Controversial results have been reported on the participation and diagnostic value of lymphocyte reactivity in cow's milk (CM) allergy. In this study, we used a specific nuclear marker to evaluate lymphocyte proliferation in IgE-mediated CM allergy in infants, and examine its relation with diets containing different CM antigen loads.|Infants with IgE-mediated CM allergy, as assessed by open provocation and RAST, were grouped according to their exclusive diet, either CM formulae, breast feeding, or hydrolysed whey formulae. A group of non-atopic infants receiving CM was also examined. Lymphocyte proliferation to beta-lactoglobulin was evaluated by quantitation of the proliferating cell nuclear antigen (PCNA) expression in peripheral blood mononuclear cells, by flow cytometry. Immunophenotypic surface markers were also examined.|A marked difference of PCNA expression between CM-fed allergic infants and healthy controls was observed (p<0.001). In this setting, PCNA expression >/=10% was highly specific and sensitive as a marker of CM allergy in CM-fed infants. Moreover, a significant correlation (p<0.001) between antigen load and PCNA was established in CM-allergic infants under different diets, higher values obtained with increasing antigen loads. In addition, within the group fed hydrolyzed formulae, low-molecular-weight products resulted in marginally lower PCNA expression than higher-molecular-weight formulae. No differences in immunophenotype were found, with the exception of a higher CD23 expression in the breast-fed group.|PCNA could be a useful marker in the assessment of lymphocyte proliferation to CM antigens. Low CM antigen diets are related with reduced lymphocyte reactivity, which may partly explain the clinical benefit observed with such diets.

Rhinoviruses are epidemiologically connected to the majority of acute asthma exacerbations; however, their ability to infect and replicate in the lower airways is disputed. A frequent argument against this possibility involves the temperature preference for rhinovirus replication, generally accepted to be 33 degrees C, the temperature of the nasal passages. However, this argument is based on studies with a single rhinovirus serotype. In this study, differences in temperature preferences were evaluated between several serotypes and relative titers were determined than can be achieved at upper and lower airway temperatures. Rhinovirus serotypes 1b, 2, 7, 9, 14, 16, 41, and 70 were titrated in Ohio-HeLa cell cultures at either 33 degrees C or 37 degrees C. Possible selection by culture temperature was examined by continuous culture at 33 degrees C and 37 degrees C for 2-4 passages and subsequent titration at both temperatures. Finally, nasal aspirate samples derived from patients with wild-type rhinoviral common colds were cultured at 33 degrees C and 37 degrees C and RT-PCR was used to assess rhinovirus replication at each temperature. The majority of the serotypes and wild-type viruses replicated slightly better at 33 degrees C than at 37 degrees C. However, titers achieved after one or more replicative cycles at 37 degrees C were still high enough to initiate infection. Furthermore, in some instances equal or even better replication was observed at 37 degrees C. It is concluded that temperature preferences may vary between rhinoviruses and are not likely to be a prohibitive factor for infection of the lower airways.

Rhinoviruses are the main cause of the common cold and precipitate the majority of asthma exacerbations. RT-PCR followed by internal probe hybridisation or Southern blotting, or nested PCRs are currently the most sensitive methods for their identification. However, none of the published techniques can differentiate satisfactorily rhinoviruses from other picornaviruses. Examination of the restriction maps of sequenced rhinoviruses, revealed a highly conserved BglI restriction site (GCCnnnnnGGC), located exactly in the middle of the 380-bp amplicon generated with the OL26-OL27 primer pair, which has been used extensively in the past to identify picornaviruses. Such a site was either not present, or positioned differently in other picornaviruses of known sequence. It was, therefore, considered that digestion of rhinovirus amplicons with this enzyme would result in two equal length fragments, generating a single 190-bp band in gel electrophoresis. In contrast, either one undigested 380-bp band or a double-band pattern would appear in amplicons from other picornaviruses. To test this hypothesis, Bgl digestions of OL26-OL27 amplicons from cultured and wild-type rhinoviruses, whose identity was confirmed by acid lability, as well as from echo, polio and coxsackie viruses were carried out. All rhinovirus samples were digested successfully generating single bands. Among the other picornaviruses, only 6.6% presented a single band pattern, while the rest were as predicted from the model. With a sensitivity of 100% and a specificity over 90%, the method described, which is rapid and remarkably easy to perform, can be used to distinguish rhinoviruses from other picornaviruses to a considerable extent.