Silva Seraceni

The role of stage-specific oligonucleotide primers in providing effective laboratory support for the molecular diagnosis of reactivated Toxoplasma gondii encephalitis in patients with AIDS

The switch from bradyzoites to tachyzoites is the fundamental pathogenic event that leads to Toxoplasma gondii encephalitis (TE) in patients with AIDS. Distinction between these stages is difficult, particularly when specific treatment has been started. A new approach consisting of a nested PCR (n-PCR) assay was performed on cerebrospinal fluid (CSF) specimens collected from AIDS patients with TE before or after antiparasitic therapy was initiated, to assess the efficacy of primer sets which amplify target sequences expressed on bradyzoites (SAG4 and MAG1), tachyzoites (SAG1) or both stages (B1) of T. gondii. CSF specimens were obtained from 46 patients with AIDS, of whom 27 had TE (16 first episode, 11 relapse) and 19 had other AIDS-related brain lesions (AIDS-OBL) in the absence of TE. CSF specimens from 26 HIV-negative and immunocompetent patients were also checked. All samples were tested with different primer pairs targeting the B1, SAG-1, SAG-4 and MAG-1 genes. With B1, 75% of patients with first episodes of TE were positive, compared with 36.3% of those with relapse of TE and 5.2% of those with AIDS-OLB. The SAG1 gene yielded positive values in 28.7% and 45.4% of patients with first episodes of TE or relapse of TE, respectively, and in none of the controls. With the SAG4 and MAG1 genes, 72.7% of patients with relapse of TE were detected, compared with 25% of patients with first episodes of TE and 5.2% with AIDS-OLB. None of the HIV-negative subjects showed positive PCR reactions. These results demonstrate that specific primers for the genes SAG4, MAG1 and SAG1 may be useful in AIDS patients with relapse of TE, in whom the use of PCR targeting the B1 gene may fail to detect DNA, especially when prophylaxis or treatment has been started.

Molecular evidence of Ureaplasma urealyticum and Ureaplasma parvum colonization in preterm infants during respiratory distress syndrome.

BackgroundUreaplasma urealyticum and U. parvum have been associated with respiratory diseases in premature newborns, but their role in the pathogenesis of the respiratory distress syndrome (RDS) is unclear. The aim of this study was to detect, using molecular techniques, the role of Mycoplasma spp. and Ureaplasma spp. in respiratory secretion and blood specimens of preterm newborns with or without RDS and to evaluate the prevalence of perinatal U. urealyticum or U. parvum infection. The influence of chemotherapy on the clinical course was also evaluated.MethodsTracheal aspirate or nasopharingeal fluid samples from 50 preterm babies with (24) or without RDS (26) were analysed for detection of U. urealyticum and U. parvum by culture identification assay and PCR. Sequencing analysis of amplicons allowed us to verify the specificity of methods. Clarithromycin (10 mg kg-1 twice a day) was administered in ureaplasma-positive patients who presented clinical signs of RDS.Results15/24 neonates with RDS (p < 0.001) and 4/26 without RDS were found PCR-positive for U. urealyticum or U. parvum. Culture identification assay was positive in 5/50 newborns, three of which with RDS. Sequencing analyses confirmed the specificity of these methods. Association of patent ductus arteriosus with ureaplasma colonization was more statistically significant (p = 0.0004) in patients with RDS than in those without RDS.ConclusionColonization of the lower respiratory tract by Ureaplasma spp. and particularly by U. parvum in preterm newborns was related to RDS. The routine use of molecular methods could be useful to screen candidate babies for etiologic therapy.

