PLATELET-AGGREGATION AND CLOTTING PARAMET ER ABNORMALITIES IN 36 PATIENTS INFECTED WITH THE HIV

In 36 HIV-infected patients (33 plasmas), a study of platelet aggregat ion in the presence of four agents (adenosine diphosphate, collagen, r istocetin, and arachidonic acid) found evidence of platelet dysfunctio n in 45% of cases, including defective aggregation and excretion, prob able Ib/IX complex deficiency, and responses indicating exaggerated pl atelet activation. These significant alterations were not accompanied with bleeding. Clotting disorders were also found, including elevation s in levels of fibrinogen (39%), D-dimers (74%), and Willebrand factor (72%); a decrease in protein S activity (50%); and presence of antiph ospholipid antibodies (28%). The clotting disorders were associated wi th greater severity of the HIV infection. No thrombotic or embolic eve nts were noted although many patients had high D-dimer levels, protein S deficiency, a lupus-type circulating anticoagulant (33%), or antiph ospholipid antibodies, suggesting that these abnormalities may not tra nslate into clinical symptoms in HIV-infected patients.