. J Clin Immtm01 1:228, 1981. Ziegler JB, Alper CA, Rosen FS, Lachmann P J, Sherington L: Restoration by purifie d C3b inactivator of complementmediated functions in vivo in a patient with C3b inactivator deficiency. J Clin Invest 55:668, 1975.

Rep&." To the Editor."

We apologize for overlooking l)he case of factor I deficiency reported by Wabn et al. The intent of our publication, however,

The Journal o f P E D ! A T R 1 C S Vol. 105, No. 4. October 1984

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