Effects of anti-TNF monoclonal antibody infusion in patients with hairy cell leukaemia

Efficacy of the anti-CD22 recombinant immunotoxin BL22 in chemotherapy-resistant hairy-cell leukemia

BACKGROUND

Hairy-cell leukemia that is resistant to treatment with purine analogues, including cladribine, has a poor prognosis. We tested the safety and efficacy of an immunotoxin directed against a surface antigen that is strongly expressed by leukemic hairy cells.

METHODS

RFB4(dsFv)-PE38 (BL22), a recombinant immunotoxin containing an anti-CD22 variable domain (Fv) fused to truncated pseudomonas exotoxin, was administered in a dose-escalation trial by intravenous infusion every other day for a total of three doses.

RESULTS

Of 16 patients who were resistant to cladribine, 11 had a complete remission and 2 had a partial remission with BL22. The three patients who did not have a response received low doses of BL22 or had preexisting toxin-neutralizing antibodies. Of the 11 patients in complete remission, 2 had minimal residual disease in the bone marrow or blood. During a median follow-up of 16 months (range, 10 to 23), 3 of the 11 patients who had a complete response relapsed and were retreated; all of these patients had a second complete remission. In 2 of the 16 patients, a serious but completely reversible hemolytic-uremic syndrome developed during the second cycle of treatment with BL22. Common toxic effects included transient hypoalbuminemia and elevated aminotransferase levels.

CONCLUSIONS

BL22 can induce complete remissions in patients with hairy-cell leukemia that is resistant to treatment with purine analogues.

The endogenous balance of soluble tumor necrosis factor receptors and tumor necrosis factor modulates cachexia and mortality in mice acutely infected with Trypanosoma cruzi

To better understand the role of tumor necrosis factor (TNF) during Trypanosoma cruzi infection in BALB/c mice, we have investigated the kinetics of circulating tumor necrosis factor (TNF), soluble TNF receptor 1 (sTNR1), and sTNFR2 levels, as well as the interactions between such factors, in relation to parasitemia, cachexia, and mortality of acutely infected animals. Our data show that the parasitemic phase of T. cruzi infection in mice is associated with high levels of circulating TNF and sTNFR2, resulting in the formation of cytokine-receptor complexes and some degree of neutralization of TNF bioactivity. Although sTNR2 levels always exceeded TNF levels, low sTNFR/TNF circulating ratios were associated with cachexia in all infected mice, whereas the lowest ratios were observed in dying animals harboring the highest parasitemia. We also studied the modulation of sTNFR/TNF ratios induced by anti-TNF antibodies administered to infected animals and their consequences on the outcome of the infection. The injection of anti-TNF monoclonal antibody (MAb) TN3 into infected mice resulted in a paradoxical overproduction of TNF (associated with a higher parasitemia), lowered the sTNFR/TNF circulating ratios, and considerably worsened cachexia and mortality of animals. Another anti-TNF MAb (1F3F3) decreased the in vivo availability of TNF as well as parasite levels and reduced cachexia. Altogether, such results highlight that, besides playing a beneficial role early in infection, TNF also triggers harmful effects in the parasitemic phase, which are limited by the in vivo simultaneous endogenous production of soluble receptors.

The tumor necrosis factor family and and correlation with disease activity and response to treatment in hairy cell leukemia

Hairy cell leukemia (HCL) is a well recognized indolent B-cell lymphoproliferative disorder. HCL cell proliferation is regulated by growth factors and cytokines, of which tumor necrosis factor-alpha (TNF-alpha) may be one of the most important. The mechanism of TNF-alpha-induced HCL cell growth is mediated via 2 receptors, which are present in both cellular and soluble forms. In this study we determined the serum levels of TNF-alpha and their soluble receptors - sTNF-R60 and sTNF-R80 - in 23 HCL patients and correlated them with clinical parameters before and after therapy. Patients were classified according to their clinical status as either "active" at diagnosis or during relapse and "non-active" (responding to therapy with partial and complete remission). Most patients were treated with 2-CDA, following which serum levels of TNF-alpha, sTNF-R60 and sTNF-R80 were significantly decreased, particularly in CR. Significant differences in paired observation values were noted for TNF-alpha and sTNF-R80, indicating a good correlation with the clinical status of disease, but this was not the case for sTNF-R60 (coefficients of correlation between levels of TNF-alpha and sTNF-R80 and of TNF-alpha and sTNF-R60 were r = 0.85 and r= 0.64, respectively). These results suggest that decreases in both TNF-alpha and sTNF-R80 are indicative of response to treatment, while increased levels accompany active disease. Accordingly, we conclude that serum levels of the TNF family, as for the sIL-2R and IL-1 family, may also be used as sensitive markers for monitoring HCL status. Levels may be indicative of the clinical efficacy of therapy and can be used as an indicator of the presence of residual disease.

