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.

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.

Augmentation of antitubercular therapy with IFNγ in a patient with dominant partial IFNγ receptor 1 deficiency.

Osteomyelitis due to Mycobacterium bovis Bacille Calmette-Guerin (BCG) often develops in patients with interferon-γ receptor 1 (IFNγR1) deficiency. In these patients, susceptibility appears to be caused by impaired interleukin-12- and IFNγ-mediated immunity. Here we report the case of a one-year-old girl with dominant partial IFNγR1 deficiency who suffered from lymphadenitis and multiple sites of osteomyelitis due to BCG infection. She was allergic to isoniazid and rifampicin--the prescribed standard treatment--and required prior desensitization therapy. She was subsequently treated with these drugs, but her symptoms did not improve. IFNγ therapy was added to the antitubercular therapy, increasing the serum level of IFNγ and leading to the resolution of the lymphadenitis and osteomyelitis. In conclusion, high dose IFNγ therapy in combination with antitubercular drugs led to resolution of BCG infection in a patient with dominant partial IFNγ deficiency.

[Diagnostic value of brain biopsy in a pediatric multiple sclerosis mimicking brain stem glioma].

Diagnosis of multiple sclerosis (MS) is difficult when the lesion mimics glioma or cerebral enchephalitis. We report a case of pediatric MS initially suspected as brain stem glioma. An 11-year-old boy developed left foot joint pain followed by progressive symptoms such as left arm and leg weakness, dysarthria, paraplegia, and decreased level of consciousness. He subsequently developed respiratory distress requiring endotracheal intubation and mechanical ventilation. Magnetic resonance imaging showed a mass measuring 2 cm in the medulla oblongata. Although this mass was initially suspected as a glioma, the patient's acutely progressive disease course was not consistent with this diagnosis. Open biopsy revealed inflammation and demyelination, but no malignant cells were detected. He was treated with steroid pulse therapy, which showed dramatic effects. Nine months later, he developed another episode characterized by several neurological symptoms, and the diagnosis of MS was clinically confirmed. Open brain stem biopsy is technically demanding, but this case demonstrates that appropriate neurosurgical evaluation can play an important role in diagnosis by ruling out glioma and confirming MS.