Alloimmunization to platelets in heavily transfused patients with sickle cell disease

Bone marrow transplantation (BMT) is now an option for some patients with sickle cell disease (SCD). Many SCD patients are multiply transfused with red blood cells (RBCs), and may be immunized to alloantigens other than erythrocyte antigens. Because platelet refractoriness is a significant complication during BMT, we wished to determine the prevalence of alloimmunization to platelets in transfused SCD patients. Sera collected from 47 transfused and 14 untransfused SCD patients were screened for HLA and platelet-specific antibodies. Transfusion and RBC antibody histories were reviewed. A subset of the patients were rescreened 1 year later. Eighty-five percent of patients with at least 50 RBC transfusions (22 of 26), 48% of patients with less than 50 transfusions (10 of 21), and none of 14 untransfused patients demonstrated platelet alloimmunization (P < .05). Platelet alloimmunization was more prevalent than RBC alloimmunization (20% to 30%). Half of the platelet reactivity was chloroquine-elutable. Eighteen of 22 patients (82%) on chronic RBC transfusion remained platelet-alloimmunized 11 to 22 months after initial testing. In summary, 85% of heavily transfused SCD patients are alloimmunized to HLA and/or platelet-specific antigens. These patients may be refractory to platelet transfusion, a condition that would increase their risk during BMT. Leukodepletion in the transfusion support of SCD patients should be considered to prevent platelet alloimmunization.     

Human papillomavirus and oral disease – emerging evidence: a review

Human papillomavirus (HPV) infections have received considerable attention in recent years. Of the 120 or so known types of the virus, some cause a variety of benign wart‐like lesions of the skin and genital and oral mucosae, whilst others are aetiologically associated with cervical and anogenital cancers. Recent epidemiologic evidence suggests that HPV may also be an independent risk factor for oropharyngeal cancer. In this context it has been suggested that HPV virus may modulate the process of carcinogenesis in some tobacco and alcohol induced oropharyngeal cancers and act as the primary oncogenic agent for inducing carcinogenesis among non‐smokers. Dental practitioners have a major role in detecting all lesions of the oral mucosa caused, or possibly caused, by HPV. This paper briefly reviews the current state of knowledge of molecular and clinical aspects of HPV infections of the oral mucosa.     

Platelet-derived growth factor in vivo: levels, activity, and rate of clearance

Platelet-derived growth factor (PDGF) is a potent mitogen for many cultured connective tissue cells. It is present in concentrated form within the platelet alpha-granules and is believed to be released during platelet degranulation at sites of vascular injury. We have used a sensitive radioreceptor assay to measure PDGF levels in whole blood serum from normal humans [17.5 +/- 3.1 (SD) ng/mL] and baboons (2.7 +/- 1.2 ng/mL). PDGF was not detected in plasma from either species. In addition, plasma was found to substantially reduce the ability of added purified PDGF to bind to the cell surface PDGF receptor on cultured cells, suggesting that plasma may contain a PDGF-binding protein that would serve to inactivate PDGF released into plasma. Calculations of PDGF concentrations in serum have been corrected for the effects of the binding protein. 125I-PDGF injected intravenously into normal baboons was cleared rapidly from the plasma (t1/2 = two minutes). The rapid clearance of 125I-PDGF did not result from iodination damage, as purified unlabeled PDGF was cleared with comparable kinetics. The rapid clearance of purified and iodinated PDGF did not result from changes in PDGF structure during purification or from removal of PDGF-associated proteins during purification, as PDGF present in freeze-thaw lysates of fresh platelets was cleared equally rapidly. We conclude that release of PDGF at sites of vascular injury would greatly increase the local concentration of PDGF and that PDGF not localized to the site of injury would be rapidly cleared from the circulation.     

