Current status of hemapheresis in the United States.

The face of automated hemapheresis in the United States is changing. No longer is it appropriate to view hemapheresis primarily in terms of therapeutic plasma exchange. For many centers, the bulk of day-to-day activities revolves around donor cytapheresis to satisfy the ever-increasing need for units of platelet concentrates. Indications of therapeutic plasma exchange are becoming better focused, with neurological patients being among those most frequently managed. New and innovative applications of automated hemapheresis technology will continue to be developed. Current examples include the production of lymphocyte-activated leukocytes for cancer therapy, use of extracorporeal photoactivation of leukocytes for immune modulation, and the collection of hematopoietic progenitors from peripheral blood for autologous transplantation. As we enter the 1990s, it is important to be aware of new technology and applications and to have the vision to apply them in innovative ways. However, it is also critical to demand rigorous scientific review before broadly adopting any new idea as a standard of practice.     

Apheresis donor safety - changes in humoral and cellular immunity

Modern techniques of mechanical hemapheresis have made it possible to selectively remove vast quantities of lymphocytes and plasma immunoglobulins, and the concentration of these substances in donor blood can fall below the normal range. It is feared that this may lead to immunosuppression; a condition associated in some clinical settings with infections, malignancy and autoimmune diseases. Using primary immunodeficiency diseases and induced immunodeficiency states (for example, therapeutic lymphocytapheresis, chronic thoracic duct drainage and intestinal lymphangiectasia) as models to judge competency of the immune system, it can be predicted that body defense mechanisms can become defective when serum IgG levels are < 200 mg/dl or the blood lymphocyte count is < 1000/μl. However, impaired immunologic function can occur in the presence of normal quantities of these substances in the blood stream; conditions that may be related either to imbalances of immune regulatory factors or to qualitative (rather than quantatitive) abnormalities of the immune system. A number of investigators have documented the losses of lymphocytes and plasma immunoglobulins incurred by donors experiencing mechanical hemapheresis. In addition, both the immediate and long-term decreases in the concentration of these substances in donor blood have been reported. In summary, the immediate decreases in blood lymphocyte counts and serum immunoglobulin concentrations are of slight to moderate degree and are without known adverse effects. Less information is available regarding long-term alterations of the immune system, and little data have been collected from prospective studies in which large numbers of donors have been thoroughly evaluated by modern techniques. In general, results of many laboratory studies have been altered. However, these abnormalities have been transient for the most part, and it has been difficult to document clinically significant adverse effects. Thus, the quantities of blood lymphocytes and plasma immunoglobulins that can be removed from healthy donors without causing significant immediate or long-term harm is unknown. Bearing these limitations in mind, the following recommendations are suggested regarding the frequency of repeated mechanical plasma-and-cytapheresis. 1) The usual requirements for whole blood donation must be met if the frequency of mechanical hemapheresis does not exceed once every eight weeks. 2) Individuals expected to experience mechanical apheresis at more frequent intervals should comply with the following additional requirements in an attempt to avoid severe lymphocytopenia (blood lymphocytes < 1000/μl): a) subjects should not be permitted to donate with a preapheresis lymphocyte count < 1200/ 1; b) donor blood lymphocyte counts should be measured initially and again after each cumulative loss of 5 × 10¹⁰ lymphocytes; c) donors who develop lymphocytopenia (< 1000/μl of blood) should be excluded from donation until the blood lymphocyte count is > 1200/μl.     

Techniques, indications, and toxicity of therapeutic hemapheresis in children

Although therapeutic hemapheresis has grown dramatically in the past decade, its utilization and popularity in pediatrics remain limited. The lack of well-defined indications for treatment and technical difficulties in the management of hemapheresis for small patients have prevented its widespread use. However, there have been more than 130 reports describing the use of hemapheresis in children less than 15 years of age, including more than 20 reports describing it in children less than 5 years. Only one controlled trial of hemapheresis in children has been published. It studied the use of plasma exchange for the treatment of diabetes mellitus. In general, practitioners depend upon the accepted indications in adults to justify usage of this therapy in children. Unfortunately, major differences exist in the adult and pediatric presentation of certain diseases and there has not been universal acceptance of the indications for this therapy in children. Numerous technical difficulties continue to plague the development of hemapheresis therapy in pediatrics and therefore continue to limit the number of studies undertaken. The major technical difficulties include vascular access and excessive extracorporeal volume. These problems are not insurmountable since several patients less than 1 year of age have been successfully treated by hemapheresis. The various techniques used in these cases will be discussed. Additional problems unique to the pediatric population are the difficulty in getting approval for research studies that involve minors, the complexity of informed consent, the problem of patient cooperation and compliance, and the difficulty of explaining a complicated procedure to children of varying developmental levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mean arterial pressure (MAP): an alternative and preferable measurement to systolic blood pressure (SBP) in patients for hypotension detection during hemapheresis

