Possible mechanisms underlying development of transfusion-related acute lung injury: roles of anti-major histocompatibility complex class II DR antibody

Anti-major histocompatibility complex (anti-MHC) antibodies (Abs) and antipolymorphonuclear neutrophil (anti-PMN) Abs are generally considered as the main causes of the development of transfusion-related acute lung injury (TRALI), which is one of the most severe and sometimes lethal side effects of transfusion. These Abs are postulated to activate recipient's leucocytes, resulting in the release of soluble factors such as reactive oxygen species and detrimental cytokines and chemokines. The harmful effects on the lung tissues and resident leucocytes of these malignant factors are suspected to be profoundly involved in TRALI reactions. Several reports have indicated the principle effect of biologically active lipids on the pathogenesis of TRALI. However, the precise mechanisms of TRALI development remain unclear. To resolve this issue, we have been investigating cytokines that induce continuous inflammation of the lungs, specifically focusing on the cytokines derived from activated PMNs. We observed that the granulocyte-macrophage colony-stimulating factor (GM-CSF) markedly enhances the expression of MHC class II DR in PMNs. Moreover, MHC class II DR-expressing PMNs were also proved to express a high-affinity receptor for immunoglobulin E (IgE) (FcepsilonRI) and to produce tumour necrosis factor-alpha, interferon-gamma and interleukin-18 following a challenge with an anti-MHC class II DR monoclonal Ab (MoAb) or anti-DR antiserum. It is strongly suggested that amongst various inflammatory mediators, at least these three cytokines may contribute to the duration of inflammatory reactions in the lungs. Furthermore, FcepsilonRI expression, in GM-CSF-treated PMNs, suggests the involvement of PMNs in IgE-mediated immune reactions.     

Role of anti-human leucocyte antigen class II alloantibody and monocytes in development of transfusion-related acute lung injury

Recently, evidence implicating the roles of the anti-human leucocyte antigen (HLA) class II antibody in the development of transfusion-related acute lung injury (TRALI), which is one of the most serious possible side effects of transfusion, has been accumulating. The aim of this study is to clarify the roles of the anti-HLA DR alloantibody in TRALI development. Cultured human lung microvascular endothelial (LME) cells were incubated with either HLA-DR15-positive or HLA-DR15-negative monocytes together with serum from a single multiparous donor previously implicated in a clinical case of TRALI and known to contain anti-HLA DR15 antibody. Production of soluble leukotriene B(4) (LTB(4)) was measured in the supernatant and found to be markedly increased in the presence of HLA-DR15-positive monocytes but not with the HLA-DR15-negative monocytes or in the absence of LME cells. The vascular cell adhesion molecule-1 expression in LME cells and leucocyte-function-associated molecule-1 (LFA-1) expression in HLA-DR15-positive monocytes were notably enhanced after combined culture of LME cells, HLA-DR15-positive monocytes and TRALI-inducing anti-HLA DR15 antibody-positive serum. In conclusion, anti-HLA DR alloantibodies may be implicated in LME dysfunction that leads to TRALI, in a monocyte-dependent manner.     

Possible involvement of heparin-binding protein in transfusion-related acute lung injury

BACKGROUND: In antibody-mediated nonhemolytic transfusion reactions, transfusion-related acute lung injury (TRALI) tends to occur typically within 2 hours after a blood transfusion. White cell antibodies or immune complexes have been frequently shown to be associated with the syndrome, although the mechanisms by which they induce TRALI are poorly understood. The aim of this study was to characterize soluble mediators that are released from cells at an early stage after immune stimulation. STUDY DESIGN AND METHODS: To explore the mechanism of TRALI, an in vitro whole-blood cell culture assay was established in which cells were stimulated by human antibodies and the activation of neutrophils was monitored by a cell surface marker (Mac-1) with flow cytometry and by measurement of the release of soluble factors, including perforin, interleukin-6, tumor necrosis factor-alpha, and heparin-binding protein (HBP) with enzyme-linked immunosorbent assays. In addition, the involvement of two neutrophil FcgammaRs (FcgammaRIIIb and FcgammaRIIa, also known as CD16 and CD32, respectively) was examined during antibody-induced cell activation with anti-FcgammaR blocking antibodies. RESULTS: Substantial amounts of HBP were released within 30 minutes of stimulation by human antibodies, although other soluble mediators were not released within the same period. Furthermore, the release of HBP was mediated via signals through both FcgammaRIIIb and FcgammaRIIa. CONCLUSION: HBP appears to be one of the primary effector molecules of antibody-mediated nonhemolytic transfusion reactions including TRALI.     

