Serodiagnosis of Chlamydia trachomatis infections by the micro-immunofluorescence test / 대한임상병리학회지

BACKGROUND: Chlamydia trachomatis (C. trachomatis) is an obligatory intracellular parasite which causes trachoma, inclusion conjunctivitis, pneumonia in infants, nongonococcal urethritis, epididymitis, cervicitis, and salpingitis. Salpingitis frequently produces tubal damage and infertility. The micro-immunofluorecence (MIF) test is the standard method for chlamydial serology and is highly sensitive and specific. This study aimed to evaluate the prevalence of C. trachomatis antibodies in healthy individuals and patients with various diseases as well as the clinical value of chlamydial serology by MIF testing. METHODS: A total of 692 serum samples were collected. Of these, 388 samples were obtained from healthy individuals (male 209, female 179). Cord blood samples were collected from 38 healthy babies. Serum samples of 53 female patients with infertility due to PID (group 1), 107 patients with respiratory diseases (group 2; pneumonia, bronchitis, etc.), and 106 patients with cardiovascular diseases (group 3; angina pectoris, acute myocardial infarction, etc.) who were admitted to Hanyang University Hospital from March 1995 to June 1998 were enrolled in this study. Serological diagnosis of a previous infection was made when IgG antibody titers to C. trachomatis were 1:32 or higher. A single titer of antibody of > or =1:512 for IgG or > or =1:16 for IgM was considered to indicate a recent infection. RESULTS: The IgG antibody detection rate in healthy individuals was 27%, broken down by age as follows: or =61 years old, 24%. For cord blood, the antibody was detected in 29% of the samples. There were 1 case (0.3%) of recent infection with C. trachomatis by IgG, and 6 cases (1.5%) for IgM. The incidence of IgG antibodies to C. trachomatis in the disease group was 70%, 28%, and 19% for group 1, group 2, and group 3, respectively. There were 3 cases of recent infection detected by IgG and 4 cases by IgM in group 1. Recent infection with C. trachomatis was detected by IgG in 1 case of group 2 and by IgM in another case of group 3. CONCLUSIONS: In healthy individuals, the prevalence of antibodies to C. trachomatis was highest in those between the ages of 21-40 years. Patients with infertility due to PID showed a significantly higher positive rate (P=0.000 by Chi-square test) and more cases of recent infection to C. trachomatis than others. The results suggest that a positive chlamydial serology indicates a higher risk for infertility due to PID.

The Re-evaluation of the Serologic ELISA tests for the Diagnosis of Helicobacter pylori Infection / 대한임상병리학회지

BACKGROUND: Helicobacter pylori (H. pylori), a Gram negative spiral bacilli, is known to be the cause of chronic gastritis and peptic ulcer disease and is strongly associated with gastric cancer. Therefore, the rapid detection of H. pylori infection is necessary for prevention and treatment. Of the diagnostic tests currently used, the serologic tests, which makes use of the immune response, do not need a biopsy specimen. This method is relatively accurate, rapid, simple and inexpensive. We re-evaluated the clinical usefulness of the isotypes of H. pylori (IgG, IgA, IgM) antibodies for the detection of H. pylori infection. MATERIALS AND METHODS: Serum samples were obtained from 1,851 patients confirmed to have gastric or duodenal disease by gastric endoscopy from June, 1993 to December, 1994 at Hanyang University Hospital. The phenol-red urease test was done during endoscopy and the H-E stain on the gastric biopsies. Serologic tests (GAP Test IgG, IgA, IgM kits) were performed with patient sera. RESULTS: The sensitivities of the GAP EIA were 80% for IgG, 27% for IgA, and 85% for IgM. The specificities were 33%, 79%, and 14%, respectively. The detection rates of H. pylori were highest for the phenol-red urease test (88%), followed by IgM by ELISA (86%), IgG (72%), H-E stain (43%), and IgA (21%). The serum levels of IgG and IgA antibodies were higher in those with H. pylori infection than in those without, but there was no difference in IgM levels. And, no difference of serologic antibody levels according to disease state. Where follow-up was possible, the majority of IgG levels decreased, but IgA or IgM levels are not changed. CONCLUSION: A positive serologic test is incapable of discriminating between actual infection and normal bacterial colonization, or between recent and past infections. Therefore a serologic test seems unsatisfactory for confirming a diagnosis of H. pylori infection, but because the serial IgG levels of treated patients decreased significantly, we believe that this test may be used as an indirect means of assessing the response to therapy.