Chronic granulomatous disease in Morocco: genetic, immunological, and clinical features of 12 patients from 10 kindreds

[Bacillus Calmette-Guérin infection and chronic granulomatous disease due to new pathogenic variants in the NCF2 gene in the Mayan ethnic group. Report of two cases.]

INTRODUCTION

Chronic granulomatous disease (CGD) is an inborn error of immunity, characterized by abnormal susceptibility to bacterial and fungal infections and a lack of systemic inflammatory regulation. Pathogenic variants in the CYBB gene are transmitted in an X-linked pattern of inheritance; while the pathogenic variants present in the EROS, NCF1, NCF2, NCF4, or CYBA genes are transmitted with an autosomal recessive inheritance pattern.

OBJETIVES

To describe the clinical, immunological, and genetic characteristics of two patients with CGD and BCG infection.

METHODS

In peripheral blood neutrophils, H₂O₂ production and the expression of NADPH oxidase subunits were measured. Detection of pathogenic variants was by Sanger sequencing of the NCF2 gene. The clinical information was extracted from the records by the treating physicians.

RESULTS

We present two male infants from two unrelated families of Mayan ethnicity, with CGD and BCG vaccine infection. Three different pathogenic variants in the NCF2 gene were identified; on the one hand, c.304 C>T (p.Arg102*) has already been reported, on the other hand, c.1369 A>T (p.Lys457*) and c.979 G>T (p.Gly327*) not reported.

CONCLUSIONS

In patients with mycobacterial infection with BCG, we should suspect an inborn error of immunity, such as CGD. The diagnosis of CGD is made through the detection of a lack of radical oxygen species in neutrophils. The reported patients had pathogenic variants in the NCF2 gene, two of which have not been previously reported in the literature.

Case Report: Symptomatic Chronic Granulomatous Disease in the Newborn

Chronic granulomatous disease (CGD) is a primary immunodeficiency, which is diagnosed in most patients between one and three years of age. Here we report on a boy who presented at birth with extensive skin lesions and lymphadenopathy which were caused by CGD. An analysis of the literature revealed 24 patients with CGD who became symptomatic during the first six weeks of life. Although pulmonary complications and skin lesions due to infection were the leading symptoms, clinical features were extremely heterogenous. As follow-up was not well specified in most patients, the long-term prognosis of children with very early onset of CGD remains unknown.

Geographic Variability and Pathogen-Specific Considerations in the Diagnosis and Management of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a rare but serious primary immunodeficiency with varying prevalence and rates of X-linked and autosomal recessive disease worldwide. Functional defects in the phagocyte nicotinamide adenine dinucleotide phosphate oxidase complex predispose patients to a relatively narrow spectrum of bacterial and fungal infections that are sometimes fastidious and often difficult to identify. When evaluating and treating patients with CGD, it is important to consider their native country of birth, climate, and living situation, which may predispose them to types of infections that are atypical to your routine practice. In addition to recurrent and often severe infections, patients with CGD and X-linked female carriers are also susceptible to developing many non-infectious complications including tissue granuloma formation and autoimmunity. The DHR-123 oxidation assay is the gold standard for making the diagnosis and it along with genetic testing can help predict the severity and prognosis in patients with CGD. Disease management focuses on prophylaxis with antibacterial, antifungal, and immunomodulatory medications, prompt identification and treatment of acute infections, and prevention of secondary granulomatous complications. While hematopoietic stem-cell transplantation is the only widely available curative treatment for patients with CGD, recent advances in gene therapy may provide a safer, more direct alternative.

A novel variant in the neutrophil cytosolic factor 2 (NCF2) gene results in severe disseminated BCG infectious disease: A clinical report and literature review

Background

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disorder (PID) affecting NADPH oxidase activity. The rarest form of the disease is considered to be caused by NCF2 gene bi‐allelic variant. Here, we report the clinical and molecular characterization of a patient presenting with early‐onset severe disease due to bi‐allelic NCF2 variant.

Methods

Gene mutational analysis was performed by whole‐exome and Sanger sequencing.

Results

The patient presented with a history of fever and rash since the age of 1 month, followed by destructive osteomyelitis and necrotizing lymphadenopathy. The patient received the Bacillus Calmette‐Guérin (BCG) vaccine at birth; she was subsequently diagnosed with disseminated BCG infection. Whole‐exome sequencing identified a private (unreported) homozygous variant in NCF2 (c.290C > A) that results in a nonconservative change, p.Ala97Asp, in the p67^phox protein. The variant is located in the third helix of the TRP domain, which is crucial for the binding of GTPase RAC2 to the NADPH oxidase complex.

Conclusion

We identified a novel NCF2 variant located in the region interacting with RAC2 that is linked to a severe and early CGD phenotype in the setting of disseminated BCG infection. Our findings support postponing BCG vaccination until 6–12 months of age and after PID assessment.

