Changes in phagocytosis and expression of microglial cells in craniocerebral injury mice models

The objective of this study was to investigate the changes in phagocytic function and expression quantities of CD11b and tumor necrosis factor-α (TNF-α) among microglia cells of craniocerebral injury mice. Modified Feeney method was used to establish the craniocerebral injury mice models. Twenty-one male SPF mice were divided into a control group and a trauma group. The scalp was incised and a bone window was opened in the control group without cerebral injury. In the trauma group, the mice were sacrificed after the craniocerebral injury at 1, 3, 6, 12, 24 and 48 h to make frozen sections of cerebral tissues. The phagocytic rate of microglia cells was observed by using fluorescent microsphere. The changes in the expression quantities of CD11b and TNF-α were detected by enzyme-linked immuno sorbent assay (ELISA). The phagocytic ability of the microglia cells after the craniocerebral injury increased at 1 h after injury compared with that of the control group (P less than 0.01). The expression of surface antigen CD11b of the microglia cells and the expression of TNF-α increased at 1, 3, 6, 12, 24 and 48 h after the injury compared with those of the control group (P less than 0.01). The phagocytic ability of the microglia cells increased. The expressions of CD11b and TNF-α were also gradually enhanced in the acute phase after craniocerebral injury, and then gradually decreased to the normal level. The expressions of CD11b and TNF-α indicated a high consistency with the changing trend of the phagocytic ability, suggesting that the microglia cells may participate in the regulation of the inflammatory process of the central nervous system through absorbing apoptotic cells and increasing and secreting inflammatory and anti-inflammatory factors.

Solitary Cranial Langerhans Cell Histiocytosis: Two case reports

Langerhans cell histiocytosis (LCH) is a proliferation of Langerhans cells intermixed with inflammatory cells, in particular eosinophils, that may manifest as a unisystem (unifocal or multifocal) or multisystem disease. We describe the clinical and histologic spectrum of LCH of the orbit and skull in our two cases. Both cases had unifocal erosive skull lesions with a history of trauma. Typical histologic features included numerous histiocytes with varying degrees of giant cell formation and scattered eosinophilic granulocytes. The presence of Langerhans cells was confirmed by CD1a and S100 immunohistochemistry. LCH has an excellent prognosis when treated with surgical resection, steroids and radiotherapy or chemotherapy. One of our patients is disease free at 7 year follow-up and one patient had regression of lesion on follow-up.

[Comparative evaluation of effectiveness of the combined immunocorrection in patients suffering severe craniocerebral trauma]

Comparative estimation of clinical efficacy of various immunocorrection schemes for the immune state correction was conducted in 106 patients in conditions ofsevere craniocerebral trauma (SCCT), combined application of immunofan and intravenous laser irradiation of blood (IVLIB). In 32 patients (I group) a standard intensive therapy (SITH) was conducted: in 21 (II group)--immunofan was applied additionally; in 25 (III group)--in addition to SITH IVLIB was conducted; in 28 (IV group)--immunofan solution was infused and sessions of IVLIB (3 - 4 sessions a day) on a background of SITH were conducted. The immunity indices were analyzed on the 1 - 2, 5 - 6-th and 9 -10-th days after trauma. Estimation of the combined therapy efficacy have shown, that in SCCT she renders a significant immunocorrecting effect on the 5 - 6-th days already, on the 9 - 10-th days the immune state parameters were really normalized, reduction of the complications rate by 26% and of lethality by 8.6% was noted.

[The dynamics of the immune status indices in conditions of cranio-cerebral trauma on background of a streptozotocin-induced diabetes mellitus in experiment]

Peculiarities of changes in the immune status in a cranio-cerebral trauma (CCT) on a background of a streptozotocin-induced diabetes mellitus (DM) were studied up. After CCT there are noted the inhibition of predominantly cellular link of immunity, accompanied by reduction of the CD3+ lymphocytes quantity, as well as lymphocytes of the main subpopulations CD4+ and CD8+, CD16+, reduction of the neutrophils phagocytic activity, a complement titer enhancement. Experimental CCT do not cause the essential changes in a CD19+ lymphocytes quantity. The CCT modelling on a background of a streptozotocin-induced DM causes the immune deficiency deepening, in a cellular and humoral links together, significant reduction of activity of a phagocytosis system and complement as well.

[The humoral immunity changes in experimental cranio-cerebral trauma, concurrent with diabetes mellitus]

The results of studying in dynamics of the humoral immunity indices were adduced in experimental cranio-cerebral truma (CCT) in conjunction with diabetes mellitus (DM). Peculiarities of the immune answer while the period of an acute reaction on trauma and early signs of posttraumatic period have been characterized by reduction of content in the main classes of immunoglobulins IgA, IgM, IgG and enhancement of the circulating immune complexes (CIC) concentration. Experimental DM was accompanied by raising of functional activity of humoral immunity in accordance with immunoglobulins level and CIC. The specificity of changes in humoral immunity in conditions of CCT on the DM background consisted of more profound lowering of the immunoglobulins level and rapid enhancement of the CIC content.

[Invasive trichosporonosis caused by Trichosporon asahii in a polytraumatized neurosurgical patient: case report]

Trichosporon asahii (formerly T. beigelii) is a rare cause of human infections with very varied clinical manifestations ranging from superficial infections to severe and systemic diseases. T. asahii is a life-threatening opportunistic pathogen especially for granulocytopenic, immunocompromised and immunodeficient patients. It is the possible cause of summer-type hypersensitivity pneumonitis in Japan and systemic infections in transplant patients, patients on corticosteroid therapy, patients with solid tumors and burn patients. Cases of infection in non-immunocompromised surgical patients and patients with long-term stay in ICU are described in the literature. We report on T. asahii fungemia in a polytraumatized neurosurgical patient with long-term stay in the hospital. Urinary tract was the source of fungemia, with the same pathogen isolated from urine and blood at the same time. In the Referral Center for Systemic Mycoses, Croatian Institute of Public Health, Zagreb, the strain from the urine and blood culture was identified as T. asahii, with good susceptibility to fluconazole, voriconazole and 5 fluorocytosine, reduced susceptibility to itraconazole and resistance to amphotericin B. The patient responded to fluconazole therapy very well. Since systemic trichosporonoses are generally associated with immunocompromised patients (hematologic, granulocytopenic and AIDS patients), this case confirms the possibility of infection with this pathogen in patients with long-term hospital stay and reduced local immunity, but without classic immunodeficiency.

Damage control immunoregulation: is there a role for low-volume hypertonic saline resuscitation in patients managed with damage control surgery?

