Naomi Kondo

Clinical features of Bloom syndrome and function of the causative gene, BLM helicase

Bloom syndrome is a rare autosomal recessive genetic disorder characterized by growth deficiency, unusual facies, sun-sensitive telangiectatic erythema, immunodeficiency and predisposition to cancer. The causative gene for Bloom syndrome is BLM, which encodes the BLM RecQ helicase homolog protein. The first part of this review describes a long-term follow-up study of two Bloom syndrome siblings. Subsequently, the focus is placed on the functional domains of BLM. Laboratory diagnosis of Bloom syndrome by detecting mutations in BLM is laborious and impractical, unless there are common mutations in a population. Immunoblot and immunohistochemical analyses for the detection of the BLM protein using a polyclonal BLM antibody, which are useful approaches for clinical diagnosis of Bloom syndrome, are also described. In addition, a useful adjunct for the diagnosis of Bloom syndrome in terms of the BLM function is investigated, since disease cells must have the defective BLM helicase function. This review also discusses the nuclear localization signal of BLM, the proteins that interact with BLM and tumors originating from Bloom syndrome.

Clinical improvement of diffuse lymphangiomatosis with pegylated interferon alfa-2b therapy: case report and review of the literature.

Diffuse lymphangiomatosis is a very rare congenital disease, characterized by diffuse or multifocal lymphangioma in the skeletal tissue, spleen, liver, mediastinum, and/or lung. The prognosis is usually poor, especially for children with thoracic lesion, and treatments for the disease are controversial. The authors report a 9-year-old boy with diffuse lymphangiomatosis involving the thorax with pleural effusions, the spleen, and systemic bone. The patient was treated with pegylated interferon alfa-2b, and achieved good clinical and radiological improvement.

Age-related changes in intracellular cytokine profiles and Th2 dominance in allergic children

The unbalanced T helper response has been pointed out in allergic diseases. Especially in childhood, it is important to consider the development of acquired immunity. We investigated the relationship between age and Th1, Th2, Tc1 or Tc2 cells. In addition, Th1, Th2, Tc1 or Tc2 cells in allergic diseases were compared with control subjects. Thirty‐four healthy controls (0–40u2003years old), 200 samples of cord blood, nine patients with atopic dermatitis (AD) (1–3u2003years old) and five patients with bronchial asthma (BA) (2–6u2003years old) were studied. Surface staining with CD4, CD8 and intracellular staining with anti‐interferon‐γ (IFN‐γ) and anti‐interleukin (IL)‐4 were carried out, and analyzed by using flow cytometry. In the healthy controls, the percentages of Th1, Tc1 or Th2 showed positive correlation with age. The absolute numbers of Th1 or Tc1 also correlated with age. Cord blood with a family history of allergic disease showed no significant difference compared to that without a family history. The percentage of Th2 in AD and BA patients was significantly higher than in the age‐matched healthy controls. The increase in Th1, Th2 and Tc1 with age might reflect on the development of acquired immunity. Age matching is important when evaluating the cytokine profiles of T cells. In allergic diseases, although cord blood showed a Th1‐dominant pattern, it changed to Th2 dominance in childhood, and this may reflect on some genetic background.

Leaky phenotype of X-linked agammaglobulinaemia in a Japanese family

X‐linked agammaglobulinaemia (XLA) is an inherited immunodeficiency that is caused by a block in early B‐cell differentiation. Whereas early B precursors in the bone marrow are present in substantial numbers, XLA‐affected individuals have dramatically reduced numbers of circulating mature B cells, plasma cells and immunoglobulins of all isotypes. We report on a Japanese family with 3 XLA patients, in whom the serum immunoglobulin levels and number of B cells showed a significant difference among them in spite of harbouring the same splice donor site mutation in the BTK gene. We developed concise method for detection of this mutation, which is helpful for discovering the carrier. Patient 2 showed a significant serum immunoglobulin levels of all isotypes, including allergen‐specific IgE. Expression of a normal and truncated size BTK gene was detected in patient 2′s peripheral blood mononuclear cells (PBMCs). Expression of BTK protein was also detected in some B cells. These results suggest that the leaky phenotype in patient 2 was caused in part by the expression of a normal BTK gene transcript. The increased frequency of infection with age expanded the number of B cells with normal BTK gene expression and produced the serum immunoglobulin, including IgE.

