Effect of renutrition on humoral and cell-mediated immunity in severely malnourished children

Vaccine and malnutrition: A narrative review

Nearly 45% of under 5 mortality is directly or indirectly linked to malnutrition. Infection adds to the increased mortality and morbidity in these groups. Vaccination is very important in these undernourished children protecting against life-threatening infections. The goal of vaccination is to produce long-term protection by generating memory cells and the generation of antibodies. Since malnutrition is a state of immunodeficiency, the immune response to vaccines in these children is a matter of concern. We did an exhaustive search to gather more recent studies and corroborated previous findings. Oral Polio Vaccine (OPV), Pneumococcal Polysaccharide Vaccine, Haemophilus influenza vaccine, rabies, and cholera vaccine showed normal response to immunization. Measles and rotavirus vaccines were found to elicit lower seroprotection and lower efficacy in undernourished children. Data regarding response to vaccination against BCG, DPwT, Hepatitis B, pneumococcal conjugate vaccine, and meningococcal vaccine was inconclusive. Although most of the studies show a normal immune response to different vaccines, excluding other confounding factors and effect modifiers had not been easy to interpret. However, with the advances in the understanding of vaccine physiology with newer immunological techniques, good-quality studies might explore the gray areas that remain untouched.

Nutritional status, diet and viral respiratory infections: perspectives for severe acute respiratory syndrome coronavirus 2

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was recognised by the WHO as a pandemic in 2020. Host preparation to combat the virus is an important strategy to avoid COVID-19 severity. Thus, the relationship between eating habits, nutritional status and their effects on the immune response and further implications in viral respiratory infections is an important topic discussed in this review. Malnutrition causes the most diverse alterations in the immune system, suppressing of the immune response and increasing the susceptibility to infections such as SARS-CoV-2. On the other hand, obesity induces low-grade chronic inflammation caused by excess adiposity, which increases angiotensin-converting enzyme 2. It decreases the immune response favouring SARS-CoV-2 virulence and promoting respiratory distress syndrome. The present review highlights the importance of food choices considering their inflammatory effects, consequently increasing the viral susceptibility observed in malnutrition and obesity. Healthy eating habits, micronutrients, bioactive compounds and probiotics are strategies for COVID-19 prevention. Therefore, a diversified and balanced diet can contribute to the improvement of the immune response to viral infections such as COVID-19.

The Impact of Age and Gender on Hematopoietic Stem Cells and Immune Contexture of the Bone Marrow Microenvironment

Hematopoietic stem cells (HSCs) are a rare population of cells that reside mainly in the bone marrow and are capable of generating and fulfilling the entire hematopoietic system upon differentiation. Thirty-six healthy donors, attending the HSCT center to donate their bone marrow, were categorized according to their age into child (0-12 years), adolescence (13-18 years), and adult (19-59 years) groups, and gender into male and female groups. Then, the absolute number of HSCs and mature immune cells in their harvested bone marrow was investigated. Here, we report that the absolute cell number can vary considerably based on the age of the healthy donor, and the number of both HSCs and immune cells declines with advancing age. The gender of the donor (male or female) did not have any impact on the number of the HSCs and immune cells in the bone marrow. In conclusion, since the number of HSCs plays a pivotal role in the clinical outcome of allogeneic HSC transplantations, identifying a younger donor regardless the gender is critical.

Undernutrition is associated with perturbations in T cell-, B cell-, monocyte- and dendritic cell- subsets in latent Mycobacterium tuberculosis infection

Undernutrition, as described by low body mass index (BMI), is a foremost risk factor for the progression of active Tuberculosis (TB). Undernutrition is also known to impact the baseline frequencies of innate and adaptive immune cells in animal models. To verify whether undernutrition has any influence on the baseline frequencies of immune cells in latent Mycobacterium tuberculosis infection (LTBI), we examined the frequencies of T cell-, B cell, monocyte- and dendritic cell (DC)- subsets in individuals with LTBI and low BMI (LBMI) and contrasted them with LTBI and normal BMI (NBMI) groups. LBMI was characterized by decreased frequencies and absolute cell counts of T cells, B cells and NK cells in comparison with NBMI. LBMI individuals demonstrated significantly enhanced frequencies of naïve and effector CD4⁺ and CD8⁺ T cells and significantly decreased frequencies of central memory, effector memory CD4⁺ and CD8⁺ T cells and regulatory T cells. Among B cell subsets, LBMI individuals demonstrated significantly diminished frequencies of naïve, immature, classical memory, activated memory, atypical memory and plasma cells. In addition, LBMI individuals showed significantly decreased frequencies of classical monocytes, myeloid DCs and plasmacytoid DCs and significantly increased frequencies of intermediate and non-classical monocytes and myeloid derived suppressor cells. BMI exhibited a positive correlation with B cell and NK cell counts. Our data, therefore, demonstrates that coexistent undernutrition in LTBI is characterized by the occurrence of a significant modulation in the frequency of innate and adaptive immune cell subsets.

