Case report: pulmonary nocardiosis caused by Nocardia exalbida in an immunocompetent patient.

BACKGROUND: Nocardiosis is known as an opportunistic infection in immunocompromised hosts, but it occasionally has been reported in immunocompetent patient. The Nocardia exalbida is first-reported in 2006 from Japan, and a few cases of have been reported in only immunocompromised host, and the characteristic is still unclear. We herein describe the first case of pulmonary nocardiosis caused by N. exalbida in an immunocompetent patient. CASE PRESENTATION: A77 -year-old Japanese man was admitted to our hospital on November 2, 2018. He was a lifelong non-smoker with no childhood history of respiratory disease. He had a medical history of dyslipidemia. One month before this admission fevers, sputum, mild cough were developed and he was evaluated in a clinic near our hospital. His diagnosis was community acquired pneumonia within his right middle lobe. He was treated with ceftriaxone 1 g/day intravenously for a week, however his symptoms relapsed a few days later. So, the physician retried ceftriaxone for another 3 days, but his symptoms did not improve. He was referred to our hospital. He was treated with sitafloxacin as an outpatient for a week, however his symptoms got worse. The chest CT showed consolidation and atelectasis in his right middle lobe. Low density area was scattered in consolidation, and right pleural effusion was observed. The patient was diagnosed with pulmonary abscess and he was admitted. Administration of piperacillin/tazobactam improved his condition. We switched antibiotics to amoxicillin/clavulanate, and he was discharged. After 2 weeks, he relapsed and was admitted again. After administration of piperacillin/tazobactam for 3 weeks, we perform bronchoscopy and Nocardia species were cultured from samples of the bronchial wash. The isolates were identified as N. exalbida using 16S rRNA gene sequencing. We prescribed Trimethoprim / Sulfamethoxazole (TMP/SMX) for 4 months. Then we switched to minocycline for renal dysfunction caused from TMP-SMX for 1 more month. After 5 months therapy, Consolidation on CT disappeared, and Nocardiosis was cured. CONCLUSION: we reported the first case of pulmonary nocardiosis caused by N. exalbida in an immunocompetent patient. N. exalbida infection might be associated with a good response to treatment.

[A case of mediastinal growing teratoma syndrome with acute megakaryoblastic leukemia].

We report a case of a 38-year-old man who was diagnosed with a mediastinal germ cell tumor. After induction chemotherapy, the tumor marker levels normalized, but the tumor itself continued to grow. Surgical resection was performed successfully, but the patient developed acute megakaryoblastic leukemia 6 months later, and induction and consolidation therapies failed to achieve remission. Leukemia cells invaded the central nervous system following hematopoietic stem cell transplantation, and the patient died 5 months after being diagnosed with leukemia. This very rare case of a mediastinal germ cell tumor met the criteria for "growing teratoma syndrome", against a background of acute megakaryoblastic leukemia.

Effects of IS-741, a synthetic anti-inflammatory agent, on bleomycin-induced lung injury in mice.

Bleomycin (BLM)-induced lung injury consists of excessive inflammatory cell infiltration and fibrosis. IS-741 has been reported to be an anti-inflammatory drug through an inhibitory action on cell adhesion. In this study we investigated whether IS-741 could inhibit the progression of pulmonary fibrosis through inflammatory cell infiltration. Lung injury was induced in female C57BL/6 mice by intratracheal instillation of BLM. IS-741 was administered daily intraperitoneally. The hydroxyproline content and fluid content in the lung on Day 28 were significantly lower in the IS-741-treated mice. The histological degree of lung injury or fibrosis was reduced in IS-741-treated mice. Administration of IS-741 caused significant reduction in the absolute number of total cells, monocyte chemoattractant protein (MCP)-1, and cysteinyl leukotriene (cysLTs) levels in bronchoalveolar lavage fluid on Day 7. Furthermore, the hydroxyproline content was significantly lower in IS-741-treated mice even though IS-741 was started on Day 14 after BLM instillation. Treatment with IS-741 had an inhibitory effect on BLM-induced lung injury and fibrosis via the repression of MCP-1 or cysLTs in this murine experimental model.

[Case of central neurosarcoidosis with panhypopituitalism].

A 63-year-old man was admitted because of dizziness, polydipsia, polyuria, and diminished libido. His brain MRI showed swelling of the pituitary gland. Because of panhypopituitarism suggested by hormonal examination, hydrocortisone, desmopressin and levothyroxine sodium were started as hormone replacement therapy. He was given a clinical diagnosis of central neurosarcoidosis with panhypopituitarism because of the presence of an abnormal lung shadow, positive gallium scintigram in bilateral hilar lymph nodes, negative tuberculin skin test, lymphocytosis and a high CD4/8 ratio in bronchoalveolar lavage fluid. After prednisolone therapy, his lung shadow and pituitary swelling reduced significantly. Anti-diuretic hormones and anterior pituitary hormones tended to increase, and his urine volume also decreased. This case suggested that endocrinological abnormalities in central neurosarcoidosis might be improved by prednisolone therapy even if the initiation of treatment is delayed.

Isolation and immunophenotyping of mononuclear cells from human lung tissue.

OBJECTIVE: To quantitatively isolate and immunologically phenotype mononuclear cells contained in human lung tissue. METHODS: Normal appearing lung tissue as far distal to the resected lesion as possible was obtained from lung cancer patients. Lung tissue was thoroughly washed and cut into small pieces and digested with collagenase. Peripheral blood mononuclear cells (PBMNC) were prepared from controls using Ficoll gradient. Isolated cells and PBMNC were analyzed by flow cytometry. We immunohistochemically stained snap-frozen lung tissue with anti-CD3, CD4, CD8, CD20, and CD161 antibodies. PARTICIPANTS: Nineteen patients with lung cancer who underwent lobectomy were enrolled. Twelve healthy volunteers also participated as controls for flow cytometric analysis of PBMNC. RESULTS: In forward scatter vs side scatter, 92.1+/-7.8% of isolated cells in the lymphoid population expressed leukocyte common antigen, CD45. The frequency of CD45-positive cells in the lymphoid population from lung tissue was as high as that from PBMNC (p=0.118). CD45-positive cells were successfully further extended by anti-CD3, CD4, CD8, CD19, and CD161 antibodies. Monocyte-macrophages bearing CD68 were also detected. CD68-positive alveolar macrophages disappeared from alveolar spaces after thorough washing by immunohistochemical staining. Mononuclear cells in the interstitium were positively stained by anti-CD3, CD4, CD8, CD20, and CD161 monoclonal antibodies. CONCLUSIONS: We could isolate interstitial cells and analyze cell surface markers via flow cytometry from fresh lung specimens by collagenase digestion without further purification. Immunohistochemistry confirmed the presence of the cells detected by flow cytometry in the lung interstitium.