The relation between aged blood products and onset of transfusion-related acute lung injury. A review of pre-clinical data

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion related morbidity and mortality. TRALI is suggested to be a "two hit" event. The "first hit" is the underlying condition of the patient which results in sequestration and priming of neutrophils in the pulmonary compartment. The "second hit" is the transfusion of either human leukocyte antibodies or aged blood products which results in activation of the primed neutrophils and finally in pulmonary edema. The present review focuses on pre-clinical studies investigating the role of blood products containing aged cells (red blood cells, RBCs, and platelet concentrates, PLTs) and the onset of TRALI. Several mechanisms are under scrutiny. The first suggested mechanism is that soluble mediators accumulating during storage of RBCs and PLTs may play a role, including bio-active lipids or soluble CD40L. These soluble factors were found to cause lung injury in the presence of a "first hit". Another proposed mechanism involves the aged erythrocyte itself. During storage, the erythrocyte undergoes numerous changes in its biochemical and structural condition and acquires pro-inflammatory properties, sometimes collectively referred to as the "red cell storage lesion". Although it could be speculated that all of these factors may be involved in the onset of TRALI, only one pre-clinical study shows an association between the aged erythrocyte and the onset of TRALI. The suggested mechanism is a decrease in the chemokine scavenging function of the erythrocyte by reduction of the Duffy antigen expression resulting in an increase in lung injury. Further research is needed to elucidate possible mechanisms of onset of TRALI by aged blood products.     

Identification of lipids that accumulate during the routine storage of prestorage leukoreduced red blood cells and cause acute lung injury

BACKGROUND: Lipids accumulate during the storage of red blood cells (RBCs), prime neutrophils (PMNs), and have been implicated in transfusion‐related acute lung injury (TRALI). These lipids are composed of two classes: nonpolar lipids and lysophosphatidylcholines based on their retention time on separation by high‐pressure liquid chromatography. Prestorage leukoreduction significantly decreases white blood cell and platelet contamination of RBCs; therefore, it is hypothesized that prestorage leukoreduction changes the classes of lipids that accumulate during storage, and these lipids prime PMNs and induce acute lung injury (ALI) as the second event in a two‐event in vivo model. STUDY DESIGN AND METHODS: RBC units were divided: 50% was leukoreduced (LR‐RBCs), stored, and sampled on Day 1 and at the end of storage, Day 42. Priming activity was evaluated on isolated PMNs, and the purified lipids from Day 1 or Day 42 were used as the second event in the in vivo model. RESULTS: The plasma and lipids from RBCs and LR‐RBCs primed PMNs, and the LR‐RBC activity decreased with longer storage. Unlike RBCs, nonpolar lipids comprised the PMN‐priming activity from stored LR‐RBCs. Mass spectroscopy identified these lipids as arachidonic acid and 5‐, 12‐, and 15‐hydroxyeicsotetranoic acid. At concentrations from Day 42, but not Day 1, three of four of these lipids individually, and the mixture, primed PMNs. The mixture also caused ALI as the second event in a two‐event model of TRALI. CONCLUSION: We conclude that the nonpolar lipids that accumulate during LR‐RBC storage may represent the agents responsible for antibody‐negative TRALI.     