Life-Threatening Infections Due to Live-Attenuated Vaccines: Early Manifestations of Inborn Errors of Immunity

Live-attenuated vaccines (LAVs) can protect humans against 12 viral and three bacterial diseases. By definition, any clinical infection caused by a LAV that is sufficiently severe to require medical intervention attests to an inherited or acquired immunodeficiency that must be diagnosed or identified. Self-healing infections can also result from milder forms of immunodeficiency. We review here the inherited forms of immunodeficiency underlying severe infections of LAVs. Inborn errors of immunity (IEIs) underlying bacille Calmette-Guérin (BCG), oral poliovirus (OPV), vaccine measles virus (vMeV), and oral rotavirus vaccine (ORV) disease have been described from 1951, 1963, 1966, and 2009 onward, respectively. For each of these four LAVs, the underlying IEIs show immunological homogeneity despite genetic heterogeneity. Specifically, BCG disease is due to inborn errors of IFN-γ immunity, OPV disease to inborn errors of B cell immunity, vMeV disease to inborn errors of IFN-α/β and IFN-λ immunity, and ORV disease to adaptive immunity. Severe reactions to the other 11 LAVs have been described yet remain "idiopathic," in the absence of known underlying inherited or acquired immunodeficiencies, and are warranted to be the focus of research efforts. The study of IEIs underlying life-threatening LAV infections is clinically important for the affected patients and their families, as well as immunologically, for the study of the molecular and cellular basis of host defense against both attenuated and parental pathogens.

Genetic and Clinical Profiles of Disseminated Bacillus Calmette-Guérin Disease and Chronic Granulomatous Disease in China

Background: Disseminated Bacillus Calmette-Guérin disease (D-BCG) in children with chronic granulomatous disease (CGD) can be fatal, while its clinical characteristics remain unclear because both diseases are extremely rare. The patients with CGD receive BCG vaccination, because BCG vaccination is usually performed within 24 h after delivery in China.

Methods: We prospectively followed-up Chinese patients with CGD who developed D-BCG to characterize their clinical and genetic characteristics. The diagnoses were based on the patients' clinical, genetic, and microbiological characteristics.

Results: Between September 2009 and September 2016, we identified 23 patients with CGD who developed D-BCG. Their overall 10-year survival rate was 34%. We created a simple dissemination score to evaluate the number of infected organ systems and the survival probabilities after 8 years were 62 and 17% among patients with simple dissemination scores of ≤3 and >3, respectively (p = 0.0424). Survival was not significantly associated with the CGD stimulation index or interferon-γ treatment. Eight patients underwent umbilical cord blood transplantation and 5 of them were successfully treated. The genetic analyses found mutations in CYBB (19 patients), CYBA (1 patient), NCF1 (1 patient), and NCF2 (1 patient). We identified 6 novel highly likely pathogenic mutations, including 4 mutations in CYBB and 2 mutations in NCF1.

Conclusions: D-BCG is a deadly complication of CGD. The extent of BCG spreading is strongly associated with clinical outcomes, and hematopoietic stem cell transplantation may be a therapeutic option for this condition.

Role of Flow Cytometry in the Diagnosis of Chronic Granulomatous Disease: the Egyptian Experience

INTRODUCTION

Chronic granulomatous disease (CGD) is an inherited mutational defect in any of the NADPH oxidase complex, CYBB (gp91-phox), NCF1 (p47-phox), CYBA (p22-phox), NCF2 (p67-phox), or NCF4 (p40-phox) leading to inability of phagocytes to perform effective respiratory burst and thus diminished killing of bacteria and fungi. The identification of defective proteins aids in establishing a diagnosis prior to genetic analysis, which is rather labor-intensive, expensive, and time-consuming.

AIM

The present study aims at assessing the NADPH proteins by performing the intracellular staining with specific monoclonal antibodies and their assessment on flow cytometry. The use of flow cytometry is less laborious and faster to perform than western blot. It also confirms the diagnosis of CGD and detects the affected components allowing proper management of patients.

MATERIALS AND METHODS

Twenty-eight patients from 25 different kindred, clinically suspected as CGD were recruited in Egypt. Dihydrorhodamine test was performed to confirm the diagnosis of the patients. Intracellular staining of NADPH components using specific monoclonal antibodies was performed followed by flow cytometric analysis.

RESULTS

The present study revealed that the most common defective protein in our cohort is p22-phox, found in 13 patients (46.4 % of cases) followed by p47-phox in 8 patients (28.6 %), gp91-phox in 5 patients (17.9 %), and finally p67-phox in 2 patients (7.1 %).

CONCLUSION

In countries with limited resources and yet large number of CGD patients, the analysis of the defective proteins by flow cytometry is an optimum solution for confirming the diagnosis and is a step for targeted sequencing in families seeking prenatal diagnosis.

Mendelian susceptibility to mycobacterial disease: genetic, immunological, and clinical features of inborn errors of IFN-γ immunity

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare condition characterized by predisposition to clinical disease caused by weakly virulent mycobacteria, such as BCG vaccines and environmental mycobacteria, in otherwise healthy individuals with no overt abnormalities in routine hematological and immunological tests. MSMD designation does not recapitulate all the clinical features, as patients are also prone to salmonellosis, candidiasis and tuberculosis, and more rarely to infections with other intramacrophagic bacteria, fungi, or parasites, and even, perhaps, a few viruses. Since 1996, nine MSMD-causing genes, including seven autosomal (IFNGR1, IFNGR2, STAT1, IL12B, IL12RB1, ISG15, and IRF8) and two X-linked (NEMO, and CYBB) genes have been discovered. The high level of allelic heterogeneity has already led to the definition of 18 different disorders. The nine gene products are physiologically related, as all are involved in IFN-γ-dependent immunity. These disorders impair the production of (IL12B, IL12RB1, IRF8, ISG15, NEMO) or the response to (IFNGR1, IFNGR2, STAT1, IRF8, CYBB) IFN-γ. These defects account for only about half the known MSMD cases. Patients with MSMD-causing genetic defects may display other infectious diseases, or even remain asymptomatic. Most of these inborn errors do not show complete clinical penetrance for the case-definition phenotype of MSMD. We review here the genetic, immunological, and clinical features of patients with inborn errors of IFN-γ-dependent immunity.