Clinical, functional and genetic characterization of 16 patients suffering from chronic granulomatous disease variants - identification of 11 novel mutations in CYBB.

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.

Specific antibody deficiency in children with recurrent respiratory infections: a controlled study with follow-up.

Specific antibody deficiency (SAD) to unconjugated pneumococcal vaccine (PPV) is an established primary B cell immunodeficiency. The occurrence and natural history of SAD in children is unclear. We conducted an observational study to identify SAD in children with recurrent respiratory infections. Ninety-nine children, mean age 5·9 (range 2-16) years, with recurrent or severe infections were vaccinated with PPV; serum antibody concentrations for serotypes 4, 6B, 9V, 14, 18C, 19F and 23F were measured before and 2 weeks after vaccination with enzyme immunoassay. The retrospective control group consisted of 89 healthy children matched for age and gender. No children had received previous conjugated pneumococcal vaccine (PCV) or PPV. The structured history of infectious diseases of all participants was collected. Ten of 91 (11%) children (eight excluded due to immunoglobulin G subclass deficiency) with recurrent respiratory infections had SAD. In the control group, three children (3%) responded inadequately to PPV (P = 0·05). Most children with SAD also had many other minor immune defects. After 0·5-5 years (medium 3·8), eight children with SAD were revaccinated with PPV; five responded adequately and three inadequately. Two SAD children were revaccinated with PCV, one developed an adequate and one an inadequate response. Two children with SAD received treatment with intravenous immunoglobulin; the remaining eight children recovered without replacement therapy during the follow-up. SAD is common in young children with recurrent respiratory infections, but it is often transient and resolves itself within a few years without specific treatment.

Virus shedding after human rhinovirus infection in children, adults and patients with hypogammaglobulinaemia.

The shedding of human rhinovirus (HRV) after an acute, naturally acquired infection has not been described in detail. We determined the duration of HRV shedding in immunocompetent children and adults, and in patients with primary hypogammaglobulinaemia. Subjects with symptoms of respiratory tract infection, and their household contacts, were screened for HRV by reverse transcription PCR. They were followed by serial, self-collected nasal swab specimens until negative for HRV or infected by another HRV type. We followed 62 HRV infections in 54 subjects. The mean (95% CI) duration of HRV shedding was 11.4 (8.2-14.7) days in children, 10.1 (7.4-12.9) days in adults, and 40.9 (26.4-55.4) days in patients with hypogammaglobulinaemia (p <0.001). The duration of respiratory tract symptoms correlated with the duration of virus shedding (p 0.002). A new infection by another HRV type soon after the first episode was common. We conclude that the shedding times of HRV are relatively short in otherwise healthy individuals. In contrast, prolonged shedding over 28 days is frequent in patients with hypogammaglobulinaemia despite immunoglobulin replacement therapy.

Diagnostic findings in 95 Finnish patients with common variable immunodeficiency.

Common variable immunodeficiency is the most frequent of the primary hypogammaglobulinemias. It is manifested by a wide variety of clinical signs and symptoms. In this retrospective, nationwide survey data were collected on all patients with common variable immunodeficiency who were receiving immunoglobulin replacement therapy in Finland to study the prediagnostic clinical picture, diagnostic delay, and diagnostic findings. Ninety-five patients were identified. The median age of the patients was 33 years. Sixteen of the patients were children. Sinopulmonary infections were the most common prediagnostic signs and symptoms; 66% had suffered from recurrent pneumonia, 60% from recurrent maxillary sinusitis, and 45% from recurrent bronchitis. There was a considerable delay in diagnosis. The mean delay was 8 years. At the time of diagnosis chronic pulmonary complications had already developed in 17% of the patients. The diagnosis was based on low serum immunoglobulin concentrations. This study showed that the awareness of common variable immunodeficiency is low. To improve the recognition of hypogammaglobulinemia, it should be suspected in every patient with recurrent bacterial infections. In addition to a low serum IgG concentration, measurement of specific antibody production is recommended to establish the diagnosis before initiation of a life-long and costly replacement therapy.

Pulmonary abnormalities in patients with primary hypogammaglobulinemia.

