Genetic and proteinic analysis of a Chinese boy with X-linked lymphoproliferative disease and his maternal relatives / 中华儿科杂志

<p><b>OBJECTIVE</b>X-linked lymphoproliferative disease (XLP), a genetic disorder characterized by immunodeficiency to Epstein-Barr virus (EBV) infection, has been linked to mutations in the SH2D1A gene. XLP patient displays EBV associated fulminant infectious mononucleosis or hemophagocytic lymphohistocytosis, hypogammaglobulinemia or malignant lymphoma. Here we report the clinical features, gene mutation and SAP expression on PBMCs of a Chinese patient with XLP and potential carriers.</p><p><b>METHOD</b>A 6 years old male patient and his maternal relatives were enrolled in this study. The patient was found to have with a renal Burkitt lymphoma on the right waist at 5 years of age by accident. His elder brother and a maternally related cousin both died of multiple systemic organ dysfunction syndrome (MODS) due to fulminant infectious mononucleosis (FIM) at the age of one year. The patient and his maternal relatives were subjected to detection of SAP expression on the PBMCs by flow cytometry and gene mutation analysis of SH2D1A by using PCR based on genomic DNA.</p><p><b>RESULT</b>The patient exhibited 536.9 copy/ml level of circulating EBV-DNA during remission. Sequence analysis showed that the patient harbored a nonsense mutation in exon 2 (C462T), resulting in a premature stop codon (Arg55X). His mother and some of the maternal relatives were proved to be carriers of this mutation. SAP expression from the patient was significantly reduced as compared to normal individual and the carriers.</p><p><b>CONCLUSION</b>We identified a Chinese XLP case genetically. Assessment of SAP expression on PBMCs by flow cytometry seemed to be an effective rapid diagnostic method for this disease. Absence of EBV infection does not diminish the possibility of XLP.</p>

Neutropenia associated with X-linked agammaglobulinemia in an Iranian referral center

X-linked Agammaglobulinemia [XLA] is a hereditary immunodeficiency, characterized by an early onset of recurrent bacterial infections, hypogammaglobulinemia and markedly reduced B lymphocytes number. In order to determine the association of neutropenia among Iranian patients with XLA, hospital records of 30 patients with confirmed XLA in Children Medical Center Hospital, were reviewed. Eight out of 30 XLA patients [26.7%] developed neutropenia during the course of the disease. In two patients, episodes of neutropenia were identified before or at the time of diagnosis of XLA. Other six patients whom were not visited regularly and did not receive periodical immunoglobulin replacement therapy experienced neutropenia after diagnosis of XLA. Neutropenia in XLA is mainly associated with infection and is resolved with intravenous immunoglobulin replacement and antibiotics therapy

Successful management of neufropenia in a patient with CD40 ligand deficiency by immunoglobulin replacement therapy

Hyper-IgM syndromes are characterized by profound reduction of serum IgG, IgA, and IgE levels with normal or increased concentrations of serum IgM. CD40 ligand deficiency is X-linked form of the disease, which results in a lack of immunoglobulin class switching from IgM to IgG in B cells. In addition to the recurrent infections, a number of patients suffer from neutropenia. There are some evidences indicating the effect of G-CSF in combination with intravenous immunoglobulin [IVIG] in improvement of neutrophil counts, which has become the most common procedure to control neutropenia. In this report we present a 6 year-old patient of CD40 ligand deficiency, who suffered from chronic, severe neutropenia. Administration of IVIG was started for him when the diagnosis was made at the age of 1.5 years and he was on the regular IVIG therapy after that time untill now for a period of 4.5 years. IVIG and prophylactic antibiotic therapy, despite cessation of granulocyte colony-stimulating factor, injection after one month, corrected the severe neutropenic state of this patient. It seems that regular administration of sufficient doses of IVIG can be useful in the management of neutropenia in CD40 ligand deficiency, which results in better quality of life with decreasing occurrence of infection

Dificient expression of brouton's tyrosine kinase in monocytes from x linked agmmaglobulinemia as evaluated by a flow cytometric analysis and its clinical application to carrier detection