Hypertonic saline (HTS) is beneficial in the treatment of head-injured patients as a result of its potent cytoprotective effects on various cell lines. We hypothesize that low-volume resuscitation with 3 per cent HTS, when used after damage control surgery (DCS), improves outcomes compared with standard resuscitation with isotonic crystalloid solution (ICS). This is a 4-year retrospective review from two Level I trauma centers. Patients included had 10 units or more of packed red blood cells during initial DCS. On arrival to the trauma intensive care unit (TICU), patients were resuscitated with low-volume 3 per cent HTS or with conventional ICS. A cohort analysis was performed comparing resuscitation strategies. Univariate analysis of continuous data was done with Student t test followed by multivariate analysis. Of 188 patients included, 76 were in the low-volume HTS group and 112 in the ICS group. Demographics were similar between the groups. Over the next 48 hours after DCS in HTS versus ISC groups, intravenous fluids were given: 1920 ± 455 mL versus 8400 ± 1200 mL (P < 0.0001); urine output was 4320 ± 480 mL versus 1940 ± 480 mL(P < 0.0001); mean TICU length of stay was 10 ± 8 versus 16 ± 15 days (P < 0.01); prevalence of acute respiratory distress syndrome was 4.0 versus 13.4 per cent (P = 0.02); sepsis was 6.6 versus 15.2 per cent (P = 0.06); multisystem organ failure was: 2.6 versus 16.1 per cent (P < 0.01); and 30-day mortality was 5.3 versus 15.2 per cent (P = 0.03). There was no difference for prevalence of renal failure at 5.3 versus 3.6 per cent (P = 0.58). Low-volume resuscitation with HTS administered after DCS on arrival to the TICU may have a protective effect on the polytrauma patient. We believe that this study demonstrates a role for low-volume resuscitation with HTS to improve outcomes in patients undergoing DCS.

The effects of Rhizoma drynariae on interleukin-2 and T-lymphocyte levels in rats after severe head injury

OBJECTIVE

To investigate the effects of Rhizoma drynariae on the levels of interleukin-2(IL-2) and T-lymphocyte subset in rats with severe head injury (SHI).

METHODS

72 Sprague Dawley (SD) rats were randomly divided into 3 groups: control group, model group, and R. drynariae group. The experimental group received intragastrical infusions of with aqueous R. drynariae extract four hours after SHI while the other groups were administered with equivalent volumes of physiological saline. Infusions were administered to the 3 groups once a day for 7 d. IL-2 and T-lymphocyte (CD3, CD4, CD8) levels were measured at 24, 72, and 168 h after initial infusion.

RESULTS

The levels of IL-2 and CD4 T cells reduced obviously after 24 h in the model group (P<0.05), but recovered to the levels of the control group after 72 h, and remained elevated after 168 h. In the R. drynariae group, IL-2 and CD4 levels were did not decrease while the level of CD8 T cells was reduced significantly (P<0.05).

CONCLUSIONS

R. drynariae can protect against immune dysfunction or improve immunity in rats with severe head injury (SHI).

Severe traumatic head injury affects systemic cytokine expression

BACKGROUND

The neuroimmunologic effect of traumatic head injury remains ill-defined. This study aimed to characterize systemic cytokine profiles among traumatically injured patients to assess the effect of traumatic head injury on the systemic inflammatory response.

STUDY DESIGN

For 5 years, 1,022 patients were evaluated from a multi-institutional Trauma Immunomodulatory Database. Patients were stratified by presence of severe head injury (SHI; head Injury Severity Score ≥4, n = 335) vs nonsevere head injury (NHI; head Injury Severity Score ≤3, n = 687). Systemic cytokine expression was quantified by ELISA within 72 hours of admission. Patient factors, outcomes, and cytokine profiles were compared by univariate analyses.

RESULTS

SHI patients were more severely injured with higher mortality, despite similar ICU infection and ventilator-associated pneumonia rates. Expression of early proinflammatory cytokines, interleukin-6 (p < 0.001) and tumor necrosis factor-α (p = 0.02), was higher among NHI patients, and expression of immunomodulatory cytokines, interferon-γ (p = 0.01) and interleukin-12 (p = 0.003), was higher in SHI patients. High tumor necrosis factor-α levels in NHI patients were associated with mortality (p = 0.01), increased mechanical ventilation (p = 0.02), and development of ventilator-associated pneumonia (p = 0.01). Alternatively, among SHI patients, high interleukin-2 levels were associated with survival, decreased mechanical ventilation, and absence of ventilator-associated pneumonia.

CONCLUSIONS

The presence of severe traumatic head injury significantly alters systemic cytokine expression and exerts an immunomodulatory effect. Early recognition of these profiles can allow for targeted intervention to reduce patient morbidity and mortality.

Immune suppression and isolated severe head injury: a significant clinical problem

In the developed world, trauma is the principal cause of death under the age of 40 and is the third largest overall killer. In the UK, approximately 25,000 people die each year as a result of major injury, 25% as a result of head injuries alone. Despite improved diagnosis and management, infection remains the commonest complication in those patients surviving the initial injury. Some 5% are reported to die as a result of septic complications. Prolonged periods of intensive care and respiratory support predispose to infective respiratory complications. These patients in the absence of significant systemic injury and, as a result of severe head injury, are unable to mount an effective immune response. This literature review examines the changes that have been reported to occur in the immune system following isolated severe head injury and explores the relationship these changes may have to the increased development of infective complications.

Predictive value of leucocytosis in head trauma

AIM

Head trauma is associated with an acute phase response which is characterized by leucocytosis due to increased levels of catecholamine and cortisol. Early edema formation following severe head injury may also be associated with microglia activation. Therefore, increased white blood cell (WBC) count after head trauma may be a predictive parameter of the severity of craniocerebral trauma.

MATERIAL AND METHODS

We retrospectively studied 59 patients with severe, moderate and minor injury between February 2007 and March 2009. WBC counts of all patients were obtained within the first day of their admission. All patients were divided into separate groups according to their Glasgow Coma Scale (GCS) scores and hospital stay durations. Their CT progressions and Glasgow Outcome Scale (GOS) scores were also assessed. The relationship between these parameters and WBC counts were evaluated by statistical methods.

RESULTS

There was a favorable correlation between WBC counts of the patients and GCS scores (pI0.01), hospital stay (p=0.006), CT progression (p < 0.01) and GOS scores (p < 0.01).

CONCLUSION

AWBC count exceeding 17.5 x 106/l has a predictive value for poor GCS score, and long hospital stay. CT progression tends to be seen in patients with moderate and severe head injury.

Isolated head injury in children affects the neutrophil function and lymphocyte count

BACKGROUND

Outcomes of treatment of postinjury complications remain unsatisfactory and research continues into the impact of trauma on innate and acquired immunity. The aim of our study was to describe how head injury affects a child's immunity by measuring the neutrophil function and lymphocytes subsets.

METHODS

The peripheral blood of 16 children with head trauma (Glasgow Coma Score < or =9) was examined. The blood samples were collected on the first and on the seventh day after trauma. The production of reactive oxygen species (ROS), spontaneous and stimulated, the expression of CD11b, and the lymphocyte subpopulations were measured. The blood of healthy children was studied as control. The impact of endotracheal intubation on the examined parameters was analyzed as well.

