11 REACTIVATION OF VIRAL REPLICATION IN CHRONIC HEPATITIS B VIRUS INFECTION

K. Krogsgaard+, J .A ldershv i le , P. Kryger, P. Andersson++, J.O. Nielsen, The Copenhagen Hepat l t ls Acuta Programme. +Department ot Medlclne, u1vlslons ot Hepatology and Infect ious Diseases, Hvidovre Hospital and ++ The Gene Technology Group, Technical Univers i ty of Copenhagen, Copenhagen, Denmark.

The aim of th is study was to examine the rate of react ivat ion of v i ra l rep l i ca t ion in chronic HBsAg carr iers and in th is context to evaluate the s ign i f icance of serum HBV DNA. F i f t y f i ve out of 107 consecutive HBsAg carr iers were avai lab le for th is study being negative for both HBeAg and HBV DNA at study entry or during fo l low-up. Eight (15%) were male homosexuals, 31 (56%) were drug addicts, 16 patients did not belong to any major r isk group. Serological HBV and HDV markers were assayed by RIA. Anti-HIV was assayed by ELISA and confirmed by Western b lo t . HBV DNA was detected by spot hybr id iza t ion . Median fol low-up time without detectable HBV rep l i ca t ion was 24 months (range, 1 month to 12 years). Reacti- vation defined as reappearance of at least one marker of act ive v i ra l rep l i ca t ion was noted in I I (20%) patients and the annual rate of react iva t ion was 8%. Reactivation was in 3 patients ascribed to immunosuppression caused by HIV in fec t ion (two) and malignant disease (one). Reactivation was also noted in 3 HDV infected patients in whom the primary loss of HBeAg and HBV DNA was preceded by HDV in fec t ion . In 5 pat ients react ivat ion occurred spon- taneously. Reactivation was in 4 pat ients revealed by reappearance of both HBeAg and HBV DNA. In the major i ty , 6 pat ients, react ivat ion was sole ly detected by reappearance of HBV DNA. Reactivation of v i ra l rep l i ca t ion occurs f requent ly among HBsAg carr iers and is often sole ly detected by reappearance of HBV DNA. Further, i t is suggested that react iva t ion may be responsible for the d ispar i t y between HBeAg and HBV DNA noted in some HBsAg car r iers .

72 REDUCED PLATELET AGGREGATION IN RESPONSE TO THROMBIN IN CIRRHOTIC PATIENTS IS RELATED TO ALTERED POLYPHOSPHOINOSITIDE METABOLISM.

G. La f f i , F. Cominell i , G. La V i l l a , M. Ruggiero*, S. Fedi§, M. Pinzani & P. Gen t i l i n i . I s t i t u t i di Cl in ica Medica I I e Patologia Generale*, Dipartimento di Fis iopatologia Cl in ica, Univers i ty of Florence, I t a l y .

P la te le t (P) aggregation is often reduced in c i r rho t i cs (C). I t is s t i l l unclear i f such defect is related to i n t r i n s i c P defect or to abnormalit ies of plasma factors. In order to focus our invest igat ion on P funct ion only, we used washed P, prelabel led with 14C-Arachidonic acid. P aggregation tr iggered by thrombin (T) and the underlying molecular mechanism was assessed in 6 C with advanced disease (Child C) in comparison to 6 healthy controls. T induces sequential ac t iva t ion of phospholipase C (with production of inos i to l phosphate, d iacy lg lycero l and phosphatidic acid - PA) and phospholipase A2, which leads to the formation of arachidonic acid (AA). Al iquots of washed, label led P were stimulated by T (0.02 UI / I ) while s t i r r i n g at 37°C in a dual channel aggregometer, in order to measure aggregation. 2 minutes la ter , the react ion was stopped by adding chlorophorm,methanol (100:200 v /v) . The formation of 14C-PA and 14CAA was measured af ter i so la t ion of these compounds by th in - layer chromatography. T induced P aggregation was s i g n i f i c a n t l y reduced in C (12.7 ± 1.7 vs. 66.7 ± 3.8, %, p L 0.001). Act ivat ion of phospholipase C, as measured by 14C-PA formation, was also great ly impaired in C (201 + 56.5 vs. 368 + 132.5) as well as the l ibera t ion of 14C-AA by phospholipase A2 (269.7 ~ 137.2 vs. 856.5 ± 134.6, p L 0.05). We conclude that : I) p la te le ts from c i r r ho t i c patients have an in t r insec aggregating defect in response to thrombin; 2) th is defect can be related to a def ic iency in the molecular mechanism of transmembrane s igna l l ing responsible for p la te le t ac t iva t ion .

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