Different cell clones in bone marrow and spleen of a patient with chronic myelocytic leukemia (CML) in blastic phase

The chromosome study of a patient with chronic myelocytic leukemia in blastic phase revealed a 46,XY,Ph1/47,XY,Ph1,+8 cytogenetic constitution in bone marrow cells and a 46,XY,Ph1/48,XY,2Ph1,+19 cytogenetic constitution in spleen cells. As the cell clones exhibiting chromosome abnormalities in addition to the Ph1 chromosome evolved apparently independently, it is suggested that the acute transformation had a bifocal, myeloid and splenic origin.

Bone marrow biopsy (BMB). II. Bone marrow biopsy in myeloproliferative disorders

The myeloproliferative disorders (MPD) are a domain in which the bone marrow biopsy (BMB) greatly proved its utility. We have studied the histology of the bone marrow (BM) in all the four entities of MPD: chronic myeloid leukemia (CML) with its subtype, chronic megakaryocytic granulocytic myelosis (CMGM), polycythemia vera (PV), hemorrhagic thrombocythemia (HT) and myeloid metaplasia with myelofibrosis (MMM). The work presents in short some of the clinical and hematologic characters of MPD with special stress upon the histologic modifications of BM, either specific or common to all MPD entities, underlying also the criteria for differential diagnosis.

Emergence of the Dickeya genus involved duplication of the OmpF porin and the adaptation of the EnvZ-OmpR signaling network

Genome evolution, and more specifically gene duplication, is a key process shaping host-microorganism interaction. The conserved paralogs usually provide an advantage to the bacterium to thrive. If not, these genes become pseudogenes and disappear. Here, we show that during the emergence of the genus Dickeya, the gene encoding the porin OmpF was duplicated. Our results show that the ompF2 expression is deleterious to the virulence of Dickeya dadantii, the agent causing soft rot disease. Interestingly, ompF2 is regulated while ompF is constitutive but activated by the EnvZ-OmpR two-component system. In vitro, acidic pH triggers the system. The pH measured in four eudicotyledons increased from an initial pH of 5.5 to 7 within 8 h post-infection. Then, the pH decreased to 5.5 at 10 h post-infection and until full maceration of the plant tissue. Yet, the production of phenolic acids by the plant's defenses prevents the activation of the EnvZ-OmpR system to avoid the ompF2 expression even though environmental conditions should trigger this system. We highlight that gene duplication in a pathogen is not automatically an advantage for the infectious process and that, there was a need for our model organism to adapt its genetic regulatory networks to conserve these duplicated genes. IMPORTANCE Dickeya species cause various diseases in a wide range of crops and ornamental plants. Understanding the molecular program that allows the bacterium to colonize the plant is key to developing new pest control methods. Unlike other enterobacterial pathogens, Dickeya dadantii, the causal agent of soft rot disease, does not require the EnvZ-OmpR system for virulence. Here, we showed that during the emergence of the genus Dickeya, the gene encoding the porin OmpF was duplicated and that the expression of ompF2 was deleterious for virulence. We revealed that while the EnvZ-OmpR system was activated in vitro by acidic pH and even though the pH was acidic when the plant is colonized, this system was repressed by phenolic acid (generated by the plant's defenses). These results provide a unique- biologically relevant-perspective on the consequence of gene duplication and the adaptive nature of regulatory networks to retain the duplicated gene.

Bone marrow biopsy (BMB). I. Generalities, material and method, normal structure of bone marrow, pathological conditions

The authors presented in their first note generalities concerning the normal and pathological structure of bone marrow (BM), based on their personal experience (1,500 BMB) and on the literature. A short historical survey and the adopted research method are presented. The advantage of Burkhardt's myelotomy with its technical process by embedding in synthetic resins to avoid decalcification are discussed. The authors have used Jamshidi's cannula (or some other similar needle) with the subsequent embedding in paraffin after decalcification. Further papers will analyse the approach, by BMB, of the myeloproliferative disorders, myelodysplasia, lymphomas and Hodgkin's disease, cancer metastases and medullar aplasia.

