ISG15 is an interferon (IFN)-α/β-inducible, ubiquitin-like intracellular protein. Its conjugation to various proteins (ISGylation) contributes to antiviral immunity in mice. We describe human patients with inherited ISG15 deficiency and mycobacterial, but not viral diseases. The lack of intracellular ISG15 production and protein ISGylation was not associated with cellular susceptibility to any viruses tested, consistent with the lack of viral diseases in these patients. By contrast, the lack of mycobacterium-induced ISG15 secretion by leukocytes — granulocytes in particular — reduced the production of IFN-γ by lymphocytes, including natural killer cells, probably accounting for the enhanced susceptibility to mycobacterial disease. This experiment of Nature shows that human ISGylation is largely redundant for antiviral immunity, but that ISG15 plays an essential role as an IFN-γ-inducing secreted molecule for optimal antimycobacterial immunity.

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by the deposition of calcium phosphate microliths throughout the lungs. We first identified a PAM locus by homozygosity mapping to 4p15, then identified, by a candidate-gene approach, the gene responsible for the disease as SLC34A2 (the type IIb sodium-phosphate cotransporter gene), which is involved in phosphate homeostasis in several organs. We identified six homozygous exonic mutations in the seven unrelated patients with PAM we studied. Three of the mutations were frameshifts, one was a chain termination, one was an amino acid substitution, and one was a deletion spanning the minimal promoter and the first exon. Absence of functional protein product of the gene is compatible with calcium phosphate deposition in alveolar airspaces. We show that impaired activity of the phosphate transporter is presumably responsible for the microliths and that PAM is a recessive monogenic disease with full penetrance. Testicular microlithiasis (TM) is a disease that is more common than PAM. It is often associated with cancer and infertility. Since the gene we identified is also expressed in testis, we searched for mutations in subjects with TM. In 2 of the 15 subjects with TM we studied, we identified two rare variants, one synonymous and the other noncoding, that are possibly associated with the condition.

Congenital lobar emphysema (CLE) is characterized by overdistension and air-trapping in the affected lobe, and is one of the causes of infantile respiratory distress. In this report, we review our 27 years of experience with 30 CLE patients. Patients' medical records were evaluated with regard to age, clinical presentation, diagnostic methods, associated diseases, treatment, histopathologic findings, and final clinical and laboratory findings at the end of a long-term period. The mean age of 30 patients (18 male) at diagnosis was 4.9 +/- 6.7 months (range, 2 days-2.5 years). Tachypnea, dyspnea, cough, cyanosis, wheezing, hoarseness, and decreased breath sounds on the affected side were the main symptoms and clinical findings. On chest X-rays, emphysema was seen in all patients; shift/herniation to the opposite lung, atelectasis, and pneumothorax were observed in 16, 5, and 2 cases, respectively. Computerized tomography of the thorax was performed in 16 cases and revealed emphysema at affected lobe/lobes in all, a shift/herniation to the opposite side in 12 cases, and atelectasis of neighbor lobe/lobes in 7 cases. All 8 patients who had perfusion scintigraphy showed reduced perfusion in the affected lobe. Narrowed and flaccid bronchi were detected in one patient by using flexible bronchoscopy. Blood gas analysis was performed in 11 patients, and hypoxia and hypercarbia were revealed in 9 and 7 of these patients, respectively. The most common affected lobe was the left upper lobe (57%), followed by the right upper lobe (30%) and right middle lobe (27%). Two lobes were involved in 4 patients. Associated abnormalities were observed in 5 patients. Twenty-one patients underwent lobectomy; 9 were followed conservatively. Ages at diagnosis were significantly younger in surgically treated patients. Emphysema was detected in all pathological specimens, with an additional bronchial cartilage deficiency in 2 patients. In the surgically treated group, 2 patients died and 2 patients were lost to follow-up. In the conservatively treated group, one patient was lost to follow-up. Mean follow-up duration of all patients was 63.2 +/- 56.2 months (range, 1-209 months). At follow-up visits, all patients were doing well. In surgically treated patients, chest X-rays were normal (9 cases), or showed hyperlucency on the operated side (6 cases) or chronic changes in the operation area (2 cases). Hyperexpansion in the affected lobe was found to be reduced in all cases in the conservatively treated group.

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