ANTIBODY-RESPONSE TO HAEMOPHILUS-INFLUENZAE TYPE-B VACCINE IN RELATION TO THE NUMBER OF CD4(-LYMPHOCYTES IN ADULTS INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS() T)

A prospective study of antibody production by adults infected with hum an immunodeficiency virus (HIV) after vaccination with tetanus toxoid- conjugated Haemophilus influenzae type b (Hib) vaccine was conducted, Concentrations of antibodies to the two immunogenic components of the vaccine (i.e., polyribosylribitolphosphate [PRP] and tetanus toxin) we re determined, Individuals were divided into three groups according to the CD4(+) T lymphocyte count: group 1, less than or equal to 100 x 1 0(6)/L; group 2, 101-300 x 10(6)/L; and group 3, >300 x 10(6)/L. After vaccination, concentrations of IgM and IgG antibodies to PRP were sig nificantly lower in group 1 than in the other patient groups and contr ols. A CD4(+) T lymphocyte count of < 100 x 10(6)/L and an impaired pr oliferative response of lymphocytes to monoclonal antibody to CD3 were independently associated with a less than threefold increase in conce ntrations of IgG antibody to PRP, Analysis of IgG subclasses demonstra ted that the production of IgG1 antibodies was predominantly affected, Postvaccination concentrations of antibody to tetanus toxin were sign ificantly lower in group 1 than in group 3 and controls, Both prevacci nation and postvaccination concentrations of antibody to tetanus toxin were not correlated with the magnitude of the response of antibody to PRP. We conclude that HN-infected individuals with CD4(+) T lymphocyt e counts of < 100 x 10(6)/L demonstrate an impaired antibody response after Vaccination with conjugated Hib vaccine.