Chlamydophila pneumoniae Infection and Its Role in Neurological Disorders

Chlamydophila pneumoniae is an intracellular pathogen responsible for a number of different acute and chronic infections. The recent deepening of knowledge on the biology and the use of increasingly more sensitive and specific molecular techniques has allowed demonstration of C. pneumoniae in a large number of persons suffering from different diseases including cardiovascular (atherosclerosis and stroke) and central nervous system (CNS) disorders. Despite this, many important issues remain unanswered with regard to the role that C. pneumoniae may play in initiating atheroma or in the progression of the disease. A growing body of evidence concerns the involvement of this pathogen in chronic neurological disorders and particularly in Alzheimers disease (AD) and Multiple Sclerosis (MS). Monocytes may traffic C. pneumoniae across the blood-brain-barrier, shed the organism in the CNS and induce neuroinflammation. The demonstration of C. pneumoniae by histopathological, molecular and culture techniques in the late-onset AD dementia has suggested a relationship between CNS infection with C. pneumoniae and the AD neuropathogenesis. In particular subsets of MS patients, C. pneumoniae could induce a chronic persistent brain infection acting as a cofactor in the development of the disease. The role of Chlamydia in the pathogenesis of mental or neurobehavioral disorders including schizophrenia and autism is uncertain and fragmentary and will require further confirmation.

Under the Microscope: Focus on Chlamydia pneumoniae Infection and Multiple Sclerosis

Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease of the Central Nervous System (CNS) of supposed autoimmune origin whose etiology still remains unknown. Epidemiological studies suggest that MS pathogenesis could be related to an infection superimposed on a predisposing genetic background. However, at present, no direct evidence for an infectious implication in MS autoimmunity exists. Recently, the potential role of Chlamydia pneumoniae as a causative agent of MS has received increasing attention. After the initial high rates reported for molecular and culture demonstration of C. pneumoniae in cerebrospinal fluid (CSF) of MS patients, the association between C. pneumoniae and MS was intensively investigated with controversial results. Seroepidemiological reports did not show any strong association between C. pneumoniae infection and the risk of MS. Isolation techniques failed to detect C. pneumoniae in CSF and brain tissue of MS patients. Polymerase chain reaction (PCR) evidence of C. pneumoniae in CSF and intrathecal synthesis of anti-C. pneumoniae IgG have been undetectable in MS patients or, if present, were not selectively associated with MS, but were shared by several inflammatory neurological conditions. Nevertheless, in a subgroup of MS patients, an association between PCR positivity for C. pneumoniae in CSF and disease activity was found. Intrathecal production of anti-C. pneumoniae high-affinity IgG predominated in MS progressive forms and metabolically active C. pneumoniae was identified in CSF. C. pneumoniae was recognized in CSF and brain tissue at immunohistochemical, molecular and ultrastructural levels. C. pneumoniae was also able to induce the animal model of MS. This growing body of data does not support a central role for C. pneumoniae as a candidate in MS pathogenesis, but suggests that, in a subset of MS patients, C. pneumoniae could induce a chronic persistent brain infection acting as a cofactor in the development of the disease. Thus, the actual involvement of C. pneumoniae in MS still remains to be elucidated.

Epstein-Barr virus-specific antibody response in cerebrospinal fluid and serum of patients with multiple sclerosis.

Cerebrospinal fluid and serum levels and intrathecal synthesis of anti-Epstein—Barr virus (EBV) IgG were measured by enzyme-linked immunosorbent assay in 80 relapsing—remitting multiple sclerosis patients grouped according to clinical and magnetic resonance imaging (MRI) evidence of disease activity. Eighty patients with other inflammatory neurological disorders (OIND) and 80 patients with non-inflammatory neurological disorders (NIND) served as neurological controls. Cerebrospinal fluid concentrations were higher in OIND than in multiple sclerosis (p < 0.0001) and NIND (p < 0.01) for anti-viral-capsid-antigen (anti-VCA) IgG, in multiple sclerosis than in NIND (p < 0.01) and in OIND than in NIND (p < 0.05) for anti-EBV nuclear antigen-1 (EBNA-1) IgG. Serum levels were more elevated in OIND than in multiple sclerosis (p < 0.05) and in MRI inactive than in MRI active multiple sclerosis (p < 0.0001) for anti-VCA IgG, and in multiple sclerosis than in OIND and NIND (p < 0.01) for anti-EBNA-1 IgG. Serum titres of anti-VCA and anti-EBNA-1 IgG were also positively (p < 0.05) and inversely (p < 0.001) correlated, respectively, with the Expanded Disability Status Scale. An intrathecal IgG production of anti-VCA and anti-EBNA-1 IgG, as indicated by Antibody Index, was present only in a limited number of multiple sclerosis patients and controls (range from 1.3 to 6.3%). These findings do not support a direct pathogenetic role of EBV-targeted humoral immune response in multiple sclerosis.

