Nasal interferon responses in leukaemia

Immunoglobulins in nasal secretions of patients with allergic rhinitis and chronic rhinosinusitis

Allergic rhinitis and chronic rhinosinusitis are the most frequently encountered inflammatory reactions of the sinonasal mucosa. Nasal-associated lymphoid tissue has been suggested as an inductive site for humoral and cellular immune responses in the upper respiratory tract. Immunoglobulins are important elements in human adaptive immune responses and deficiencies of serum immunoglobulins may be associated with recurrent or refractory infections. However, the local humoral immune response to offending antigens in the nasal environment has not been well elucidated. To determine the levels of IgA and IgG subclasses antibodies in the nasal secretions of patients with allergic rhinitis and chronic rhinosinusitis, 25 patients with allergic rhinitis and 20 with chronic rhinosinusitis were included and their nasal secretions were collected to measure the levels of secretary IgA (sIgA), total IgA (tIgA), and IgG subclasses antibodies. There was a significant elevation of IgG(3) in the nasal secretions of patients with chronic rhinosinusitis. No difference was noted in the levels of sIgA, tIgA, IgG1, IgG2 and IgG4 among the three groups. The local defense mechanism of nose reacts to microorganisms and pathogenic antigens by inducing the adaptive humoral immune response to increase the amount of immunoglobulins, with IgG3 being the major up-regulated antibody.

Local antibody production and respiratory syncytial virus infection in children with leukaemia

Children undergoing therapy for acute lymphoblastic leukaemia (ALL) are at increased risk of severe viral respiratory infection, and some find it difficult to terminate virus secretion. This increased severity may result from a defect in the mucosal immune response. To test this hypothesis, nasal immunoglobulin secretion and specific antiviral antibody responses to infection with respiratory syncytial (RS) virus in children with ALL have been compared with those in a normal age-matched comparison group. Children with leukaemia secreted normal levels of IgA and slightly raised IgM levels. IgG levels were depressed. Following RS virus infection, the majority of children with leukaemia secreted normal amounts of IgA and IgG nasal antibody and successfully cleared the virus. However, three of the 13 children studied made poor or undetectable nasal antibody responses, which correlated with their inability to clear the virus.

Interferon alfa, infectious virus, and virus antigen secretion in respiratory syncytial virus infections of graded severity

Interferon alfa was measured by an immunoradiometric assay in the nasopharyngeal secretions of a group of infants admitted to hospital with respiratory syncytial virus infection. Virus replication in the upper respiratory tract was assessed by infectivity assay and by an enzyme linked immunoadsorbent assay for the viral fusion protein on the same nasopharyngeal secretions. All infants were examined daily while in hospital and allocated a score based upon a subjective assessment of the severity of their illness. There was no significant correlation between interferon, virus, or fusion (F) protein secretion and severity of illness or age of infant. It is concluded that poor interferon alfa secretion does not underly the susceptibility of infants to severe infections with this virus.

An improved method for recovery of secretory immunoglobulins and lymphocytes from the nasal mucosa

The difficulty of obtaining adequate specimens for assay has severely restricted in vivo investigations of local immune responses in humans. Washing the posterior nasopharynx for an extended period using chilled saline to stimulate serous secretions has improved yields of both secretory immunoglobulins and functionally competent immunocytes. The proportions of T- and B-cells found in such washings appear to differ from those found in blood.

Virus infections in childhood malignant disease

The viruses isolated during infective episodes over a 5-year period of 93 children with acute lymphoblastic leukemia (ALL) and 107 children with other malignancies have been studied. Viruses were identified by the fluorescent antibody technique (FAT), electron microscopy, and culture. Viruses were isolated on 204 occasions. Rhinovirus and RSV occurred significantly more often in the patients with ALL, and adenovirus more commonly in the solid tumor patients. Viruses were responsible for 4 of the 69 deaths. Multiple different virus isolation during the same infective episode was significantly more common than in a control group. Where paired sera were available, only 10 out of 27 children showed at least a fourfold rise to the isolated virus. A rise in complement-fixing antibody is confirmed as a very unreliable method of detecting virus infection in immunosuppressed children. Viruses are important pathogens in children with cancer and assume greater relevance now that over 60% of malignant disease in childhood can be cured.