Respiratory tract infections due to different rhinovirus serotypes and the influence of maternal antibodies on the clinical expression of the disease in infants.

Rhinoviruses were isolated from nasopharyngeal secretions of 49 children hospitalized because of severe respiratory tract infection. The isolates were typed using 90 type-specific antisera. No obvious relation between certain serotypes and the severity of illness was found. Serum samples were drawn from all children simultaneously with the nasopharyngeal secretions and screened for the presence of type-specific neutralizing antibodies. Children aged 1 week to 6 months had higher neutralizing antibody titers and revealed a lower degree of morbidity than older children. The decline of neutralizing serum antibodies with increasing age was correlated with a higher incidence of severe disease in those aged 7-12 months. Nevertheless, also in this age group children with mild clinical courses of disease were observed despite a low concentration or an absence of neutralizing serum antibodies. This indicates that not only neutralizing serum antibodies, but other factors also influence the clinical expression of RHV-induced disease.     

Prevalence of hepatitis-C virus RNA in serum and throat washings of children with chronic hepatitis

Serum samples from 46 children with chronic and probably transfusion acquired hepatitis were tested for the presence of hepatitis C virus (HCV) RNA by a “nested” polymerase chain reaction (PCR) assay, to judge a possible risk of HCV transmission from these patients. In 73% of the samples, viral RNA was detected, indicating a high virus prevalence in this patient group. High titers of HCV-RNA were observed in some sera as shown by the detection of virus in some samples even at dilutions of 10^?3. Comparison of simultaneously obtained PCR results and ALT values revealed no significant correlation between virus presence in serum and higher ALT levels. It was, however, shown that unusually high ALT values may reflect a high titer of viral RNA in serum. To investigate the prevalence of viral RNA in saliva, which could be a vehicle of virus transmission, 35 throat washing samples from the HCV-infected children were screened by PCR. Using three different sample preparation procedures, 20% of the throat washings were found to be positive for HCV-RNA. This indicates a prevalence of virus in this fluid lower than that reported previously. © 1994 Wiley-Liss, Inc.     

The Value of Claims-Based Nontraditional Risk Factors in Predicting Long-term Mortality After MitraClip Procedure

Background

We sought to identify nontraditional risk factors coded in administrative claims data and evaluate their ability to improve prediction of long-term mortality in patients undergoing percutaneous mitral valve repair.

The KIT D816V allele burden predicts survival in patients with mastocytosis and correlates with the WHO type of the disease

KIT D816V is present in a majority of patients with systemic mastocytosis (SM). We determined the KIT D816V allele burden by quantitative real‐time PCR in bone marrow and peripheral blood of 105 patients with mastocytosis. KIT D816V was detected in 92/105 patients (88%). Significant differences in the median allele burden were observed between disease subgroups: cutaneous mastocytosis (0.042%), indolent SM (0.285%), smoldering SM (5.991%), aggressive SM (9.346%), and SM with associated hematologic non‐mast cell lineage disease (3.761%) (P < 0.001). The KIT D816V burden also correlated with serum tryptase (R = 0.5, P < 0.005) but not with mast cell infiltration in bone marrow or mediator symptoms. Moreover, the allele burden was of prognostic significance regarding survival (P < 0.01). Patients responding to cytoreductive therapy showed a significant decrease in KIT D816V (P < 0.05). To conclude, the KIT D816V burden correlates with the variant of mastocytosis, predicts survival, and is a valuable follow‐up parameter in SM.     

Correlation between ELISA,hemagglutination inhibition,and neutralization tests after vaccination against tick-borne encephalitis

The significance of IgG antibody levels determined by a binding assay (ELISA) was investigated as a surrogate marker for the presence of neutralizing and hemagglutination inhibiting antibodies in sera from individuals vaccinated against tick-borne encephalitis (TBE). To assess the extent of interference by flavivirus cross-reactive antibodies, sera from persons with a proven or suspected history of other flavivirus infections and/or vaccinations were also examined. An excellent and highly significant correlation was found between ELISA IgG units and the antibody titers obtained by the hemagglutination inhibition (HI) as well as by the neutralization test (NT), provided that there was no other exposure to flavivirus antigens except TBE vaccination. Yellow fever vaccination and/or dengue virus infections induced significant levels of antibodies reactive in the TBE ELISA and HI test, which did not exhibit, however, neutralizing activity against TBE virus. The phenomenon and problem of “original antigenic sin” was demonstrated in a TBE vaccinee with a history of previous flavivirus infections. TBE vaccination first induced a booster reaction resulting in a rise in the level of cross-reactive antibodies only, whereas TBE virus-neutralizing antibodies became detectable only after the third vaccination. It is concluded that the level of IgG antibodies determined by ELISA is a good marker for predicting the presence of neutralizing antibodies after TBE vaccination, but only in the absence of flavivirus cross-reactive antibodies. Otherwise, a neutralization assay is necessary for assessing immunity. © 1996 Wiley-Liss, Inc.