Infectious complications of the primary immunodeficiencies

The primary manifestation of the immunodeficiencies is undue susceptibility to infection. This means too many, too severe, too prolonged, too complicated and too unusual infections. Infections in immunodeficiency have a characteristic cause depending on the nature of the immune deficiency. Antibody deficiencies are associated with infections with gram-positive infections. Cellular immune deficiencies are associated with mycobacterial, protozoan, fungus, virus, and opportunistic bacterial infection. Phagocytic disorders are associated with staphylococcal, fungal, and gram-negative organisms. Complement disorders are associated by neisserial infections. Infections have also been implicated in the pathogenesis of some immunodeficiencies in some circumstances. These include human T lymphotropic virus type III (HTLV-III), rubella virus, cytomegalovirus, and Epstein-Barr virus. Several infectious syndromes in specific immunodeficiencies have been identified. Examples include enteric cytopathic human orphan (ECHO) virus encephalitis in agammaglobulinemia, and meningococcal meningitis in C6 deficiency. Infections can also be induced by live vaccines given in immunodeficiency (e.g., paralytic polio in agammaglobulinemia.) Unusual infectious syndromes will be illustrated including parainfluenza infection in severe combined and immunodeficiency, Legionella pneumonia in chronic granulomatous disease, and Cryptosporidium infection in hyper-IgM immunodeficiency.     

Kaposi's sarcoma-associated herpesvirus serology in Europe and Uganda: multicentre study with multiple and novel assays

A multicentre study was undertaken to define novel assays with increased inter-assay concordance, sensitivity, specificity and predictive value for serological diagnosis of human herpesvirus type 8 (HHV-8) infection. A total of 562 sera from European and Ugandan human immunodeficiency virus (HIV)-infected or uninfected individuals with or without Kaposi's sarcoma (KS) and blood donors were examined under code by 18 different assays in seven European laboratories. Sera from KS patients and all non-KS sera found positive by at least 70%, 80%, or 90% of the assays were considered "true positive." The validity of the assays was then evaluated by univariate logistic regression analysis. Two immunofluorescence assays (IFA) for detection of antibodies against HHV-8 lytic (Rlyt) or latent (LLANA) antigens and two enzyme-linked-immunosorbent assays (ELISA) (M2, EK8.1) for detection of antibodies against HHV-8 structural proteins were found to be highly concordant, specific, and sensitive, with odds ratios that indicated a high predictive value. When used together, the two IFA (Rlyt-LLANA) showed the best combination of sensitivity (89.1%) and specificity (94.9%). The performance of these assays indicate that they may be used for the clinical management of individuals at risk of developing HHV-8 associated tumours such as allograft recipients.     

Discriminatory power and reproducibility of novel DNA typing methods for Mycobacterium tuberculosis complex strains

In recent years various novel DNA typing methods have been developed which are faster and easier to perform than the current internationally standardized IS6110 restriction fragment length polymorphism typing method. However, there has been no overview of the utility of these novel typing methods, and it is largely unknown how they compare to previously published methods. In this study, the discriminative power and reproducibility of nine recently described PCR-based typing methods for Mycobacterium tuberculosis were investigated using the strain collection of the interlaboratory study of Kremer et al. This strain collection contains 90 M. tuberculosis complex and 10 non-M. tuberculosis complex mycobacterial strains, as well as 31 duplicated DNA samples to assess reproducibility. The highest reproducibility was found with variable numbers of tandem repeat typing using mycobacterial interspersed repetitive units (MIRU VNTR) and fast ligation-mediated PCR (FLiP), followed by second-generation spoligotyping, ligation-mediated PCR (LM-PCR), VNTR typing using five repeat loci identified at the Queens University of Belfast (QUB VNTR), and the Amadio speciation PCR. Poor reproducibility was associated with fluorescent amplified fragment length polymorphism typing, which was performed in three different laboratories. The methods were ordered from highest discrimination to lowest by the Hunter-Gaston discriminative index as follows: QUB VNTR typing, MIRU VNTR typing, FLiP, LM-PCR, and spoligotyping. We conclude that both VNTR typing methods and FLiP typing are rapid, highly reliable, and discriminative epidemiological typing methods for M. tuberculosis and that VNTR typing is the epidemiological typing method of choice for the near future.     

