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S t r i f e , Elizabeth C. Jackson, J u d i t h F o r r i s t a l andClark D. West. Division of Nephrology, Children's Hospital Research Foundation and t h e Department of P e d i a t r i c s , Univers i t y of Cincinnati, Cincinnati, Ohio 45229.The concentration of twelve component and four control p r o t e i n s o f the complement system were measured i n serum from 43 c h i l d r e n with a nephrotic syndrome which subsequently proved t o be s t e r o i d responsive and from 13 c h i l d r e n with focal glome r u l o s c l e r o s i s (FGS) and compared t o values from 197 normal s u b j e c t s .Of c l a s s i c a l pathway complement components, 40% of p a t i e n t s had low Clq and 20%, low C2 l e v e l s . Mean serum l e v e l s of Cls, C4, ClINH and C4bp were eleyated. Of a l t e r n a t i v e pathway components, f a c t o r s B and I were low i n one-third while l e v e l s o f C3 and H were commonly elevated.Of t h e terminal components, only C8 and C9 were low. In f i v e FGS p a t i e n t s with hypoalbuminemia without edema, a l l component l e v e l s were normal.With the exception of Clq, Cls and C8, high molecular weight components were i n high concentration and low molecular weight components i n low concentration.The three exceptions may be explained by the sub-unit s t r u c t u r e of C1 and C8. From a p r a c t i c a l standpoint, the study i n d i c a t e s t h a t edematous p a t i e n t s with a n e~h r o t i c syndrome may have low serum l e v e l s of Clq and C2, simulating c l a s s i c a l pathway complement a c t i v a t i o n such a s commonly occurs i n glomerulonephritis.However, low l e v e l s of C4 and possibly Cls can be used as i n d i c a t o r s of c l a s s i c a l pathway a c t i v a t i o n since t h e i r l e v e l s are not reduced by a nephrotic syndrome. PROSTACYCLIN DEFICIENCY DOES NOT PLAY A PIVOTAL ROLEa1640 I N HEMOLYTIC UREMIC SYNDROME (HUS). Marie J . S t u a r t , Roger E. S p i t z e r , Ronald W. Walenga, Sherry Boone. SUNY, Upstate Medical Center, Dept. of P e d i a t r i c s , Syracuse, N.Y.A decrease i n the prostacyclin (PGI2) s t i m u l a t i n g a c t i v i t y of plasma has been reported i n children with HUS. Although no study h a s attempted t o a s s e s s plasma PC12 l e v e l s themselves, t h e presence of a decrease i n the PC12 s t i m u l a t i n g a c t i v i t y has been equated with a deficiency of PC12 i n HUS. We have conducted an evaluation of plasma prostanoids (PGI2 and TXB2) i n 5 children admitted t o SUNY during an epidemic of HUS i n t h e n o r t h e a s t and i n 23 c o n t r o l s . We were unable t o document a p i v o t a l r o l e f o r PC12 deficiency i n HUS. Using an R I A f o r plasma 6KPGFb(the s t a b l e hydrolysis product of PGIZ), p a t i e n t s with HUS demonstrated elevated 6KPGFla l e v e l s of 1 . 0 5~0 . 3 (1SD) pmol/ml when compared t o c o n t r o l s ( 0 . 4 1 c . 1 3 ; p<0.001). Increased production of PC12 i n HUS was accompanied by a concomitant i n c r e a s e i n plasma thromboxane. Compared t o ...

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