RESULTS

Head trauma leads to the increase of leukocytosis; the total production of ROS by peripheral blood neutrophils does not change after head injury. Correction of the results according to the number of neutrophils revealed a significant decrease in ROS production by a single neutrophil. The expression of adhesion molecule CD11b did not change. Head injury in children causes the decrease of the total lymphocyte count, CD3, CD4, CD8, and natural killer cells count on both the first and the seventh postinjury day. On the seventh day the significant decrease of natural killer cells subset was observed. The CD4/CD8 ratio increased from 1.5 (the first day) to 2.5 (the seventh day). The intubation did not affect the examined parameters.

CONCLUSIONS

After head injury, total ROS production and adhesion molecule CD11b expression remained unchanged when compared with control. The study did not demonstrate evidence for neutrophil activation in patients with head injuries. The total lymphocyte count was found to be decreased and the composition of lymphocytes' subsets was deeply impaired.

Systemic complications after head injury: a clinical review

Non-neurological organ dysfunction is common after traumatic brain injury and is an independent contributor to morbidity and mortality. It represents a risk factor that is potentially amenable to treatment, and early recognition and prompt intervention may improve outcome. This article reviews the current evidence for the mechanisms and treatment of non-neurological organ dysfunction after head injury.

The potential of melatonin in reducing morbidity-mortality after craniocerebral trauma

Craniocerebral trauma (CCT) is the most frequent cause of morbidity-mortality as a result of an accident. The probable origins and etiologies are multifactorial and include free radical formation and oxidative stress, the suppression of nonspecific resistance, lymphocytopenia (disorder in the adhesion and activation of cells), opportunistic infections, regional macro and microcirculatory alterations, disruptive sleep-wake cycles and toxicity caused by therapeutic agents. These pathogenic factors contribute to the unfavorable development of clinical symptoms as the disease progresses. Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine endogenously produced in the pineal gland and in other organs and it is protective agent against damage following CCT. Some of the actions of melatonin that support its pharmacological use after CCT include its role as a scavenger of both oxygen and nitrogen-based reactants, stimulation of the activities of a variety of antioxidative enzymes (e.g. superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase), inhibition of pro-inflammatory cytokines and activation-adhesion molecules which consequently reduces lymphocytopenia and infections by opportunistic organisms. The chronobiotic capacity of melatonin may also reset the natural circadian rhythm of sleep and wakefulness. Melatonin reduces the toxicity of the drugs used in the treatment of CCT and increases their efficacy. Finally, melatonin crosses the blood-brain barrier and reduces contusion volume and stabilizes cellular membranes preventing vasospasm and apoptosis of endothelial cells that occurs as a result of CCT.

The role of inflammation in CNS injury and disease

For many years, the central nervous system (CNS) was considered to be 'immune privileged', neither susceptible to nor contributing to inflammation. It is now appreciated that the CNS does exhibit features of inflammation, and in response to injury, infection or disease, resident CNS cells generate inflammatory mediators, including proinflammatory cytokines, prostaglandins, free radicals and complement, which in turn induce chemokines and adhesion molecules, recruit immune cells, and activate glial cells. Much of the key evidence demonstrating that inflammation and inflammatory mediators contribute to acute, chronic and psychiatric CNS disorders is summarised in this review. However, inflammatory mediators may have dual roles, with detrimental acute effects but beneficial effects in long-term repair and recovery, leading to complications in their application as novel therapies. These may be avoided in acute diseases in which treatment administration might be relatively short-term. Targeting interleukin (IL)-1 is a promising novel therapy for stroke and traumatic brain injury, the naturally occurring antagonist (IL-1ra) being well tolerated by rheumatoid arthritis patients. Chronic disorders represent a greater therapeutic challenge, a problem highlighted in Alzheimer's disease (AD); significant data suggested that anti-inflammatory agents might reduce the probability of developing AD, or slow its progression, but prospective clinical trials of nonsteroidal anti-inflammatory drugs or cyclooxygenase inhibitors have been disappointing. The complex interplay between inflammatory mediators, ageing, genetic background, and environmental factors may ultimately regulate the outcome of acute CNS injury and progression of chronic neurodegeneration, and be critical for development of effective therapies for CNS diseases.

Immunological and clinical aspects of cell therapy in the treatment of aftereffects of craniocerebral injury

Cell suspension consisting of cells from immature nervous and hemopoietic tissues was transplanted subarachnoidally to patients with craniocerebral injury aftereffects. In some patients cell therapy led to immune sensitization to donor antigens, detected by the leukocyte migration inhibition test. No signs of tissue-destructive autoimmune reactions were detected in patients receiving cell therapy. Follow-up of 56 patients showed that cell therapy was associated with significant improvement of the neurological status. No serious complications of this treatment modality were observed. Presumably, cell therapy is a safe method which can be used in the treatment of craniocerebral injury aftereffects.

Impairment of lymphocyte function in head-injured rats: effects of standard and immune-enhancing diets for enteral nutrition

BACKGROUND

The metabolic response to head injury (HI) is characterized by a dysimmunity which may be a risk factor of a septic state. The use of immune enhancing diets (IEDs) could be a promising approach to improve immune functions. The aim of the study was to investigate the consequences of HI on lymphocyte function and to determine the effects of an enteral IED comparatively to a standard enteral nutrition.

METHOD

A rat model of HI by fluid percussion was used. Twenty-five male Sprague-Dawley rats were randomized into 4 groups: rats receiving standard chow diet ad libitum (AL), rats sustaining HI and receiving standard chow diet and enteral saline (HI), rats receiving the enteral standard diet Sondalis HP (HIS), and rats receiving the IED Crucial (HIC). The two enteral diets were infused continuously during 4 days after the HI and were isocaloric, isonitrogenous and isovolumic.

RESULTS

HI induced a thymus atrophy (HI vs. AL, P<0.05), and an impairment in lymphocyte CD25 receptor density responsiveness to stimulation. The IED blunted thymus atrophy and allowed to preserve the stimulation of blood and Peyer patches lymphocytes (HIC: Stimulated vs. Basal, P<0.05).

CONCLUSION

IED seems more adapted for preserving lymphocyte function than standard diet in HI patients.

An investigation of auto-reactivity after head injury

Murine models of CNS injury show auto-reactive T cell responses directed at myelin antigens, associated with improved neuronal survival and functional recovery. This pilot study shows, for the first time, that similar immune responses against myelin occur in human traumatic brain injury (TBI), with an expansion of lymphocytes recognising myelin basic protein observed in 40% of patients studied. "Reactive" patients did not have greater contusion volume on imaging, but were younger than the "unreactive" subgroup and tended towards a more favorable outcome. These findings are consistent with the concept of "beneficial autoimmunity".

