Antipneumolysin antibody titers in HIV-seropositive injection drug users before and after pneumococcal bacteremia.
Lower baseline antipneumolysin antibody (alpha-PLY) levels have been found in populations with a higher incidence of pneumococcal infections. To determine whether predisease alpha-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 alpha-PLY titers before bacteremia in 28 HIV- seropositive IDU cases with alpha-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 alpha-PLY titers in cases relative to the change in alpha-PLY titers in control subjects during the same interval; alpha-PLY titers were measured using quantitative ELISA, and functional activity was assessed using antihemolysin assays. Predisease alpha-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 alpha-PLY titers postdisease between cases (1.18) and HIV-seronegative control subjects (0.76), p = 0.03. Baseline alpha-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.
Johns Hopkins School of Medicine and Johns Hopkins School of Public Health, Department of International Health, Baltimore, Maryland; , USA.
J H
JH
Sullivan
T J
TJ
Mitchell
M C
MC
Steinhoff
D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000097:blood*; D016470:Bacteremia / Q000097:blood* / Q000276:immunology*; D001426:Bacterial Proteins; D018791:CD4 Lymphocyte Count; D016022:Case-Control Studies; D003603:Cytotoxins / Q000276:immunology*; D005260:Female; D006679:HIV Seropositivity / Q000097:blood*; D006801:Humans; D008297:Male; D011008:Pneumococcal Infections / Q000097:blood* / Q000276:immunology*; D011446:Prospective Studies; D013301:Streptolysins / Q000276:immunology*; D019966:Substance-Related Disorders / Q000097:blood*
D000906:Antibodies; D001426:Bacterial Proteins; D003603:Cytotoxins; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae