Antichlamydial Antibodies Research Articles

Prevalência de Chlamydia Pneumoniae e Mycoplasma Pneumoniae em diferentes formas da doença coronariana

Several infectious agents have been investigated since the association between atherosclerosis and infection was demonstrated; however, the results of these studies are contradictory.To test the association between serum titers of anti-Chlamydia and anti-Mycoplasma antibodies in different forms of acute coronary syndromes (ACS).One hundred and twenty-six patients were divided in 4 groups: ACS with ST-segment elevation (32 patients), ACS without ST-segment elevation (30 patients), chronic coronary artery disease (30 patients) and blood donors without known coronary disease (34 patients--control group). In the two first groups, serum samples were collected at hospital admission (first 24 hours of hospitalization) and after a 6-month follow-up. In the other two groups, only a basal sample was collected. Anti-Chlamydia and anti-Mycoplasma antibodies were measured by indirect immunofluorescence in all samples.Significant differences were observed between the basal sample and the one measured after a 6-month follow-up in patients with myocardial infarction with ST-segment elevation for Chlamydia (650+/-115.7 versus 307+/-47.5, p=0.0001) as well as Mycoplasma (36.5+/-5.0 versus 21.5+/-3.5, p=0.0004). The groups with ACS had higher anti-Chlamydia and anti-Mycoplasma serum antibody levels in the basal measurement, when compared to the patients with chronic coronary disease and the control group, but the differences were not statistically significant.The present study showed an association between the serum titers of anti-Chlamydia and anti-Mycoplasma antibodies in the acute phase of patients with unstable angina or myocardial infarction.

Chlamydia trachomatis urogenital infection in women with infertility

The study objective was to evaluate the prevalence of urogenital Chlamydia trachomatis (C.tr.) infection in women with diagnosed infertility. The study involved patients from the Department of Gynecological Endocrinology and from the Center for Reproductive Medicine "Kriobank" in Bialystok. Female patients (n=71), aged 23-41, were divided into two groups according to the main diagnosis: A--tubal infertility (23) and B--infertility of another origin (48). For direct testing, PCR method was used to detect C.tr. infection in cervical samples (Roche, Molecular Systems, N.J., USA). Specific IgA and IgG anti-chlamydial antibodies in the serum were determined by immunoenzymatic assay (medac, Hamburg, Germany). Diagnostic procedures were performed at the Centre for STD Research and Diagnostics in Bialystok. In group A, C.tr. infection was detected in: 8.7% patients, in group B--8.3%. Specific anti-C.tr. antibodies IgA were detected in: 13.0% in group A and 6.3% in group B, IgG respectively in 39.1% and in 10.4%. 1. C.tr. infection is very important etiological factor of female infertility. 2. The detection of specific antichlamydial antibodies is a valuable, noninvasive diagnostic procedure. 3. Infertile women should be routinely tested for C.tr. infection.

The influence of Chlamydia trachomatis infection on spontaneous abortions

The aim of the study was to evaluate the frequency of Chlamydia trachomatis (C.t.) infection among women who experienced a miscarriage. Patients referred to the Centre for STD Research and Diagnostics in Bialystok from the Department of Perinatology and from gynaecological outpatient clinics, after spontaneous abortion were enrolled in the study. C.t. infection diagnostics were performed among 76 women with 1 miscarriage and 44 patients with > or =2 miscarriages in anamnesis. Forty-six patients in the 2nd and the 3rd trimester of normal pregnancy served as a comparative group. Endocervical swabs as well as blood serum were obtained. To detect chlamydial DNA, direct PCR method was performed (Roche, Molecular Systems, N.J., USA). To detect IgA and IgG specific anti-chlamydial antibodies we used immunoenzymatic assay (medac, Hamburg, Germany). In patients with 1 miscarriage (gr.1), C.t. infection by means of PCR was detected in 11.8% of women (p=0.029), in patients with > or =2 miscarriages (gr.2) in 9.1% (p=0.198) and in the comparative group (gr.0) in 2.2%. Specific anti-chlamydial antibodies IgA class were detected in: 7.9 (p=0.082) in group 1, 4.5% (p=0.236) in group 2 and in 0% in group 0, and IgG class in 21.1% (p=0.024), 36.4% (p=0.000) and in 4.4%, respectively. 1. C.t. infection is an important causative agent of miscarriages in women. 2. C.t. infection diagnostic procedures should be considered in screening tests during pregnancy.

Immunoglobulin Gene Repertoire in Ocular Adnexa Lymphomas (OAL): Hints on the Nature of the Antigenic Stimulation

OALs arising in the ocular adnexae account for 15% of all extranodal lymphomas and are mostly represented by mucosa-associated lymphoid tissue (MALT)-type lymphomas (OAML). OAML have been described to be significantly associated, although with a variable geographic distribution, with Chlamydiophila psittaci (CP) infection, the etiologic agent of human psittacosis. Though the role played by Chlamydiae in OAML pathogenesis is also strongly supported by the observation of clinical remissions after bacterial eradication alone, the actual mechanisms have not been yet elucidated.Previous analysis of the Immunoglobulin Heavy Chain Variable (IGHV) genes in OAML showed a restricted repertoire with mutated genes and ongoing somatic mutations, thereby alluding to an origin from an antigen–experienced B cell, which has undergone antigen-selection; however, data on the potential antigenic elements stimulating OAML B lymphocytes are not available.In order to get hints on the potential ligands, we aimed at investigating the Immunoglobulin structure and, in particular, the molecular features of the antigen binding site (i.e. the HCDR3) of IG genes expressed by OAML. We analyzed the monoclonal IGHV-D-J rearrangements in a series of 30 OAML cases. IGHV3 subgroup genes predominated (24/30, 80%), followed by IGHV4 (4/30, 13.3%) and IGHV1 (2/30, 6,7%) subgroup genes, in keeping with the normal B cell IG gene repertoire. According to the 98% identity cut-off value, 23/30 sequences (76,7%) were defined as “mutated”, with a percentage of identity ranging between 89.3% and 97.7%, whereas the remainder (7/30 sequences; 23.3%) had “unmutated” IGHV genes. At individual gene level, IGHV3-23 and IGHV3-43 were the most frequently used genes (6/30 sequences, 20%, and 4/30 sequences, 13,3%, respectively); interestingly, the latter is rarely used in the normal repertoire. No significant correlations were found between IGHV gene usage and CP infection. HCDR3 length ranged from 9 to 30 amino acids (median 16) and 20/28 HCDR3 sequences showed an isoelectric point (pI) value >6.0, (in 10/28 pI>8.0), a feature shared with antibodies with anti–DNA reactivity. Shared epitope recognition was excluded by cluster analysis of HCDR3 sequences, also among OAML cases using the same IGHV genes. When we aligned HCDR3 sequences to a panel of 8214 unique IGHVD- J sequences from various types of normal, autoreactive or malignant B cell clones, we observed significant similarity between 3 OAML cases and 2 auto-reactive antibodies, present in rheumatoid arthritis and Sjoegren's syndrome, respectively, and 1 antibody with anti-thyroid peroxidase (TPO) reactivity. The latter case showed a HCDR3 similarity also with the IG gene of a Chronic Lymphocytic Leukemia case, a disease characterized by frequent expression of auto-reactive Igs. Interestingly, the same search performed using anti-Chlamydia antibodies did not show any significant similarity.In conclusion, these results suggest that OAML express a distinctive IG gene repertoire and may originate from B cells selected for their capacity to bind to auto-antigens in a similar way to what reported for gastric MALT lymphomas, where malignant B cells, instead of directly reacting against Helicobacter Pylori, are actually stimulated by tissue auto-antigens exposed during the inflammatory reaction, as confirmed by molecular analyses of antigen binding sites of the monoclonal IG. Our findings support the hypothesis that stimulation by auto-antigens, likely generated within an inflammatory background promoted by Chlamydial infection, may be the driving force also in OAML pathogenesis, rather than a direct action of the bacteria on B cells.

Structural and Immunochemical Analysis of the Lipopolysaccharide from Acinetobacter lwoffii F78 Located Outside Chlamydiaceae with a Chlamydia‐Specific Lipopolysaccharide Epitope

Chemical analyses, NMR spectroscopy, and mass spectrometry were used to elucidate the structure of the rough lipopolysaccharide (LPS) isolated from Acinetobacter lwoffii F78. As a prominent feature, the core region of this LPS contained the disaccharide alpha-Kdo-(2-->8)-alpha-Kdo (Kdo=3-deoxy-d-D-manno-oct-2-ulopyranosonic acid), which so far has been identified only in chlamydial LPS. In serological investigations, the anti-chlamydial LPS monoclonal antibody S25-2, which is specific for the epitope alpha-Kdo-(2-->8)-alpha-Kdo, reacted with A. lwoffii F78 LPS. Thus, an LPS was identified outside Chlamydiaceae that contains a Chlamydia-specific LPS epitope in its core region.

