Imaging Findings in Chronic Granulomatous Disease (CGD)

OBJECTIVES

To describe prevalence of various imaging findings in chronic granulomatous disease (CGD) patients; and find imaging biomarkers for differentiating chest infections caused by different micro-organisms.

METHODS

A retrospective study was conducted on 15 patients (49 scans) with proven CGD. Scans which had a correlative microbiological diagnosis for organisms were included in the analysis. The scans were reviewed by 3 radiologists on a predefined proforma, under the lung parenchymal, airway, pleural, mediastinal, and extrathoracic abnormalities. Analysis of various imaging parameters on a semiquantitative scale was performed, followed by a correlation of each imaging findings with causative organisms.

RESULT

The mean age of presentation was nearly 7 y, with a male preponderance. Definitive proof of causative organisms was obtained in 22 scans. Bacterial infection was found in 7, fungal in 12, tubercular in 2, and viral in 1 scan. Most prevalent thoracic imaging manifestations included lymphadenopathy (commonest), consolidation, nodules, air trapping, and bronchiectasis. Fungal infections showed necrotic conglomerate lymphadenopathy, cavitating nodules, and multilobar consolidation more frequently than bacterial infections (though not statistically significant). Abscesses and lymphadenopathy were the most common extrathoracic manifestations.

CONCLUSION

In patients with CGD, multifocal or multilobar consolidation, mass-like consolidation, cavitating nodules, and conglomerate necrotic lymphadenopathy should alert the radiologist to a possible fungal cause.

Clinical Features of Female Taiwanese Carriers with X-linked Chronic Granulomatous Disease from 2004 to 2019

PURPOSE

Female carriers with X-linked chronic granulomatous disease (XL-CGD) who have < 10% reactive oxygen species (ROS) production due to profound X-chromosome inactivation (XCI or lyonization) are more susceptible to infections. We assessed ROS production in Taiwanese female carriers with XL-CGD to investigate whether the level of ROS correlated to their clinical features of infection, autoimmunity, and autoinflammation.

METHODS

Clinical course, ROS production, flavocytochrome b558 (Cyto b558) expression, and genetic analysis in carriers were investigated after identifying their index cases between 2004 and 2019.

RESULTS

A total of 19 mothers (median 27 years; range 25-60 years) and three of four girls (range 4-6 years) relative to 22 male index XL-CGD cases from 19 unrelated families were enrolled. Approximately half (8/19, 42%) of the mothers had novel one-allele mutations. Twenty-two of the 23 females were carriers. One carrier with de novo [Arg290X]CYBB who suffered from refractory salmonella sepsis and chorioretinitis as an XL-CGD phenotype had extreme XCI, absent Cyto b558 expression, and only 8% ROS production. The remaining carriers had bimodal patterns of Cyto b558 expressions (median 40.2%, 26.8-52.4%) and ROS production (38.3%, range 28.2-54.2%) sufficient to prevent significant infections, although neck lymphadenitis recurred in one mother and sister who had ROS expressions of 28.2% and 38.0%, respectively. However, none of the carriers had manifestations of autoimmunity or autoinflammation (e.g., photosensitivity, aphthous stomatitis, or joint disorders), of which each was seen in approximately one-third of XL-CGD carriers from the Western world.

CONCLUSION

One carrier had undetectable Cyto b558 expression and an extremely low ROS production, and consequently presented with an XL-CGD phenotype. One mother and her daughter experienced recurrent neck lymphadenitis despite having sufficient ROS production. Significant autoimmunity/autoinflammation did not develop in any of the carriers. Studies with a longer follow-up period are needed to validate our findings.

Macrophage activation syndrome/haemophagocytic lymphohistiocytosis secondary to Burkholderia cepacia complex septicaemia in an elderly female carrier of X-linked chronic granulomatous disease with extreme lyonisation: 'cepacia syndrome' revisited

X-linked carriers of chronic granulomatous disease (CGD) may become phenotypically affected if substantial skewing from lyonisation occurs. We describe a 73-year-old female carrier with an overt CGD phenotype due to skewed lyonisation, complicated by macrophage activation syndrome (MAS)/haemophagocytic lymphohistiocytosis (HLH) secondary to Burkholderiacepacia complex septicaemia that was successfully treated with a combination of three antibiotics, an antifungal, granulocyte colony stimulating factor, intravenous immune globulin (IVIG) and ciclosporin. Fully phenotypic immunodeficiency is possible in X-linked CGD carriers when skewed lyonisation occurs, rendering such patients to all the same sequelae of CGD such as MAS/HLH. MAS/HLH should be thoroughly excluded when evaluating 'cepacia syndrome' in non-CGD patients.

