Previous Article
Journal of Clinical Microbiology, September 2001, p. 3425-3426, Vol. 39, No. 9
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.9.3425-3426.2001
LETTERS TO THE EDITOR
Labsystems Enzyme Immunoassay for Chlamydia
pneumoniae Also Detects Chlamydia psittaci
Infections
 |
LETTER |
In a recent article, Bas and collaborators compared different
serological methods to detect chlamydial antibodies in patients with
Chlamydia trachomatis infections and healthy blood donors (1). Using the Labsystems enzyme immunoassay (EIA) for
C. pneumoniae, no cross-reaction between C. trachomatis and C. pneumoniae was found. However,
Gnarpe and collaborators recently showed cross-reactions between
C. trachomatis and C. pneumoniae, when the
Labsystems EIA for C. pneumoniae was used on sera containing
high titers of C. trachomatis antibodies documented by the
microimmunofluorescence (MIF) test (2). A broader
cross-reactivity between the different chlamydial species was
suspected. The Labsystems EIA test has previously been shown to have
high sensitivity and specificity in the diagnosis of acute infections
caused by C. pneumoniae during an epidemic of C. pneumoniae (3).
To examine the Labsystems EIA test for C. pneumoniae more
extensively, we tested it on paired sera, taken from 43 patients for
etiological diagnosis of pneumonia. The immunoglobulin G (IgG) and IgM
antibody results for C. pneumoniae, C. psittaci,
and C. trachomatis had previously been documented by the MIF
tests, and IgG and IgM antibodies were now determined by the Labsystems
EIA for C. pneumoniae. Of seven patients who were positive
by the MIF test for C. pneumoniae, only three were positive
by the EIA for C. pneumoniae, while five out of five
patients who were positive by the MIF test for C. psittaci
were positive by the EIA for C. pneumoniae. One patient with
positive MIF test results for both C. pneumoniae and
C. psittaci also tested positive for C. pneumoniae by the EIA. Sera from the remaining 30 patients, who
showed no significant IgG or IgM antibody changes with the MIF test,
also produced negative results with the EIA.
Because infections caused by C. pneumoniae and C. psittaci have important epidemiological differences, it is
important to make a correct etiological diagnosis. The study of Gnarpe
and collaborators and the present study indicate that cross-reactions between the chlamydial species occur when the Labsystems EIA for C. pneumoniae is used. The EIA could be used for the purpose
of screening for chlamydial infections, but in nonepidemic situations we suggest that a method that differentiates between the chlamydial species, such as the MIF test, should be used directly (or,
alternatively, as a second step after a screen with the EIA).
| |
FOOTNOTES |
*
Phone: 46-19-6023619
Fax: 46-19-184855
E-mail:
kristoffer.stralin{at}orebroll.se
| |
REFERENCES |
| 1.
|
Bas, S.,
P. Muzzin,
B. Ninet,
J. E. Bornand,
C. Scieux, and T. L. Vischer.
2001.
Chlamydial serology: comparative diagnostic value of immunoblotting, microimmunofluorescence test, and immunoassays using different recombinant proteins as antigens.
J. Clin. Microbiol.
39:1368-1377[Abstract/Free Full Text].
|
| 2.
|
Gnarpe, J.,
J. Nääs, and A. Lundbäck.
2000.
Comparison of a new commercial EIA kit and the microimmunofluorescence technique for the determination of IgG and IgA antibodies to Chlamydia pneumoniae.
APMIS
108:819-824[Medline].
|
| 3.
|
Persson, K., and J. Boman.
2000.
Comparison of five serological tests for diagnosis of acute infections by Chlamydia pneumoniae.
Clin. Diagn. Lab. Immunol.
7:739-744[Abstract/Free Full Text].
|
| | | | |
Kristoffer Strålin*
Department of Infectious Diseases
Örebro Medical Centre Hospital
SE-701 85 Örebro, Sweden
|
| | | | |
Hans Fredlund
Per Olcén
Örebro Medical Centre Hospital
SE-701 85 Örebro, Sweden
|
| |
AUTHORS' REPLY |
In our study (1), we compared two different methods of
serodiagnosis for Chlamydia pneumoniae infections (an enzyme
immunoassay from Labsystems and the microimmunofluorescence [MIF]
test) but no statistical analysis concerning possible
cross-reactions between anti-C. trachomatis and
anti-C. pneumoniae antibodies was presented. The analysis
shows that the percentage of positive samples for immunoglobulin G
(IgG) anti-C. pneumoniae antibodies, determined by either
enzyme immunoassay or MIF, is always higher for positive IgG
anti-C. trachomatis antibody samples than for negative ones. However, this difference was only significant when the presence of IgG
anti-C. trachomatis and -C. pneumoniae antibodies
was determined with the MIF test. Indeed, 92% of IgG anti-C.
trachomatis antibody-positive samples also had IgG anti-C.
pneumoniae antibodies while at the same time only 45% of IgG
anti-C. trachomatis antibody-negative samples were found to
be positive for IgG anti-C. pneumoniae antibodies (P = 0.0037, chi-square test). When the presence of IgG
anti-C. trachomatis antibodies was documented by the MIF
test and that of IgG anti-C. pneumoniae was identified by
the Labsystems enzyme immunoassay, 77% of IgG anti-C.
trachomatis antibody-positive but only 48% of the
antibody-negative samples also had IgG anti-C. pneumoniae
antibodies. The difference was not significant.