Risk factors for coronary artery disease in Indians

Background: A case control study was carried out to study the emerging risk factors for coronary artery disease in Indians. Methods: The diagnosis of coronary artery disease was based on correlation of clinical, biochemical, electrocardiography, echocardiography, treadmill testing and coronary arteriography findings. The study comprised 100 cases of coronary artery disease (acute coronary syndrome and chronic coronary artery disease) and 100 controls in two tertiary care service hospitals. The subjects were evaluated for total plasma homocysteine, insulin, C-reactive protein (CRP), lipoprotein fibrinogen and antichlamydial anti-bodies. Result: Male to female ratio was 10:1 in study group with similar predominance of males in controls. Mean age of the cases was 47 years (range 25-59 years) and that of controls was 43 years (range 23–56 years). 64% cases had acute coronary syndrome and 34% had chronic coronary artery disease. In the coronary artery disease population, 76% cases had hyperhomocyteinemia, 9% hyperinsulinaemia, 11% abnormal CRP values, 23% abnormal lipoprotein (a) levels, 40% IgG anti-chlamydial anti-bodies and only 11% had Ig M anti-chlamydial antibodies. In the control population, 72% had hyperhomocystinaemia and 6% hyperinsulinaemia while 23 % and 9% controls had IgG and IgM anti chlamydial antibodies respectively. In control group 19% cases had abnormal lipoprotein(a) levels and only 2% had abnormal C reactive protein values. Significant correlation of CAD was seen with CRP values and Ig G anti-chlamydial antibodies. Both the study group and controls had higher homocysteine levels than that observed in some Indian and Western studies. Conclusion: High C reactive protein levels and Ig G anti-chlamydial antibodies are associated with coronary artery disease in Indians. Insulin, lipoprotein A, fibrinogen, lgM anti-chlamydial antibodies and higher levels of total plasma homocysteine have no significant association with coronary artery disease.

CHRONIC CHLAMYDIA PNEUMONIAE INFECTION AND BRONCHIAL ASTHMA: IS THERE A LINK?

Purpose: Besides well-defined environmental causes, accumulating evidence suggests that respiratory tract infections play an important role in the pathogenesis of asthma. Among these Chlamydia pneumoniae infection has been discussed as possibly inducing the development of asthma. Methods: This study was designed to investigate the presence of anti chlamydial IgG, IgA, and IgM antibodies by ELISA in serum samples of 60 adults with a clinical history of asthma and 100 healthy age and sex matched controls. All the samples positive for Chlamydial genus specific IgG antibodies were then subjected to Chlamydia pneumoniae species specific IgG antibody ELISA. Results: The IgG anti chlamydial antibody-positivity rate in the patients with bronchial asthma (80%) was significantly higher in all age groups than that in the healthy age and sex matched controls (59%). No significant association was observed for IgA and IgM anti chlamydial antibodies. C. pneumoniae species specific IgG antibody seroprevalence was also found to be significantly higher in all age groups in comparison to controls (61.66% vs 38%). Conclusions: Serological evidence of chronic infection with C. pneumoniae was more frequent in patients with asthma compared with control subjects. Our results support the correlation of bronchial asthma and chronic infection with C. pneumoniae in Indian population.

Recent developments in the laboratory diagnosis of chlamydial infections

There are two main approaches to diagnosing infections by Chlamydia and Chlamydophila spp. in mammals and birds. The first involves the direct detection of the agent in tissue or swab samples, while the second involves the serological screening of blood samples for the presence of anti-chlamydial antibodies. Ultimately, the test that is used is dependent on the types of samples that are submitted to the diagnostic laboratory for analysis. The present paper gives an overview on methodologies and technologies used currently in diagnosis of chlamydial infections with emphasis on recently developed tests. The performance characteristics of individual methods, such as the detection of antigen in smears and in pathological samples, the isolation of the pathogen, various antibody detection tests and DNA-based methods utilising conventional and real-time PCR, as well as DNA microarray technology are assessed, and specific advantages and drawbacks are discussed. Further, a combination of a specific real-time PCR assay and a microarray test for chlamydiae is proposed as an alternative reference standard to isolation by cell culture.