The function of RecQ helicase gene family (especially BLM) in DNA recombination and joining.

Bloom syndrome is a rare autosomal recessive genetic disorder characterized by lupus-like erythematous telangiectasias of the face, sun sensitivity, stunted growth, and immunodeficiency. Chromosome instability syndromes have a common feature, being associated at high frequency with neoplasia. BS is considered as one of the chromosome instability syndromes since the fibroblasts or lymphocytes of BS patients show excessive spontaneous chromosome instability. The causative gene of BS (BLM) was identified as a RecQ helicase homologue. In this review, we showed the characteristic phenotypes of BS, especially two Japanese siblings. In the latter of the review, the functional domains of BLM, those are nuclear localization signal and the interacting proteins such as ATM, are shown. Several lines of reports indicates that BLM helicase is involved in the re-initiation of DNA replication at sites where replication forks have arrested or collapsed. To elucidate the precise function of RecQ helicase in DNA repair and replication aims not only to improve our understanding of the molecular basis for tumorigenesis, but also to extend the range of potential therapeutic targets.

Effects of dioxins on the quantitative levels of immune components in infants

Dioxins (polychlorinated dibenzo-p-dioxin (PCDD)=polychlorinated dibenzofuran (PCDF)) and polychlorinated biphenyls (PCBs) are potentially hazardous compounds and have structural similarity with thyroid hormones. Animal studies have demonstrated that PCDDs, PCDFs and PCBs can alter immune functions. However, in humans it is not yet elucidated whether dioxins contained in breast milk have any effects on the immune functions in infants. To investigate the effects of dioxins on the immune system, we compared the quantitative levels of immune components between a breast-fed group and bottle-fed group, in which dioxin concentration is almost zero. Ratios of immune cells, such as CD4= and CD8= T-lymphocytes, as well as B-lymphocytes (CD19= and/or CD20=) and NK cells (CD16=, CD56=) in peripheral blood lymphocytes, serum immunoglobulin level, and level of specific IgE antibody to allergens in the venous blood at 12 months of age were assessed in a subgroup of 281 infants. The relationship of post-natal dioxin exposure via breast feeding with the ratio of immunological markers and the level of humoral antibodies up to 12 month of age was not demonstrated. In conclusion, it would appear that the content of dioxins in breast milk in the Japanese general population is not enough to induce any change in theses-examined immunological parameters during the first year of life, although long-term effects remain to be evaluated.

A common variable immunodeficient patient who developed acute disseminated encephalomyelitis followed by the Lennox-Gastaut syndrome.

Common variable immunodeficiency (CVID) is a primary disorder characterized by impaired antibody production. CVID patients may develop recurrent infections, autoimmune disorders, and malignant lymphomas, but to our knowledge, there is no report on CVID patients who develop acute disseminated encephalomyelitis (ADEM) or the Lennox‐Gastaut syndrome. We describe a 1‐yr‐old female CVID patient with ADEM who evolutionally manifested the Lennox‐Gastaut syndrome. She was admitted with convulsions and T2‐weighted magnetic resonance imaging (MRI) revealed high‐intensity areas in the right temporal lobe and the left fronto‐parietal region but she became conscious soon. Her serum findings showed severe hypogammaglobulinemia and a follow up MRI revealed that these areas had diminished. Consequently, she was diagnosed as having CVID with ADEM. After 5u2003months, she fell to having tonic and absence seizures and we diagnosed her as having the Lennox‐Gastaut syndrome from electroencephalograms (EEG) and the seizure pattern. She is now 7u2003yr old and her tonic seizures are controlled with valproic acid, clobazam, and immunoglobulin replacement therapy which is administrated every 2u2003wk. It is well known that the immune and neurologic systems have a close relationship. We suspect that a genetic defect in the immune system of our patient might also be associated with the neurologic disorders of ADEM and the Lennox‐Gastaut syndrome.

