A new monoclonal antibody (CAL2) detects CALRETICULIN mutations in formalin-fixed and paraffin-embedded bone marrow biopsies

Recent advances in the diagnostic of myeloproliferative neoplasms (MPNs) discovered CALRETICULIN (CALR) mutations as a major driver in these disorders. In contrast to JAK2 mutations being mainly associated with polycythaemia vera, CALR mutations are only associated with primary myelofibrosis (PMF) and essential thrombocythaemia (ET). CALR mutations are present in the majority of PMF and ET patients lacking JAK2 and MPL mutations. As these CALR mutations are absent from reactive bone marrow (BM) lesions their presence indicates ET or PMF. So far these mutations are detectable only by molecular assays. Their molecular detection is cumbersome because of the great CALR mutation heterogeneity. Therefore, the availability of a simple assay would be of great help. All CALR mutations reported lead to a frameshift generating a new 36 amino-acid C-terminus. We generated a monoclonal antibody (CAL2) to this C-neoterminus by immunizing mice with a representative peptide and compared its performance with Sanger sequencing data in 173 MPNs and other BM diseases. There was a 100% correlation between the molecular and the CAL2 immunohistochemical (IHC) assays. Thus, the detection of CALR mutations by the CAL2 IHC is a specific, sensitive, rapid, simple and low-cost method.

[Therapy of febrile neutropenia episodes in systemic hematologic illnesses with new once daily ceftriaxone administration]

In this open label prospective multicenter trial, 420 patients with neutropenia < 1000/microliter, fever > 38.5 degrees C and hematological malignancies were treated with ceftriaxone. Acute leukemia (n = 238) and high-grade lymphoma patients (n = 182) from 35 centers were enrolled. Between February 1992 and January 1996, patients were treated with 2 g ceftriaxone i.v. per day either as monotherapy (n = 135), or in combination with aminoglycosides (n = 235), glycopeptides (n = 37), or other antimicrobial agents (n = 13). Patients' median age was 54 years (range 15 to 97) with a median Karnofsky-performance-score of 6.0. The median neutrophil counts were 400/microliter. Fever was of unknown origin (FUO) in 268 (63.8%) of patients. Clinically defined infections (CDI) were diagnosed in 152 (36.2%) cases, including 74 (17.8%) episodes with pneumonia. Response to the initial approach with ceftriaxone was observed in 56.2% of febrile episodes, including 93 (68.8%) treatment courses with ceftriaxone alone. Concerning defervescence of fever ceftriaxone monotherapy was successful as compared to ceftriaxone in combination. Analysis revealed a low risk characterized by higher neutrophil counts (> or = 500/microliter; p < 0.0001), better Karnofsky-performance-score (> or = 7; p = 0.01), duration of neutropenia (< or = 5 days; p = 0.008) from start of antimicrobial treatment and duration of neutropenia per cycle (< or = 10 days; p = 0.0016). At the end of the observation, an overall response was obtained in 88.3% of the patients (n = 371) without statistical difference between patients treated with ceftriaxone alone or in combination. Once daily ceftriaxone either alone or in combination was effective in patients with hematological malignancies. Monotherapy was effective in a low risk group characterized by neutrophil counts (> or = 500/microliter), a Karnofsky-performance-score (> or = 7) and a duration of neutropenia (< or = 5 days) at the commencement of treatment.

Ceftriaxone monotherapy in the treatment of low-risk febrile neutropenia

Febrile neutropenia in patients who have undergone chemotherapy is usually treated with a combination of broad-spectrum antibiotics. There are no exactly defined protocols for single-agent treatment because a clear definition of low risk febrile neutropenia is lacking. This paper examines the safety and efficacy of once-daily ceftriaxone in 376 cases.

MATERIAL AND METHODS

In a prospective observational study carried out between February 1992 and January 1996, 959 febrile episodes at 48 hospitals were recorded. Inclusion criteria were neutropenia (absolute neutrophil count, ANC <1,000/ microl) with fever (>/=38.5 degreesC) or a C-reactive protein concentration >1 mg/dl and suspected infection. Nine hundred and one episodes (acute leukemia n = 396, lymphoma n = 220, solid tumors n = 272 and other disorders n = 13) in 828 patients aged between 1 and 97 years were analyzed, of which 876 episodes were evaluable for response. All patients initially underwent empirical treatment with ceftriaxone (adults: 2 g/day; children: 80 mg/kg/day), either alone (376) or in combination with other agents (525).

RESULTS

The mean ANC was 423/ microl (SD +/- 316) and the median duration of neutropenia 10 days. Of the 363 episodes treated initially with ceftriaxone alone, 70.8% responded versus 56.9% in the combination therapy group. The favorable response to the initial monotherapy treatment was explained by a low-risk population in the monotherapy group. A KI >6 (p < 0.0001), ANC >/=500/ microl (p = 0.0001) and a duration of ANC <5 days (p < 0.05) were significantly more frequent in the monotherapy arm and were predictive of lower risk at the commencement of treatment.

CONCLUSION

Ceftriaxone is effective in febrile neutropenia. Treatment with ceftriaxone alone was safe and highly effective in low-risk patients. Single-agent regimens appear to be a suitable treatment option in low-risk febrile neutropenia.