Current protocols utilize systolic blood pressure (SBP) of less than 80 mmHg as objective evidence of hypotension during hemapheresis. However, tissue hypoperfusion is the pathophysiologic endpoint of low blood pressure, and mean arterial pressure (MAP), rather than SBP, is the physiologic driving force behind blood flow to organs and tissues. It is thus hypothesized that MAP is more appropriate than SBP in the assessment of hypotension and that a threshold MAP can be utilized as a sensitive indicator of hypotension during hemapheresis. Thirty-one patients who experienced hypotension during hemapheresis over a 4.5 year period reflecting forty-four hypotensive episodes were selected. The initial phase of each hemapheresis procedure provided baseline MAP and blood pressure (BP) measurements as control values. BP and MAP were then determined at the onset of subjective hypotension and compared to one another by using regression and sensitivity analyses. Correlation coefficients between SBP and MAP were found to be 0.8097 in baseline normotensive patients and 0.7725 in hypotensive patients. Sensitivity in the detection of hypotension was 0.09% for SBP equal to 80 mmHg and 56.81% for MAP equal to 70 mmHg. An SBP of 80 mmHg or less was therefore concluded to be a less sensitive and physiologically less appropriate measurement of hypotension than MAP. As a single value less than 70 mmHg or a series of successive measurements trending downward toward 70 mmHg, MAP provides an objective assessment of hypotension that may precede hemodynamic decompensation.     

Can better information increase hemapheresis?

We created a questionnaire in order to understand why donors generally did not want to give plasma and platelets the first time they were asked to donate. The hypothesis is that donors have a negative perception of hemapheresis due to insufficient information about procedures and emocomponent use. We collected 745 Questionnaires in the Marche and Abruzzo regions from February to April 2001. Results show that donors have an unfavourable perception of the hemapheresis compared to blood donation. We found differences in donors' perception between all kinds of donations regarding these aspects: (1) information about donation procedures, (2) awareness of emocomponent use, (3) importance of different kinds of donation, (4) availability of donors in relation to length of donations, (5) level of safety (regarding the possibility to contracting some viruses and also regarding possible immediate side-effects), (6) level of importance for saving lives. A key factor in determining an unfavourable perception of hemapheresis is the information level; in fact we found by linear regression that the information level affects the perception of safety and donation importance. These differences of perception show that there are prejudices about hemapheresis which are caused by a lack of Information. So we are convinced, also by statistical analysis, that better information is the most effective way to increase hemapheresis.     

A survey of therapeutic hemapheresis in Norway year 2000.

In a survey of therapeutic hemapheresis in Norway, we sent a questionnaire to all regional and central hospitals, asking about hemapheresis activities, patients, indications, and adverse events. All units responded to the questionnaire: 17 dialysis units, 7 blood units, and 2 specialized units for stem cell apheresis. In total, they performed 2141 procedures that is 5.0 stem cell collections and 42.5 therapeutic apheresis procedures per 100,000 inhabitants. The most frequent indications were Guillain-Barré syndrome, hypercholesterolemia, and myasthenia gravis. Adverse effects were frequent, but mild. Dialysis units performed a majority of the procedures, leading to an extensive use of filtration techniques.     

血液成分单采术在血液病中的应用及不良反应的观察

目的 初步探讨血液成分单采术在血液病治疗中的应用并观察其不良反应.方法 对524例患者应用CS-3000 plus血细胞分离机进行916次治疗性血液成分单采,根据病人情况选择不同细胞收集程序,分析临床效果和实验室指标的改善情况,并分析其不良反应及处理措施.结果 行血细胞单采术后210例高白细胞患者白细胞由(230.1±48.5)×109/L降至(49.3±10.0)×109/L;123例真性红细胞患者血红蛋向由(216.0±23.0)g/L降至(150.0±12.0)g/L,红细胞由(7.1±0.5)×1012/L降至(4.3±O.8)×1012/L;158例高血小板患者血小板由(1 080.0±314.0)×109/L降至(341.0±82.0)×109/L,治疗前后差异均有统计学意义(P<0.01).32例血栓性血小板减少性紫癜患者行血浆置换后,90.6%患者临床症状、体征及实验室指标均明显改善.少部分患者出现枸橼酸盐中毒(3.0%)、低血容量休克(0.7%)、过敏反应(4.6%)等不良反应,经对症处理后均得以缓解.结论 利用血细胞分离机进行治疗性血液成分单采术和血浆置换术可迅速缓解临床症状,减少并发症的发生,疗效肯定且安全可靠,不良反应少,并对提高临床药物治疗效果有很大意义.     

