Presence of hepatitis-associated antigen in systemic lupus erythematosus.

Presence of hepatitis-associated antigen (HAA) was investigated in 504 sera from 116 patients with SLE and was found in 41% of them. HAA was present in at least one serum in 75% of the patients but there were variations in presence and titres in the same patient at different times. Except for a tendency of HAA to appear or rise in titre with lupusi nactivation following corticosteroid or immunosuppresive therapy, there was no correlation between its presence and disease activity, specific organ involvement, antinuclear antibodies or immunoglobulin levels. All but one of twelve lupus patients with recurrent bacterial infections had HAA at high titres. HAA appeared in the serum of a patient upon development of IgA deficiency. HAA antigenaemia in systemic lupus erythematosus seems a consequence rather than a cause of the immunological derangement in this disease.