Myelodysplasia after clonal hematopoiesis with APOBEC3-mediated CYBB inactivation in retroviral gene therapy for X-CGD.

Stem cell gene therapy using the MFGS-gp91phox retroviral vector was performed on a 27-year-old patient with X-linked chronic granulomatous disease (X-CGD) in 2014. The patient's refractory infections were resolved, whereas the oxidase-positive neutrophils disappeared within 6 months. Thirty-two months after gene therapy, the patient developed myelodysplastic syndrome (MDS), and vector integration into the MECOM locus was identified in blast cells. The vector integration into MECOM was detectable in most myeloid cells at 12 months after gene therapy. However, the patient exhibited normal hematopoiesis until the onset of MDS, suggesting that MECOM transactivation contributed to clonal hematopoiesis, and the blast transformation likely arose after the acquisition of additional genetic lesions. In whole-genome sequencing, the biallelic loss of the WT1 tumor suppressor gene, which occurred immediately before tumorigenesis, was identified as a potential candidate genetic alteration. The provirus CYBB cDNA in the blasts contained 108 G-to-A mutations exclusively in the coding strand, suggesting the occurrence of APOBEC3-mediated hypermutations during the transduction of CD34-positive cells. A hypermutation-mediated loss of oxidase activity may have facilitated the survival and proliferation of the clone with MECOM transactivation. Our data provide valuable insights into the complex mechanisms underlying the development of leukemia in X-CGD gene therapy.

Decline in pediatric admission on an isolated island in the COVID-19 pandemic.

BACKGROUND: A decrease in pediatric hospitalizations during the COVID-19 pandemic has been reported worldwide; however, few studies have examined areas with a limited number of COVID-19 cases, where influenced by viral interference by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is minimum. METHODS: We conducted an epidemiological study of pediatric hospitalizations on Sado, an isolated island in Niigata, Japan, that was unique environment with few COVID-19 cases and reliable pediatric admissions monitoring. We compared numbers of monthly hospitalizations and associated diagnoses for the periods April 2016 to March 2020 (pre-pandemic period) and April 2020 to March 2021 (pandemic period). RESULTS: Data were analyzed for 1,144 and 128 patients in the pre-pandemic and pandemic periods, respectively. We observed only three adults and no pediatric COVID-19 cases during the pandemic period. The number of monthly admissions was significantly lower in the pandemic period (median [interquartile ranges (IQR)]: 11.0 [7.0-14.0]) than in the pre-pandemic period (23.0 [20.8-28.3]; P < 0.001). Similar decreases were observed for hospitalizations due to respiratory tract infection (P < 0.01), but not for asthma exacerbation (P = 0.15), and gastrointestinal tract infection (P = 0.33). CONCLUSIONS: Pediatric hospitalizations during the pandemic significantly decreased on an isolated Japanese island where COVID-19 was not endemic and all pediatric admissions were ascertainable. This observation highlights the impact of decreased travel and increased awareness of infection control measures on pediatric hospitalizations due to infectious diseases, not by the SARS-CoV-2 viral interference.

Severe and Rapid Progression in Very Early-Onset Chronic Granulomatous Disease-Associated Colitis.

PURPOSE: Chronic granulomatous disease (CGD) is a primary immunodeficiency disease that leads to recurrent infection and hyper-inflammation, occasionally represented by CGD-associated colitis (CGD colitis). Although clinical symptoms of CGD colitis mimic those of ulcerative colitis (UC), there is no reliable standard measurement of disease activity or standard therapeutic strategy for CGD colitis. Here, we examined the clinical manifestation of CGD colitis based on severity using a noninvasive measure of disease activity, the Pediatric Ulcerative Colitis Activity Index (PUCAI), which has been validated and widely used for pediatric UC. METHODS: Sixteen of 35 CGD patients, who were diagnosed with CGD colitis based on colonoscopic and histological findings, were examined using the PUCAI. Both the PUCAI and the physician global assessment (PGA) tool were retrospectively scored by reviewing medical records. RESULTS: Disease activity defined by PUCAI was correlated with PGA, and increased at diagnosis of CGD colitis, especially in patients who were younger than 6 years of age (very early-onset CGD colitis: VEO-CGD colitis) when diagnosed with CGD colitis. All severe patients had a more progressive form of VEO-CGD colitis. Unlike mild and moderate patients, severe patients required multidrug therapy of corticosteroids and immunomodulator/immunosuppressants, and some were eventually treated with hematopoietic stem cell transplantation. CONCLUSIONS: Although the validation of PUCAI in CGD colitis should be considered for future use, our results indicate that noninvasive measures could be effective to measure disease activity and help to determine suitable treatment for CGD colitis. In patients with VEO-CGD colitis, multidrug therapy would need to be considered at an early stage on the basis of disease activity.

Interstitial lung disease with multiple microgranulomas in chronic granulomatous disease.

BACKGROUND: Chronic granulomatous disease (CGD) is a primary immunodeficiency disease that is characterized by susceptibility to bacterial and fungal infections. CGD patients also suffer from immune regulatory disorders, such as CGD-associated bowel inflammation with granuloma, which could be caused by excessive inflammation without demonstrable infection. PURPOSE: We investigated the clinical manifestation of interstitial lung disease (ILD) resulting from excessive inflammation in X-linked CGD patients. METHODS: Pulmonary CT images and testing of serum KL-6 levels were performed to assess ILD in the patients. For this study, patients with pulmonary lesions due to demonstrable infections were excluded from among ILD patients. RESULTS: Among 33 CGD patients, four developed ILD; they had increased reticulo-nodular opacities on CT images and elevated serum KL-6 levels. Histopathological examinations revealed multiple homogeneous microgranulomas in the lesions of inflammatory cell infiltration. Mononuclear cells obtained from their pulmonary lesions produced higher amounts of inflammatory cytokines than the peripheral blood mononuclear cells of CGD patients, suggesting that the only infiltrating cells in the pulmonary lesions were activated and produced large amounts of inflammatory cytokines in ILD patients. Interestingly, an anti-inflammatory drug, such as a corticosteroid or thalidomide, but not anti-bacterial or anti-fungal drugs, improved CT image findings and reduced their KL-6 levels. CONCLUSIONS: CGD patients' daily exposures to inhaled antigens may induce excessive reactions with the production of inflammatory cytokines leading to the development of ILD with multiple microgranulomas, which could be due to an inadequate production of reactive oxygen species in CGD.