A longitudinal study of serum beta 2-microglobulin levels in haemophilia.

Serum beta 2-microglobulin (beta 2-m) levels were measured in 75 adults with haemophilia A. Beta 2-microglobulin was found to be significantly elevated in haemophiliacs compared with the non-haemophiliac population. There was a greater rise in beta 2-m in HIV antibody-positive haemophiliacs. No further significant increase occurred in the subgroup with HIV-related disease but all these patients had beta 2-m levels greater than or equal to 3 mg/l. Over the study period of 18 months no significant increase in beta 2-m was documented in either HIV antibody-negative or -positive groups. Beta 2-microglobulin was elevated in HIV antibody-negative subjects with raised transaminase levels. No correlation was found between beta 2-m and the amount of factor VIII concentrate infused, T-cell subsets, thrombocytopenia or age. It is concluded that probable reasons for elevated beta 2-m levels in haemophiliacs include infection with HIV and other viruses, chronic liver disease, and repeated antigenic challenge from multiple infusions of factor VIII. The role of serial measurement of beta 2-m in haemophiliacs with a view to predicting the onset of HIV-related disease warrants further study.