Bacillus Calmette-Guérin (BCG) Infections at High Frequency in Both AR-CGD and X-CGD Patients Following BCG Vaccination

Description of BCG and Tuberculosis Disease in a Cohort of 79 Patients with Chronic Granulomatous Disease

PURPOSE

Chronic granulomatous disease (CGD) is an inherited immunodeficiency caused by pathogenic variants of genes encoding the enzyme complex NADPH oxidase. In countries where tuberculosis (TB) is endemic and the Bacillus Calmette-Guérin (BCG) vaccine is routinely administered, mycobacteria are major disease-causing pathogens in CGD. However, information on the clinical evolution and treatment of mycobacterial diseases in patients with CGD is limited. The present study describes the adverse reactions to BCG and TB in Mexican patients with CGD.

METHODS

Patients with CGD who were evaluated at the Immunodeficiency Laboratory of the National Institute of Pediatrics between 2013 and 2024 were included. Medical records were reviewed to determine the clinical course and treatment of adverse reactions to BCG and TB disease.

RESULTS

A total of 79 patients with CGD were included in this study. Adverse reactions to BCG were reported in 55 (72%) of 76 patients who received the vaccine. Tuberculosis was diagnosed in 19 (24%) patients. Relapse was documented in three (10%) of 31 patients with BGC-osis and six (32%) of 19 patients with TB, despite antituberculosis treatment. There was no difference in the frequency of BCG and TB disease between patients with pathogenic variants of the X-linked CYBB gene versus recessive variants.

CONCLUSIONS

This report highlights the importance of considering TB in endemic areas and BCG complications in children with CGD to enable appropriate diagnostic and therapeutic approaches to improve prognosis and reduce the risk of relapse.

Clinical features and outcomes of patients with chronic granulomatous disease in Taiwan

BACKGROUND

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disease characterized by defective neutrophil killing of microbial pathogens and recurrent infections. We aimed to investigate the clinical, genetic features, treatment, and outcomes in patients with CGD.

METHODS

Pediatric patients diagnosed with CGD from a medical center in Taiwan were enrolled from January 1999 to Oct 2021.

RESULTS

Nine pediatric patients with CGD were enrolled: six X-linked (XL) CGD with CYBB gene mutations, three autosomal recessive (AR) CGD with two NCF1 and one CYBA gene mutations. The median age of onset and age of diagnosis was 0.92 and 2.64 years, respectively. Patients with XL-CGD had a younger age of onset (4.6 months vs. 1.83 years, P = 0.06) and age of diagnosis (1.71 vs. 8.86 years, P = 0.024) than AR-CGD patients. The most common sites of infections were skin and soft tissue abscesses. The most common pathogens were Staphylococcus, Serratia, and Salmonella spp. Prophylactic antibiotics, anti-fungal agents, and interferon-gamma (IFN-γ) were given in 9 (100%), 7 (77.8%), and 8 (88.9%) patients, respectively. The mean duration of IFN-γ usage was 5.15 years. One male patient with XL-CGD was successfully treated with hematopoietic stem cell transplantation at 2.2 years. The mortality rate was 11.1%, and the estimated overall survival at 20 years was 66.7%.

CONCLUSION

Staphylococcus aureus, Serratia marcescens, and Salmonella infections are important in Taiwanese CGD patients. Patients with XL-CGD have early disease onset. IFN-γ prophylaxis and prophylactic anti-microbial agents might have an effect on alleviating the infection episodes in CGD patients.

De Novo Somatic Mosaicism of CYBB Caused by Intronic LINE-1 Element Insertion Resulting in Chronic Granulomatous Disease

Chronic granulomatosis disease (CGD) is a rare inborn error of immunity, characterized by phagocytic respiratory outbreak dysfunction. Mutations causing CGD occur in CYBB on the X chromosome and in the autosomal genes CYBA, NCF1, NCF2, NCF4, RAC2, and CYBC1. Nevertheless, some patients are clinically diagnosed with CGD, due to abnormal respiratory outbursts, while the pathogenic gene mutation is unidentified. Here, we report a patient with CGD who first presented with Bacillus Calmette-Guérin disease and had recurrent pneumonia. He was diagnosed with CGD by nitro blue tetrazolium and respiratory burst tests. Detailed assessment of neutrophil activity revealed that patient neutrophils were almost entirely nonfunctional. Sanger sequencing detected a 6-kb insertion of a LINE-1 transposable element in the third intron of CYBB, leading to abnormal splicing and pseudoexon insertion, as well as introduction of a premature termination codon, resulting in predicted protein truncation. Clonal analysis demonstrated that the patient had somatic mosaicism, and the phagocytes were almost all variant CYBB, while the mosaicism rate of PBMC was about 65%. Finally, deep RNA sequencing and gp91^phox expression analysis confirmed the pathogenicity of the mutation. In conclusion, we demonstrate that insertion of a LINE-1 transposon in a CYBB intron was responsible for CGD in our patient. Intron LINE-1 transposon element insertion should be examined in CGD patients without any known disease-causing gene mutation, in addition to identification of new genes.

Hematologically important mutations: The autosomal forms of chronic granulomatous disease (third update)

Chronic granulomatous disease (CGD) is an immunodeficiency disorder affecting about 1 in 250,000 individuals. CGD patients suffer from severe, recurrent bacterial and fungal infections. The disease is caused by mutations in the genes encoding the components of the leukocyte NADPH oxidase. This enzyme produces superoxide, which is subsequently metabolized to hydrogen peroxide and other reactive oxygen species (ROS). These products are essential for intracellular killing of pathogens by phagocytic leukocytes (neutrophils, eosinophils, monocytes and macrophages). The leukocyte NADPH oxidase is composed of five subunits, four of which are encoded by autosomal genes. These are CYBA, encoding p22^phox, NCF1, encoding p47^phox, NCF2, encoding p67^phox and NCF4, encoding p40^phox. This article lists all mutations identified in these genes in CGD patients. In addition, cytochrome b₅₅₈ chaperone-1 (CYBC1), recently recognized as an essential chaperone protein for the expression of the X-linked NADPH oxidase component gp91^phox (also called Nox2), is encoded by the autosomal gene CYBC1. Mutations in this gene also lead to CGD. Finally, RAC2, a small GTPase of the Rho family, is needed for activation of the NADPH oxidase, and mutations in the RAC2 gene therefore also induce CGD-like symptoms. Mutations in these last two genes are also listed in this article.