mTORC1 as a cell-intrinsic rheostat that shapes development, preimmune repertoire, and function of B lymphocytes

Ample evidence indicates that nutrient concentrations in extracellular milieux affect signaling mediated by environmental sensor proteins. For instance, the mechanistic target of rapamycin (mTOR) is reduced during protein malnutrition and is known to be modulated by concentrations of several amino acids when in a multiprotein signaling complex that contains regulatory-associated protein of mTOR. We hypothesized that a partial decrease in mTOR complex 1 (mTORC1) activity intrinsic to B-lineage cells would perturb lymphocyte development or function, or both. We show that a cell-intrinsic decrease in mTORC1 activity impacted developmental progression, antigen receptor repertoire, and function along the B lineage. Thus, preimmune repertoires of B-lineage cells were altered in the marrow and periphery in a genetic model of regulatory-associated protein of mTOR haplo-insufficiency. An additional role for mTORC1 was revealed when a B-cell antigen receptor transgene was found to circumvent the abnormal B-cell development: haploinsufficient B cells were profoundly impaired in responses to antigen in vivo. Collectively, our findings indicate that mTORC1 serves as a rheostat that shapes differentiation along the B lineage, the preimmune repertoire, and antigen-driven selection of mature B cells. The findings also reveal a range in the impact of this nutrient sensor on activity-response relationships for distinct endpoints.-Raybuck, A. L., Lee, K., Cho, S. H., Li, J., Thomas, J. W., Boothby, M. R. mTORC1 as a cell-intrinsic rheostat that shapes development, preimmune repertoire, and function of B lymphocytes.

Use of tuberculin skin test for assessment of immune recovery among previously malnourished children in Ethiopia

OBJECTIVE

To compare levels of immunity in children recovering from severe acute malnutrition (cases) against those of community controls (controls).

RESULTS

At baseline children recovering from severe acute malnutrition had lower, mid upper arm circumference (122 mm for cases and 135 mm for controls; p < 0.001), weight-for-height Z-score (- 1.0 for cases and - 0.5 for controls; p < 0.001), weight-for-age Z-score (- 2.8 for cases and - 1.1 for controls; p < 0.001) and height/length-for-age Z-score (- 3.6 for cases and - 1.4 for controls; p < 0.001), than controls. Age and gender matched community controls. At baseline, prevalence of a positive tuberculin skin test, assessed by cutaneous delayed-type hypersensitivity reaction skin test, was very low in both cases (3/93 = 3.2%) and controls (2/94 = 2.1%) and did not significantly increase at 6 months follow up (6/86 = 7.0% in cases and 3/84 = 3.4% in controls). The incidences of common childhood morbidities, namely fever, diarrhoea and cough, were 1.7-1.8 times higher among cases than controls. In conclusion, these results show that tuberculin skin test does not enable any conclusive statements regarding the immune status of patients following treatment for severe acute malnutrition. The increased incidence of infection in cases compared to controls suggests persistence of lower resistance to infection even after anthropometric recovery is achieved.

Malnutrition and vaccination in developing countries

Malnutrition contributes to an estimated 45% of deaths among children under 5 years of age in developing countries, predominantly due to infections. Malnourished children therefore stand to benefit hugely from vaccination, but malnutrition has been described as the most common immunodeficiency globally, suggesting that they may not be able to respond effectively to vaccines. The immunology of malnutrition remains poorly characterized, but is associated with impairments in mucosal barrier integrity, and innate and adaptive immune dysfunction. Despite this, the majority of malnourished children can mount a protective immune response following vaccination, although the timing, quality and duration of responses may be impaired. This paper reviews the evidence for vaccine immunogenicity in malnourished children, discusses the importance of vaccination in prevention of malnutrition and highlights evidence gaps in our current knowledge.

