T-cell prolymphocyte leukaemia: A clinical and immunological study

2 cases of T-cell prolymphocytic leukaemia (T-PLL) were investigated for their reactivity with a series of monoclonal antibodies (MoAbs) as well as for the cytochemical expression and functional activity of the pathological cells. Both patients showed morphological (large cells with abundant cytoplasm and eccentric and irregularly shaped nucleous with large and prominent nucleoli) and clinical (high leucocyte count and splenomegaly) features typical of T-PLL. The cells from 1 patient expressed a helper/inducer phenotype (T4+, T8^-) and were reactive with the anti-Tac (interleukin-2 receptor) MoAb, while the other case co-expressed both the T4 and the T8 antigens. The response to phytohaemagglutinin and the natural killer activity (assessed by ⁵¹chromium release) were significantly reduced in both cases, while the helper capacity, tested in a pokeweed mitogen-driven system, was maintained only in the 1st case. This latter case which expressed a more mature phenotype (T4+, T8^-) responded well to chemotherapy.     

Targeting of Cytotoxic Conjugates to Kaposi's Sarcoma-Derived Cells

We assayed the cytotoxicity of conjugates in which the plant toxin saporin (SAP) was linked to human basic fibroblast growth factor (bFGF) and urokinase-type plasminogen activator (uPA). Both bFGF and uPA play an important role in angiogenesis, and their cell surface receptors are expressed at high levels in cancer cells. The conjugates were tested on a Kaposi's sarcoma-derived cell line, IST-KS2, as a model of an actively proliferating component of Kaposi's sarcoma lesions which are highly vascularized. Both bFGF and uPA were very effective at targeting saporin to KS cells, leading to cell killing even at low concentrations of the conjugates. The bFGF-SAP and uPA-SAP mitotoxins were also highly toxic toward the permanent, endothelium-derived EAhy926 cell line. EAhy926 cells were very sensitive to two immunotoxins containing an anti-endothelium monoclonal antibody coupled to saporin or ricin A chain, whereas IST-KS2 cells were not affected by these conjugates, in agreement with immuno cytochemical observations.     

Adaptive immune contexture at the tumour site and downmodulation of circulating myeloid-derived suppressor cells in the response of solitary fibrous tumour patients to anti-angiogenic therapy

Background:

Host immunity is emerging as a key player in the prognosis and response to treatment of cancer patients. However, the impact of the immune system and its modulation by therapies are unknown in rare soft tissue sarcomas such as solitary fibrous tumours (SFTs), whose management in the advanced forms includes anti-angiogenic therapy. Here, we studied the in situ and systemic immune status of advanced SFT patients and the effects of sunitinib malate (SM) in association with the clinical efficacy.

Methods:

Immune contexture of SFTs was assessed by immunohistochemistry in lesions from untreated or SM-treated patients. Frequency of circulating myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) and T-cell functions was assessed ex vivo in SFT patients prior and during anti-angiogenic therapy. Patients with long-term tumour control were included to correlate immune profiles and clinical responses.

Results:

Anti-angiogenic naïve SFT lesions were heavily infiltrated by CD163⁺CD14⁺CD68⁻ and CD163⁺CD14⁻CD68⁻ myeloid cells but devoid of T cells. Conversely, post-SM tumours acquired a new subset of CD68⁺CD14⁺ myeloid cells and displayed traits of an on-going adaptive immunity, strongly enriched in activated CD8⁺ and CD4⁺ T cells. These changes at the tumour site paralleled the alleviation of systemic immunosuppression and the drop in the frequency of circulating monocytic MDSCs (mMDSCs) and granulocytic MDSCs (gMDSCs). Rebound in the number of mMDSCs, but not of gMDSCs occurred at disease progression, and a reduced percentages of mMDSCs, comparable to those found in healthy donors (HDs), endured only in the SM-responsive patients.

Conclusions:

The immune contexture of SFT patients is heavily involved in anti-angiogenic therapy and it could be exploited to achieve more durable disease control through immune-based combination strategies.     