Platelets induce neutrophil extracellular traps in transfusion-related acute lung injury

There is emerging evidence that platelets are major contributors to inflammatory processes through intimate associations with innate immune cells. Here, we report that activated platelets induce the formation of neutrophil extracellular traps (NETs) in transfusion-related acute lung injury (TRALI), which is the leading cause of death after transfusion therapy. NETs are composed of decondensed chromatin decorated with granular proteins that function to trap extracellular pathogens; their formation requires the activation of neutrophils and release of their DNA in a process that may or may not result in neutrophil death. In a mouse model of TRALI that is neutrophil and platelet dependent, NETs appeared in the lung microvasculature and NET components increased in the plasma. We detected NETs in the lungs and plasma of human TRALI and in the plasma of patients with acute lung injury. In the experimental TRALI model, targeting platelet activation with either aspirin or a glycoprotein IIb/IIIa inhibitor decreased NET formation and lung injury. We then directly targeted NET components with a histone blocking antibody and DNase1, both of which protected mice from TRALI. These data suggest that NETs contribute to lung endothelial injury and that targeting NET formation may be a promising new direction for the treatment of acute lung injury.     

Pulmonary contusion induces alveolar type 2 epithelial cell apoptosis: role of alveolar macrophages and neutrophils

Alveolar type 2 (AT-2) cell apoptosis is an important mechanism during lung inflammation, lung injury, and regeneration. Blunt chest trauma has been shown to activate inflammatory cells such as alveolar macrophages (AMs) or neutrophils (polymorphonuclear granulocytes [PMNs]), resulting in an inflammatory response. The present study was performed to determine the capacity of different components/cells of the alveolar compartment (AMs, PMNs, or bronchoalveolar lavage [BAL] fluids) to induce apoptosis in AT-2 cells following blunt chest trauma. To study this, male Sprague-Dawley rats were subjected to either sham procedure or blunt chest trauma induced by a single blast wave. Various time points after injury (6 h to 7 d), the lungs were analyzed by immunohistochemistry, for AT-2 cells, or with antibodies directed against caspase 3, caspase 8, Fas, Fas ligand (FasL), BAX, and BCL-2. Bronchoalveolar lavage concentrations of TNF-alpha, IL-1beta, and soluble FasL were determined by enzyme-linked immunosorbent assay. Furthermore, cultures of AT-2 cells isolated from healthy rats were incubated with supernatants of AMs, PMNs, or BAL fluids obtained from either trauma or sham-operated animals in the presence or absence of oxidative stress. Annexin V staining or TUNEL (terminal deoxynucleotidyl transferase) assay was used to detect apoptotic AT-2 cells. Histological evaluation revealed that the total number of AT-2 cells was significantly reduced at 48 h following trauma. Fas, FasL, active caspase 8, and active caspase 3 were markedly up-regulated in AT-2 cells after chest trauma. BAX and BCL-2 did not show any significant changes between sham and trauma. IL-1beta, but not TNF-alpha, levels were markedly increased at 24 h after the injury, and soluble FasL concentrations were significantly enhanced at 6, 12, 24, and 48 h after the insult. Apoptosis of AT-2 cells incubated with supernatants from cultured AMs, isolated at 48 h following chest trauma was markedly increased when compared with shams. In contrast, no apoptosis was induced in AT-2 cells incubated with supernatants of activated PMNs or BAL fluids of traumatized animals. In summary, blunt chest trauma induced apoptosis in AT-2 cells, possibly involving the extrinsic death receptor pathway. Furthermore, mediators released by AMs appeared to be involved in the induction of AT-2 cell apoptosis.     

