Ryosuke Inoue

Roles of anti-hemagglutinin IgA and IgG antibodies in different sites of the respiratory tract of vaccinated mice in preventing lethal influenza pneumonia.

The roles of IgA and IgG antibodies (Abs) against hemagglutinin (HA) in the prevention of lethal influenza pneumonia in vaccinated mice were examined in terms of distribution and concentration of the Abs in the mucus or the serous fluid in different sites of the respiratory tract (RT), mucosa of the nose, trachea, bronchi and bronchioli and the alveolar epithelia of pulmonary acinus. First, the surface areas of the tracheal, bronchial and bronchiolar mucosa and alveolar epithelia were measured to be 20, 260 and 217, 433 mm(2), respectively, using serial tissue sections of the trachea and lungs. Then, the volumes of the tracheal mucus, the bronchial and bronchiolar mucus and the serous fluid of alveolar epithelia were estimated to be 0.2, 2.6 and 21.7 mm(3), respectively, by calculating each from the surface area and an assumed thickness of the mucus layer (0.01 mm) or that of the serous fluid (0.0001 mm). Next, anti-HA IgA and IgG Ab responses in the nasal wash, the trachea-lung wash and the trachea wash were measured in BALB/c mice immunized intranasally with an adjuvant-combined A/PR/8/34 (H1N1) virus vaccine and challenged with a lethal dose of the virus. Then the values of Ab responses were converted to the mucus and serous fluid Ab concentration based on two premises that the serum Abs diffuse at a constant rate to the surface of the tracheal, bronchial and bronchiolar mucosa, and that the active transepithelial transport of IgA Abs does not work in the alveolar epithelia. Results showed that 21.4 microg/ml IgA Abs and 3.6 microg/ml IgG Abs in the tracheal mucus (19.1 and 0.3% of the trachea-lung wash IgA and IgG Ab amounts, respectively), 5.9 microg/ml IgA Abs and 3.6 microg/ml IgG Abs in the bronchial and bronchiolar mucus (66.0 and 3.4% of the trachea-lung wash IgA and IgG Ab amounts, respectively) and about 0.1 microg/ml IgA Abs and 12.3 microg/ml IgG Abs in the serous fluid of alveolar epithelia (14.9 and 96.3% of the trachea-lung wash IgA and IgG Ab amounts, respectively) were present in the vaccinated mice, at which concentrations influenza pneumonia was prevented. Thus, 96.3% of anti-HA IgG Abs in the trachea-lung wash work on the alveolar epithelia, whose surface area is about 800 times larger than that of tracheal, bronchial and bronchiolar mucosa and seem to play a more important role than the mucosal IgA Abs in the prevention of lethal influenza pneumonia.

Identification of β-lactoglobulin-derived peptides and class II HLA molecules recognized by T cells from patients with milk allergy

Background Cows milk allergy impairs the health and development of many infants since it deprives them of adequate nutrition. Cows milk fractions contain many allergens, and β‐lactoglobulin (BLG) is one of the major allergens.

IGG2 DEFICIENCY ASSOCIATED WITH DEFECTS IN PRODUCTION OF INTERFERON-GAMMA : COMPARISON WITH COMMON VARIABLE IMMUNODEFICIENCY

We report a novel mechanism of IgG2 deficiency. Several investigators have reported patients with IgG subclass deficiencies due to homozygous deletion of immunoglobulin heavy chain constant region genes. However, it is unclear what mechanism is responsible for IgG subclass deficiency in cases where no gene deletions have been detected and which are accompanied by recurrent infections due to aberrant immunoregulation. In the present study, we have focused our attention on production by peripheral blood mononuclear cells (PBMCs) of interferon‐gamma (IFN‐γ), which is known to induce IgG2 expression. PBMCs from four patients with IgG2 deficiency and their families were studied. Mitogen‐induced IFN‐γ production by PBMCs was decreased in all of the patients, although the proliferative responses of PBMCs and the percentages of CD3, CD4, and CD8 T cell subsets were not decreased. IgG2 production by PBMCs was restored upon addition of IFN‐γ and mitogen to the PBMCs of the patients with IgG2 deficiency though it was not restored in the patients with common variable immunodeficiency. We conclude that defects in production of IFN‐γ play an important role in IgG2 deficiency.

