Hypercoagulable states are found in up to 10 per cent of patients with a history of unexplained venous thrombosis. To investigate the prevalence in arterial thrombosis, thrombophilia screening was performed on 124 patients who had previously undergone lower-limb revascularization, 45 claudicants and 27 controls. Of the patients who had undergone revascularization 40 per cent had a hypercoagulation abnormality (low levels of protein C, protein S and antithrombin III or presence of the lupus anticoagulant) in comparison with 27 per cent of claudicants and 11 per cent of controls (P < 0.01). Furthermore, patients who had suffered reocclusion after revascularization were significantly more likely to have a hypercoagulation abnormality than those who had not (P < 0.05), even if the occlusion had occurred more than 6 months previously. Lupus anticoagulant was the abnormality most frequently detected and, like low protein C levels, was found only in patients with peripheral vascular disease. It appears that hypercoagulable states are common in patients with arterial disease and may predispose to failure of revascularization.

Pure erythrocyte aplasia is a recognised feature of systemic lupus erythematosus (SLE); here we report two cases, one predating the onset of SLE, the other following a long period of disease quiescence. One case demonstrates the typical features of this disorder and was successfully treated with prednisolone. The second case is unusual in being resistant to immunosuppressive treatment. Bone marrow culture from the second patient revealed an inhibition of BFU-E colony formation in the presence of the patient's serum, indicating that a serum inhibitor of haemopoiesis was present. Furthermore, following T cell depletion of this patient's marrow, there was an increase in BFU-E, CFU-G and CFU-GM colony growth implicating, in addition, a possible T cell-mediated inhibition of marrow haemopoiesis. This is a novel observation and may explain the resistance shown by this patient to standard treatment.

Increased activated protein C resistance appears to be an important factor in women with recurrent abortions. These data indicate the need for routine investigation of activated protein C resistance in women with recurrent abortions.

Hypercoagulable abnormalities are common prior to arterial revascularisation and are independently associated with subsequent failure.