Chronic Granulomatous Disease First Diagnosed in Adulthood Presenting With Spinal Cord Infection

Chronic granulomatous disease (CGD) is a rare genetic immunodeficiency, which is characterized by recurrent severe bacterial and fungal infections caused by a defect in phagocytic cells due to loss of superoxide production. The disease usually manifests within the first years of life. Early diagnosis allows therapeutic intervention to improve the limited life expectancy. Nevertheless, only half of the patients exceed the age of 25. Here, we present the case of a 41-year old female patient who presented with an extensive spinal cord infection and atypical pneumonia mimicking tuberculosis. The medical history with recurrent granulomatous infections and microbiological findings with multiple unusual opportunistic pathogens was the key to the diagnosis of CGD, which is exceptionally rare first diagnosed in patients in the fifth decade of life. The late diagnosis in this case was likely due to the lack of knowledge of the disease by the treating teams before but not because the patient did not have typical CGD infections along her life. The extensive progressive developing granulomas in our patient with fatal outcome raise the question of early immunosuppressive therapy in addition to anti-infectious treatment. We recommend appropriate CGD diagnostics in adult patients with unclear granulomatous diseases of the nervous system.

Salmonella Enteritidis cholecystitis with chronic granulomatous disease

We describe a 40-year-old woman with Salmonella cholecystitis complicating adult-onset X-linked chronic granulomatous disease (CGD) caused by a de novo mutation in the paternal-origin CYBB gene. CGD was diagnosed by familial genetic analysis of the CYBB gene encoding NADPH oxidase gp91^phox after detection of a refractory subcutaneous abscess at the age of 28. At age 40, she began experiencing frequent fever and diarrhea over a period of 3 months that were refractory to antibacterial treatment. Cholecystitis was evident. Her symptoms improved after percutaneous trans-hepatic gallbladder aspiration puncture with stand-by cholecystectomy. Salmonella enterica serotype Enteritidis (S. Enteritidis) was detected in blood, stool, and bile acid samples. Due to her suppressed bactericidal ability caused by CGD, S. Enteritidis was considered to have translocated from the gut to reside in the gallbladder, causing her repeated enteritis and sepsis. When encountering CGD with recurrent salmonellosis, the possibility of cholecystitis should be considered as another infection focus.

Flow Cytometry, a Versatile Tool for Diagnosis and Monitoring of Primary Immunodeficiencies

Genetic defects of the immune system are referred to as primary immunodeficiencies (PIDs). These immunodeficiencies are clinically and immunologically heterogeneous and, therefore, pose a challenge not only for the clinician but also for the diagnostic immunologist. There are several methodological tools available for evaluation and monitoring of patients with PIDs, and of these tools, flow cytometry has gained prominence, both for phenotyping and functional assays. Flow cytometry allows real-time analysis of cellular composition, cell signaling, and other relevant immunological pathways, providing an accessible tool for rapid diagnostic and prognostic assessment. This minireview provides an overview of the use of flow cytometry in disease-specific diagnosis of PIDs, in addition to other broader applications, which include immune phenotyping and cellular functional measurements.

Advances in the diagnosis and treatment of chronic granulomatous disease

PURPOSE OF REVIEW

Chronic granulomatous disease (CGD), characterized 50 years ago as a primary immunodeficiency disorder of phagocytic cells (resulting in failure to kill a defined spectrum of bacteria and fungi and in concomitant chronic granulomatous inflammation) now comprises five genetic defects impairing one of the five subunits of phagocyte NADPH oxidase (Phox). Phox normally generates reactive oxygen species (ROS) engaged in intracellular and extracellular host defence and resolving accompanying inflammatory processes. 'Fatal' granulomatous disease has now changed into a chronic inflammatory condition with a median survival of 35 years and is now of interest to both paediatricians and internists. Clinical vigilance and expert knowledge are needed for early recognition and tailored treatment of this relatively rare genetic disorder.

