ABSTRACT
Chronic granulomatous disease (CGD) is a rare inherited disorder in which phagocytes lack nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. The most common form is the X-linked CGD (X91-CGD), caused by mutations in the CYBB gene. Clinical, functional and genetic characterizations of 16 CGD cases of male patients and their relatives were performed. We classified them as suffering from different variants of CGD (X910 , X91- or X91+ ), according to NADPH oxidase 2 (NOX2) expression and NADPH oxidase activity in neutrophils. Eleven mutations were novel (nine X910 -CGD and two X91- -CGD). One X910 -CGD was due to a new and extremely rare double missense mutation Thr208Arg-Thr503Ile. We investigated the pathological impact of each single mutation using stable transfection of each mutated cDNA in the NOX2 knock-out PLB-985 cell line. Both mutations leading to X91- -CGD were also novel; one deletion, c.-67delT, was localized in the promoter region of CYBB; the second c.253-1879A>G mutation activates a splicing donor site, which unveils a cryptic acceptor site leading to the inclusion of a 124-nucleotide pseudo-exon between exons 3 and 4 and responsible for the partial loss of NOX2 expression. Both X91- -CGD mutations were characterized by a low cytochrome b558 expression and a faint NADPH oxidase activity. The functional impact of new missense mutations is discussed in the context of a new three-dimensional model of the dehydrogenase domain of NOX2. Our study demonstrates that low NADPH oxidase activity found in both X91- -CGD patients correlates with mild clinical forms of CGD, whereas X910 -CGD and X91+ -CGD cases remain the most clinically severe forms.
Subject(s)
Granulomatous Disease, Chronic/genetics , Mutation, Missense/genetics , NADPH Oxidase 2/genetics , Adult , Cell Line , Exons/genetics , Female , Granulomatous Disease, Chronic/metabolism , Humans , Male , Membrane Glycoproteins/genetics , Neutrophils/metabolism , Young AdultABSTRACT
The association of lymphoma and autoimmune manifestations has been predominantly studied in adults affected by non-Hodgkin lymphoma. Few publications exist in the literature concerning Hodgkin lymphoma, particularly in children and adolescents. The objectives of this study were to define the characteristics of the link between Hodgkin disease and autoimmunity in childhood. The present 25-year retrospective study was conducted in all centers affiliated with the French Society of Paediatric Oncology (SFCE). Eleven children with Hodgkin disease presented manifestations of disimmunity preceding or following their diagnosis. Four patients had thrombocytopenic purpura, the remaining 7 each had a different autoimmune pathology: lupus syndrome, antiphospholipid syndrome with transient ischemic attack, Evans syndrome, leukocytoclastic vasculitis, autoimmune hemolytic anemia, autoimmune thyroiditis, and juvenile idiopathic arthritis. Lymphoma relapse occurred in 3 patients. Two children died, death being directly attributed to the autoimmune disease in 1 case. Our data suggest that development of autoimmunity is related to significant morbidity. Possible pathophysiological mechanisms include lymphocyte proliferation secondary to chronic inflammation, cell-mediated immune deficiency in Hodgkin disease, molecular mimetics, and antineoplastic phenomena are discussed. A study with a larger patient population is needed to identify the group of children at high risk of autoimmunity for whom additional investigations and modified therapy may be indicated.