[The importance of nutritional support for head injured patients]

Serious head injuries lead to any metabolic disorders such as, in particular a protein types cataolism and immunodepression. Early nutritional support for the patient in this case is definitely beneficial. It should be started as soon as the patient is out of danger. Enteral feeding should be preferred to parenteral feeding. In case of disorder of the bavel habit or of malabsorption, parenteral protein-energy intake should be prescribed for a short period. In case of neuroagression, a suppementary intake of amino-acids (glutamine, arginine) seems beneficial for a betten immuniy defence system.

[Traumatic brain injury: impact on timing and modality of fracture care]

Traumatic brain injury (TBI) represents the major "killing factor" after trauma in young individuals. Those patients who survive the initial injury are highly susceptible to secondary insults to the injured brain which are mainly caused by hypotension and/or hypoxia in the early resuscitative period. Furthermore, a potent inflammatory cascade is initiated within the injured brain which leads to the development of brain edema and delayed neuronal cell death. This profound endogenous neuroinflammatory response after TBI, which is phylogenetically aimed at repairing lesioned tissue and defending the brain from invading pathogens, is in large part responsible for the extent of secondary brain damage and adverse outcome. Thus, the optimal management of the multiply injured patient, based on a thorough understanding of the pathophysiological alterations after TBI, should avoid an iatrogenic "second hit" which may be devastating to the injured brain. The standard approach of "early total care" for isolated fractures should be strictly avoided in brain-injured patients in favor of an "orthopedic damage control" concept with temporary external fixation of long bone fractures and priority given to early transfer to intensive care. The present review provides an up-to-date overview on the neuroinflammatory pathophysiology of brain injury and its implications for an optimized concept of fracture care in TBI patients.

Miller-Fisher syndrome mimicking intracranial hypertension following head trauma

INTRODUCTION

Miller-Fisher syndrome (MFS) is a polyneuropathy with benign outcome characterized by ophthalmoplegia, limb ataxia and tendon areflexia. Impaired consciousness level and intracranial hypertension are very rare symptoms in MFS.

CASE REPORT

We describe the case of a 5-year-old girl who showed intracranial hypertension, transient coma and respiratory failure after mild head injury; moreover the patient showed mild ataxia, areflexia, ophthalmoplegia and autonomic disturbances. These symptoms were suggestive of MFS. Electrophysiologic studies and laboratory tests confirmed the diagnosis and immunoglobulins and steroids were given. The child showed a progressive clinical improvement and the final outcome was good.

CONCLUSION

This case, initially managed as trauma injury due to the presence of suggestive signs and clinical history, maskered an atypical presentation of Miller-Fisher syndrome, a rare disorder of central nervous system.

New indications for corticosteroids in intensive care units

In last years an increasing number of evidences has been gained that inflammatory response plays a major role in critical illness. The acronym SIRS (Systemic Inflammatory Response Syndrome) has been introduced to define the condition in which the inflammatory reaction exceeds local mechanisms of containment and inflammatory mediators invade the bloodstream causing systemic disturbances. Theoretically, the use of corticosteroids offers a potent tool to control the excess of inflammatory reaction, but initial trials on Adult Respiratory Distress Syndrome (ARDS), head trauma, and septic shock showed not only that mortality was unaffected, but also that morbidity could increase. Recently, however, some new studies have suggested that corticosteroids given at dosages lower than those initially tested, could positively affect late stages of ARDS by preventing pulmonary fibrosis, and septic shock by improving hemodynamics and facilitating the weaning from catecholamines. To date, it is not clear whether these effects are related to the correction of an adrenocortical dysfunction.

Changes in monocytic expression of aminopeptidase N/CD13 after major trauma

HLA-DR expression on monocytes as marker for monocytic function is severely depressed after major trauma. The membrane enzyme aminopeptidase N/CD13 can trigger help in antigen processing by MHC class II molecules of antigen-presenting cells. We determined the simultaneous expression of HLA-DR and CD13 on peripheral blood monocytes of patients with major trauma (injury severity score of > or =16). 1 : 1 conjugates of phycoerythrin (PE)-to-monoclonal antibody were used in combination with QuantiBRITE PE beads for a standardized quantification in terms of antibodies bound per cell (ABC). The very low expression of HLA-DR antigen on monocytes of patients at day 1 after major trauma confirmed previous results in the literature. Monocytic HLA-DR expression increased slowly to reach values in the lower range of healthy volunteers at day 14. Monocytic CD13 expression at day 1 showed values in the range of healthy volunteers, and a strong rise afterwards. Fourteen days after trauma, the monocytic expression of CD13 was still much higher than in the control group. Because lipopolysaccharide (LPS) and the anti-inflammatory cytokine interleukin (IL)-10 have been shown to be involved in the depressed HLA-DR expression on monocytes in trauma patients, we studied the in vitro effects of LPS and interleukin (IL)-10 on the expression of CD13 on monocytes prepared from the peripheral blood of healthy volunteers. Whereas a 3-day IL-10 treatment resulted in a down-regulation of both HLA-DR and CD13 expression on monocytes, LPS caused a down-regulation of HLA-DR but a rapid up-regulation of CD13 levels. Therefore we suggest that, with respect to monocytic CD13 expression, LPS rather than IL-10 could well be the explanation for monocytic surface molecules after severe injury, although other mediators with a CD13 regulating function have to be considered.

Mild hypothermia reduces expression of heat shock protein 60 in leukocytes from severely head-injured patients

BACKGROUND

Infectious complications are among the most serious problems that occur in severely head-injured patients treated with mild hypothermia. The mechanism underlying the susceptibility to infection has not been clarified. Heat shock protein (HSP) 60 has been reported to play an essential role in innate immunity. Thus, we conducted a study to clarify the impact of mild hypothermia on the expression of HSPs in polymorphonuclear leukocytes (PMNLs) in severely head-injured patients.

METHODS

Between September 1997 and November 1999, 17 severely head-injured patients with a Glasgow Coma Scale score of 8 or less at admission in whom intracranial pressure could be maintained below 20 mm Hg by conventional therapy were randomly assigned to two treatment groups: a mild hypothermia group (HT group, nine patients) and a normothermia group (NT group, eight patients). The HT group was subjected to mild hypothermia (intracranial temperature, 34 degrees C) for 48 hours followed by rewarming at a rate of 1 degrees C per day for 3 days, whereas the NT group was subjected to normothermia (intracranial temperature, 37 degrees C) for 5 days. Blood samples were serially obtained at three time points; days 0 to 1, days 2 to 5, and days 6 to 14 after head injury. We measured the expression of HSP27, HSP60, HSP70, and HSP90 by flow cytometry.

RESULTS

The two groups were similar with respect to prognostic factors, and there was no difference in clinical outcome. The expression of PMNL HSP60 in the HT group was significantly lower in all three time periods compared with that in the NT group (p < 0.05), whereas expression of the other HSPs did not differ significantly between the groups. The incidence of infectious complications was significantly increased in the HT group over that in the NT group (p < 0.05). In in vitro studies, PMNLs from 10 healthy volunteers were incubated at 37 degrees C, 34 degrees C, or 26 degrees C for 1 hour with sodium arsenite (100 micromol/L), an HSP inducer. The expression of HSP60 at 26 degrees C and 34 degrees C was significantly lower than that at 37 degrees C (p < 0.05), whereas expression of the other HSPs did not differ significantly at 26 degrees C, 34 degrees C, or 37 degrees C.