RECENT FINDINGS

Infections by unanticipated pathogens and noncirrhotic portal hypertension need to be recognized as new CGD manifestations. Adult-onset CGD too is increasingly observed even in the elderly. Conservative treatment of fungal infections needs close monitoring due to the spread of azole resistance following extensive use of azoles in agriculture. Curative haematopoietic stem cell transplantation (HSCT) in early childhood has expanded with impressive results following use of matched, unrelated or cord blood donors and of a reduced intensity conditioning (RIC) regimen. Gene therapy, however, still has major limitations, remaining experimental.

SUMMARY

CGD is more prevalent than initially believed with a birth prevalence of 1: 120 000. As patients are increasingly diagnosed around the world and grow older, further manifestations of CGD are expected. While fungal infections have lost some threat, therapeutic research focuses on two other important aims: pharmacologic cure of chronic inflammation and long-term cure of CGD by gene therapy.

P67-phox (NCF2) lacking exons 11 and 12 is functionally active and leads to an extremely late diagnosis of chronic granulomatous disease (CGD)

Two brothers in their fifties presented with a medical history of suspected fungal allergy, allergic bronchopulmonary aspergillosis, alveolitis, and invasive aspergillosis and pulmonary fistula, respectively. Eventually, after a delay of 50 years, chronic granulomatous disease (CGD) was diagnosed in the index patient. We found a new splice mutation in the NCF2 (p67-phox) gene, c.1000+2T→G, that led to several splice products one of which lacked exons 11 and 12. This deletion was in frame and allowed for remarkable residual NADPH oxidase activity as determined by transduction experiments using a retroviral vector. We conclude that p67-phox which lacks the 34 amino acids encoded by the two exons can still exert considerable functional activity. This activity can partially explain the long-term survival of the patients without adequate diagnosis and treatment, but could not prevent progressing lung damage.

A Case of Chronic Granulomatous Disease with a Necrotic Mass in the Bronchus: A Case Report and a Review of Literature

Chronic granulomatous disease is a rare phagocytic disorder with recurrent, severe bacterial and fungal infections. We describe an unusual case of chronic granulomatous disease manifesting as an invasive pulmonary aspergillosis with an obstructive necrotic mass at the right middle bronchus. The patient was successfully treated with a bronchoscopic intervention for the removal of the obstructive mass and a medical therapy.

Relevance of laboratory testing for the diagnosis of primary immunodeficiencies: a review of case-based examples of selected immunodeficiencies

The field of primary immunodeficiencies (PIDs) is one of several in the area of clinical immunology that has not been static, but rather has shown exponential growth due to enhanced physician, scientist and patient education and awareness, leading to identification of new diseases, new molecular diagnoses of existing clinical phenotypes, broadening of the spectrum of clinical and phenotypic presentations associated with a single or related gene defects, increased bioinformatics resources, and utilization of advanced diagnostic technology and methodology for disease diagnosis and management resulting in improved outcomes and survival. There are currently over 200 PIDs with at least 170 associated genetic defects identified, with several of these being reported in recent years. The enormous clinical and immunological heterogeneity in the PIDs makes diagnosis challenging, but there is no doubt that early and accurate diagnosis facilitates prompt intervention leading to decreased morbidity and mortality. Diagnosis of PIDs often requires correlation of data obtained from clinical and radiological findings with laboratory immunological analyses and genetic testing. The field of laboratory diagnostic immunology is also rapidly burgeoning, both in terms of novel technologies and applications, and knowledge of human immunology. Over the years, the classification of PIDs has been primarily based on the immunological defect(s) ("immunophenotype") with the relatively recent addition of genotype, though there are clinical classifications as well. There can be substantial overlap in terms of the broad immunophenotype and clinical features between PIDs, and therefore, it is relevant to refine, at a cellular and molecular level, unique immunological defects that allow for a specific and accurate diagnosis. The diagnostic testing armamentarium for PID includes flow cytometry - phenotyping and functional, cellular and molecular assays, protein analysis, and mutation identification by gene sequencing. The complexity and diversity of the laboratory diagnosis of PIDs necessitates many of the above-mentioned tests being performed in highly specialized reference laboratories. Despite these restrictions, there remains an urgent need for improved standardization and optimization of phenotypic and functional flow cytometry and protein-specific assays. A key component in the interpretation of immunological assays is the comparison of patient data to that obtained in a statistically-robust manner from age and gender-matched healthy donors. This review highlights a few of the laboratory assays available for the diagnostic work-up of broad categories of PIDs, based on immunophenotyping, followed by examples of disease-specific testing.

