Relationship of serum immunoglobulin and IgG subclass levels to race, ethnicity and behavioral characteristics in HIV infection.

Background: To determine whether demographic and behavioral factors affect immunoglobulin regulation in HIV infection, we studied injection drug users, women, and minority ethnic and racial groups with and without HIV infection.

Material/methods: A prospective cross-sectional study of ambulatory persons with or at risk for HIV infection was conducted. We enrolled 48 injection drug users (IDUs) and 43 non-IDUs seropositive for HIV and 22 seronegative at-risk individuals in the Bronx, New York City. Sixteen HIV-seronegative, non-IDUs controls were also studied. Total serum immunoglobulin levels, IgG subclasses and lymphocyte phenotypes were measured.

Results: Serum IgG, IgA, IgG(1) and IgG(3) were increased in all stages of HIV infection controlling for injection drug use, gender, race and age (p0.05). Serum IgM levels were significantly decreased in HIV seropositives compared to HIV seronegatives (p<0.02). Two patterns of serum immunoglobulin level elevation were found in HIV infection: 1) IgG, IgG(1) and IgG(3) levels were elevated in early and advanced HIV infection; 2) IgA, IgG(2) and IgG(4) levels were elevated only in advanced HIV infection. IgG levels were increased in Blacks compared to Caucasians with HIV infection (p=0.01).

Conclusions: Serum IgG, IgG(1) and IgG(3) levels are increased in early HIV infection, while serum IgA, IgG(2), and IgG(3) levels are increased only in advanced HIV infection. In contrast, serum IgM levels are decreased in HIV infection. HIV-seropositive Blacks have higher serum IgG levels than HIV-seropositive Caucasians. Further studies are necessary to determine the mechanism(s) underlying the different patterns of immunoglobulin elevation in HIV infection.