Sepsis syndromes: understanding the role of innate and acquired immunity

An intact innate and acquired immune response are essential for defeating systemic microbial infections. Recognition molecules, inflammatory cells, and the cytokines they produce are the principal means for host tissues to recognize invading microbes and to initiate intercellular communication between the innate and acquired immune systems. However, activation of host innate immunity may also occur in the absence of microbial recognition, through expression of internal "danger" signals produced by tissue ischemia and necrosis. When activation of the innate immune system is severe enough, the host response itself can propel the patient into a systemic inflammatory response syndrome (SIRS), or even multiple system organ failure (MSOF) and shock. Although most patients survive the initial SIRS insult, these patients remain at increased risk of developing secondary or opportunistic infections because of the frequent onset of a compensatory anti-inflammatory response syndrome (CARS). The initial activation of the innate immune response often leads to macrophage deactivation, T-cell anergy, and the rapid apoptotic loss of lymphoid tissues, which all contribute to the development of this CARS syndrome and its associated morbidity and mortality. Initial efforts to treat the septic patient with anticytokine therapies directed at the SIRS response have been disappointing, and therapeutic efforts to modify the immune response during sepsis syndromes will require a more thorough understanding of the innate and acquired immune responses and the increased apoptosis in the lymphoid tissue.     

Gene transfer approaches in cancer immunotherapy

The idea of enhancing or establishing effective immune response against endogenously developed tumor cells is not novel. More than a hundred years ago, bacterial components were used to develop antitumor immune response. Later, when a number of immune system-effecting cytokines had been discovered, they were used for systemic treatment of cancer patients. However, systemic treatment often resulted in even negative outcome. Recent developments of genetic approaches of cell modifications allowed developing of modern techniques of targeted tumor cell elimination. In the present paper, we review modern trends of the antitumor response enhancement based on immunoregulatory gene transfer into different cell types both in vivo and in vitro. Almost all these approaches are based on the activation of the adaptive arm of the immune system in response to tumor cells. However, recent studies indicate that the innate arm of the immune system, as well as adaptive arm, is involved in tumor suppression. The innate immune system uses nonrearranging germline receptors, which could trigger cellular effector responses that are conditional (or instructive) to the subsequent adaptive immune response. Last years' viewpoints on 'self' and 'non-self' recognition and primary induction of the immune response have changed. The key role of lymphocytes is pathogen recognition and, following immune response induction, switched on the central role of dendritic cells in 'non-self' recognition and induction of both innate and adaptive responses. Moreover, innate response is supposed to be an essential starting point in induction of successful and effective acquired response. Most cancer vaccines do not have 'non-self' marks presentation due to their endogenous origin, thus lacking their effectiveness in the induction of the specific long-lasting immune response. Taking this point into consideration, we can conclude that to make cancer vaccine more effective we have to present tumor antigens, together with the molecules that can potentially activate downstream 'non-self' recognition events not in parallel, but as a consequence of tumor antigen processing and presentation.     

白细胞功能多极化及其意义

免疫与造血是实验血液学的基本课题之一。免疫功能是白细胞的主要功能,免疫反应的多样性和复杂性令人困惑。30年前发现的免疫细胞的功能性极化促进了对淋巴细胞分化的研究,近年来对淋巴细胞、单核/巨噬细胞功能多极化的研究为阐明免疫细胞的调控网络奠定了基础,为阐明免疫反应的多样性和复杂性提供了线索,也为深入研究造血细胞的分化拓展了思路。本文对淋巴细胞、单核/巨噬细胞和树突细胞的多极化及其作用和意义,尤其是在细胞因子风暴和白血病、肿瘤的前炎症状态发生中的可能作用进行评述。     

Peripheral blood lymphocyte numbers, lymphocyte proliferative responses in vitro, and serum immunoglobulins in regular hemapheresis donors

