Thrombosis has been reported in up to 2% of people with HIV infection.  Risk factors for this group  are  age over 45 years, advanced  stage of HIV infection,  co-existing  opportunistic infections,  hospitalisation,  and therapy  with indinavir  and megestrol acetate.22  A number of potentially pro-thrombotic abnormalities  have  been reported  in association with HIV infection, including decreased levels of (a) antithrombin (seen in HIV nephropathy), (b)  free protein S, (c)  protein C and (d)  heparin cofactor II;  lupus anticoagulant and anticardiolipin antibodies; co-existent malignant, inflammatory and autoimmune disorders; as well as vascular damage due to injecting drug use, vascular catheters and CMV infection.23 Lupus anticoagulant or anticardiolipin antibodies are weakly associated with venous thrombosis  but cerebrovascular  accidents,  bone and skin necrosis and brachial artery thrombosis have been reported.1