Adult-onset presentations of genetic immunodeficiencies: genes can throw slow curves

PURPOSE OF REVIEW

The molecular and genetic mechanisms behind adult presentations of primary immunodeficiency diseases are examined, with particular emphasis on cases where this was heralded by severe, recurrent, or opportunistic infection.

RECENT FINDINGS

A detailed analysis over the last two decades of the relationship between genotype and clinical phenotype for a number of genetic immunodeficiencies has revealed multiple mechanisms that can account for the delayed presentation of genetic disorders that typically present in childhood, including hypomorphic gene mutations and X-linked gene mutations with age-related skewing in random X-chromosome inactivation. Adult-onset presentations of chronic granulomatous disease, X-linked agammaglobulinemia, IL-12/Th1/IFN-gamma and IL-23/Th17/IL-17 pathway defects, and X-linked lymphoproliferative disorder are used to illustrate these mechanisms. Finally, certain genetic types of common variable immunodeficiency are used to illustrate that inherited null mutations can take decades to manifest immunologically.

SUMMARY

Both genetic mechanisms and environmental factors can account for adult-onset infectious and noninfectious complications as manifestations of disorders that are typically present in childhood. This emphasizes the potential complexity in the relationship between genotype and phenotype with natural human mutations.

Hematologically important mutations: X-linked chronic granulomatous disease (third update)

Chronic granulomatous disease (CGD) is an immunodeficiency disorder affecting about 1 in 250,000 individuals. The disease is caused by a lack of superoxide production by the leukocyte enzyme NADPH oxidase. Superoxide is used to kill phagocytosed micro-organisms in neutrophils, eosinophils, monocytes and macrophages. The leukocyte NADPH oxidase is composed of five subunits, of which the enzymatic component is gp91-phox, also called Nox2. This protein is encoded by the CYBB gene on the X chromosome. Mutations in this gene are found in about 70% of all CGD patients. This article lists all mutations identified in CYBB in the X-linked form of CGD. Moreover, apparently benign polymorphisms in CYBB are also given, which should facilitate the recognition of future disease-causing mutations.

Chronic granulomatous disease (CGD) mimicking neoplasms: a suspected mediastinal teratoma unmasking as thymic granulomas due to X-linked CGD, and 2 related cases

Patients with chronic granulomatous disease (CGD) suffer from severe bacterial and fungal infections and deregulated inflammation, which are often associated with granuloma formation. We describe a 2-year-old boy who was seemingly healthy at the age of 1 year when a conventional chest radiograph was taken to exclude pulmonary aspiration of a piece of apple. Incidentally, a space-occupying mediastinal mass was revealed that was further evaluated by magnetic resonance imaging. Varying solid and also cystic, septated parts of the mass could be discerned and it was considered to be a teratoma. Removal of the mass by surgery was arduous because of adhesiveness to surrounding areas and led to severe complications. Unexpectedly, histopathologic examination revealed massive acute granulomatous inflammation with liquefied thymic cysts. X-linked CGD was subsequently diagnosed by a dihydrorhodamine 123 assay and sequencing of the CYBB gene (hotspot mutation c.742-743insA). This is the third example that we are aware of, where CGD granulomas were mistaken for neoplasms. The other 2 patients were initially believed to have tumors of the stomach and the urinary bladder, respectively. All patients initially received inadequate treatment. We discuss possible strategies to avoid such tragic confusions.

Chest radiographic and CT manifestations of chronic granulomatous disease in adults

OBJECTIVE

The purpose of this study was to describe the thoracic radiologic findings of chronic granulomatous disease in adults.

MATERIALS AND METHODS

We retrospectively analyzed the chest radiographic and CT findings in four adults with chronic granulomatous disease during five episodes of lower respiratory tract infection.

RESULTS

Chest radiographic findings included areas of consolidation (60%), diffuse reticulonodular opacities (40%), pleural effusion (20%), and pulmonary artery enlargement (20%). CT findings included areas of consolidation (60%), pulmonary nodules in a random distribution (60%), centrilobular nodules (60%), tree-in-bud opacities (40%), areas of scarring and traction bronchiectasis (100%), emphysematous changes (75%), areas of decreased attenuation and vascularity associated with air trapping on expiratory CT (50%), mediastinal and/or hilar lymphadenopathy (60%), pulmonary artery enlargement (50%), and pleural effusion (20%). Areas of consolidation and nodules were the most prominent findings and at histologic examination were found to be associated with infection or granulomatous inflammation.

