USE OF BETA-2-MICROGLOBULIN LEVEL AND CD4 LYMPHOCYTE COUNT TO PREDICT DEVELOPMENT OF ACQUIRED-IMMUNODEFICIENCY-SYNDROME IN PERSONS WITH HUMAN IMMUNODEFICIENCY VIRUS-INFECTION

Serum β2-microglobulin (β2M) levels were measured by radioimmunoassay in 962 unmarried man recruited by probability sampling from areas in San Francisco, Calif, most severely affected by the epidemic of acquired immunodeficiency syndrome (AIDS). From July 1984 to December 1987, 65 incident AIDS cases occurred in 388 homosexual/bisexual men infected by the human immunodeficiency virus (HIV) at the time of recruitment. The mean level of β2M in uninfected individuals at entry was 170 nmol?L. In HIV-seropositive patients who had not developed AIDS, the mean β2M level was 254 nmol/l, and in those who had developed AIDS, the β2M level was 347 nmol/L. After 36 months of follow-up, 34% of individuals with β2M levels greater than 322 nmol/L at entry developed AIDS, 21% of individuals with levels between 246 and 322 nmol/L developed AIDS, while only 7.3% of those with levels below 246 nmol/L developed AIDS. The β2M level predicted the development of AIDS independently of the CD4 lymphocyte count in HIV-seropositive individuals. Thus, 65.5% of HIV-seropositive individuals with β2M levels above 322 nmol/L and CD4 lymphocyte counts of below 500/μL developed AIDS in 3 years. This represents an 18.4-fold increased relative hazard at 3 years over individuals with β2M and CD4 cell counts within the reference range for uninfected individuals. A nomogram is provided that allows the easy calculation of the probability of an HIV-infected person developing AIDS in 36 months depending on prevalent levels of CD4 lymphocytes and serum β2M.