Calretinin expression in human normal and neoplastic tissues: a tissue microarray analysis on 5233 tissue samples

Calretinin is a calcium-binding protein expressed in different normal and neoplastic tissues. Early studies suggested that calretinin is a useful marker to differentiate adenocarcinomas from malignant mesotheliomas of the lung, but subsequent work has shown that calretinin can be expressed in several other tumor types. To systematically investigate the epidemiology of calretinin expression in normal and neoplastic tissues, we used tissue microarrays (TMAs) to analyze the immunohistochemically detectable expression of calretinin in 5233 tissue samples from 128 different tumor categories and 76 different normal tissue types. At least 1 case with weak expression could be found in 74 of 128 (58%) different tumor types and 46 entities (36%) had at least 1 tumor with strong positivity. In normal tissues, a particularly strong expression was found in Leydig cells of the testis, neurons of the brain, theca-lutein and theca interna cells of the ovary, and mesothelium. In tumors, strong calretinin expression was most frequently found in malignant mesotheliomas (6 of 7), Leydig cell tumors of the testis (5 of 5), adenomas of adrenal gland (5 of 9), and adenomatoid tumors (4 of 9). In summary, calretinin is frequently expressed in many different tumor types. Metastases of various different origins must be included in the differential diagnosis of calretinin-positive pleura tumors.     

Molecular typing of Mycobacterium tuberculosis by mycobacterial interspersed repetitive unit-variable-number tandem repeat analysis, a more accurate method for identifying epidemiological links between patients with tuberculosis

IS6110 fingerprinting of Mycobacterium tuberculosis is the standard identification method in studies on transmission of tuberculosis. However, intensive epidemiological investigation may fail to confirm transmission links between patients clustered by IS6110-restriction fragment length polymorphism (RFLP) typing. We applied typing based on variable numbers of tandem repeats (VNTRs) of mycobacterial interspersed repetitive units (MIRUs) to isolates from 125 patients in 42 IS6110 clusters, for which thorough epidemiological data were available, to investigate the potential of this method in distinguishing epidemiologically linked from nonlinked patients. Of seven IS6110 clusters without epidemiological links, five were split by MIRU-VNTR typing, while nearly all IS6110 clusters with proven or likely links displayed conserved MIRU-VNTR types. These results provide molecular evidence that not all clusters determined on the basis of multibanded IS6110 RFLP patterns necessarily reflect transmission of tuberculosis. They support the use of MIRU-VNTR typing as a more reliable and faster method for transmission analysis.     

Clinical validation of a new real-time PCR assay for detection of enteroviruses and parechoviruses, and implications for diagnostic procedures.

BACKGROUND: Enteroviruses (EV) and parechoviruses (HPeV) are the most common causes of aseptic meningitis, encephalitis and sepsis-like syndrome in neonates. Detection by nucleic acid amplification methods improves patient management. OBJECTIVE: Development of a real-time PCR assay on a LightCycler for simultaneous detection of EV, HPeV and an internal control to monitor inhibition. STUDY DESIGN: We investigated the value of the new assay, prospectively, in a variety of samples from patients suspected of having viral meningitis or sepsis-like syndrome. RESULTS: The assay detected 64 EV serotypes and HPeV types 1-4. Of 186 patients, 63 (33.9%) were EV positive and 18 (9.7%) HPeV positive in one or more samples. In 43 of 159 feces and 6 of 57 throat samples viral culture and PCR were positive. With real-time PCR 27 extra EV and 19 HPeV positives were found. Blood and CSF were present from 33 patients. In 19 patients blood and CSF were positive, one was only positive in CSF, two were only positive in blood, 11 were negative. From 96 patients CSF and/or blood samples were tested and compared to results in throat and/or feces samples. Forty patients were EV-PCR and 14 HPeV-PCR positive in blood and/or CSF. All of these were confirmed by a positive PCR for the respective virus in feces and/or throat. CONCLUSIONS: Simultaneous detection of EV and HPeV with this two-step real-time PCR is specific, faster and more sensitive than viral culture. All systemic infections (blood or CSF positive) were confirmed in feces. Culture is no longer necessary for clinical diagnosis and should only be performed on PCR-positive samples to obtain isolates for typing purposes. Application of this assay is an important improvement for patient management since the outcome of the analysis is available within the time frame of clinical decision-making.