HIV seroconversion in Swedish haemophiliacs: relation to type and dosage of factor concentrate

Human immunodeficiency virus (HIV) seroconversion among 40 Swedish haemophilia A patients has been investigated by retrospective sera testing. 22/40 patients had developed HIV antibodies before 1983, i.e., when heat-treatment of American factor concentrates was introduced. All patients had received American and Swedish factor concentrates, thus no case of seroconversion was seen among patients treated exclusively with non-heat-treated Swedish concentrates. Of 79 patients with severe or moderate haemophilia, all of whom had received both American and Swedish concentrates, the 36 seropositives were compared with the 43 seronegatives. The total number of units received did not differ between the two groups, though the seropositive group had received significantly more American concentrate. Two batches of concentrate were proved to have been infected. 29 seropositive and 13 seronegative patients had been treated with at least one of these batches. As expected, and unlike most of the seronegative patients, patients in the seropositive group generally had abnormal lymphocyte subsets.