Proton spectroscopic imaging (Dixon method) of the liver: clinical utility

The contribution of proton spectroscopic (PS) imaging to magnetic resonance (MR) imaging of the liver was assessed at 0.5 T in 55 patients with known or suspected hepatic malignancy. PS images were compared subjectively with T1- and T2-weighted spin-echo (SE) images for hepatic lesion detection and conspicuity. For hepatic metastases (n = 27), PS images were equal to T1-weighted images in lesion detection in 17 patients but showed fewer lesions in five patients and false-negative results in two. When compared with T2-weighted images, PS images depicted more lesions in six patients, an equal number of lesions in 18, and fewer lesions in two. Hepatomas (n = 8) were detected with each sequence in all patients. Hepatomas were often more conspicuous on PS images than on T2-weighted images; they were of equal conspicuity on PS and T1-weighted images in most cases. Whereas fatty infiltration (n = 16) appeared on PS images as areas of low signal intensity similar to that of paraspinal muscle, it produced no detectable abnormality on either T1- or T2-weighted images. PS imaging is inferior to T1-weighted SE imaging in the detection of hepatic metastases. The major role of PS imaging at intermediate field strength is to differentiate focal fatty infiltration from hepatic metastases.     

Phenotypic and functional characterization of the circulating NK compartment in hairy cell leukaemia.

A phenotypic and functional analysis of the circulating natural killer (NK) cell population was carried out in a series of patients with hairy cell leukaemia (HCL). The overall mean NK activity of both the mononuclear and T cell fractions was reduced compared to that of normal controls (466 lytic units (lu) v 573 lu and 226 lu v 381 lu, respectively), though this difference did not reach statistical significance (P less than 0.05). Individual analysis of the data showed that in five out of 15 and in seven out of 16 cases the K562 killing by the mononuclear and T cells respectively was below the lowest s.d. limit for normal subjects. This reduced NK function was associated with a decreased ability of the effector cells to bind the target. The NK response to exogenous human leucocyte interferon was also generally depressed in cases with a low basal NK activity. The functional studies were complemented with the evaluation of the membrane expression of NK associated antigens. The percentage of circulating T cells recognized by the monoclonal antibody (MoAb) Leu-7 was significantly higher (P less than 0.001) in HCL than in normal blood (25.2% +/- 10.2 v 11.9 +/- 5.9 s.d.). However, the reactivity with two other NK-related MoAb, Leu-11 and AB8.28, was significantly lower (7.1% +/- 6.9 and 9.8% +/- 8.5; P less than 0.002) than with Leu-7 and moderately reduced compared with that of normal circulating T cells (11.7% + 6.1 & 12% + 5.5). These findings suggest that in a proportion of patients with HCL there is an impairment of the NK compartment, which may contribute towards the occurrence of the infective complications which are the primary cause of death in this disease.     

Human spleen cell generation of factors stimulating human pluripotent stem cell, erythroid, and myeloid progenitor cell growth

Mitogen-stimulated murine spleen cells produce humoral substances capable of supporting murine hematopoiesis and pluripotent stem cell proliferation in vitro. Thus, we evaluated conditioned media generated by human spleen cells (SCM) in the presence or absence of mitogens for factors stimulatory for human pluripotent (CFU-GEMM), erythroid (BFU- E), and myeloid (CFU-GM) precursors. Two and one half percent to 10% SCM stimulated proliferation of all three types of precursor cells from nonadherent buoyant human marrow target cells. Mitogen-stimulated SCM augmented CFU-GM (175% to 225%), whereas CFU-GEMM and BFU-E growth was essentially unchanged. Cell separation procedures used to determine which cells provided these microenvironmental stimuli indicated that nonadherent mononuclear spleen cells provided the bulk of the CSF-GM, whereas adherent cells (95% nonspecific esterase + monocyte- macrophages) and nonadherent cells provided similar proportions of CSF- mix and erythroid burst-promoting activity (BPA). The nonadherent cells generating high levels of CSF-mix, BPA, and CSF-GM were predominantly Leu-1-negative, ie, non-T, cells. In the presence or absence of mitogens, SCM was a more potent source (1.3- to 3.8-fold) than peripheral leukocyte CM of the growth factors for the three progenitor cell types. Specific in situ cytochemical stains for analyzing morphology of myeloid colonies demonstrated that SCM stimulated the proliferation of the same types and proportions of colonies as human placental CM, suggesting that these CMs may contain similar CSF-GMs. These data show the contribution of spleen cell subsets to the generation of hematopoietic growth factors and the responsiveness of these cells to various mitogenic stimuli.