Exosomal vaccines containing the S protein of the SARS coronavirus induce high levels of neutralizing antibodies

Infection with the SARS-associated coronavirus (SARS-CoV) induces an atypical pulmonary disease with a high lethality rate. Although the initial SARS epidemic was contained, sporadic outbreaks of the disease still occur, suggesting a continuous need for a vaccine against this virus. We therefore explored exosome-based vaccines containing the spike S proteins of SARS-CoV. S-containing exosomes were obtained by replacing the transmembrane and cytoplasmic domains of the S protein by those of VSV-G. The immunogenicity and efficacy of the S-containing exosomes were tested in mice and compared to an adenoviral vector vaccine expressing the S protein. Both, S-containing exosomes and the adenoviral vector vaccine induced neutralizing antibody titers. After priming with the SARS-S exosomal vaccine and boosting with the adenoviral vector the neutralizing antibody titers exceeded those observed in the convalescent serum of a SARS patient. Both approaches were effective in a SARS-S-expressing tumor challenge model and thus warrant further investigation.     

SOS1 is the second most common Noonan gene but plays no major role in cardio-facio-cutaneous syndrome

Background

Heterozygous gain‐of‐function mutations in various genes encoding proteins of the Ras‐MAPK signalling cascade have been identified as the genetic basis of Noonan syndrome (NS) and cardio‐facio‐cutaneous syndrome (CFCS). Mutations of SOS1, the gene encoding a guanine nucleotide exchange factor for Ras, have been the most recent discoveries in patients with NS, but this gene has not been studied in patients with CFCS.

Methods and results

We investigated SOS1 in a large cohort of patients with disorders of the NS–CFCS spectrum, who had previously tested negative for mutations in PTPN11, KRAS, BRAF, MEK1 and MEK2. Missense mutations of SOS1 were discovered in 28% of patients with NS. In contrast, none of the patients classified as having CFCS was found to carry a pathogenic sequence change in this gene.

Conclusion

We have confirmed SOS1 as the second major gene for NS. Patients carrying mutations in this gene have a distinctive phenotype with frequent ectodermal anomalies such as keratosis pilaris and curly hair. However, the clinical picture associated with SOS1 mutations is different from that of CFCS. These findings corroborate that, despite being caused by gain‐of‐function mutations in molecules belonging to the same pathway, NS and CFCS scarcely overlap genotypically.     

Myokardiales Pumpversagen bei dilatativer Kardiomyopathie und Phäochromozytom

Zusammenfassung Bei einer 37 j?hrigen, bisher gesunden Patientin entwickelte sich eine über 2 Monate progrediente Dyspnoe. Radiologisch und echokardiographisch zeigte sich eine massive Dilatation s?mtlicher Herzh?hlen mit biventrikul?ren Thromben und eine stark herabgesetzte Kontraktilit?t. Die Endomyokardbiopsien wurden von 2 Instituten als Myokarditis eingestuft. Im weiteren Verlauf entwickelten sich thrombembolische Komplikationen und ein therapierefrakt?res Pumpversagen, in dem die Patientin schlie?lich verstarb. Bei der Obduktion fand sich au?er einem dilatierten 600 g schweren Herzen mit biventrikul?ren Thromben ein klinisch bisher unbekanntes Ph?ochromozytom der linken Nebenniere. Die eingehende histologische und immunhistologische Aufarbeitung des Herzmuskelgewebes einschlie?lich Reevaluierung der Endomyokardbiopsien führte zur Revision der ursprünglichen Diagnose: Das Krankheitsbild der 37 j?hrigen Patientin war durch eine katecholamininduzierte dilatative Kardiomyopathie verursacht worden.      

Epidemiology of Human Cytomegalovirus (HCMV) in an urban region of Germany: what has changed?