Bone marrow biopsy (BMB). III. Bone marrow biopsy in Hodgkin's disease (HD)

Bone marrow biopsies have been investigated in 330 cases of Hodgkin's disease totalising 298 patients, out of which 32 with repeated biopsies. Positive biopsies with typical lesions were found in 32% of patients, the majority in stages III and IV (88.6%), rarely in stage I or II (11.4%). Nonspecific lesions were very frequent (75%), either isolated or accompanied by typical lesions. The majority of the positive biopsies were found in patients with lymphocytic predominance and lymphocytic depletion, or in polytreated patients in an advanced stage of the disease. The specific marrow involvement consisted in lymphocytic infiltrations either nodular or diffuse, Reed-Sternberg (R-St) or Hodgkin cells. The lymphocytic depletion is often accompanied by diffuse fibrosis, atypical histiocytes, fibroblasts and R-St cells. Hodgkin typical granulomas are rare. The positive biopsies were associated with nonspecific reactions including hyperplasia of granulopoiesis, megakaryocytes, territories with hyperplasia or aplasia, fibrosis, disruption of sinus walls, oedema, plasmocytosis, necrosis, myelomonoblastic cells, lymphocyte nodes, etc. The bone marrow histology has a prognostic significance.

Angio-immunoblastic lymphadenitis: remarks about two cases

Two patients with clinical and pathological symptoms of so-called angioimmunoblastic lymphadenitis are presented. Both patients were over 50, with multiple lymphadenopathies, fever, pruritus and hyperglobulinemia. The lymph node changes exhibited a characteristic histological triad consisting of diffuse lymphoid proliferation, small arborizing vessels proliferation and paraamyloid-like amorphous material deposition. As previous authors suggested, the disease seems to be the expression of a prolonged hyperimmune response induced by the hypersensitivity to certain factors.

Incidence and significance of micronuclei in pernicious anemia

The incidence of micronuclei in bone marrow erythroblasts of patients with pernicious anemia ranged between 0.5-5.6% as compared with the value of 0-0.5% noted in hematologically healthy patients. The mechanism of formation and the possible significance of micronuclei in megaloblastic anemia are briefly discussed.

Microscopic patterns in surgically removed spleens

348 spleens surgically removed have been examined microscopically and classified into 3 groups: (I) 154 emergency splenectomies (86 traumatic ruptures, 44 enlarged supramesocolic exeresis, 44 cirrhosis), (II) 143 therapeutic splenectomies (135 cases of hypersplenism among which 10 apparently primitive, 7 myeloproliferative syndromes, 1 hairy cell leukemia), and (III) 51 diagnostic splenectomies (7 non specific inflammations, 2 tuberculosis, 1 mycosis, 6 echinococcosis, 12 leukemias, 9 non-Hodgkin's lymphomas, 13 Hodgkin's lymphomas, 1 primary splenic hemangioma). The study of the first group material, obtained especially of traumatic rupture, has been very valuable to follow the spleen microscopic structure in normal humans of different age. The latter two group cases have raised interesting problems of microscopic diagnosis, permitting at the same time a better understanding of the pathology of this organ.

Targeted proteomics links virulence factor expression with clinical severity in staphylococcal pneumonia

Introduction

The bacterial pathogen Staphylococcus aureus harbors numerous virulence factors that impact infection severity. Beyond virulence gene presence or absence, the expression level of virulence proteins is known to vary across S. aureus lineages and isolates. However, the impact of expression level on severity is poorly understood due to the lack of high-throughput quantification methods of virulence proteins.

Methods

We present a targeted proteomic approach able to monitor 42 staphylococcal proteins in a single experiment. Using this approach, we compared the quantitative virulomes of 136 S. aureus isolates from a nationwide cohort of French patients with severe community-acquired staphylococcal pneumonia, all requiring intensive care. We used multivariable regression models adjusted for patient baseline health (Charlson comorbidity score) to identify the virulence factors whose in vitro expression level predicted pneumonia severity markers, namely leukopenia and hemoptysis, as well as patient survival.

Results

We found that leukopenia was predicted by higher expression of HlgB, Nuc, and Tsst-1 and lower expression of BlaI and HlgC, while hemoptysis was predicted by higher expression of BlaZ and HlgB and lower expression of HlgC. Strikingly, mortality was independently predicted in a dose-dependent fashion by a single phage-encoded virulence factor, the Panton-Valentine leucocidin (PVL), both in logistic (OR 1.28; 95%CI[1.02;1.60]) and survival (HR 1.15; 95%CI[1.02;1.30]) regression models.

Discussion

These findings demonstrate that the in vitro expression level of virulence factors can be correlated with infection severity using targeted proteomics, a method that may be adapted to other bacterial pathogens.