Experimental enteric infection of gnotobiotic piglets with Chlamydia suis strain S45

Enteric chlamydial infections of pigs with Chlamydia ( C.) suis are frequent and often subclinical. The enteric pathogenicity of C. suis strain S45 was investigated in gnotobiotic piglets. Piglets from three litters ( n = 31) were inoculated with egg-grown chlamydiae at 2–3 days of age ( n = 17) or used as controls ( n = 14). They were observed for clinical signs, killed and necropsied sequentially at 2–13 days postinoculation (DPI). Feces were collected daily and investigated with an ELISA for chlamydial antigen. At necropsy, specimens were collected for histopathology and for immunohistochemical, PCR-based, and serological (complement fixation test, ELISA) detection of chlamydiae. Chlamydial replication and associated symptoms and lesions were observed from 2 to 13 DPI and were particularly pronounced within the first week PI. Clinical symptoms consisted of moderate-to-severe diarrhea, slight and transient anorexia, weakness and body weight loss. Immunohistochemistry and ELISA revealed that chlamydial replication was particularly marked at 2–4 DPI and primarily located in the small intestinal villus enterocytes. Further sites of replication included large intestinal enterocytes, the lamina propria and Tunica submucosa, and the mesenteric lymphnodes. Histopathological changes included moderate-to-severe villus atrophy with flattened enterocytes and focal villus tip erosions, and moderate mucosal inflammatory cell infiltrates and lymphangitis in the small intestine. PCR of spleen tissue and blood was mostly negative for chlamydiae , indicating that they did not substantially disseminate into the host up to 13 DPI. All sera were negative for anti-chlamydial antibodies. In conclusion, C. suis strain S45 elicited significant enteric disease and lesions in gnotobiotic piglets indicating its pathogenic potential for swine.

Serological diagnosis of Chlamydia infections: proposal of a cost-effective approach

Infections caused by genus Chlamydia are challenging for phisicians, as a results of a complicated pathogenesis and a variable clinical picture. Furthermore, potential sequelae following Chlamydia trachomatis, Chlamydia pneumoniae, Chlamydia psittaci infections are of clinical relevant interest. Serodiagnosis is a clue tool when the direct antigen research or the bacteria fragments detection is impaired. Some serological tests such as the ELISA or the indirect micro-immunofluorescence methods are routinely performed. To improve the diagnostic efficiency of these tests, a selective coating of specie-specific reactive antigens on microwells or on microscopic slides is proposed.A highly selective coating is essential to generate a specific immune response for each Chlamydia species and high levels of distinct IgA, IgG, IgM antibody classes.The goal of serology is the diagnostic value of results, therefore the correct choice of the best screening and confirmation test is of extreme relevance due to the clinical impact of results for the therapeutical approach and management of acute and chronic infections. In conclusion, a quantitative specific anti-Chlamydia IgG and IgA antibody detection is a useful method to improve the follow up of complicated chronic clinical sequelae.

Detection of anti-Chlamydia trachomatis antibodies in Patients with Acquired Immune Deficiency Syndrome in Abuja, Nigeria

Detection of anti-Chlamydia trachomatis antibodies in Patients with Acquired Immune Deficiency Syndrome in Abuja, Nigeria

Seroprevalence of <i>Entamoeba histolytica</i> Infection in Female Outpatients at a Sexually Transmitted Disease Sentinel Clinic in Tokyo, Japan

From 2003 to 2006, we surveyed the seroprevalence of amoebic infection in female outpatients at a gynecologist's office, which was designated as a sexually transmitted disease sentinel clinic by the Tokyo Metropolitan Government, using an enzyme-linked immunosorbent assay (ELISA). The annual rate of anti-Entamoeba histolytica (HM-1:IMSScl6 strain; HM-1) antibody-positive cases as detected by ELISA increased during that period, and anti-Chlamydia trachomatis antibodies were detected in 60%, i.e., 24 of 40 anti-HM-1 antibody-positive individuals, suggesting sexual transmission of E. histolytica. We designed an ELISA with better sensitivity using the antigen extracted from the virulence-augmented E. histolytica strains (LHM-1 and LLA526 strains) by liver-passaging in hamsters. The average ratios of the S/N value (optical density [OD] of sample/OD of negative control) of ELISA with either the LHM-1 or LLA526 antigen and that of ELISA with the HM-1 antigen were significantly higher in intestinal amoebiasis cases with low S/N values than in amoebic liver abscess cases. In the present study of the seroprevalence of E. histolytica infection, the sera testing positive with low S/N values (<10) by ELISA with HM-1 antigen exhibited higher S/N values by ELISA using LHM-1 and LLA526 antigens. This modification of the antigen preparation for ELISA is expected to be effective in detecting anti-E. histolytica antibodies from such asymptomatic patients who have low antibody titers.