Defective Calcium-Dependent Signal Transduction in T Lymphocytes of Ataxia-Telangiectasia

T‐cell functions of two patients with ataxia‐telangiectasia were investigated. Patients with ataxia‐telangiectasia had reduced percentages of circulating CD3+ cells and CD4+ cells, although neither patient had a reduced percentage of circulating CD8+ cells. The proliferative responses and interleukin‐2 production of peripheral blood mononuclear cells to T‐cell mitogens were reduced in the patients. The intracellular calcium concentration in T cells or CD4+ cells from both patients was only slightly increased after phytohaemagglutinin stimulation. Moreover, the concentration after OKT3 stimulation was not or only slightly increased in T cells or CD4+ cells from both patients. Our results suggest that the functional defect of T cells is caused by defective Ca2+‐dependent signal transduction through the CD3 complex of the surface in T cells of ataxia‐telangiectasia.

Changes of autonomic nervous system function in patients with breath-holding spells treated with iron

To evaluate the autonomic nervous system of patients with breath-holding spells after iron treatment, we attempted to determine whether a dysregulation of the autonomic nervous system reflexes exists in children with severe cyanotic breathholding spells. An electrocardiogram for each subject was recorded for 24 hours in the subjects home and parasympathetic activity was investigated by the fast Fourier transform method. Hematologic data and clinical symptoms of all three patients treated with iron improved and attacks of severe breath-holding spells disappeared. After iron treatment was started, the heart rate variability increased during sleep. It appears that supplementation of iron is effective in improving the dysregulation of autonomic nervous system reflexes. (J Child Neurol 2002;17:337-340).

Autonomic regulation after exercise evidenced by spectral analysis of heart rate variability in asthmatic children

BACKGROUND Bronchial asthma is associated with abnormal autonomic nervous function in childhood. Exercise is one of the most common precipitating factors of acute asthmatic crises although the exact mechanism of autonomic regulation in asthmatic children after exercise is unclear. OBJECTIVE The aim of this study was to investigate the features of autonomic regulation after exercise in asthmatic and control children. METHODS Pulmonary function tests and heart rate variability spectral analysis were performed in 15 asthmatic children and 7 control children (age 6 to 15 years) during and after an exercise challenge. RESULTS The maximum % fall of forced expiratory volume in 1 second (FEV1) was significantly greater (P < .01) in asthmatic subjects (9.1 +/- 5.1%) than in normal control subjects (1.0 +/- 2.5%). The high frequency band (HF) amplitude, an index of cardiac vagal tone, 5 minutes after exercise was significantly higher (P < .05) in the asthmatic subjects (14.4 +/- 7.9 msec) than in control subjects (5.9 +/- 2.6 msec). Furthermore, the difference in the HF amplitude between the control group and the exercise-induced asthma group was significant both 5 minutes (P < .01) and 10 minutes (P < .05) after challenge. There was a significant correlation (P = .565, P = .0165) between HF amplitude 5 minutes after exercise and the magnitude of the decrease in FEV1. On the other hand, no significant difference was observed in the low frequency band amplitude between the controls and the asthmatic subjects. The ratio of low frequency to high frequency power, which is suggested to correlate with cardiac sympathetic activity, did not differ between the two groups. CONCLUSION These findings suggest that autonomic nervous activities, particularly vagal response after exercise, in asthmatic children is different from that in control children.

