Interleukin-2-induced lung permeability is mediated by leukotriene B4

Alteration in hemodynamic effects of interleukin 2 after treatment with indomethacin in anesthetized rats

The cardiovascular effects of interleukin 2 (IL2), were investigated in animals pretreated with indomethacin. Bolus intravenous administration of IL2 alone caused a significant reduction in cardiac output over time. Pretreatment with indomethacin significantly accentuated the reduction in cardiac output produced by IL2. The administration of IL2 or indomethacin alone or combined had no significant effects on dP/dt, heart rate or plasma troponin levels. As well, administration of either compound alone or combined had limited effects on mean circulatory filling pressure and arterial blood pressure. Injection of IL2 alone significantly increased resistance to venous return and arterial resistance at 3h post injections. Pretreatment with indomethacin caused IL2 to produce a significantly greater increase in arterial resistance and resistance to venous return. Administration of IL2 and indomethacin combined also produced significant reduction in stroke volume than IL2 or indomethacin alone. The injection of IL2 or indomethacin alone or combined had no significant impact on blood volume. Acute administration of IL2 appears to have no negative inotropic or chronotropic effects and its impact in reducing cardiac output is the result of an increase in vascular resistance. It seems that activation of prostanoids, possibly prostacyclin, has an acute beneficial effect in attenuating the initial negative effects of IL2 on cardiac output.

Hantavirus cardiopulmonary syndrome: immune response and pathogenesis

Hantaviruses are emerging viruses in the Americas that cause cardiopulmonary syndrome with high lethality. The intense cellular immune response to hantavirus alters normal endothelial cell barrier functions and seems to be harmful to the host. On the other hand, the humoral immune response seems to be essential for recovery from infection.

Vascular leak syndrome: a side effect of immunotherapy

The major dose-limiting toxicity of interleukin-2 (IL-2) and of immunotoxin (IT) therapies is vascular leak syndrome (VLS). VLS is characterized by an increase in vascular permeability accompanied by extravasation of fluids and proteins resulting in interstitial edema and organ failure. Manifestations of VLS include fluid retention, increase in body weight, peripheral edema, pleural and pericardial effusions, ascites, anasarca and, in severe form, signs of pulmonary and cardiovascular failure. Symptoms are highly variable among patients and the causes are poorly understood. The pathogenesis of endothelial cell (EC) damage is complex and can involve activation or damage to ECs and leukocytes, release of cytokines and of inflammatory mediators, alteration in cell-cell and cell-matrix adhesion and in cytoskeleton function. VLS restricts the doses of IL-2 and of ITs which can be administered to humans and, in some cases, necessitates the cessation of therapy. This review discusses the diversity of clinical manifestation, possible mechanisms and therapeutic modalities for VLS induced by IL-2 and ITs.

Respiratory mechanics after chronic diethylcarbamazine

This study was performed to evaluate the role of diethylcarbamazine (DEC), the drug of choice for treating Lymphatic Filariasis and Tropical Pulmonary Eosinophilia, on respiratory mechanics of higid rats. Thus, during 30 days two groups of six rats each received intraperitoneally either isotonic saline solution, or 12 mg/kg per day of DEC. Thereafter, they were sedated, anesthetized, paralysed and mechanical ventilation followed. After airway occlusion at end inspiration, respiratory system, pulmonary and chest wall resistive pressures (delta P1,rs, delta P1,L, and delta P1,w, respectively) and viscoelastic/inhomogeneous pressures (delta P2,rs, delta P2,L and delta P2,w, respectively) were determined in each group. Total delta pressures (delta Ptot) were calculated as the sum of delta P1 and delta P2, yielding the values of delta Ptot,rs, delta Ptot,L, and delta Ptot,w, respectively. Respiratory system, lung and chest wall static (Est,rs, Est,L, and Est,w, respectively) and dynamic elastances (Edyn,rs, Edyn,L, and Edyn,w, respectively), and the corresponding delta elastances (calculated as Edyn-Est) were also obtained. DEC therapy significantly decreased delta Ptot,rs, delta P tot,L, delta P2,rs, delta P2,L, Est,ts, Est,L, delta Ers and delta EL, in relation to the respective control values. It can be concluded that DEC decreases respiratory system impedance, being potentially useful for allowing airway dilation at the lung periphery.

High-dose interleukin 2 promotes bacterial translocation from the gut

Toxicity associated with high-dose recombinant interleukin 2 (rIL-2) therapy simulates a sepsis syndrome, but the mechanism remains unclear. We hypothesised that translocated gut-origin bacteria may be important. Fifty-one male rats were randomised to receive rIL-2 by intraperitoneal injection at doses (IU) of 10(5) (n = 15), 10(4) (n = 8), 10(3) (n = 8) or 10(2) (n = 8) twice daily, or a saline bolus (n = 12). After 5 days, ileal histomorphology was assessed and the mesenteric lymph node complex cultured. Results showed that colonisation of mesenteric lymph nodes with Escherichia coli occurred in all rats treated with 10(5) IU of rIL-2, and in 62%, 37% and 12% of rats treated with decreasing doses of rIL-2. No translocation was observed in control animals. An increase in submucosal lymphatics and occasional mucosal disruption was seen only in the group receiving 10(5) IU. These data show that rIL-2 promotes bacterial translocation and suggests a mechanism that may fuel high-dose rIL-2 toxicity in man.