The immune system in children with malnutrition--a systematic review

BACKGROUND

Malnourished children have increased risk of dying, with most deaths caused by infectious diseases. One mechanism behind this may be impaired immune function. However, this immune deficiency of malnutrition has not previously been systematically reviewed.

OBJECTIVES

To review the scientific literature about immune function in children with malnutrition.

METHODS

A systematic literature search was done in PubMed, and additional articles identified in reference lists and by correspondence with experts in the field. The inclusion criteria were studies investigating immune parameters in children aged 1-60 months, in relation to malnutrition, defined as wasting, underweight, stunting, or oedematous malnutrition.

RESULTS

The literature search yielded 3402 articles, of which 245 met the inclusion criteria. Most were published between 1970 and 1990, and only 33 after 2003. Malnutrition is associated with impaired gut-barrier function, reduced exocrine secretion of protective substances, and low levels of plasma complement. Lymphatic tissue, particularly the thymus, undergoes atrophy, and delayed-type hypersensitivity responses are reduced. Levels of antibodies produced after vaccination are reduced in severely malnourished children, but intact in moderate malnutrition. Cytokine patterns are skewed towards a Th2-response. Other immune parameters seem intact or elevated: leukocyte and lymphocyte counts are unaffected, and levels of immunoglobulins, particularly immunoglobulin A, are high. The acute phase response appears intact, and sometimes present in the absence of clinical infection. Limitations to the studies include their observational and often cross-sectional design and frequent confounding by infections in the children studied.

CONCLUSION

The immunological alterations associated with malnutrition in children may contribute to increased mortality. However, the underlying mechanisms are still inadequately understood, as well as why different types of malnutrition are associated with different immunological alterations. Better designed prospective studies are needed, based on current understanding of immunology and with state-of-the-art methods.

Effect of honey on 50% complement hemolytic activity in infants with protein energy malnutrition: a randomized controlled pilot study

Protein energy malnutrition (PEM) is associated with a significant impairment of cell-mediated immunity and complement system, which may be responsible for the high incidence of infections among these patients. This study was designed to examine the effect of honey, as a natural substance, on the 50% complement hemolytic activity (CH50) in patients with PEM. Thirty patients with PEM and 20 healthy infants serving as controls participated in this study. The patients were randomized to receive either honey (group 1) or placebo (group 2), in addition to conventional nutritional rehabilitation therapy. Measurements of weight, midarm circumference, skin fold thickness, serum albumin, and CH50 were done for all patients before and after 2 weeks of rehabilitation. Before nutritional rehabilitation, the CH50 was significantly lower in the PEM groups compared with the control. However, after rehabilitation, the CH50 increased significantly in both PEM groups, compared with the pre-interventional state and with the controls. Moreover, the rise of CH50 was significantly more in the honey group compared with the placebo. On the other hand, the improvement in the anthropometric measures and serum albumin did not differ significantly between the honey and placebo groups after rehabilitation. Thus honey supplementation in patients with PEM increased the level of CH50. Whether this would have an effect on the frequency and severity of infections in patients with PEM needs further studies.

Amino acids and immune function

A deficiency of dietary protein or amino acids has long been known to impair immune function and increase the susceptibility of animals and humans to infectious disease. However, only in the past 15 years have the underlying cellular and molecular mechanisms begun to unfold. Protein malnutrition reduces concentrations of most amino acids in plasma. Findings from recent studies indicate an important role for amino acids in immune responses by regulating: (1) the activation of T lymphocytes, B lymphocytes, natural killer cells and macrophages; (2) cellular redox state, gene expression and lymphocyte proliferation; and (3) the production of antibodies, cytokines and other cytotoxic substances. Increasing evidence shows that dietary supplementation of specific amino acids to animals and humans with malnutrition and infectious disease enhances the immune status, thereby reducing morbidity and mortality. Arginine, glutamine and cysteine precursors are the best prototypes. Because of a negative impact of imbalance and antagonism among amino acids on nutrient intake and utilisation, care should be exercised in developing effective strategies of enteral or parenteral provision for maximum health benefits. Such measures should be based on knowledge about the biochemistry and physiology of amino acids, their roles in immune responses, nutritional and pathological states of individuals and expected treatment outcomes. New knowledge about the metabolism of amino acids in leucocytes is critical for the development of effective means to prevent and treat immunodeficient diseases. These nutrients hold great promise in improving health and preventing infectious diseases in animals and humans.