CONCLUSION

Mild hypothermia reduces the expression of HSP60 in PMNLs from severely head-injured patients. Thus, mild hypothermia may suppress innate immunity.

Influence of small mechanical head injuries on peripheral blood natural killer cytotoxicity (NKCC) in rats

Many neurophysiological experiments and some human's brain tissue stimulatory therapies require surgery intervention, which results in small mechanical skull and brain tissue injuries. Additionally, these procedures need some local or short general anaesthesia, which is not neutral for immune system action. Clinical data unambiguously shows that severe head and brain injuries and anaesthesia can suppress immunity. The aim of the present study was to investigate the influence of small mechanical skull and brain tissue injuries, accompanied by electrode fixation for experimental or therapeutic brain tissue stimulation, on peripheral blood natural killer cytotoxicity (NKCC) assessed in a 4h standard cytotoxic test. Additionally, we assessed a number of leukocytes, lymphocytes and large granular lymphocytes (LGL), which are NK cell subset and plasma corticosterone concentration. The results showed that small mechanical skull and meninges injuries or alone-administered Nembutal did not evoke any significant changes as those caused by electrode placement 4.2 mm below the skull surface. Deeper electrode fixation, 6.1; 7.6 and 8.4 mm below the skull surface, significantly increased NKCC (p < 0.05) and LGL number (p < 0.05) on the 3rd day after the electrode placement. Moreover, the results showed that some small brain tissue injuries could transiently influence the number of LGL and NKCC.

[Cerebral homeostasis disorder in patients with severe craniocerebral trauma during acute period]

Liquor distension, disorders of the cerebral hemodynamics as well as vegetative disorders and changes of immune reactivity in patients after a severe craniocerebral trauma are discussed. The examination of patients during the initial 10 days after trauma pointed at the relation of a cerebral trauma type with liquor distension, cerebral perfusion pressure, changes of the vegetative balance and with disorders of the auto-immune status. The most profound changes were observed in a severe craniocerebral trauma involving a severe cerebral contusion and compression.

Promising strategies to minimize secondary brain injury after head trauma

OBJECTIVE

To review novel therapeutic approaches in the treatment of severe traumatic brain injury.

DESIGN

Eighty-three studies were reviewed specific to the treatment of traumatic brain injury, in either experimental models or in patients.

CONCLUSION

Four therapeutic strategies appear to be the most promising approaches currently in clinical trials for severe traumatic brain injury: a) the novel pharmacologic agent dexanabinol; b) hypertonic saline; c) mild hypothermia; and d) decompressive craniectomy. Each of these therapies share the common feature of targeting multiple mechanisms, suggesting this may be an important factor to the development of a successful approach to severe traumatic brain injury.

Association between injury pattern of patients with multiple injuries and circulating levels of soluble tumor necrosis factor receptors, interleukin-6 and interleukin-10, and polymorphonuclear neutrophil elastase

BACKGROUND

Our knowledge about the bidirectional interactions between brain and whole organism after trauma is still limited. It was the purpose of this prospective clinical study to determine the influence of severe head trauma (SHT) as well as trauma in different anatomic injury regions on posttraumatic inflammatory mediator levels from patients with multiple injuries.

METHODS

Thirty-five healthy controls, 33 patients with an isolated SHT, 47 patients with multiple injuries without SHT, and 45 patients with both SHT and multiple injuries were studied. The posttraumatic plasma levels of soluble tumor necrosis factor receptors p55 and p75, interleukin (IL)-6, IL-10, and polymorphonuclear neutrophil (PMN) elastase were monitored using enzyme-linked immunosorbent assay technique. The influence of head injuries as well as thorax, abdomen, and extremity injuries on the mediator release from patients with multiple injuries was investigated by multivariate linear regression models.

RESULTS

The soluble tumor necrosis factor receptor p55/p75 ratio was significantly elevated within 3 hours of trauma in all three injury groups and returned to reference ratios after 12 hours. The lowest increase was found in patients suffering from an isolated SHT. Lowest mediator levels in this patient population were also found for IL-6, IL-10, and PMN elastase during the first 36 hours after trauma. Additional injuries to the head, thorax, abdomen, and extremity modulated mediator levels to a different degree. No specific effect was found for SHT when compared with other injury groups. Thorax injuries caused the quickest rise in mediator levels, whereas abdominal injuries significantly increased PMN elastase levels 12 to 24 hours after trauma.

CONCLUSION

Traumatic injuries cause the liberation of various mediators, without any specific association between anatomic injury pattern and the pattern of mediator release.

[The possible role of alpha 2-macroglobulin in regulating the immune components of the brain in tick-borne encephalitis]

In tick-borne encephalitis certain immunopathological reactions develop in the tissues of the central nervous system; alpha 2-macroglobulin may serve as the marker of the activity of these reactions. The dynamic study of liquor taken from 16 patients with the meningeal and focal forms of tick-borne encephalitis (TBE), 8 patients with severe craniocerebral traumas accompanied by meningitis and 10 patients with osteochondrosis was made. As revealed in this study, in TBE patients the level of alpha 2-macroglobulin increases 3.5-fold and remains stable during the acute period of the disease.

Correlation between serum IL-6 and CRP levels and severity of head injury in children

OBJECTIVE

To examine interleukin-6 (IL-6) and C-reactive protein (CRP) release in children with head injury (HI) and investigate if there is a correlation between the levels of these two proteins and the severity of HI.

DESIGN

Prospective clinical investigation.

SETTING

Eight-bed paediatric intensive care unit in a university hospital.

PATIENTS

Forty-five children were followed up for 4 days after HI and their serum IL-6 and CRP levels were measured.

MEASUREMENTS AND RESULTS

Peak serum IL-6 levels occurred 4 h postinjury, decreasing over time. CRP was normal 4 h after injury, then increased reaching peak levels in 48 h. Children with admission Glasgow Coma Scale (GCS) scores of 8 or less had higher IL-6 levels compared to children with GCS scores higher than 8, 4 and 12 h post-injury (p<0.01 and p<0.05, respectively). IL-6 was higher in children with admission PRISM scores of 10 or more than in those with PRISM scores lower than 10 at 4 and 12 h (p<0.05). CRP levels were higher in patients with GCS scores of 8 or less compared to patients with GCS scores higher than 8 at 24, 48 and 72 h (p<0.05, p<0.02 and p<0.02, respectively) . Patients with PRISM scores of 10 or more had higher CRP levels compared to those with PRISM scores lower than 10 at 24, 48 and 72 h (p<0.05). Peak CRP levels correlated well with peak IL-6 levels (r = 0.49, p<0.001). No correlation between IL-6 or CRP levels and mortality or clinical outcome was found.