CONCLUSION

The pulmonary radiologic findings of chronic granulomatous disease include consolidation, nodules, areas of scarring, traction bronchiectasis, emphysema, air trapping, mediastinal and hilar lymphadenopathy, pulmonary artery enlargement, and pleural effusion.

X-linked chronic granulomatous disease secondary to skewed X chromosome inactivation in a female with a novel CYBB mutation and late presentation

Chronic granulomatous disease (CGD) is characterized by defects in the superoxide producing enzyme NADPH oxidase causing phagocytes to improperly clear invading pathogens. Here we report findings of a late presenting 16-year-old female with X-linked CGD. The patient presented with community-acquired pneumonia, but symptoms persisted for 2 weeks during triple antimicrobial coverage. Cultures revealed Aspergillus fumigatus which was resolved through aggressive voriconazole treatment. Neutrophil studies revealed NADPH oxidase activity and flavocytochrome b(558) levels that were 4-8% of controls and suggested carrier status of the mother. We found a null mutation in the CYBB gene (c.252insAG) predicting an aberrant gp91(phox) protein (p.Cys85fsX23) in the heterozygous state. Methylation analysis demonstrated extremely skewed X chromosome inactivation favoring the maternally inherited defective gene. In conclusion, a novel mutation in the CYBB gene and an extremely skewed X-inactivation event resulted in the rare expression of the CGD phenotype in a carrier female.

Adult onset X-linked chronic granulomatous disease in a woman patient caused by a de novo mutation in paternal-origin CYBB gene and skewed inactivation of normal maternal X chromosome

We report a 28-year-old woman patient suffering from refractory subcutaneous abscess. Stimuli-induced microbicidal reactive oxygen metabolites formation test of the patient's neutrophils revealed that only 9.6% of the neutrophils produced H2O2. DNA analysis of the CYBB that encodes gp91(phox) demonstrated that she was heterozygous for a nonsense mutation, 206Trp(TGG)/stop(TGA) and therefore, a diagnosis of adult onset X-linked chronic granulomatous disease was made. Our molecular biological study revealed that her disease was caused by a de novo mutation in the CYBB gene on the paternal-origin X-chromosome and a skewed inactivation of the normal maternal X-chromosome.

Chronic granulomatous disease (CGD) and complete myeloperoxidase deficiency both yield strongly reduced dihydrorhodamine 123 test signals but can be easily discerned in routine testing for CGD

BACKGROUND

The flow cytometric dihydrorhodamine 123 (DHR) assay is used as a screening test for chronic granulomatous disease (CGD), but complete myeloperoxidase (MPO) deficiency can also lead to a strongly decreased DHR signal. Our aim was to devise simple laboratory methods to differentiate MPO deficiency (false positive for CGD) and NADPH oxidase abnormalities (true CGD).

METHODS

We measured NADPH-oxidase and MPO activity in neutrophils from MPO-deficient patients, CGD patients, NADPH-oxidase-transfected K562 cells and cells with inhibited and substituted MPO.

RESULTS

Eosinophils from MPO-deficient individuals retain eosinophilic peroxidase and therefore generate a normal DHR signal. The addition of recombinant human MPO enhances the DHR signal when simply added to a suspension of MPO-deficient cells but not when added to NADPH-oxidase-deficient (CGD) cells. Lucigenin-enhanced chemiluminescence (LCL) is increased in neutrophils from MPO-deficient patients, whereas neutrophils from patients with CGD show a decreased response.

CONCLUSIONS

A false-positive result caused by MPO deficiency can be easily ascertained because, unlike cells from a CGD patient, cells from MPO-deficient patients (a) contain functionally normal eosinophils, (b) show a significant enhancement of the DHR signal following addition of rhMPO, and (c) generate a strong LCL signal.

Characterization of 17 new cases of X-linked chronic granulomatous disease with seven novel mutations in the CYBB gene

OBJECTIVE

Molecular identification and clinical characterization of genetic mutations in patients with X-linked chronic granulomatous disease (CGD).

PATIENTS AND METHODS

Genomic DNA from 17 male patients with proven X-linked CGD based on clinical history, clinical examination, and specific granulocyte function tests were amplified by polymerase chain reaction (PCR) for sequences of the CYBB gene encoding gp91-phox. Mutations in the resulting PCR products were identified by DNA sequencing.