MHC class I-specific antibody binding to nonhematopoietic cells drives complement activation to induce transfusion-related acute lung injury in mice

Transfusion-related acute lung injury (TRALI), a form of noncardiogenic pulmonary edema that develops during or within 6 h after a blood transfusion, is the most frequent cause of transfusion-associated death in the United States. Because development of TRALI is associated with donor antibodies (Abs) reactive with recipient major histocompatibility complex (MHC), a mouse model has been studied in which TRALI-like disease is caused by injecting mice with anti-MHC class I monoclonal Ab (mAb). Previous publications with this model have concluded that disease is caused by FcR-dependent activation of neutrophils and platelets, with production of reactive oxygen species that damage pulmonary vascular endothelium. In this study, we confirm the role of reactive oxygen species in the pathogenesis of this mouse model of TRALI and show ultrastructural evidence of pulmonary vascular injury within 5 min of anti-MHC class I mAb injection. However, we demonstrate that disease induction in this model involves macrophages rather than neutrophils or platelets, activation of complement and production of C5a rather than activation of FcγRI, FcγRIII, or FcγRIV, and binding of anti-MHC class I mAb to non-BM-derived cells such as pulmonary vascular endothelium. These observations have important implications for the prevention and treatment of TRALI.     

Enhancement of endothelial permeability by coculture with peripheral blood mononuclear cells in the presence of HLA Class II antibody that was associated with transfusion-related acute lung injury

BACKGROUND: HLA Class II antibody–initiated activation of monocytes possessing the corresponding antigen is thought to participate in the pathogenesis of transfusion‐related acute lung injury (TRALI). Pulmonary edema, a hallmark of TRALI, is caused by increasing vascular permeability. STUDY DESIGN AND METHODS: To investigate the contribution of HLA Class II antibody and monocytes to the development of pulmonary edema in TRALI, we studied whether the permeability of human lung microvascular endothelial cells (HMVECs) could be enhanced by coculturing HMVECs with peripheral blood mononuclear cells (PBMNCs) in the presence of HLA Class II antibody–containing plasma, which was implicated in TRALI (anti‐HLA‐DR plasma). In addition, similar experiments were performed with human umbilical vein endothelial cells (HUVECs). The endothelial permeability to fluoresceinated dextran, which was added from the start of coculture, was measured. RESULTS: The coculture of HMVECs or HUVECs with PBMNCs in the presence of anti‐HLA‐DR plasma resulted in the increase of endothelial permeability in the corresponding antigen‐antibody–dependent manner. CV‐3988, a platelet‐activating factor (PAF) receptor antagonist, almost completely suppressed the increase in endothelial permeability. Neutralizing antibodies to tumor necrosis factor (TNF)‐α alone and simultaneous addition of the antibodies to TNF‐α and interleukin (IL)‐1β to the coculture partially suppressed the permeability increase of HMVECs and HUVECs, respectively. CONCLUSIONS: HLA Class II antibody and monocytes in the corresponding antigen‐antibody combination caused the enhancement of endothelial permeability. PAF, TNF‐α, and/or IL‐1β might be involved in the endothelial permeability increase. HLA Class II antibody–initiated monocyte activation could lead to the development of pulmonary edema in TRALI.     

Cytokine-induced neutrophil chemoattractant mediates neutrophil influx in immune complex glomerulonephritis in rat.

Chemokines are a family of cytokines whose participation in inflammation in vivo remains to be established. Using the rat model of anti-glomerular basement membrane (GBM) nephritis, we found that mRNA for the chemokine CINC (cytokine-induced neutrophil chemoattractant) was induced in the kidney, and the corresponding protein was elaborated by isolated inflamed glomeruli. Production of CINC by glomeruli was unaffected by complement- or leukocyte-depletion prior to disease induction. Cytokines which induce CINC expression in renal cells (TNF-alpha and IL-1 beta) were also expressed in the kidney during glomerular inflammation. TNF-alpha production, unlike CINC, was complement and leukocyte dependent. In vivo administration of anti-CINC, but not anti-human IL-8, IgG selectively attenuated the influx of PMNs into the glomerulus and commensurately diminished proteinuria. The participation of CINC was not tissue-specific: anti-CINC IgG also diminished the influx of PMNs in dermal immune complex inflammation. In sum, we propose that glomerular immune complex deposition/complement activation leads to cytokine production which results in CINC expression by endogenous glomerular cells. The CINC produced plays a contributory role in the influx of PMNs into the glomerulus in the context of the activation of other inflammatory mediators. These results suggest a potential role for CINC homologues, IL-8 and the GRO family of chemokines, in human immune complex-mediated disease.     

