The Serologic response to Cryptosporidium in HIV-infected persons: implications for epidemiologic research
Eisenberg, J.N.; Priest, J.W.; Lammie, P.J.; Colford, J.M.
Emerging Infectious Diseases 7(6): 1004-1009
2001
ISSN/ISBN: 1080-6040 PMID: 11747729 DOI: 10.3201/eid0706.010614Document Number: 243319
Advances in serological assays for Cryptosporidium parvum have made serology an attractive surveillance tool. The sensitivity, specificity and predictive value of these new assays for surveillance of immunocompromised populations, however, have not been reported. Using stored serum specimens collected for the San Francisco Men's Health Study, we conducted a case-control study with 11 human immunodeficiency virus (HIV)-infected, clinically confirmed (aged 25-54 years) cases of cryptosporidiosis who were followed from 1984 through 1992, in California, USA. Based on assays using a 27-kDa antigen (CP23), the serum specimens from cases had a median response immunoglobulin (Ig) G level following clinical diagnosis (1334) and a net response (433, change in IgG level from baseline) that were significantly higher than their respective control values (329 and -32, Wilcoxon P value=0.01). Receiver operator curves estimated a cutoff of 625 U as the optimal sensitivity (0.86 (0.37, 1.0)) and specificity (0.86 (0.37, 1.0)) for predicting Cryptosporidium infection. These data suggest that the enzyme-linked immunosorbent assay technique can be an effective epidemiological tool to monitor Cryptosporidium infection in immunocompromised populations.