Selected tests of lymphoid function were used to screen a population of volunteer hemapheresis donors. Testing included: 1) absolute lymphocyte numbers, and percentage of T-cell, B-cell, and mononuclear phagocytes, 2) serum immunoglobulins, and, 3) in vitro proliferative responses to lectin mitogens (phytohemagglutinin, concanavalin A, and pokeweed mitogen), soluble antigens (staphylococcal filtrate, candida, and streptococcal varidase), and cell-bound alloantigens (mixed lymphocyte culture). A control population of first-time plateletpheresis donors was examined similarly. Regular donors manifested a small but statistically significant decrease in absolute lymphocyte counts (p less than 0.02), and IgM (p less than 0.02) compared to controls. Leukapheresis donors also manifested significant decreases in percentage of T cells (p less than 0.02). These findings are qualitatively similar to changes reported following intensive lymphocytapheresis and indicate the need for conservative policies regarding donation frequency in hemapheresis programs.     

Novel immunotherapeutic approaches for treatment of infertility

One of the most important reasons of infertility and human reproductive failure is related to uncontrolled immunological response of maternal immune system to early embryo or fetus, that cause rejection of this semi-allograft. Therefore, a tolerance in the immune system is essential to modulate the reactions against the fetus to avoid rejection. The immune system imbalance during implantation or pregnancy may lead to implantation failure or miscarriage. So, use of immunosuppressive or immunomodulator agents can be helpful to prevent immunological attack. Initially, there was a focus on steroids like prednisolone or intralipids in treatment of miscarriage that suppressed the activity of most immune cells, Intravenous Immunoglobulin (IVIG) was then introduced with various mechanisms. Nowadays, novel and specific strategies are established such as monoclonal antibodies and cytokines. More recently, Tacrolimus and Cyclosporine, which were utilized in prevention of transplantation reject, are used as immunosuppressive factors in modulation of immune responses against the fetus. This review is focused on the main immunotherapeutic methods of infertility treatment.     

A critical role for Fas ligand in the active suppression of systemic immune responses by ultraviolet radiation

Induction of antigen-specific suppression elicited by environmental insults, such as ultraviolet (UV)-B radiation in sunlight, can inhibit an effective immune response in vivo and may contribute to the outgrowth of UV-induced skin cancer. Although UV-induced DNA damage is known to be an initiating event in the immune suppression of most antigen responses, the underlying mechanism(s) of such suppression remain undefined. In this report, we document that Fas ligand (FasL) is critical for UV-induced systemic immune suppression. Normal mice acutely exposed to UV exhibit a profound suppression of both contact hypersensitivity and delayed type hypersensitivity (DTH) reactions and the development of transferable antigen-specific suppressor cells. FasL-deficient mice exposed to UV lack both transferable suppressor cell activity and primary suppression to all antigens tested, with the exception of the DTH response to allogeneic spleen cells. Interestingly, suppression of this response is also known to occur independently of UV-induced DNA damage. Delivery of alloantigen as protein, rather than intact cells, restored the requirement for FasL in UV-induced immune suppression of this response. These results substantiate that FasL/Fas interactions are essential for systemic UV-induced suppression of immune responses that involve host antigen presentation and suggest an interrelationship between UV-induced DNA damage and FasL in this phenomenon. Collectively, our results suggest a model whereby UV-induced DNA damage disarms the immune system in a manner similar to that observed in immunologically privileged sites.     

Essential role of lymph nodes in contact hypersensitivity revealed in lymphotoxin-alpha-deficient mice

Lymph nodes (LNs) are important sentinal organs, populated by circulating lymphocytes and antigen-bearing cells exiting the tissue beds. Although cellular and humoral immune responses are induced in LNs by antigenic challenge, it is not known if LNs are essential for acquired immunity. We examined immune responses in mice that lack LNs due to genetic deletion of lymphotoxin ligands or in utero blockade of membrane lymphotoxin. We report that LNs are absolutely required for generating contact hypersensitivity, a T cell-dependent cellular immune response induced by epicutaneous hapten. We show that the homing of epidermal Langerhans cells in response to hapten application is specifically directed to LNs, providing a cellular basis for this unique LN function. In contrast, the spleen cannot mediate contact hypersensitivity because antigen-bearing epidermal Langerhans cells do not access splenic white pulp. Finally, we formally demonstrate that LNs provide a unique environment essential for generating this acquired immune response by reversing the LN defect in lymphotoxin-alpha(-/)- mice, thereby restoring the capacity for contact hypersensitivity.     