TRALI : aspects physiopathologiques

Transfusion-related acute lung injury (TRALI) is defined clinically as a pulmonary edema occurring within 6 hours after transfusion of blood products. This is a major cause of morbidity and mortality associated with blood transfusion. Its pathophysiology is complex and not fully understood. TRALI is the result of a neutrophil-mediated damage to the pulmonary endothelium. Possible causal agents include alloantibodies against leucocytes and biologically active mediators accumulated in stored blood products. Leucostasis in the recipient??s lung is a predisposing state due to leucocyte priming preceding the activation of neutrophils by blood transfusion leading to lung injury. TRALI is frequent in critical ill patients as they meet several risk factors associated with this injury. This review focuses on the pathogenesis of TRALI based on epidemiologic and experimental published data.     

Cyclin-dependent kinase inhibition reduces lung damage in a mouse model of ventilator-induced lung injury

Mechanical ventilation (MV) has the potential to induce lung damage in healthy lungs or aggravate existing lung injury. Polymorphonuclear neutrophil (PMN) recruitment plays an important role in driving the inflammatory response in ventilator-induced lung injury (VILI). The cyclin-dependent kinase inhibitor r-roscovitine has been shown to induce apoptosis in PMNs. In this study, we investigated the potential of r-roscovitine treatment in reducing lung damage in a mouse model of VILI. Mice were tracheotomized and subjected to lung-protective MV with lower (～7.5 mL/kg) or lung-injurious MV with higher (～15 mL/kg) tidal volume (VT). R-roscovitine treatment enhanced apoptosis in PMNs in vitro. Ventilator-induced lung injury was associated with pulmonary PMN influx in low and high VT MV. During lung-injurious MV, r-roscovitine treatment reduced the number of PMNs and lowered levels of the lung damage markers RAGE (receptor for advanced glycation end products) and total immunoglobulin M in bronchoalveolar lavage fluid. R-roscovitine did not affect cytokine or chemokine levels in the bronchoalveolar space, neither during lung-protective nor lung-injurious MV. Thus, r-roscovitine treatment reduces lung damage in VILI, possibly dependent on increased apoptosis of PMNs.     

Neutrophil chemotactic activity produced by normal and activated human bronchoalveolar lavage cells

Activated macrophages can secrete a number of mediators that can attract inflammatory cells and enhance secretion of phlogistic substances from these cells. The ultimate effect of activated bronchoalveolar lavage (BAL) cells may be fibrotic lung injury. Inasmuch as pulmonary sarcoidosis is a disease associated with spontaneous activation of macrophages and lymphocytes among BAL cells, cells obtained from patients with sarcoidosis were compared with normal cells. We report that adherent BAL cells in culture from patients with sarcoidosis (n = 21) release during a resting period in vitro more chemotactic activity for neutrophils (PMNs) than do BAL cells from normal individuals (n = 14). After density fractionation of the respiratory cells by albumin gradient, cells from high-density fractions in the group with sarcoidosis secrete more chemotactic activity for neutrophils than cells from less dense fractions. The PMN chemotactic activity spontaneously released in vitro by BAL cells from patients with sarcoidosis correlates with the percentage of PMNs recovered by BAL. Immunochemical bioassay and high-performance liquid chromatographic (HPLC) analysis of BAL cell supernatants revealed a complex pattern of chemotactic factors to be present. Generally, three peaks of chemotactic activity were noted on HPLC 1-60 separations at greater than 20 kd, 8 to 10 kd, and less than 1 kd apparent molecular weights. Significantly, interleukin-1 was present in these supernatants, whereas complement components and leukotriene B4 were absent. Sarcoid BAL cells, principally alveolar macrophages, are activated in vivo as manifested by spontaneous secretion of chemotactic factors for PMNs in vitro. Interleukin-1 and other less well characterized molecules were detected. The presence of PMNs among the lavage cells of some patients with sarcoidosis appears to be an in vivo biologic correlate of this activation. These data provide additional criteria of BAL cell activation in patients with pulmonary sarcoidosis and provide further evidence concerning factors that attract inflammatory cells into the lung.     