Autoimmune response to Chlamydia trachomatis infection and in vitro fertilization outcome

This observational study was conducted in 235 patients undergoing IVF who had a cervical swab positive for Chlamydia trachomatis and who underwent antibiotic treatment until a negative cervical swab before IVF attempt. After oocyte retrieval, follicular fluids of 109 patients out of 228 still showed the presence of IgA antichlamydia antibodies and a significantly lower pregnancy and implantation rate; therefore we conclude that patients should undergo IVF procedure after serum antichlamydia IgA tests negative.

ChronicChlamydia pneumoniaeinfection and bronchial asthma: Is there a link?

Besides well-defined environmental causes, accumulating evidence suggests that respiratory tract infections play an important role in the pathogenesis of asthma. Among these Chlamydia pneumoniae infection has been discussed as possibly inducing the development of asthma. This study was designed to investigate the presence of anti chlamydial IgG, IgA, and IgM antibodies by ELISA in serum samples of 60 adults with a clinical history of asthma and 100 healthy age and sex matched controls. All the samples positive for Chlamydial genus specific IgG antibodies were then subjected to Chlamydia pneumoniae species specific IgG antibody ELISA. The IgG anti chlamydial antibody-positivity rate in the patients with bronchial asthma (80%) was significantly higher in all age groups than that in the healthy age and sex matched controls (59%). No significant association was observed for IgA and IgM anti chlamydial antibodies. C. pneumoniae species specific IgG antibody seroprevalence was also found to be significantly higher in all age groups in comparison to controls (61.66% vs 38%). Serological evidence of chronic infection with C. pneumoniae was more frequent in patients with asthma compared with control subjects. Our results support the correlation of bronchial asthma and chronic infection with C. pneumoniae in Indian population.

Bioinformatic and biochemical evidence for the identification of the type III secretion system needle protein of Chlamydia trachomatis.

Chlamydia spp. express a functional type III secretion system (T3SS) necessary for pathogenesis and intracellular growth. However, certain essential components of the secretion apparatus have diverged to such a degree as to preclude their identification by standard homology searches of primary protein sequences. One example is the needle subunit protein. Electron micrographs indicate that chlamydiae possess needle filaments, and yet database searches fail to identify a SctF homologue. We used a bioinformatics approach to identify a likely needle subunit protein for Chlamydia. Experimental evidence indicates that this protein, designated CdsF, has properties consistent with it being the major needle subunit protein. CdsF is concentrated in the outer membrane of elementary bodies and is surface exposed as a component of an extracellular needle-like projection. During infection CdsF is detectable by indirect immunofluorescence in the inclusion membrane with a punctuate distribution adjacent to membrane-associated reticulate bodies. Biochemical cross-linking studies revealed that, like other SctF proteins, CdsF is able to polymerize into multisubunit complexes. Furthermore, we identified two chaperones for CdsF, termed CdsE and CdsG, which have many characteristics of the Pseudomonas spp. needle chaperones PscE and PscG, respectively. In aggregate, our data are consistent with CdsF representing at least one component of the extended Chlamydia T3SS injectisome. The identification of this secretion system component is essential for studies involving ectopic reconstitution of the Chlamydia T3SS. Moreover, we anticipate that CdsF could serve as an efficacious target for anti-Chlamydia neutralizing antibodies.

Serological evidence of chronic Chlamydia pneumoniae infection in coronary artery disease

Background : Recent studies have suggested that Chlamydia pneumoniae infection could be involved in atherosclerosis and related clinical manifestations such as coronary artery disease, carotid artery stenosis and myocardial infarction. Methods : Serum IgG, IgM and IgA antibodies to chlamydia genus specific antigen were measured by enzyme linked immunosorbent assay (ELISA) in 100 cases of angiographically demonstrated coronary artery disease (CAD) and 100 randomly selected healthy individuals as controls after matching for age and sex. All the samples positive for chlamydia genus specific IgG antibodies were then subjected to Chlamydia pneumoniae species specific IgG antibody ELISA. Results : Seroprevalence of chlamydia genus specific IgG antibodies in control group was 59% with an increase in seropositivity with increasing age. The overall seroprevalence of IgG antibodies was 76% in CAD group and the prevalence was significantly high in all age groups as compared to controls. The odds ratio was 2.20 for seropositivity of chlamydia genus specific IgG antibodies in patients with myocardial infarction (MI) and/or angina than in control group. No significant association was observed for IgA and IgM anti-chlamydial antibodies. The odds ratio for prevalence of Chlamydia pneumoniae species specific IgG antibodies in CAD patients increased to 2.55 in comparison to age and sex matched controls. Conclusion : Current study supports the reported association between C pneumoniae infection and CAD in Indian population.