BACKGROUND: Pulmonary complications are common in patients with primary hypogammaglobulinemia. Intravenous immunoglobulin replacement therapy has been thought to reduce the occurrence of pulmonary complications, yet they do occur. OBJECTIVE: The purpose of this study was to evaluate pulmonary abnormalities in 22 patients with primary hypogammaglobulinemia (18 with common variable immunodeficiency, 4 with X-linked agammaglobulinemia) and to conduct a prospective 3-year follow-up study to assess the possible progression of pulmonary abnormalities. METHODS: Pulmonary changes were evaluated with use of pulmonary imaging (chest radiographs, high-resolution computed tomography), and pulmonary function testing. RESULTS: High-resolution computed tomography revealed pulmonary abnormalities in 21 patients. Bronchiectasis was present in 16 patients, whereas chest radiographs revealed bronchiectasis in only 3 patients. Pulmonary function testing showed obstruction in 5 patients. A prospective 3-year follow-up was conducted in 14 patients. It showed silent progression of bronchiectasis in 5 of the 14 patients, all of whom were receiving intravenous immunoglobulin replacement therapy and had preinfusion serum IgG concentrations of 5 g/L or more. CONCLUSIONS: Pulmonary abnormalities develop in most patients with primary hypogammaglobulinemia. A new finding is that silent and asymptomatic progression of pulmonary changes may occur in patients despite an adequate immunoglobulin replacement therapy. High-resolution computed tomography is the method of choice in monitoring pulmonary changes.

Viruses and bacteria in bronchial samples from patients with primary hypogammaglobulinemia.

Viruses and bacteria in bronchoalveolar lavage fluids, protected specimen brush samples, and bronchial biopsies from 14 patients with primary hypogammaglobulinemia (11 patients with common variable immunodeficiency [CVID] and three patients with X-linked agammaglobulinemia [XLA]) were analyzed. At the time of the study, the patients had no signs of acute respiratory infections, and no antibiotics were administered. In addition to routine bacterial and viral cultures, polymerase chain reaction tests were used for the detection of adenovirus, cytomegalovirus (CMV), herpes simplex virus 1, enterovirus, rhinovirus, Borrelia burgdorferi, Chlamydia pneumoniae, Legionella spp., Mycoplasma pneumoniae, Pneumocystis carinii, and Ureaplasma urealyticum. Viruses (four adenoviruses, one CMV, and one rhinovirus) were detected in four of the 11 (36%) CVID patients. No viruses were found in the three patients with XLA or in 13 control patients. Bacteria from the lower respiratory tract were detected in nine of the 14 (64%) patients with hypogammaglobulinemia and three of the 13 (23%) control patients. Haemophilus influenzae was the most prevalent bacterium (43%) in the hypogammaglobulinemia patients. The study shows that patients with CVID harbor viral and bacterial infections in the lower respiratory tract, which may predispose to the development of changes in the respiratory tract.

IL-4 synergizes with IL-10 and anti-CD40 MoAbs to induce B-cell differentiation in patients with common variable immunodeficiency.

In the present study the phenotype and function of lymphocytes from patients with common variable immunodeficiency (CVI) were studied. Five out of 12 patients had abnormally low proportion of CD4+ T cells, but PBMC of these patients were capable of proliferating in response to polyclonal T-cell mitogens or PPD antigen. The phenotype of patients' B cells, as determined by expression of CD10, CD19 and CD34, was comparable to that of healthy controls. IL-4 and anti-CD40 MoAbs induced moderate B-cell differentiation in PBMC derived from patients with CVI, but the frequencies of Ig-secreting cells were generally at levels spontaneously observed in healthy controls. IL-10 was completely ineffective in inducing IgG-secreting cells in cultures of PBMC derived from patients with CVI even in the presence of anti-CD40 MoAbs, whereas high frequencies of Ig-secreting cells were induced under similar condition in cultures of PBMC derived from healthy controls. Importantly, when IL-4 was added to cultures stimulated with anti-CD40 MoAbs and IL-10, a very strong synergistic effect on the numbers of Ig-secreting cells and the levels of Ig secretion was observed in PBMC from both patients and controls. Moreover, the frequencies of Ig-secreting cells after activation with anti-CD40 MoAbs, IL-4 plus IL-10 in PBMC from some patients were comparable to those observed in PBMC from healthy controls. Taken together, these results indicate that B cells from patients with CVI have impaired capacity to differentiate into Ig-secreting cells in response to IL-10 and anti-CD40 MoAbs, and that this unresponsiveness can be restored by exogenous IL-4 in a proportion of the patients.

Systemic amyloidosis in a patient with hypogammaglobulinaemia.

A 49-year-old patient with an 18-year history of hypogammaglobulinaemia presented with nephrotic syndrome due to systemic amyloidosis. Recurrent infections as a consequence of an inadequate gammaglobulin substitution therapy were regarded as the main reason for the development of amyloidosis. When a high-dose intravenous immunoglobulin therapy was started, the clinical symptoms declined and the patient felt moderately well. Later the patient developed symmetrical polyarthritis clinically suggestive of rheumatoid arthritis. Although the incidence of arthritis is increased in hypogammaglobulinaemia, arthritis has not been reported in any of the few previously described patients with hypogammaglobulinaemia-associated amyloidosis. Moreover, this case provides further evidence that, in these patients, the amyloid fibrils may be of the AA type.