Am. J. Respir. Crit. Care Med.,
Volume 163, Number 3, March 2001, 680-684
Antipneumolysin Antibody Titers in HIV-Seropositive
Injection Drug Users before and after
Pneumococcal Bacteremia
JEFFREY H.
SULLIVAN,
TIMOTHY J.
MITCHELL,
and
MARK C.
STEINHOFF
Johns Hopkins School of Medicine and Johns Hopkins School of Public Health, Department of International Health, Baltimore, Maryland;
and University of Glasgow, Division of Infection and Immunity, Glasgow, Scotland
Lower baseline antipneumolysin antibody (
-PLY) levels have been
found in populations with a higher incidence of pneumococcal infections. To determine whether predisease -PLY titer is associated with invasive pneumococcal disease in HIV-seropositive injection drug users (IDU), we utilized a prospective cohort of IDU in
Baltimore to compare -PLY titers before bacteremia in 28 HIV-
seropositive IDU cases with -PLY titers in 56 matched (CD4 and
seroconversion date) HIV-seropositive IDU control subjects and 28 matched (calendar time) HIV-seronegative IDU control subjects remaining free of pneumococcal disease. We also compared the postinfection fold-rise of -PLY titers in cases relative to the change in
-PLY titers in control subjects during the same interval; -PLY titers were measured using quantitative ELISA, and functional activity was assessed using antihemolysin assays. Predisease -PLY titer
did not differ between cases (66 units) and HIV-seropositive control subjects (70 units, p = 0.56) or HIV-seronegative control subjects (80 units, p = 0.10). There was a significant difference in fold-rise of -PLY titers postdisease between cases (1.18) and HIV-seronegative control subjects (0.76), p = 0.03. Baseline -PLY titers do not differ significantly between HIV-seropositive IDU who develop pneumococcal bacteremia from HIV-seropositive and HIV-seronegative IDU control subjects remaining free of severe pneumococcal disease.