RESULTS

Sequence analysis revealed four deletions (453_454delAG; 802delC; 962delG; 993delG), one combined deletion/insertion/duplication [156_173delTCAGCACTGGCACTGGCC/174_175insT/175_176insCCTGCCTGAATTTCT(dupl187_200)]; one insertion (574_575insCCTCAT), four nonsense mutations (332G > A; 402C > T; 690C > T; 1340C>G), two missense mutations (933A > C; 1041A > C) and four potential splice-site mutations (5'intron1 gt-->at; 3'intron1ag-->at; 5'intron3 gtaag-->gtaaa; 5'intron4 gtaa-->ctaa). Seven of these mutations were indeed novel, whereas four mutations not previously reported to the X-CGDbase were found to be of the same type as database reports of unrelated families. The six remaining mutations have been reported previously to the X-CGDbase but have as yet not been described in detail.

CONCLUSION

Our findings underline the great heterogeneity of mutations involving the CYBB gene. Neither a mutational hot spot in the gp91-phox gene nor a clear correlation between molecular defect and clinical manifestation in unrelated families could be demonstrated. Remarkable is a splice-site mutation (5'intron3 gtaag-->gtaaa) identified in a 40-year-old patient with late onset "adult" CGD and residual nicotinamide adenine dinucleotide phosphate reduced oxidase activity. The enormous delay of clinical symptoms of this particular mutation could be explained by an age-related variable sensitivity of the splicing machinery to the present splice-site mutation.

Skewing of X-chromosome inactivation in three generations of carriers with X-linked chronic granulomatous disease within one family

BACKGROUND

Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by impairment of intracellular microbicidal activity of phagocytes. Mutations in one of the four known NADPH-oxidase components preclude generation of superoxide and related antimicrobial oxidants, leading to the phenotype of CGD. Defects in gp91-phox, encoded by CYBB, lead to X-linked CGD, responsible for approximately 70% of all CGD cases. The aim of the study was to evaluate the hypothesis that age-related skewing of X-chromosome inactivation, as described in several CGD families, is caused by preferential survival of bone marrow clones with an inactive NADPH oxidase.

MATERIALS AND METHODS

We studied the neutrophils from three patients and four carriers in three generations of a Turkish family with X-linked CGD. Carrier detection was carried out by the dihydrorhodamine (DHR)-1,2,3 assay, which measures on a per-cell basis the NADPH oxidase-dependent oxidation of DHR by phagocytes. The X-chromosome inactivation pattern was determined with the HUMARA assay in DNA from leucocytes as well as in DNA from a buccal smear of the four carriers.

RESULTS

The three patients were identified by a negative DHR test, and the mutation in their CYBB gene was characterized by DNA sequencing. Moreover, we found an age-related degree of skewing of X-chromosome inactivation in the leucocytes of the four X-CGD carriers, both at the protein level (NADPH oxidase activity) and at the DNA level (HUMARA assay). However, similar skewing of X-chromosome inactivation was found in the buccal DNA from these women.

CONCLUSIONS

These novel findings indicate that the age-related degree of skewing was probably a chance finding, not related to preferential survival of NADPH oxidase-deficient precursor cells, because this enzyme is not expressed in (buccal) epithelial cells.

A splice-supporting intronic mutation in the last bp position of a cryptic exon within intron 6 of the CYBB gene induces its incorporation into the mRNA causing chronic granulomatous disease (CGD)

Chronic granulomatous disease (CGD) is caused by a defect in both the host's defenses and its regulation of inflammation normally provided by phagocytes and other leukocytes. As in the case described here, it is not uncommon that CGD patients are diagnosed late, only after organ-damaging manifestations have already progressed. In this patient, we found that CGD arose due to a splice-supporting mutation in the last position of a cryptic exon towards the middle of intron 6 of the CYBB (gp91-phox) gene. The mutation led to the insertion of 56 bp into most of the CYBB mRNA of leukocytes causing a frame shift and a premature stop codon. The normal cryptic exon was also found to be mildly active in some tissues other than leukocytes in healthy donors, to be conserved in many primates, and to a lesser degree in other mammals. Some sequence similarity suggests that the cryptic exon may have originated from a mammalian interspersed repetitive (MIR) element. Taken together, we clarify an unusual disease-causing mutation, indicate its evolutionary background and emphasize the importance of a timely diagnosis of CGD.