Suppression of IFN-gamma production in atopic group at the acute phase of RSV infection.

Several studies have suggested that respiratory syncytial virus (RSV) bronchiolitis induced the change of cytokine production profile in childhood. We sought to determine whether the RSV‐induced cytokine production was affected by the patients atopic background. We quantified interferon‐gamma (IFN‐gamma) and interleukin (IL)‐4 in the supernatant of peripheral blood mononuclear cells (PBMCs) cultured for 24u2003h and in the presence of phytohemaglutinin (PHA), IL‐12, or IL‐18, from 14 infants who were divided into two groups, those who are non‐atopic and an atopic group. In RSV‐infected infants with atopic diseases, IFN‐gamma production from IL‐12‐ or especially IL‐18‐stimulated PBMCs was subtotally suppressed in the acute phase, whereas in RSV‐infected infants without atopic diseases IFN‐gamma production was not suppressed on acute phase. The IFN‐gamma suppression observed in the atopic group is not caused by the immaturity of an infants immune system since reduced IFN‐gamma production to RSV is not observed in the infants of non‐atopic group. IFN‐gamma suppression in regard to RSV infection might be caused by some genetic factor involved in the development of atopic disease such as IL‐18 signal cascade.

Autologous peripheral blood stem cell transplantation in a patient with relapsed pleuropulmonary blastoma.

Pleuropulmonary blastoma (PPB) is a rare and aggressive primary intrathoracic neoplasma of children. The prognosis is extremely poor with frequent metastasis to the brain and bone. We present a 4-year-old girl with a tumor mass in the right hemithorax initially diagnosed as pneumoniae. Tumor resection was performed and the histologic report indicated the diagnosis of PPB. The patient received chemotherapy comprising vincristine, actinomycin D, doxorubicin, cisplatin, and cyclophosphamide. Irradiation was performed with total 45 Gy at the right lower pulmonary lobe. She relapsed 29 months later at the pleura between the right middle and lower pulmonary lobe. Tumor resection and total 45 Gy of irradiation were performed again. High-dose chemotherapy comprising cisplatin, adriamycin, and cyclophosphamide was performed followed by autologous peripheral blood stem cell transplantation (PBSCT). The patient achieved complete hematologic recovery. Thirty-one months after PBSCT, no signs of relapse have been observed. Although it might be that the patient could have been cured with second surgery alone or by the surgery and subsequent chemotherapy, high-dose chemotherapy and PBSCT should be considered for the treatment of relapsed PPB.

A positive Donath-Landsteiner test in paroxysmal cold haemoglobinuria.

A 5-year-old girl presented to our hospital for a fever, abdominal pain and dark red urine. On admission, she was pale and jaundiced. Blood examination revealed haemolytic anaemia with a haemoglobin (Hb) level of 8.7 g ⁄dL, and urinalysis showed haemoglobinuria. A direct antiglobulin test was strongly positive for complement C3b and C3d, but negative for IgG and a direct Donath-Landsteiner test was positive (Fig. 1A: One tube (a) was maintained at 37 degrees centigrade. The other tube (b) was incubated at 0 degree centigrade for 30 min and then kept at 37 degrees centigrade for an additional 30 min). We diagnosed her as having paroxysmal cold haemoglobinuria. The haemoglobinuria continued for 3 d after admission (Fig. 1B: Urine sample in chronological order. Samples no. 1 to 10 were obtained at 8, 13, 19, 20, 31, 33, 34, 42, 52 and 58 hours respectively, after admission), and the Hb had fallen to 5.5 g ⁄dL. However, she recovered gradually without any treatment, and was healthy during a 5-month follow-up.