The B-cell defect in X-linked agammaglobulinemia [XLA] is caused by mutations in the gene for Bruton's tyrosine kinase [BTK]. BTK mutations result in deficient expression of BTK protein in peripheral blood monocytes. Using the anti-BTK monoclonal antibody [48-2H], a flow cytometric analysis of intra cytoplasmic BTK protein expression in monocytes was performed to identify Iranian patients with XLA phenotype. To examine the possible identification of XLA patients and female carriers by this assay, we studied 13 XLA families. The flow cytometric assay showed deficient expression of the BTK protein in 12 [92%] families. One patient exhibited a normal level of BTK expression. The cellular mosaicism of BTK expression in monocytes from obligate carriers was clearly shown in 9 of 12 [75%] families. The results suggested that most XLA patients have deficient expression of the BTK protein; therefore we conclude that deficient expression of BTK protein can be evaluated by a flow cytometric assay

Primary immunodeficiencies inducing EBV-associated severe illnesses

Epstein-Barr virus [EBV] is a ubiquitous human gamma-herpesvirus that infects about 95% of the adult population. The majority of primary infections occurs in early childhood and is generally subclinical; it can cause infectious mononucleosis [IM], which is usually a self-limiting lymphoproliferative disorder. However, infection of EBV occasionally results in severe, often lethal diseases, which include fatal IM, hemophagocytic syndrome, polyclonal lymphoproliferative disorders, and malignant lymphoma. These severe EBV-related illnesses occur secondary to some primary immunodeficiency diseases showing inefficient immune reaction to EBV. One example is X-linked lymphoproliferative disease [XLP], which is caused by mutations in the SLAM-associated protein [SAP] gene. The major clinical manifestations of XLP are fulminant IM, malignant lymphoma and dysgammaglobulinemia. Aplastic anemia, virus-associated hemophagocytic syndrome, and vasculitis have also been reported in XLP. We have developed a flow cytometric method using the anti-SAP monoclonal antibody to search for XLP. This clinically useful assay has successfully been used to identify XLP patients in Japan. In this review, clinical and mutational characteristics of XLP in Japan are mainly described. In addition, it is shown that the similar situations to XLP can occur in other primary immunodeficiencies involving T-cell killing function, such as autoimmune lymphoproliferative syndrome caused by Fas gene mutations or familial hemophagocytic lymphohistiocytosis caused by perforin gene mutations. Finally, the EBV-related terrible disease condition, namely chronic active EBV infection, which is common in Asian areas but its genetic background remains to be elucidated, will be touched on

Screening of the Bruton tyrosine kinase [BTK] gene mutations in 13 Iranian patients with presumed x-linked agammaglobulinemia

X-linked agammaglobulinemia [XLA] is an immunodeficiency caused by mutations in the Bruton tyrosine kinase [Btk] gene. In order to identify the mutations in Btk gene in Iranian patients with antibody deficiency, 13 male patients with an XLA phenotype from 11 unrelated families were enrolled as the subjects of investigation for Btk mutation analysis using PCR-SSCP followed by sequencing. Five different mutations were identified in 5 patients from 5 unrelated families. Three mutations had been reported previously including TTTG deletion in intron 15 [4 bps upstream of exon 16 boundary], nonsense point mutation [1896G>A] that resulted in a premature stop codon [W588X] in kinase domain, and nucleotide alteration in invariant splice donor site of exon12 [IVS12+1G>A]. While 2 novel missense mutations [2084A>G, 1783T>C] were identified leading to amino acid changes [I651T, Y551H]. The results of this study further support the notion that molecular genetic testing represents an important tool for definitive and early diagnosis of XLA and may allow accurate carrier detection and prenatal diagnosis

Medical Informatics Training During Clinical Clerkship and the Shift from Computer Literacy to Information Literacy / 医学教育

A clinical clerkship in medical informatics was introduced in the 5th year of medical school. One goal is computer literacy, which means comprehension of the hospital information system including security policy and privacy preservation. The other is information literacy; The students make presentations concerning the medical information system and information technology within approximately ten minutes. All participants were enthusiastic about preparing the presentation. Seventy percent of them acknowledged the significance of explaining persuasively to others what they studied and the usefulness of these skills developed in this clerkship in their future. This result implies the importance of the shift to information literacy.