[Eosinophil cationic protein in a 39-year-old patient with Churg-Strauss syndrome]

HISTORY AND CLINICAL FINDINGS

A 39-year-old woman in good health suddenly developed painful paraesthesia and incomplete paresis of all four limbs. Furthermore, arterial hypertension and tachycardia were found. The patient reported a history of chronic allergic rhinitis for 10 years and asthma one year.

INVESTIGATIONS

Laboratory data showed an increased leucocyte count with a substantial increase in eosinophils in peripheral blood as well as in bone marrow. Nonspecific inflammatory markers such as erythrocyte sedimentation rate, C-reactive protein, fibrinogen as well as eosinophil cationic protein (ECP) were also increased. Histological investigations of a skin-muscle biopsy of the quadriceps revealed necrotizing vasculitis with extravascular granulomata and histiocytic giant cells.

DIAGNOSIS, TREATMENT AND COURSE

Based on the diagnosis of Churg-Strauss syndrome treatment with methylprednisolone (500 mg every second day) was started, but was found to be ineffective after 10 days. Symptoms responded well to a subsequent course of 150 mg cyclophosphamide combined with 50 mg prednisolone per day. Pareses and pain were significantly reduced and all qualitative nerve functions returned to normal within two weeks of treatment. Laboratory parameters, especially the ECP, were similarly normalized.

CONCLUSION

Churg-Strauss syndrome should be considered in the differential diagnosis of unexplained polyneuropathy. Determination of ECP may not only help in the diagnosis but does also facilitate monitoring of treatment and of further course of the disease.

Topoisomerase II activities in AML blasts and their correlation with cellular sensitivity to anthracyclines and epipodophyllotoxines

We have developed a method to quantify topoisomerase (topo) II activities in partially purified nuclear extracts from human leukemia cells. By virtue of their different pH optima in the reaction buffer, two different topo II activities were found with activity optima at pH 7.9 and at pH 8.9 under high stringency conditions. The activities could be identified as topo II beta activity (pH 7.9) and topo II alpha activity (pH 8.9) by their different sensitivities to topo II alpha inhibitors, dephosphorylation experiments and immunoprecipitation with polyclonal antibodies. Seventy-two bone marrow or blood samples from patients with acute myeloid leukemias have been examined and their in vitro sensitivities to anthracyclines and epipodophyllotoxines correlated to the activities of topo II alpha and topo II beta. Although the topo II alpha activity could be directly inhibited by incubation of the cells with the mentioned drugs, no correlation between the topo II alpha activity and the sensitivity of the cells could be found. In contrast, the topo II beta activity which was not substantially inhibited by the drugs inversely correlated with the sensitivity of the cells. These findings were statistically significant for idarubicin (P=0.017) and daunorubicin (P=0.006). Vice versa, resistant cells (IC90 > median) had a higher topo II beta activity. Clinical relevance might be indicated by the finding that cells from patients that relapsed after initial treatment with anthracyclin-containing regiments had a significantly higher topo II alpha/beta activity ratio (P=0.0276). Obviously, the sensitivity of AML cells is substantially influenced by the activity of the resistant topo II (topo II beta) which gives evidence that the remaining topo II activity after treatment helps the cell to survive the DNA repair phase.

Topoisomerase II activities in AML and their correlation with cellular sensitivity to anthracyclines and epipodophyllotoxines

We have developed a method to quantify topoisomerase (topo) II activities in partially purified nuclear extracts from human leukemia cells. By virtue of their different pH optima in the reaction buffer, two different topo II activities were found with activity optima at pH 7.9 and at pH 8.9 under high stringency conditions. The activities could be identified as topo II beta activity (pH 7.9) and topo II alpha activity (pH 8.9) by their different sensitivities to topo II alpha inhibitors, dephosphorylation experiments and immunoprecipitation with polyclonal antibodies. Seventy-two bone marrow or blood samples from patients with acute myeloid leukemias have been examined and their in vitro sensitivities to anthracyclines and epipodophyllotoxines correlated to the activities of topo II alpha and topo II beta. Although the topo II alpha activity could be directly inhibited by incubation of the cells with the mentioned drugs, no correlation between the topo II alpha activity and the sensitivity of the cells could be found. In contrast, the topo II beta activity which was not substantially inhibited by the drugs inversely correlated with the sensitivity of the cells. These findings were statistically significant for idarubicin (P= 0.017) and daunorubicin (P = 0.006). Vice versa, resistant cells (IC50 > median) had a higher topo II beta activity. Clinical relevance might be indicated by the finding that cells from patients that relapsed after initial treatment with anthracyclin-containing regiments had a significantly higher topo II alpha/beta activity ratio (P=0.0276). Obviously, the sensitivity of AML cells is substantially influenced by the activity of the resistant topo II (topo II beta) which gives evidence that the remaining topo II activity after treatment helps the cell to survive the DNA repair phase.

[Genetic studies in etiologically different chronic liver diseases]

In 198 patients with chronic liver diseases of different etiology 16 genetic feature systems were investigated (blood groups, erythrocytic enzymes, immunoglobulin allotypes, proteins). In comparison to a representative normal population significant differences of the frequency of the distribution of phenotypes of various systems were found. In these cases is remarkable that association between genetic markers and hepatopathies were above all proved in their classification according to etiopathogenetic criteria. We evaluate our findings as a reference to the importance of genetic factors in the development of chronic liver diseases.