Diagnostic de lignée dans les leucémies aiguës : confrontation entre cytologie et immunophénotypage

Objective

The determination of the cellular lineage in acute leukemia is a crucial step in the diagnosis and the later therapeutic conduct. In Tunisia, emerging country, some cases of acute leukemias are still treated on the basis of an only cytologic study because of lack of cytometry. Our objective is to realize a confrontation between cytology and flow cytometry in the diagnosis of AL and to analyze discrepancies.

Patients and methods

The study concerns 100 cases of AL. A second double-blind examination of the bone marrow smears of acute leukemias is realized by two cytologists and confronted to immunophenotyping.

Results

In two cases of AML, flow cytometry reassigned lineage into T ALL and biphenotypic AL. In three cases of ALL the lineage was reassigned into undifferentiated acute leukemia (2 cases) and biphenotypic acute leukemia (1 case). Lineage was not established in four cases, immunophenotyping allowed the diagnosis of B ALL in 3 cases, and of biphenotypic acute leukemia in 1 case. In both cases of discrepant findings, flow cytometry allowed the diagnosis of biphenotypic acute leukemia in a case and of AML in the other one.

Conclusion

The cytological study remains insufficient in the diagnosis of lineage even with experimented cytologists. Immunophenotyping is essential in lineage assignment and reassignment.     

Conditional ablation of NKp46+ cells using a novel Ncr1greenCre mouse strain: NK cells are essential for protection against pulmonary B16 metastases

To study gene functions specifically in NKp46⁺ cells we developed novel Cre mice allowing for conditional gene targeting in cells expressing Ncr1 (encoding NKp46). We generated transgenic Ncr1^greenCre mice carrying an EGFPcre fusion under the control of a proximal Ncr1 promoter that faithfully directed EGFPcre expression to NKp46⁺ cells from lymphoid and nonlymphoid tissues. This approach allowed for direct detection of Cre‐expressing NKp46⁺ cells via their GFP signature by flow cytometry and histology. Cre was functional as evidenced by the NKp46⁺ cell‐specific expression of RFP in Ncr1^greenCreRosa‐dtRFP reporter mice. We generated Ncr1^greenCreIl2rg^fl/fl mice that lack NKp46⁺ cells in an otherwise intact hematopoietic environment. Il2rg encodes the common gamma chain (γ_c), which is an essential receptor subunit for cytokines (IL‐2, ‐4, ‐7, ‐9, ‐15, and ‐21) that stimulate lymphocyte development and function. In Ncr1^greenCreIl2rg^fl/fl mice, NK cells are severely reduced and the few remaining NKp46⁺ cells escaping γc deletion failed to express GFP. Using this new NK‐cell‐deficient model, we demonstrate that the homeostasis of NKp46⁺ cells from all tissues (including the recently described intraepithelial ILC1 subset) requires Il2rg. Finally, Ncr1^greenCreIl2rg^fl/fl mice are unable to reject B16 lung metastases demonstrating the essential role of NKp46⁺ cells in antimelanoma immune responses.     

Formes pseudo-tumorales de l’amibiase digestive. A propos de 3 cas

Amoeboma is a cosmopolitan parasitic tumor. It is often difficult to distinguish it from cancer. We report 3 cases of patients operated for digestive cancer. The final diagnosis was amoeboma of the gallbladder, the caecum and the left colon. In the first case, the patient was operated for a mass in the fourth segment of the liver in contact with the gallbladder. For the two other cases, patients were operated in emergency for a complication (abscess and peritonitis).     

A microprocessor-controlled tracheal insufflation-assisted total liquid ventilation system

A prototype time cycled, constant volume, closed circuit perfluorocarbon (PFC) total liquid ventilator system is described. The system utilizes microcontroller-driven display and master control boards, gear motor pumps, and three-way solenoid valves to direct flow. A constant tidal volume and functional residual capacity (FRC) are maintained with feedback control using end-expiratory and end-inspiratory stop-flow pressures. The system can also provide a unique continuous perfusion (bias flow, tracheal insufflation) through one lumen of a double-lumen endotracheal catheter to increase washout of dead space liquid. FRC and arterial blood gases were maintained during ventilation with Rimar 101 PFC over 2–3 h in normal piglets and piglets with simulated pulmonary edema induced by instillation of albumin solution. Addition of tracheal insufflation flow significantly improved the blood gases and enhanced clearance of instilled albumin solution during simulated edema.