Extreme leucocytosis and splenomegaly in metastasised melanoma.

A 63-year-old woman presented to the internist with fatigue, cough, low-grade fever, splenomegaly and leucocytosis up to 130 x 10(9)/l. Although a diagnosis of chronic myelogenous leukaemia was initially entertained, she turned out to have a metastasised melanoma. The differential diagnosis and workup is discussed, as well as potential mechanisms by which the tumour could have induced the leucocytosis, such as the production of G-CSF or similar mediators, and the prognostic significance of this phenomenon.

[Hypercalcemia due to chronic vitamin A use by an elderly patient with renal insufficiency]. / Hypercalciëmie door chronisch vitamine-A-gebruik bij een bejaarde patiënte met nierinsufficiëntie.

An 86-year-old woman presented with anorexia, thirst and nycturia. Laboratory results revealed a hypercalcaemia with renal failure. The patient used 1-6 vitamin A-D tablets daily (1 tablet contains 600 IU retinol palmitate and 200 IU cholecalciferol). The diagnosis was: hypercalcaemia due to chronic vitamin A ingestion. This diagnosis was supported by the finding of the elevated vitamin A concentration in the patient's serum and the exclusion of other causes of hypercalcaemia. In chronic vitamin A ingestion risk factors for vitamin A toxicity are age, body weight and renal insufficiency. The hypercalcaemia caused by chronic vitamin A ingestion is explained through the up-regulation of osteoclasts by retinol metabolites.

Frequency of major hemorrhage in patients treated with unfractionated intravenous heparin for deep venous thrombosis or pulmonary embolism: a study in routine clinical practice.

BACKGROUND: The rate of major hemorrhage during the initial treatment with unfractionated heparin (UFH) in patients with deep venous thrombosis (DVT) and pulmonary embolism (PE) in routine clinical practice is understudied. In recent clinical trials an overall average of 3.8% was reported. However, the incidence of this complication in routine patient care might be higher owing to less strict patient selection and lack of standardization in the administration of heparin. We have determined major bleeding rates during heparin treatment for DVT or PE in routine practice and compared these rates with data from clinical trials. METHODS: Data on the occurrence of major hemorrhage were retrieved according to strict criteria from the records of patients who had received continuous intravenous UFH therapy to treat objectively documented DVT or PE in 3 hospitals. RESULTS: After exclusion of 29 patients because of lack of objective diagnosis of DVT or PE and 25 patients because of initial treatment with low-molecular-weight heparin, 424 consecutive patients were available for detailed analysis. Among them, 17 patients (4.0%; 95% confidence interval, 2.1%-5.9%) experienced major hemorrhage during UFH treatment, which in most patients occurred at the end of planned heparin therapy; one of the hemorrhages was fatal. Six patients (1.4%; 95% confidence interval, 0.3%-2.5%) developed clinically suspected recurrent venous thromboembolism (fatal in 1 case) during UFH treatment or within 7 days' cessation. CONCLUSIONS: Administration of continuous intravenous UFH in patients with DVT or PE in routine clinical practice leads to a major bleeding rate of 4.0%. This rate is comparable to the rate of major bleeding in patients who received UFH in clinical trials. Our findings are relevant to the discussion of major bleeding rates in patients with DVT and PE treated in daily clinical practice with subcutaneous low-molecular-weight heparin and newer antithrombotic drugs.

Selective response of CD5+ B cell malignancies to activation of the CD72 antigen.

The function of the simultaneous expression of CD5 and its ligand CD72 on B cell malignancies like chronic lymphocytic leukemia and mantle cell lymphoma was assessed. It is unknown if reciprocal interactions between CD72 and CD5 exert an autocrine growth-promoting or -inhibiting effect. CD5+ (n = 13) and CD5- (n = 9) B cell malignancies were cultured with the anti-CD72 mAb WL225. For comparison, five other anti-CD72 mAbs were tested. Only CD5+ B cell malignancies proliferated upon CD72 activation (9 out of 13 cases). A strong suppressive effect of IL-4 on the anti-CD72-induced [3H]thymidine incorporation, partially caused by downmodulation of the CD72 expression, was seen. Stimulation of the CD5 antigen by L cells transfected with human CD72 (LhCD72) and the anti-CD5 mAb 1C12 exerted no (n = 9) or a minor effect (2 out of 8 cases), respectively. Finally, the results of CD72 stimulation were compared with CD40 stimulation, as this "CD40 system" is an effective method for stimulating B cell malignancies. In 4 of the 7 anti-CD72 responsive cases a costimulatory effect was seen.