HLA-DR antibodies in transfusion-related acute lung injury (TRALI): a case report.

Transfusion-related acute lung injury (TRALI) is a serious adverse consequence of blood product transfusion. Cases of TRALI have gone unrecognized or misdiagnosed, since the symptoms can be confused with other transfusion-related events or with non-transfusion related comorbidities. Suspected cases of TRALI may be insufficiently investigated, and mild or moderate cases may not be investigated or reported at all. We report here the case of a 73-year man who developed TRALI following a transfusion of packed red blood cells (pRBCs) mediated by HLA class II antibodies (HLA-DR) detected by luminex technology. A very few cases of TRALI have been described being caused by HLA class II antibodies without the simultaneous presence of anti-HLA class I antibodies. Technology for antibody detection has increased the power and the specificity, especially with the use of flow cytometry with a better definition of the antigen/antibody pairs that have resulted in TRALI episodes. In this sense, HLA class II antibodies can exactly be detected with these methods and have surely been underestimated until now.     

Hypocapnic alkalosis enhances oxidant-induced apoptosis of human alveolar epithelial type II cells

Apoptosis of alveolar epithelial type II (AEC-II) cells induced by reactive oxygen species (ROS) contributes to extensive alveolar damage during acute lung injury. Hypercapnic acidosis and hypocapnic alkalosis are known to modulate ROS-mediated lung damage. This study assessed the effects of acid-base balance disturbances on hydrogen peroxide (H2O2)-induced apoptosis of the AEC-II-like human cell line A549, which was cultured under different conditions of pH and CO2 tension (normal pH and CO2, hypercapnic acidosis, metabolic acidosis, hypocapnic alkalosis and metabolic alkalosis). H2O2-induced apoptosis was assessed by a dye-uptake bioassay and induction of caspase activity, which were quantified using analytical digital photomicroscopy. Acidosis or alkalosis of the culture medium alone did not induce A549 cell apoptosis. Hypocapnic alkalosis significantly increased H2O2-induced apoptosis and caspase activation of A549 cells. Metabolic alkalosis non-significantly increased H2O2-induced A549 cell apoptosis and caspase activation. These data suggest that hypocapnic alkalosis intensifies oxidative-induced apoptosis of alveolar epithelial cells.     

Erythema multiforme: a possible pathogenetic role of increased reactive oxygen species

Recently, it has been suggested that reactive oxygen species (ROS) produced by activated polymorphonuclear leukocytes (PMNs) exert auto-oxidative tissue damage at the site of inflammation. In the present study, a possible role of ROS in the pathogenesis of erythema multiforme (EM) was investigated by determining the capacity of the sera from patients for generating ROS from PMNs. Significantly increased hydroxyl radical production was observed, which is one of the most potent ROS capable of causing tissue damage. This change was not observed when PMNs were incubated with sera from patients with bullous pemphigoid (BP) or inflammatory acne, indicating that this finding was not a common feature of immunologically mediated and/or inflammatory cutaneous disorders. Elevated C1q activities and depositions of immunoreactants in the blood vessels were also noticed in some patients. These findings suggest that ROS generated by PMNs are involved in the formation of cutaneous lesions of EM and that immune complexes (ICs) may provide an important mechanism in PMN activation.     