Treatment with recombinant tissue plasminogen activator (r-TPA) induces neutrophil degranulation in vitro via defined pathways

Thrombolysis is recommended for reperfusion following acute ischemic stroke (AIS), but its effects on stroke-associated injury remain to be clarified. Here, we investigated the effects of recombinant tissue plasminogen activator (r-tPA) on neutrophil pathophysiology in vitro and in a case-control study with AIS patients submitted (n=60) or not (n=30) to thrombolysis. Patients underwent radiological and clinical examination as well as blood sampling at admission and after 1, 7 and 90days. In vitro, 30-min incubation with 0.1-1 mg/ml r-tPA induced neutrophil degranulation in different substrate cultures. Pre-incubation with kinase inhibitors and Western blot documented that degranulation was associated with activation of PI3K/Akt and ERK1/2 pathways in Teflon dishes and PI3K/Akt in polystyrene. In thrombolysed patients, a peak of neutrophil degranulation products (matrix metalloproteinase [MMP]-9, MMP-8, neutrophil elastase and myeloperoxidase), was shown during the first hours from drug administration. This was accompanied by serum augmentation of protective tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. An increased rate of haemorrhagic transformations on day 1 after AIS was shown in thrombolysed patients as compared to non-thrombolysed controls. In conclusion, r-tPA treatment was associated with in vitro neutrophil degranulation, indicating these cells as potential determinants in early haemorrhagic complications after thrombolysis in AIS patients.

Molecular identification and antibody testing of Chlamydophila pneumoniae in a subgroup of patients with HIV-associated dementia complex. Preliminary results.

Chlamydophila pneumoniae DNA was investigated by polymerase chain reaction (PCR), in cerebrospinal fluid (CSF) specimens from patients suffering from HIV-1-associated dementia complex (HADC). Four (17.3%) cases of C. pneumoniae infection were identified among 23 HADC individuals with DNA amplification of major outer membrane protein (MOMP) gene and 16S rRNA gene sequences. Sequence analysis revealed significant homologies with C. pneumoniae compared to Chlamydia trachomatis and Chlamydia psittaci. High mean levels of CSF specific anti-C. pneumoniae antibodies and C. pneumoniae antibody specific index values significantly elevated were also found by enzyme-linked immunosorbent assay (ELISA) in these patients. The results suggest a hypothetical role of C. pneumoniae in the pathogenesis or progression of HADC.

Evidence of cerebrospinal fluid free kappa light chains in AIDS patients with Toxoplasma gondii encephalitis

Cerebrospinal fluid (CSF) free light chains of kappa or lambda (FLC kappa/lambda) type were investigated by affinity mediated blotting technique (AMI) and ELISA in 28 patients of which nine with AIDS and Toxoplasma gondii encephalitis (AIDS, TE), 11 with AIDS with or without other CNS AIDS-related opportunistic infections (non-TE AIDS) and eight control patients with or without inflammatory neurological disorders (control group). CSF restricted oligoclonal FLC bands either of k or lambda isotype or both were found by AMI in 18 (90%) out of 20 AIDS patients, while a CSF pattern predominantly characterized by FkappaLC rather than FlambdaLC was observed in eight (88.8%) out of nine TE patients. No FLC components were detected in the matched sera of TE or non-TE AIDS patients or in the CSF and sera from control group. The anti-parasite-specific FkappaLC CSF/serum mean levels and the T. gondii-specific FkappaLC index values were found by ELISA to be significantly more elevated in TE patients when compared to non-TE AIDS or control group. These findings suggest that the increased production of T. gondii-specific FkappaLC could provide insights into pathogenesis of reactivated TE in immunocompromised patients and may have important diagnostic usefulness.