Proliferation of precursor B-lineage acute lymphoblastic leukaemia by activating the CD40 antigen.

No reliable culture system exists for B-lineage acute lymphoblastic leukaemia (ALL). Recently we found that many different mature B-cell malignancies proliferate upon stimulation via the CD40 antigen, and this led us to investigate whether a similar CD40 activation on ALL cells could also induce proliferation. First, we measured CD40 expression in 21 ALL cases; all were CD40+, although mostly weak. Next, we triggered the CD40 antigen by anti-CD40 antibodies and by a CD40 ligand-expressing cell line. In addition, we measured the influence of IL-3, IL-4 and IL-7 with and without these stimuli. In 8/10 cases proliferation, measured by 3H-thymidine incorporation, could be induced after CD40 crosslinking, especially in the presence of IL-3. Stimulation via the CD40 ligand was more successful than using crosslinked anti-CD40 antibodies. IL-4 inhibited the spontaneous proliferation found in three cases, but stimulated proliferation after CD40 crosslinking. IL-7 did not contribute to proliferation. Morphology, immunophenotyping and surface marker analysis, combined with DNA flow cytometry confirmed that the proliferation found could be ascribed to the ALL cells. In conclusion, B-lineage ALL cases are CD40+, and many can be cultured using CD40 stimulation and IL-3.

The role of the CD40 antigen on malignant B cells.

An increasing amount of literature has been published concerning the interaction of the CD40 antigen and its ligand with regard to normal B cell ontogeny. In this review, an overview of the CD40 antigen and the CD40 ligand is given, focussing on their possible role in B cell malignancies. Data on the expression of the CD40 antigen on various B cell malignancies (acute and chronic leukemias, non-Hodgkin's lymphoma and multiple myeloma) are presented. The recently developed novel culture "CD40 system" is described. This system is a powerful tool used to culture normal B cells, but also most malignant B cells. We demonstrate in addition a more prominent role of the human Fc receptor presenting murine fibroblasts in the "CD40 system", especially in relation to cultured plasma cells. Finally, some important applications of the "CD40 system" are also summarized.

Proliferation of B cell malignancies in all stages of differentiation upon stimulation in the 'CD40 system'.

Stimulation of the CD40 antigen on normal B cells by crosslinking of anti-CD40 mAbs via their Fc receptor using a Fc gamma RII(CD32)-transfected mouse fibroblast cell line ('CD40 system') results in activation and proliferation. Not only normal B cells, but also malignant B cells fitting in the low-grade malignancy category such as chronic lymphocytic leukemia (CLL), hairy cell leukemia and follicular lymphoma could be induced to proliferation upon CD40 stimulation. Here, the 'CD40 system' has also been used to culture intermediate and high grade malignancies. Proliferation was measured by 3H-thymidine incorporation and cell counting after culture. Time curves showed that at day 7 most cultures were optimal. By flow cytometry, morphology and assessment of light chain restriction the monoclonal nature of the cultured B cells was proven. We confirmed that B cell malignancies with a more slowly evolving course, such as CLL (n=11), PLL (n=5), and low-grade NHL (immunocytoma and follicular cb/cc n=9), could successfully be cultured in the 'CD40 system'. In contrast, four out of seven cases of mantle cell lymphoma did not proliferate. Cases of precursor B lineage ALL (n=7), high grade NHL (n=3) and multiple myeloma (n=10) showed a heterogenous growth pattern. We conclude that the 'CD40 system', although not always successful, is a useful tool to culture a whole variety of B cell malignancies.