Is TNF-alpha a prognostic factor in patients with sepsis?

OBJECTIVE: To determine tumor necrosis factor-alpha (TNF-alpha) levels in a prospective study in 58 hospitalized patients in a department of internal medicine (63 episodes, 29 in immunocompromised patients) during a 7-month period. METHODS: Patients fulfilling the following criteria were included: clinical evidence of acute infection, temperature >38.2 degrees C, tachycardia >90 beats/min, tachypnea >20 breaths/min. Samples were taken from day 1 up to day 13 after an infection was diagnosed, and TNF-alpha was determined by enzyme immunoassay. RESULTS: In 29 episodes (46.0%) the infection was microbiologically documented. The median of the TNF-alpha levels in the Gram-negative episodes was significantly higher than that in the Gram-positive episodes (p=0.002). Thirteen of 63 episodes (20.6%) had a fatal outcome. With respect to all measured values, the non-survivors had a significantly higher median of TNF-alpha levels than the survivors (p=0.0001). There was, however, great interpatient and intrapatient variability in TNF-alpha levels; thus, no unequivocal correlation between TNF-alpha and outcome could be documented. CONCLUSIONS: Our data indicate that the influence of the infecting organism on TNF-alpha kinetics is less pronounced than that of the underlying disease.

Evidence for a paracrine pathway of B-cell stimulation in hairy cell leukaemia

It is a well-known phenomenon that the growth of malignant B-lymphocytes, i.e. hairy cells, is regulated by cytokines. Several investigators have suggested that the stimulating cytokines are produced by the malignant B cells themselves, indicating an autocrine growth regulation. In this paper we demonstrate that T-lymphocyte clones produce soluble mediators which stimulate the growth of malignant B lymphocytes. The incidence of the growth-stimulating T-cell clones derived from peripheral blood is identical in patients with hairy cell leukaemia (HCL) and healthy controls. About 50% of the clones stimulate the growth of hairy cells, but not the growth of purified B lymphocytes of healthy donors. The stimulating activity of a single clone varies when tested on different hairy cells. Interferon alpha (IFN alpha), but not antibodies against tumour necrosis factor alpha (TNF alpha) or interleukin-2 (IL-2), completely inhibit the growth-stimulating activity. Our results indicate that a paracrine growth regulation has to be considered in addition to the postulated autocrine loop in the growth regulation of malignant B cells.

Cytokine-binding proteins: stimulating antagonists

Cytokine-binding proteins (CBPs) block the ability of cytokines to interact with their receptors. These agents can potentially provide a means of treating pathological conditions that have a significant cytokine involvement. However, a major drawback of such approaches relates to the fact that CBPs stabilize the cytokine in the form of a cytokine-CBP complex in vivo. Here, Bernard Klein and Hervé Brailly discuss the possibility that CBPs behave either as agonists or antagonists according to their pharmacokinetic characteristics in vivo, and suggest a mechanism by which stable complexes might be cleared from the system.

Down-regulation of cytokine action

The study of cytokines that regulate all areas of cellular communication has expanded over the past few years. The control and modulation of the complex network of cytokine action remains an area of intense interest. Agents that will modulate cytokine signal transduction at the cellular level will assist in the understanding of the molecular basis of cytokine cellular activation and in the design of drugs for the management of clinical disease. Recent work has demonstrated the existence of complex mechanisms of negative regulation of cytokine action. New methods utilizing isolated protein products that participate in immunomodulation may prove useful for clinical regulation of the host response to cytokine up-regulation. Currently, most interest in soluble cytokine receptors, natural cytokine inhibitors, genetically engineered cytokine antagonists and single or combinations of anti-inflammatory cytokines has focused on the possibility that they may become standard pharmacological agents for the treatment of inflammatory complications of clinical disease. Specifically, TNF and IL-1 inhibitors and the cytokines IL-10 and TGF-beta, alone or in combination may be effective for the inhibition of severe clinical inflammation. Soluble receptors for other cytokines such as IL-6 may prove to be carrier proteins that enhance cytokine action and will require cautious investigation. Because most cytokines are pleiomorphic in their activities, down-regulation through the utilization of direct inhibitors or anti-inflammatory cytokines may cause immunosuppression, making the host susceptible to opportunistic infection. Selective and short-term inhibition of inflammatory cytokine action may be necessary to prevent unwanted clinical side-effects.