Detection of Chlamydophila pneumoniae in patients with arthritis: significance and diagnostic value.

The aim of this study was to assess the potential clinical implications of Chlamydophila pneumoniae in patients with acute and chronic arthritic diseases and to investigate whether blood monocytes might reflect a concomitant synovial or persistent systemic infection. C. pneumoniae was investigated with advanced PCR and reverse transcriptase (RT) PCR techniques targeting different genes and combined with cell line cultures, in synovial fluid (SF) and peripheral blood mononuclear cell (PBMC) specimens collected from 28 patients with arthritis. Five out of twenty-eight patients (17.8%) were found to have C. pneumoniae DNA in either SF or PBMC specimens. Their diagnosis was reactive arthritis (ReA), S.A.P.H.O syndrome, psoriatic arthritis, undifferentiated oligoarthritis (UOA) and ankylosing spondylitis (AS). Specimens from patients with UOA and AS had also mRNA transcripts but those from AS yielded C. pneumoniae growth after co-culture. Moreover, C. pneumoniae DNA levels measured by Real-Time PCR (LightCycler) were higher in PBMC specimens compared to those found in SF at the end of antibiotic treatment. C. pneumoniae may have a role as triggering factor also in chronic arthritides including AS. The combined use of culture and molecular tools increases detection rates and improves the overall sensitivity, suggesting their potential use to detect C. pneumoniae. The different kinetics of bacterial DNA at both peripheral and synovial levels should be taken into consideration when monitoring and evaluating the effectiveness of antibiotic treatment.

Chlamydia pneumoniae-specific intrathecal oligoclonal antibody response is predominantly detected in a subset of multiple sclerosis patients with progressive forms

The purpose of this study was to verify the actual involvement of Chlamydia pneumoniae in multiple sclerosis (MS) by the evaluation of its specific intrathecal humoral immune response in MS. We measured by enzyme-linked immunosorbent assay (ELISA) technique cerebrospinal fluid (CSF) and serum levels of anti-C. pneumoniae immunoglobulin G (IgG) in 27 relapsing-remitting (RR), 9 secondary progressive (SP), and 5 primary progressive (PP) MS patients, grouped according to clinical and magnetic resonance imaging (MRI) evidence of disease activity. Twenty-one patients with other inflammatory neurological disorders (OIND) and 21 with noninflammatory neurological disorders (NIND) were used as controls. Quantitative intrathecal synthesis of anti-C. pneumoniae IgG was determined by antibody-specific index (ASI), whereas the presence of C. pneumoniae—specific CSF oligoclonal IgG bands was assessed by antigen-specific immunoblotting. ASI values indicative of C. pneumoniae—specific intrathecal IgG synthesis were present in a small proportion of MS (29.3%), OIND (33.3%), and NIND (4.8%) patients and were significantly more frequent (P <.05) in total MS and in OIND than in NIND and in SP (P <.01) and PP MS (P <.05) than in RR MS. C. pneumoniae—specific CSF-restricted OCB were detected only in three SP, one PP, and one RR MS patients. These findings suggest that an intrathecal production of anti-C. pneumoniae IgG is part of humoral polyreactivity driven by MS chronic brain inflammation. However, an intrathecal release of C. pneumoniae—specific oligoclonal IgG can occur in a subset of patients with MS progressive forms in whom a C. pneumoniae— persistent brain infection may play a pathogenetic role.