急性肺损伤炎性细胞凋亡异常及粒细胞集落刺激因子调控的研究

目的 探讨急性肺损伤时支气管肺泡灌洗液(BALF)中的中性粒细胞(PMN)凋亡发生规律及其与粒细胞集落刺激因子调控关系.方法 豚鼠30只,分为3组:组1为生理盐水正常对照组,组2为油酸致病组,组3为油酸+粒细胞集落刺激因子组.组2、组3分别由尾静脉注射油酸(0.12 ml/kg)造成豚鼠急性肺损伤模型.组1则注入生理盐水.组3在实验造模前2 d由皮下注射粒细胞集落刺激因子1.0μg/kg,1次/d.组1、组2、组3分别于注射后2 h用生理盐水进行全肺支气管肺灌洗,收集BALF.用梯度密度法离心收集PMN.用原位末端标记法检测BALF中PMN凋亡.结果 组2、组3和组1BALF中PMN凋亡百分比分别为(2.500±1.080)%、(3.500±0.850)%、(6.400±1.505)%.组2、组3较组1 BALF中PMN凋亡均显著降低(均P＜0.01).结论 急性肺损伤炎性细胞PMN凋亡延迟,PMN持续激活和释放毒性内容物与肺损伤有密切关系.粒细胞集落刺激因子能调控干预急性肺损伤时PMN凋亡延迟.     

HLA class II antibodies in transfusion-related acute lung injury

BACKGROUND: Transfusion-related acute lung injury (TRALI) is a serious, sometimes fatal, complication of transfusion. Granulocyte and HLA class I antibodies present in blood donors have been associated with TRALI. HLA class II antibodies have recently been described in a few cases of TRALI. STUDY DESIGN AND METHODS: Donors involved in TRALI reactions reported to a blood center over an 18-month period were tested for HLA class I and II antibodies as well as granulocyte antibodies, if HLA antibodies were not identified. RESULTS: HLA class II antibodies were identified, in at least one donor, in 7 (64%) of 11 cases of TRALI. HLA class I antibodies were identified in combination with HLA class II antibodies in 5 of these 7 cases. HLA class I antibodies were exclusively identified in 2 cases. Granulocyte antibodies were identified in 1 case, and no antibodies were identified in another. CONCLUSION: In addition to HLA class I antibodies, HLA class II antibodies are associated with TRALI. Testing of donors for HLA class II antibodies as well as HLA class I and granulocyte antibodies is recommended as part of the investigation of suspected cases of TRALI.     

Activation of human T cells by FcR nonbinding anti-CD3 mAb,hOKT3gamma1(Ala-Ala)

Dimeric Fc receptor (FcR) nonbinding anti-CD3 antibodies have been developed to minimize toxicities associated with classical anti-CD3 monoclonal antibodies (e.g., OKT3). Studies with murine analogs of non-FcR-binding antibodies have shown reduced mitogenicity compared to OKT3. In a trial of an FcR nonbinding humanized anti-CD3 mAb hOKT3gamma1(Ala-Ala) for treatment of patients with type 1 diabetes, we found significant increases in IL-10 and IL-5 in the serum of 63% and 72% of patients, respectively, and TNF-alpha and IL-6 levels that were lower than those previously reported following OKT3 therapy. The activation signal delivered by hOKT3gamma1(Ala-Ala) was associated with calcium signaling and cytokine production by previously activated human cells in vitro. However, the production of IL-10, compared to IFN-gamma on a molar basis, was greater after culture with hOKT3gamma1(Ala-Ala) than with OKT3. Flow cytometric studies confirmed that OKT3 induced IFN-gamma and IL-10 production, but hOKT3gamma1(Ala-Ala) induced only detectable IL-10 production in CD45RO(+) cells. Moreover, in vivo, we found IL-10(+)CD4(+) T cells after drug treatment. These cells were heterogeneous but generally CD45RO(+), CTLA-4(-), and expressed CCR4. A subgroup of these cells expressed TGF-beta. Thus, the non-FcR binding anti-CD3 mAb, hOKT3gamma1(Ala-Ala) delivers an activation signal to T cells that is quantitatively and qualitatively different from OKT3. It leads to the generation of T cells that might inhibit the autoimmune response and may be involved in the beneficial effect on beta cell destruction in Type 1 diabetes.