CONCLUSIONS

Serum IL-6 and CRP levels are elevated in children with HI and there is a relation between the severity of HI and the levels of these proteins. There was no correlation between IL-6, CRP and outcomes of the patients.

Delayed intracranial hypertension: relationship to leukocyte count

OBJECTIVE

Secondary intracranial hypertension has been linked to leukocytosis. We examined our data bank containing physiologic recordings and outcome data of severely head injured patients to investigate the relationship between delayed increases in intracranial pressure (ICP), defined as occurring after a 12-hr period of normal ICP values, and leukocytosis.

DESIGN

A retrospective study of observational data.

SETTING

Regional neurosurgical unit and intensive care unit.

PATIENTS

Sixty-four patients suffered increased ICP >20 mm Hg. Thirty-five patients fulfilled selection criteria for delayed increases in ICP (group 1). Twenty-nine patients with increased ICP with no preceding or intervening periods of normal ICP were selected as a comparison group (group 2).

MEASUREMENTS AND MAIN RESULTS

Comparison of 12-month outcome revealed that 11% of group 1 patients died, with 49% remaining severely disabled, in contrast to group 2, where 35% of patients died and 14% were left severely disabled (p = .021). The pattern of outcome was independent of monitoring time, or injury severity. Regression modeling was performed for prediction of delayed increase in ICP. Of 46 patients with an initial increase then decrease in leukocyte count in the first 48 hrs, 65% experienced delayed increases in ICP, as compared with 18% of the 11 patients without this pattern p = .01 1).

CONCLUSIONS

Patients with delayed increases have a significantly different pattern of outcome. Change in leukocyte count from admission to day 2 is a significant predictor of such a delayed increase.

Increased mRNA levels for components of the lysosomal, Ca2+-activated, and ATP-ubiquitin-dependent proteolytic pathways in skeletal muscle from head trauma patients

The cellular mechanisms responsible for enhanced muscle protein breakdown in hospitalized patients, which frequently results in lean body wasting, are unknown. To determine whether the lysosomal, Ca2+-activated, and ubiquitin-proteasome proteolytic pathways are activated, we measured mRNA levels for components of these processes in muscle biopsies from severe head trauma patients. These patients exhibited negative nitrogen balance and increased rates of whole-body protein breakdown (assessed by [13C]leucine infusion) and of myofibrillar protein breakdown (assessed by 3-methylhistidine urinary excretion). Increased muscle mRNA levels for cathepsin D, m-calpain, and critical components of the ubiquitin proteolytic pathway (i.e., ubiquitin, the 14-kDa ubiquitin-conjugating enzyme E2, and proteasome subunits) paralleled these metabolic adaptations. The data clearly support a role for multiple proteolytic processes in increased muscle proteolysis. The ubiquitin proteolytic pathway could be activated by altered glucocorticoid production and/or increased circulating levels of interleukin 1beta and interleukin 6 observed in head trauma patients and account for the breakdown of myofibrillar proteins, as was recently reported in animal studies.

Early nutrition support modifies immune function in patients sustaining severe head injury

BACKGROUND

Immunosuppression after severe head injury has been characterized by a depressed CD4 (T-helper/inducer)-CD8 (T-suppressor/cytotoxic) ratio and decreased T-lymphocyte responsiveness. Some investigators propose that this immunocompromized state is the result of an injury-associated hypermetabolic response and inadequate nutrient delivery during the immediate postinjury recovery phase. Previous observations from our institution demonstrated a preserved CD4-CD8 ratio in severe closed-head injury (CHI) patients receiving early parenteral nutrition (PN). It was unclear whether early PN or other aspects of patient care eliminated the characteristic depression in cellular immunity. The purpose of this study was to further investigate the effect of early PN on the immune function of CHI patients.

METHODS

Nine patients sustaining severe CHI were prospectively randomized to either early PN (n = 4) at day 1 or delayed PN (n = 5) at day 5. Total nutrient administration was delivered at 2 g of protein/kg per day and 40 nonprotein kcal/kg per day for at least the first 14 days of hospitalization. Analysis for T-lymphocyte expression of CD4 and CD8 cell surface antigens and interleukin-6 was performed on days 1, 3, 7, and 14 of hospitalization. T-lymphocyte activation in response to stimulation by concanavalin A (Con A), phytohemagglutinin (PHA), and pokeweed mitogens (PWM) was also assessed on these days.

RESULTS

Significant increases in total CD4 cell counts (2048 +/- 194 to 2809 +/- 129 vs 1728 +/- 347 to 1825 +/- 563, p < .05) and CD4% (42.6 +/- 4.4% to 56.2 +/- 2.6% vs 36.6 +/- 6.6% to 36.6 +/- 11.3%, p < .05) were observed at day 14 in patients receiving early vs delayed PN. An improved lymphocyte response from baseline to day 14 after Con A stimulation was demonstrated in the early PN group (3850 +/- 1596 to 16144 +/- 5024 cpm, p < .05). A significant rise in the CD4-CD8 ratio over baseline to day 14 was also noted in the early PN group (1.43 +/- 0.17 to 2.38 +/- 0.54, p < .05).

CONCLUSIONS

The early aggressive nutrition support of CHI patients appears to modify immunologic function by increasing CD4 cells, CD4-CD8 ratios, and T-lymphocyte responsiveness to Con A.

Nutrition in the head-injured patient

Neurologic injury initiates a cascade of local and systemic metabolic responses. Patients become hypermetabolic, hypercatabolic, and hyperglycemic and develop decreased immune competency and altered gastrointestinal function. Provision of an adequate supply of nutrients is associated with improved outcome. Because of the high incidence of gastroparesis, enteral nutritional support of patients with acute head injury has traditionally been difficult and led to frequent use of parenteral nutrition. New methods of early enteral feeding allow a majority of these patients to receive adequate nutrition via the enteral route. Evidence indicates that early small bowel feeding of patients with acute head injury results in a decreased incidence of infections and shorter ICU stay. The roles of specific nutrients in modulating injury responses are currently being evaluated. The optimal nutritional support for improving neurologic recovery following head injury remains to be established.

Alterations in immune function following head injury in children

OBJECTIVE

To investigate cellular and humoral immunity in children immediately after severe head injury and during the early recovery period.

DESIGN

Prospective, observational study with factorial design.

SETTING

Pediatric ICU of a university teaching hospital.

PATIENTS

Fifteen children (median age 9.6 yrs, range 1.7 to 18) with head injury and Glasgow Coma Score of < or = 7.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Skin testing with seven standard antigens was performed and blood samples were obtained for the following measurements: total lymphocyte count and subsets; proliferative response to phytohemagglutinin, concanavalin A, and pokeweed mitogen; and immunoglobulin concentrations on days 1, 7, and 14 and 3 months after injury. The effect of patient plasma on phytohemagglutinin-induced proliferative responses of normal donor lymphocytes was also assessed at these times. Anergy was present in 71% of patients on day 1, 54% of patients on day 7, 31% of patients on day 14, and 18% of patients at 3 months. Total, helper, and suppressor T-cell counts were decreased on day 1, and the T-cell response to phytohemagglutinin was decreased on days 1, 7, and 14 compared with values at 3 months. B-cell counts were increased on day 1, followed by an increase in serum immunoglobulin concentrations 1 to 2 wks later. The B-cell response to pokeweed mitogen was unchanged over the 3-month study period. The phytohemagglutinin responses of normal donor lymphocytes were decreased when incubated with patient plasma obtained on day 7 after injury.

