A 73-year-old female was found to have prolonged thrombin and reptilase times in the immediate post-operative period. These abnormalities were not corrected by the addition of normal plasma. They were subsequently shown to be due to an IgG immunoglobulin which inhibited fibrin monomer polymerization. The IgG immunoglobulin activity could be neutralized completely by prior incubation with either patient or normal fibrinogen, uncrosslinked fibrin monomers or IgG antisera. No inhibitory effect on thrombin activity, fibrinopeptide A release or on the fibrin cross-linking reaction of factor XIIIa could be detected. Purified patient fibrinogen was functionally normal as demonstrated by normal fibrinogen-fibrin polymerization and fibrinopeptide A release. No underlying cause for this phenomenon was found. The presence of the inhibitor was associated with excessive blood loss during the post-operative period.

Patients with acute non‐lymphoblastic leukaemia were studied to determine if the presence of la‐like antigens on leukaemic cells was related to the maturity of a leukaemic cell line. Ia‐like antigens were present in the majority of acute myeloblasts and myelomonoblastic leukaemias. 4 patients with acute promyelocytic leukaemia were la‐negative. This finding suggests that la‐like antigens reflect normal differentiation linked events in haemopoiesis. The presence of Ia‐like antigens on leukaemic cells did not alter the patient's response to chemotherapy.

Summary In February 1986, 40 out of 75 adult patients with haemophilia A attending St. James's University Hospital were human immunodeficiency virus (HIV) antibody positive. Over a three‐year period these patients were prospectively studied with regard to possible prognostic indicators for the development of the acquired immune deficiency syndrome (AIDS). Using the Centres for Disease Control (CDC) classification of HIV infection, 17 patients (42.5%) developed group 4 disease during this time, giving an actuarial three‐year progression rate of 44%, and 5 patients (12.5%) died. The following parameters measured at recruitment were found independently to predict progression to AIDS: a serum β2‐m level of greater than 3.5 mg/l, (χ2= 1595, P < 0.001), a serum IgA level of greater than 4.5 g/l (χ2= 6.08, P < 0.02) and p24 antigenaemia (χ2= 5.7, P < 0.05). The actuarial three‐year progression rate in those patients abnormal by two or more of these parameters was 100% (n= 7), compared to only 7% in patients who were normal by all three values (n= 15). CD4 + lymphocyte counts and CD4 +: CD8+ ratios were significantly lower in HIV positive compared with HIV negative patients (P < 0.01), but did not predict the development of AIDS.