Since the dynamics of transmission of human cytomegalovirus (HCMV) have not been clarified yet, we assessed a possible change in HCMV seroprevalence in Frankfurt am Main, Germany during the past twenty years and tried to detect variables with an impact on epidemiology. Between 1/1/1988 and 10/15/2008, a total of 54443 serum samples were collected for routine diagnostics and analyzed using Enzygnost Anti HCMV-IgG enzyme immunoassay (Siemens/Dade Behring, Marburg, Germany). Two decades, 1/1/1988–12/31/1997 and 1/1/1998–10/15/2008, and several groups (type of health insurance, gender, age, HIV-status) were evaluated to assess changes in seroprevalence. Regarding both decades, the overall age-adjusted prevalence of HIV-negative patients dropped from 63.70% (confidence interval (CI) 95% 63.15–64.25) to 57.25% (CI 95% 56.57–57.93; P < 0.0001). Private health insurance (PHI) patients showed significant lower HCMV seroprevalences than members of obligatory health insurances (OHI) in both decades (1988–1997: PHI = 55.79%, OHI = 64.27%; P < 0.0001; 1998–1908: PHI = 47.02%, OHI = 58.74%; P < 0.0001). Furthermore, comparing the two decades, there was generally a gender-specific statistically significant decrease in HCMV seroprevalence for males (63.54–55.54%) and females (63.83–58.73%) as well as for members of PHI and OHI (PHI males: 57.59% to 47.19%, PHI females 54.10–46.80%; OHI males: 64.00–57.06%, OHI females 64.50–60.11%). Also, while female HIV-positive patients showed significant difference in HCMV seroprevalence between the two decades (83.17 and 87.80%, P = 0.023), there was no significant difference in male patients with HIV (88.76 and 87.32% in the first and second decade, respectively (P = 0.196). The cumulative HCMV prevalence of all HIV-negative patients tested in the past 20 years demonstrates a biphasic, age-related rise of HCMV seroprevalence throughout all age-groups. The seroprevalence of HCMV has declined between 1988–1997 and 1998–2008 in Frankfurt am Main, Germany. The decline varied between different age-groups. HCMV prevalence correlates with the type of health insurance, gender, age, and HIV-status.     

Laboratory diagnosis of influenza--virology or serology?

Although classical influenza is a clinically typical illness ("unchanging disease due to a changing agent"), laboratory investigations are essential at the beginning of each influenza epidemic. They should confirm suspected influenza cases and exclude "flu-like illnesses" which may be caused by numerous other viral and bacterial agents. Different virological as well as serological methods are available. For early diagnosis of acute influenza virus infections, virus detection using rapid procedures for virus isolation or antigen staining and molecular biological techniques have been developed. The determination of specific antibodies (IgG, IgM) has traditionally been widely used diagnostically. Conventional serological diagnosis is possible by means of the complement fixation and hemagglutination inhibition tests and allows the detection of type- and subtype-specific antibodies, respectively. As part of an automated serology, immunofluorescence test and enzyme-linked immunosorbent assay are the mostly widely available methods. In comparison, virus detection is clearly superior to antibody determination for diagnosis of influenza virus infections. However, antibody testing may be useful as a complementary tool to confirm the diagnosis retrospectively.     

Growth of heterokaryotic monozygotic twins discordant for Ullrich-Turner syndrome during the first years of life

The rare observation of different karyotypes in monozygotic (MZ) twins, i.e., heterokaryotic monozygosity, occurs due to chromosomal aberration in one of the twins after separation of the embryos. We report on the differences of heterokaryotic MZ Turkish twins who are discordant for Ullrich-Turner syndrome. Chromosomal analyses from peripheral lymphocytes revealed a 45,X/46,XX mosaicism in both twins. FISH analyses of buccal smears showed 99% of nuclei 45,X in twin A and 98% of nuclei 46,XX in twin B. These results are consistent with a non-mosaic 45,X and 46,XX karyotype, respectively. The girls showed a different growth pattern in the first years. As their genotype should be identical except for the number of X chromosomes, the difference in phenotype may be a pure result of loss of one X chromosome in the affected girl. Special interest is set on the spontaneous and growth hormone induced growth of the twins.