CONCLUSIONS

Severe head injury in children is associated with depressed cell-mediated immunity. Plasma immunosuppressive factors may contribute to T-cell dysfunction.

Altered immunoexpression of microglia and macrophages after mild head injury

In this study we examined the temporal response of microglia and macrophages to mild head injury in the rat. Microglia and macrophages were identified by their distinct morphology and by immunophenotype. With regard to the latter, antibodies to OX42 and ED1 were used to define microglia and macrophages, respectively. Although there was no change in the morphology of brain macrophages after mild head injury, the morphology of microglia was dramatically altered. Microglial cell bodies appeared larger with a more elaborate arborization of cellular processes. After head injury certain populations of macrophages and microglia were more intensely immunostained. By 3 days postinjury these intensely stained cells exhibited a characteristic distribution in the brain. Prominently stained microglia were detected in the thalamus, hippocampus, lateral and medial geniculate body, and the substantia nigra. Intensely stained macrophages were located primarily in the cortex and subarachnoid space adjacent to the site of impact. By 7 days postinjury intensely immunostained macrophages and microglia were widespread throughout the injured cortex. These results demonstrate that microglia and macrophages are sensitive to mild head injury. Early changes in the macrophage population are more directly correlated with the most damaged tissue and may reflect migration of these cells from either the subarachnoid space or across the damaged blood-brain barrier. The early widespread microglial response in regions exhibiting no overt neuronal cell damage suggests that these cells are responding to more subtle factor(s) that are expressed in the mildly traumatized brain.

Immunoglobulins and IgG subclasses in children following severe head injury

OBJECTIVE

To study immunoglobulin production after severe blunt head trauma in children.

DESIGN

Serum for IgG, IgM, IgA, IgE, and IgG subclasses were drawn from 10 children admitted with severe head injury (ISS 31.2, GCS 5.4) on day 1, 7, 14 and 21 after injury.

RESULTS

5 of the 10 patients developed infection between 7 and 14 days and 2 died of complications of pneumonia. On day 1, IgM levels averaged 95.6% of the mean of the age-specific normal controls. By day 7, IgM levels averaged 383% (p < 0.01). While all patients were within the age-specific normal range (+/- 2 SD) on day 1, 7 of 10 patients were above the normal range by day 7. There was no difference in IgM levels between infected and non-infected patients. Five patients were below the age-specific normal range for IgG on day 1, with 3 still low on day 7. By day 21, IgG levels averaged 141% of the mean of the age-specific normal controls. IgG subclasses followed a pattern similar to total IgG levels. Marked increases in IgE were seen in 3 patients.

CONCLUSIONS

IgM levels increased dramatically in all patients within seven days of the injury. While 50% of these children had a deficit of IgG in the first week, total IgG and IgA levels increased after injury, but not as rapidly as IgM levels. Unlike pediatric burn patients, there is no persistent hypogammaglobulinemia following severe blunt trauma in children.

Effect of recombinant human insulin-like growth factor I and early total parenteral nutrition on immune depression following severe head injury

OBJECTIVE

To determine the effects of insulin-like growth factor I (IGF-I) and aggressive nutrition on CD4/CD8 ratios following head injury.

DESIGN

Randomized controlled trial.

SETTING

An urban level 1 trauma center.

PARTICIPANTS

Head-injured patients with a Glasgow Coma Scale score of 4 to 10 within 6 hours of hospital admission requiring no major extracranial surgery with the exception of isolated lower-extremity fracture fixation. Fourteen patients were recruited and 11 completed the study.

INTERVENTIONS

Patients were randomized to a continuous infusion of saline or 0.01 mg/kg per hour of recombinant human (rh) IGF-I. Both groups received parenteral nutrition and rapidly advanced to a total protein intake of 2 g/kg per day and a maximum nonprotein calorie intake of 40 kcal/kg per day. The nonprotein prescription was 1.25 times the metabolic energy expenditure determined by metabolic cart not to exceed a nonprotein calorie intake of 40/kcal.

MAIN OUTCOME MEASURES

The CD4/CD8 ratios and serum IGF-I levels on days 1, 7, and 14.

RESULTS

Administration of early aggressive nutrition eliminated the depressed CD4/CD8 ratio usually seen after head injury; administration of IGF-I increased the CD4/CD8 ratio while IGF-I levels were elevated.

CONCLUSIONS

Infusion of rhIGF-I and aggressive early intravenous nutrition affects the immunologic response of patients with severe head injury.

Ubiquitin marks the reactive swellings of diffuse axonal injury

Ubiquitin is a protein that targets proteins for non-lysosomal degradation. It has been found to be present in a number of inclusions characteristic of neurodegenerative diseases. Using the fluid percussion model of closed head injury in the cat, a well-established model of diffuse axonal injury (DAI), we now report that the reactive axonal swellings and the retraction balls produced in this model stain positively with anti-ubiquitin immunohistochemistry. Furthermore, the affected axons become ubiquitin positive quickly (within the first 6 h after injury). Anti-ubiquitin immunohistochemistry compares well with the recently reported ability of antibodies to low molecular weight neurofilament proteins to demonstrate reactive axonal change in DAI, and it could provide additional clues to the pathogenesis of axonal transection.

Cell-mediated immunity in severely head-injured patients: the role of suppressor lymphocytes and serum factors

Severe head injury results in suppression of cellular immunity associated with defective in vitro functioning of effector lymphocytes, such as helper T cells and cytotoxic T cells. It is not known whether this suppression in effector lymphocyte function is due to intrinsic lymphocyte dysfunction, to suppressor peripheral blood mononuclear cells (PBMC's) such as suppressor lymphocytes or suppressor monocytes, or to serum factors capable of inhibiting effector lymphocyte function. The purpose of this study was to determine whether a subpopulation of PBMC's and/or serum factor(s) are responsible for this observed suppression in cell-mediated immunity. Cell-mediated immune activity was determined measuring in vitro lymphokine-activated killer (LAK) cytotoxicity following incubation of PBMC's from 15 head-injured patients with those from 15 heterologous normal subjects. The PBMC's were separated into lymphocyte-enriched and monocyte-enriched subpopulations by plastic adherence techniques, and the effect of each population on LAK cytotoxicity was determined. Additionally, the effect on cytotoxicity of serum from the head-injured patients was determined in a dose-response fashion. There was significant depression in LAK cytotoxicity when: 1) PBMC's from normal subjects were incubated with PBMC's from head-injured patients (p < 0.001); 2) lymphocytes (PBMC's depleted of monocytes) from head-injured patients were incubated with PBMC's from normal subjects (p < 0.001); and 3) PBMC's from normal subjects were incubated with serum from head-injured patients (p < 0.001). No suppression in cellular immunity was noted when lymphocytes from normal subjects were incubated with monocytes from head-injured patients. The results indicate that lymphocytes rather than monocytes actively inhibit cellular immunity following severe head injury. The detection of immunosuppressive serum factors suggests a mechanism by which lymphocytes might be modulated by severe head injury.