When the presence of IgG anti-C. trachomatis antibodies was
determined with other methods, such as enzyme immunoassays using either
synthetic peptides derived from species-specific epitopes in the
variable domain IV of the major outer membrane protein or pgp3 as the
antigen(s), the presence of IgG anti-C. pneumoniae antibodies was found in 62 to 72% of IgG anti-C.
trachomatis antibody-positive samples and in 50 to 62% of
antibody-negative samples. Therefore, though the differences were not
significant in most cases, samples positive for anti-C.
trachomatis antibody had a tendency to be more often anti-C.
pneumoniae antibody-positive than do samples negative for
anti-C. trachomatis antibody. However, if C. trachomatis infection was proven in these patients, the presence
or absence of C. pneumoniae or C. psittaci was
not demonstrated by culture, direct immunofluorescence, or nucleic acid
amplification. It is therefore only possible to speculate about the
presence or absence of anti-C. pneumoniae or anti-C.
psittaci antibodies and about their probable cross-reactivities.
In conclusion, in our study, the detection of cross-reacting antibodies
could be expected to occur more often with the MIF test than with
enzyme immunoassays. Several studies have already reported that MIF
specificity is lower than that generally thought (2-4,
6-9). Because MIF tests are detecting antibodies against surface protein antigens and because the protein composition of the
C. pneumoniae outer membrane complex is similar to those
described for C. trachomatis and C. psittaci
(5), the detection of cross-reacting antibodies is not
surprising. Moreover, recognition of the major outer membrane protein
(4, 6, 7) and the 60-kDa proteins of the three species was
shown to be cross-reactive (5).
| |
REFERENCES |
| 1.
|
Bas, S.,
P. Muzzin,
B. Ninet,
J. E. Bornand,
C. Scieux, and T. L. Vischer.
2001.
Chlamydial serology: comparative diagnostic value of immunoblotting, microimmunofluorescence test, and immunoassays using different recombinant proteins as antigens.
J. Clin. Microbiol.
39:1368-1377.
|
| 2.
|
Biendo, M.,
F. Eb,
J. F. Lefebvre, and J. Orfila.
1996.
Limits of the microimmunofluorescence test and advantages of immunoblotting in the diagnosis of chlamydiosis.
Clin. Diagn. Lab. Immunol.
3:706-709[Abstract].
|
| 3.
|
Bourke, S. J.,
D. Carrington,
C. E. Frew,
R. D. Stevenson, and S. W. Banham.
1989.
Serological cross-reactivity among chlamydial strains in a family outbreak of psittacosis.
J. Infect.
19:41-45[CrossRef][Medline].
|
| 4.
|
Kern, D. G.,
M. A. Neill, and J. Schachter.
1993.
A seroepidemiologic study of Chlamydia pneumoniae in Rhode Island. Evidence of serologic cross-reactivity.
Chest
104:208-213[Abstract/Free Full Text].
|
| 5.
|
Melgosa, M. P.,
C. C. Kuo, and L. A. Campbell.
1993.
Outer membrane complex proteins of Chlamydia pneumoniae.
FEMS Microbiol. Lett.
112:199-204[CrossRef][Medline].
|
| 6.
|
Moss, T. R.,
S. Darougar,
R. M. Woodland,
M. Nathan,
R. J. Dines, and V. Cathrine.
1993.
Antibodies to Chlamydia species in patients attending a genitourinary clinic and the impact of antibodies to C. pneumoniae and C. psittaci on the sensitivity and the specificity of C. trachomatis serology tests.
Sex. Transm. Dis.
20:61-65[Medline].
|
| 7.
|
Ozanne, G., and J. Lefebvre.
1992.
Specificity of the microimmunofluorescence assay for the serodiagnosis of Chlamydia pneumoniae infections.
Can. J. Microbiol.
38:1185-1189[Medline].
|
| 8.
|
Wagenvoort, J. H.,
D. Koumans, and M. van de Cruijs.
1999.
How useful is the Chlamydia microimmunofluorescence (MIF) test for the gynaecologist?
Eur. J. Obstet. Gynecol. Reprod. Biol.
84:13-15[CrossRef][Medline].
|
| 9.
|
Wong, Y. K.,
J. M. Sueur,
C. H. Fall,
J. Orfila, and M. E. Ward.
1999.
The species specificity of the microimmunofluorescence antibody test and comparisons with a time resolved fluoroscopic immunoassay for measuring IgG antibodies against Chlamydia pneumoniae.
J. Clin. Pathol.
52:99-102[Abstract].
|
| | | | |
S. Bas
T. L. Vischer
Division of Rheumatology
Department of Internal Medicine
University Hospital
Geneva, Switzerland
|
Journal of Clinical Microbiology, September 2001, p. 3425-3426, Vol. 39, No. 9
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.9.3425-3426.2001
This article has been cited by other articles:
-
Klein, M., Kotz, A., Bernardo, K., Kronke, M.
(2003). Detection of Chlamydia pneumoniae-Specific Antibodies Binding to the VD2 and VD3 Regions of the Major Outer Membrane Protein. J. Clin. Microbiol.
41: 1957-1962
[Abstract]
[Full Text]