Reduced Interferon-γ Production and Mutations of the Interleukin-12 Receptor β2 Chain Gene in Atopic Subjects

Background: The atopic patient has a predisposition to selective synthesis of IgE antibodies to common environmental antigens. IgE production is upregulated by interleukin-4 (IL-4) and downregulated by interferon-γ (IFN-γ). IL-12 is a cytokine that induces IFN-γ production. The signal of IL-12 is transduced through the IL-12 receptor (IL-12R) and Stat4. Methods: We examined IFN-γ production in peripheral blood mononuclear cells (PBMCs) following stimulation with IL-12 or phytohemagglutinin (PHA) in healthy controls and atopic patients. Moreover, sequences of the IL-12R β2 chain gene were analyzed. Results: The serum IgE levels were negatively correlated (p < 0.001) with IFN-γ production. In 24 out of 75 atopic patients, IFN-γ production in PBMCs following stimulation with IL-12 was under the detection limit, but PHA stimulation elicited detectable IFN-γ production. Sequence analysis of the cDNA of IL-12R β2 revealed three kinds of distinct genetic mutations (2496 del 91, 1577 A to G and 2799 A to G) in 10 unrelated subjects of the 24 whose IFN-γ production following IL-12 stimulation was under the detection limit. PBMCs cultured with IL-12 and PHA in these 10 subjects showed decreased tyrosine phosphorylation of Stat4. Conclusions: The results of our study indicate that atopic diseases are caused, in part, by impairment of the IL-12 signal cascade, which downregulates IgE production, and that the mutation of the IL-12R β2 chain gene is one of the causative genes for atopy.

Ataxia telangiectasia associated with B-cell lymphoma : The effect of a half-dose of the drugs administered according to the acute lymphoblastic leukemia standard risk protocol

Ataxia telangiectasia (A-T) is a rare autosomal recessive disorder characterized by cerebellar ataxia, oculocutaneous telangiectasia, and variable degrees of humoral and cellular immunodeficiency. Affected individuals are known to exhibit a high incidence of lymphoma and leukemia. Because of increased chemosensitivity, the treatment of A-T patients with malignancies requires extremely careful planning and caution with respect to the use of chemotherapy. The authors report on a 12-year-old boy with A-T who developed B-cell lymphoma. He received a half-dose of the drugs administered according to the acute lymphoblastic leukemia (ALL) protocol issued by our childrens cancer study group (9104 Standard Risk Protocol, Tokai Pediatric Oncology Study Group). As a result, he continues to be in complete remission and free of treatment complications 32 months after the diagnosis of B-cell lymphoma.

Chediak‐Higashi syndrome: report of a case with an ovarian tumor

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Ataxia‐telangiectasia in the Japanese population: Identification of R1917X, W2491R, R2909G, IVS33+2T→A, and 7883del5, the latter two being relatively common mutations

We analyzed the data regarding six Japanese ataxia‐telangiectasia (A‐T) patients from four unrelated families, at the DNA level, to search for possible common mutations in the Japanese population. Among eight mutant alleles in the four families, c. 4612del165 (exon 33 skipping) was identified in two alleles, and c. 5749A to T (R1917X), c. 7471T to C (W2491R), c.7883del5, and c. 8725A to G (R2909G) were identified in one allele each. We found no mutations in the other two alleles. The IVS33+2T→A mutation was identified at the genomic level as the cause of exon 33 skipping. We also identified the IVS33+2T→A mutation in a Japanese patient ATL105 who was previously found to be a homozygote of c. 4612del165. W2491R and R2909G mutations were not detected in more than 100 control Japanese alleles. The latter is located in a highly conserved PI‐3 kinase domain and is a completely conserved residue among ATM‐related proteins. Taken together with previously documented mutations in five other Japanese A‐T patients, IVS33+2T→A and 7883del5 were identified in four and five alleles, respectively, in a total of 18 mutant alleles of Japanese A‐T patients. These results suggest that these two mutations are relatively common mutations in the Japanese population. Hum Mutat 12:338–343, 1998.© 1998 Wiley‐Liss, Inc.