Fighting in a wasteland: deleterious metabolites and antitumor immunity

As cancers progress, they produce a local environment that acts to redirect, paralyze, exhaust, or otherwise evade immune detection and destruction. The tumor microenvironment (TME) has long been characterized as a metabolic desert, depleted of essential nutrients such as glucose, oxygen, and amino acids, that starves infiltrating immune cells and renders them dysfunctional. While not incorrect, this perspective is only half the picture. The TME is not a metabolic vacuum, only consuming essential nutrients and never producing by-products. Rather, the by-products of depleted nutrients, “toxic” metabolites in the TME such as lactic acid, kynurenine, ROS, and adenosine, play an important role in shaping immune cell function and cannot be overlooked in cancer immunotherapy. Moreover, while the metabolic landscape is distinct, it is not unique, as these toxic metabolites are encountered in non-tumor tissues, where they evolutionarily shape immune cells and their response. In this Review, we discuss how depletion of essential nutrients and production of toxic metabolites shape the immune response within the TME and how toxic metabolites can be targeted to improve current cancer immunotherapies.     

Immunotherapy with plasmid DNA encoding mycobacterial hsp65 in association with chemotherapy is a more rapid and efficient form of treatment for tuberculosis in mice

Tuberculosis (TB) remains a threat for public health, killing around 3 million people a year. Despite the fact that most cases can be cured with antibiotics, the treatment is long and patients relapse if chemotherapy is not continued for at least 6 months. Thus, a better characterization of the working principles of the immune system in TB and identification of new immunotherapeutic products for the development of shorter regimens of treatment are essential to achieve an effective management of this disease. In the present work, we demonstrate that immunotherapy with a plasmid DNA encoding the Mycobacterium leprae 65 kDa heat-shock protein (hsp65) in order to boost the efficiency of the immune system, is a valuable adjunct to antibacterial chemotherapy to shorten the duration of treatment, improve the treatment of latent TB infection and be effective against multidrug-resistant bacilli (MDR-TB). We also showed that the use of DNA-hsp65 alone or in combination with other drugs influence the pathway of the immune response or other types of inflammatory responses and should augment our ability to alter the course of immune response/inflammation as needed, evidencing an important target for immunization or drug intervention.     

Risk of AIDS-related virus (human immunodeficiency virus) transmission through apheresis procedures

Since exposure to blood products occurs on a daily basis during hemapheresis, the acquired immunodeficiency syndrome (AIDS) epidemic has a serious impact both for patients undergoing apheresis procedures as well as for health professionals working in the field. We studied serum samples from 110 patients who underwent therapeutic plasmapheresis for a variety of diseases not related to AIDS for the presence of antibodies to human immunodeficiency virus (HIV). Exchange fluids used in the majority of the patients were plasma protein fraction and 5% human albumin. Four patients received only fresh-frozen plasma. Fifty-five patients also received IV gammaglobulin. The follow-up period exceeded 24 months. All patients who did not belong to any known high-risk group for AIDS were negative for HIV antibodies prior to treatment and remained negative at last follow-up. Seven patients were homosexual men. All seven were seropositive prior to plasmapheresis and remained so throughout the treatment period. Seven health professional working in a busy haemapheresis unit were followed for 2 1/2 years. All remain HIV seronegative with normal immune function. These data indicate that transmission of HIV is unlikely through haemapheresis procedures.     

Pathogenesis and treatment of immune-mediated renal disease

There is now convincing evidence to suggest that most forms of glomerulonephritis and tubulointerstitial nephropathy involve the immune system in the destructive process. Such involvement can be mediated by a humoral immune response, a cell-mediated immune response, or a coordinated response of both limbs of the immune system derived from complementary T- and B-cell interactions.     

The new B7s: playing a pivotal role in tumor immunity

B7-H1, B7-DC, B7-H2, B7-H3, and B7-H4, all new additions to the B7 family, here termed "the new B7s," are emerging as important tools in directing immune function; each with unique, yet often overlapping functions. Clearly, each B7 molecule has developed its own indispensable niche in the immune system. The expression of both stimulatory and inhibitory B7 molecules seems to play an essential role in regulating the immune response to transformed cells through a variety of mechanisms. As specific niches of B7 family members continue to be dissected, their diagnostic and therapeutic potential becomes ever more apparent. In this review, we will discuss the role of the new B7s in activation and inhibition of antitumor immune responses, their prospects in diagnostics, and also potential and developing immunotherapy protocols.