Antichlamydial antibodies and citric acid in patients with chronic prostatitis.

.IntroductionThe aim of the study was to evaluate the correlation between the presence of anti-C. trachomatis (C.t.) antibodies in serum and expressed prostatic secretions (EPS) and the concentration of citric acid in patients with chronic prostatitis.Materials and MethodsThe study involved 34 men with chronic prostatitis. The leukocyte count, presence of anti-C.t. antibodies (IgA, IgG), and citric acid concentration were determined in the EPS. The serum was examined for IgM, IgA, and IgG anti-C.t. antibodies. Specific antibodies were determined using the EIA method. The concentration of citric acid was measured using the ultraviolet method.ResultsInflammation of the prostate (≥10 PMN) was found in 61.8% of the patients. A reduction in citric acid concentration in the EPS was detected in 58.8% of the men. Specific serum antibodies were detected in 58.8% of the patients, including 23.5% with IgM, 32.4% with IgA, and 44.1% with IgG. In all patients, serum IgM and IgA antibody titers were low, while those of IgG antibodies were strongly positive in 46.7% of the patients. Anti-C.t. antibodies in the EPS were detected in 44.1% of the patients, including 32.4% with IgA and 35.3% with IgG. In contrast to serum, the titers of IgG antibodies in the EPS were low in all the patients, while those of IgA were strongly positive in 54.5% of cases. In patients with positive serological outcomes, 85% had reduced concentrations of citric acid.ConclusionsThe occurrence of anti-C.t. antibodies is usually accompanied by a decrease in the concentration of citric acid in the prostatic secretion.

Past chlamydial infection is not associated with primary fallopian tube carcinoma

We conducted a retrospective seroepidemiological study to evaluate the relationship between past chlamydial infection and primary fallopian tube carcinoma (PFTC). Postoperative serum samples were drawn from 79 consecutive patients treated for PFTC in 1985–2000. For each case two controls were selected. Serum samples were analysed for IgG antibodies to different C. trachomatis serotype pools and to C. pneumoniae. Seropositivity in general or serum antibody levels to different C. trachomatis serovars or C. pneumoniae did not differ between PFTC patients and controls. The lack of association between anti-chlamydial antibodies and PFTC suggests that past chlamydial infection does not play a role in the etiopathogenesis of PFTC. However, because chlamydial infection is common at young age and PFTC develops decades later, we cannot definitively exclude the possibility that C.trachomatis contributes to the development of PFTC.

642 Chlamydia pneumoniae liver gene expression and anti-chlamydial antibody response in patients with primary biliary cirrhosis

642 Chlamydia pneumoniae liver gene expression and anti-chlamydial antibody response in patients with primary biliary cirrhosis

Development of diabetes in non‐obese diabetic mice promotes Chlamydia pneumoniae dissemination from lung to peripheral blood

We examined a possible association between development of diabetes in non-obese diabetic (NOD) mice and dissemination of Chlamydia (Chlamydophila) pneumoniae from lung to peripheral blood. By real-time reverse transcription-polymerase chain reaction (RT-PCR) with primers for C. pneumoniae 16S rRNA, following multiple intranasal inoculations, we detected bacteria in lung in NOD mice with diabetes (38.5%) as well as Institute of Cancer Research, USA (ICR) mice (40%), but prevalence of bacteria in NOD mice without diabetes (pre-diabetic NOD mice and non-diabetic retired NOD mice) was very low (4.8%). The bacteria were only detected in peripheral blood mononuclear cells (PBMCs) cultured with hydrocortisone of the NOD mice with diabetes (53.8%). Results of immunostaining with fluorescein isothiocyanate-conjugated antichlamydia monoclonal antibody also showed the presence of bacterial antigens in the lungs and the PBMCs judged as positive by the RT-PCR. However, C. pneumoniae from cultured PBMCs of all NOD mice was undetected by cultivation method with inclusion-forming units assay. In addition, no influence of C. pneumoniae intranasal inoculation on development of diabetes in NOD mice was confirmed. Thus, the development of diabetes in NOD mouse appears to be one of critical factors for promoting the dissemination of C. pneumoniae from lung to peripheral blood.