The significance of immunosuppression and hormonal alteration in neurotraumatology

Thirty head trauma patients receiving no steroid treatment were investigated for a period of 20 days. The patients were divided into three groups according to their Glasgow Coma Scale (GCS) scores: GCS = 4-8 and GCS = 9-13. We studied their immunological and hormonal status with special reference to the relationship among severity of trauma, immunosuppression and hormonal alteration. The immunity tests included lymphocyte transformation, lymphocyte phenotyping and delayed hypersensitivity (DH) skin tests. The hormone study consisted of serum cortisol and ACTH level determinations. The following results were obtained: (1) The entire group suffered from significant suppression in lymphocyte responses to mitogens PHA and Con A on day 1 and day 10 after injury, but later they improved; (2) There was a significant fall (P less than 0.05) in OKT3 OKT4 and active T-cell on day 10, especially in patients with GCS less than or equal to 8; (3) A significant increase in OKT8 and decrease in OKT4 was concurrently noted causing an inversion in the ratio of OKT4 to OKT8 on the 10th day (patients 0.96:1, normal 1.6:1, P less than 0.01); (4) No significant change was observed in the number of B-cells, suggesting that cell-mediated immunity may be affected earlier and more severely than antibody producing capacity; (5) Delayed hypersensitivity skin test showed a high incidence of anergy in the severe (GCS less than or equal to 8) and fetal cases. A high mortality in anergic cases was also noted; (6) Elevated ACTH and cortisol levels detected upon arrival rapidly declined to normal value at day 5. In addition, we found no correlation between the curve of serum ACTH and cortisol alteration and the biphasic suppression curve of lymphocyte transformation in later study period. These findings suggest that the severity of natural resistance impairment seems to be related to the gravity of clinical manifestations and to the serum hormonal alteration only in the initial stages. Also, we find that the development of anergy may be an index of poor prognosis.

Assessments of nutritional status and immunological responses in head trauma: alterations in zinc and C-reactive protein

A prospective longitudinal evaluation of zinc and C-reactive protein (CRP) in serum and 24-hour urine was carried out in 24 head-trauma patients. The patients were divided into two groups: group I (14 patients) with Glasgow Coma Scale scores between 4 and 8, and group II (10 patients) with Glasgow Coma Scale scores between 9 and 13. To understand the influence of severity of injury on the two acute-phase reactants, all patients were studied for a period of up to 20 days after hospital admission. The average serum zinc concentration in all patients decreased from day 1 to day 5, but gradually increased thereafter. The hypozincemia was more severe in group I than in group II. All patients lost zinc throughout the study period and urinary zinc excretion was greater in group I than in group II patients. In group I, the mean peak urinary zinc loss exceeded 5000 micrograms/day (normal value less than 800 micrograms/day). Serum C-reactive protein levels were markedly elevated on admission especially in group I, then gradually declined but were still above the normal range on day 20. Acute zinc deficiency with concomitant elevation of CRP supports the hypothesis that acute hypozincemia observed in our patients may be stress-induced and zinc activity may be part of altered nutritional and metabolic responses to severe head injury.

Impairment of helper T-cell function following severe head injury

Major infections, such as sepsis and pneumonia, occur in 50-75% of patients following isolated severe head injury. Previous studies have demonstrated that this high incidence of infection following severe head injury may be related to a decrease in helper T-cell activation and function. The present study was designed to investigate the effect of severe head injury on specific subgroups of helper T cells known to enhance or suppress cellular immune function. Specifically, peripheral blood lymphocytes (PBLs) from 10 head-injured patients and 10 matched controls were evaluated following in vitro stimulation with the T-cell mitogen, phytohemagglutinin (PHA). Subsets of helper T cells evaluated included activated helper (CD4+/CD25+) T cells; helper/inducer (CD4+/CDw29+) T cells, which enhance cellular immune activity; and suppressor/inducer (CD4+/CD45R+) T-cells, which induce suppressor (CD8+) T-cells. In addition, the effect of intraventricular fluid (IVF) on PHA-stimulated in vitro CD4 and CD25 expression was investigated to determine whether severe head injury results in the production of mediators within the central nervous system capable of affecting T-cell activation. The results of this study indicate that isolated severe head injury selectively reduces the ability of PHA-stimulated PBLs to express the helper/inducer (CD4+/CDw29+) T-cell (p = 0.023) and activated helper (CD4+/CD25+) T-cell (P = 0.041) phenotypes. There was no significant change in PHA-stimulated CD4 or CD25 expression following incubation of PBLs with intraventricular fluid (IVF) from head-injured patients. The relationship between these changes in specific helper T-cell subpopulations and the infectious complications of severe head injury are discussed.

Impairment of helper T-cell function and lymphokine-activated killer cytotoxicity following severe head injury

Infection is a major complication of severe head injury, occurring in 50% to 75% of patients who survive to hospitalization. Previous investigations of immune activity following head injury have demonstrated suppression of helper T-cell activation. In this study, the in vitro production of interferon-gamma (INF-gamma), interleukin-1 (IL-1), and interleukin-2 (IL-2) was determined in 25 head-injured patients following incubation of peripheral blood lymphocytes (PBL's) with the lymphocyte mitogen phytohemagglutin (PHA). In order to elucidate the functional status of cellular cytotoxicity, lymphokine-activated killer (LAK) cell cytotoxicity assays were performed both prior to and following incubation of PBL's with IL-2 in five patients with severe head injury. The production of INF-gamma and IL-2 by PHA-stimulated PBL's was maximally depressed within 24 hours of injury (p less than 0.001 for INF-gamma, p = 0.035 for IL-2) and partially normalized within 21 days of injury. There was no change in the production of IL-1. When comparing the in vitro LAK cell cytotoxicity of PBL's from head-injured patients and normal subjects, there was a significant depression in LAK cell cytotoxicity both prior to (p = 0.010) and following (p less than 0.001) incubation of PBL's with IL-2. The results of this study indicate that IL-2 and INF-gamma production, normally required for inducing cell-mediated immunity, is suppressed following severe head injury. The failure of IL-2 to enhance LAK cell cytotoxicity suggest that factors other than decreased IL-2 production, such as inhibitory soluble mediators or suppressor lymphocytes, may be responsible for the reduction in cellular immune activity following severe head injury. These findings may have significant implications in designing clinical studies aimed at reducing the incidence of infection following severe head injury.