Presentation of Interleukin-12/-23 Receptor β1 Deficiency with Various Clinical Symptoms of Salmonella Infections

Clinical disease caused by weakly pathogenic mycobacterial species, Mycobacterium bovis Bacille Calmette-Guérin (BCG) and non-tuberculous environmental mycobacteria (EM), which is known as Mendelian susceptibility to mycobacterial disease (MSMD), is a rare entity defined recently. Infections with the more virulent Mycobacterium species, M. tuberculosis, may have largely gone unnoticed in these patients due to early death. Mutations in five proteins (IFNgammaR1, IFNgammaR2, IL-12/IL-23Rbeta1, IL-12/IL-23p40 and STAT1) have been found in MSMD. These patients are prone to surprisingly few other infectious diseases mainly to salmonellosis. Here we present three IL-12/IL-23Rbeta1 deficient patients from three different families and with different genetic mutations, who presented exclusively with Salmonella infections. Bacteremia and lymph node involvement were common clinical expressions. Leukocytoclastic vasculitis developed in one of these patients. Two patients were not inoculated with BCG, the third patient did not develop BCG infection although BCG vaccine had been given twice at ages of 1 and 7 years. All three patients responded well to antibiotic treatment. In conclusion, patients with chronic, recurrent or complicated Salmonella infections should be screened for MSMD, particularly for IL-12/IL-23p40/IL-12R/-23Rbeta1 deficiency. Conversely, in patients with genetic IL-12/-23Rbeta1 deficiency a full evaluation for Salmonella infection is required. IL-12/IL-23p40/IL-12R/IL-23Rbeta1 deficiency seem to be underdiagnosed in patients with salmonellosis, and since such patients need prolonged therapy, diagnosis is important.

Unusual late presentation of X-linked chronic granulomatous disease in an adult female with a somatic mosaic for a novel mutation in CYBB

Most patients with chronic granulomatous disease (CGD) have mutations in the X-linked CYBB gene that encodes gp91phox, a component of the phagocyte NADPH oxidase. The resulting X-linked form of CGD is usually manifested in boys. Rarely, X-CGD is encountered in female carriers with extreme expression of the mutated gene. Here, we report on a woman with a novel mutation in CYBB (CCG[90-92] → GGT), predicting Tyr30Arg31 → stop, Val in gp91phox, who presented with clinical symptoms at the age of 66. The mutation was present in heterozygous form in genomic DNA from her leukocytes but was fully expressed in mRNA from these cells, indicating that in her leukocytes the X chromosome carrying the nonmutated CYBB allele had been inactivated. Indeed, only 0.4% to 2% of her neutrophils showed NADPH oxidase activity. This extreme skewing of her X-chromosome inactivation was not found in her cheek mucosal cells and is thus not due to a general defect in gene methylation on one X chromosome. Moreover, the CYBB mutation was not present in the DNA from her cheek cells and was barely detectable in the DNA from her memory T lymphocytes. Thus, this patient shows a somatic mosaic for the CYBB mutation, which probably originated during her lifetime in her bone marrow.

Severe phenotype of chronic granulomatous disease presenting in a female with a de novo mutation in gp91-phox and a non familial, extremely skewed X chromosome inactivation

Chronic granulomatous disease (CGD) is an inherited immunodeficiency resulting from defects in the multienzyme complex NADPH-oxidase (phagozyte oxidase, phox), which normally produces microbicidal reactive oxygen metabolites (ROM). The reason for our patient's CGD was unusual, as revealed by the following in vitro findings in neutrophils and EBV-transformed B-cells: lack of flavocytochrome b(558) expression, restoration of significant ROM production after transduction with gp91-phox cDNA by a retrovirus vector, an 879G-->A, Trp289-->Stop mutation in one X chromosomal gp91-phox allele, a one-sided paternal X chromosome inactivation, as shown by a lyonization assay at the HUMARA locus, and the result of a dihydrorhodamine 123 flow cytometry assay revealing consistently that 1 in 2500 neutrophils produced ROM at normal levels. Our conclusion: A presumed autosomal form of CGD has been excluded. Instead, a spontaneous mutation in gp91-phox coinciding with an extreme X chromosome inactivation ratio resulted in X-linked CGD in this young woman.