Effects of cyclic enteral nutrition on the immunological status of malnourished patients

The effects of 2 weeks of refeeding by cyclic enteral nutrition on chronically malnourished (mean global nutritional deficiency 19.9 +/- 1.1%) hospitalized patients were assessed in a prospective study with special attention paid to immunological status. All patients were immunodeficient, with cell-mediated immunity being more affected than humoral immunity. After 2 weeks of refeeding, nutritional status had improved by 29.8%. Initially abnormal parameters of humoral immunity (IgM, C3 and C4) improved significantly (P < 0.05) between day 0 and day 15. The following cell-mediated immunity parameters also improved significantly (P < 0.05): CD8, monocyte count, natural killer cell activity and skin tests. Short-term refeeding by cyclic enteral nutrition appears to be a safe and effective way of improving immunodeficiency in chronically malnourished patients, with predictable consequences on infection.

Effect of Moderate White Wine Consumption on Serum IgA and Plasma Insulin under Fasting Conditions

BACKGROUND/AIMS

The present study aims to investigate the contribution of alcohol toxicity to the development of malnutrition by assessing the effect of consuming a moderate amount of white wine on plasma insulin and serum IgA under fasting conditions.

METHODS

A total of 5 non-alcoholic males aged between 19 and 22 years participated in the current investigation. The experimental procedure required participants to undergo a 6-hour fast before ingesting 4 standard units of alcohol (40 g) in the form of white wine over a 120-min period. The level of blood alcohol, plasma insulin and serum IgA was assessed at 30-min intervals across the 120-min experimental period.

RESULTS

Consuming alcohol promotes a significant increase in serum IgA in the absence of any change in plasma insulin or ketone production in fasted individuals.

CONCLUSION

White wine prior to a meal does not promote glucose metabolism and utilization and may increase the risk of developing a transient diabetic condition due to an alteration in energy metabolism.

Blood concentrations of Th2-type immunoglobulins are selectively increased in weanling mice subjected to acute malnutrition

Male and female C57BL/6J mice, initially 19 days old, consumed a complete purified diet either ad libitum (age-matched control) or in restricted daily quantities (energy deficiency), or they consumed a purified isocaloric low-protein diet ad libitum (protein and energy deficit). In a 14-day experimental period, malnourished animals lost approximately 1.5% of their initial body weight daily. Zero-time controls, 19 days old, were also included in the study. Serum levels of Th2-type (IgG1 and IgE) and Th1-type (IgG2a and IgG3) immunoglobulins were quantified by enzyme-linked immunosorbent assay, and total IgG concentration was also assessed. Both malnourished groups exhibited high serum concentrations of IgG1 and IgE relative to the age-matched control group, whereas levels of the Th1-type immunoglobulins were unaffected. Total IgG concentration in the malnourished groups reflected the usual finding in humans (i.e., no effect or elevated). The results are consistent with the proposition of Th2-polarized immune competence in acute weanling deficiencies of energy, protein, or both.

Effect of renutrition on natural and cell-mediated immune response in infants with severe malnutrition

BACKGROUND

The purpose of this study was to evaluate whether a 4-week nutritional recovery period with a starting infant formula and 3.35 kJ/mL energy density would favorably affect the natural and cell-mediated immune response in infants with severe and primary protein-energy malnutrition.

METHODOLOGY

The study included 12 severely malnourished infants, 3 to 18 months of age. For 2 weeks, infants were fed a starting infant formula, with energy density increased to 0.8 kcal/mL, through a nasogastric tube. Infants were fed "ad libitum" for 2 more weeks. On the fifth day, 837 kJ/kg and 4 g/kg protein were given daily. At the beginning and at the end of the 4-week period, weight, length, phagocytosis, microbicidal activity, chemotaxis, and cell proliferation indices were measured. Null hypothesis was rejected with a paired t test and a P value less than 0.05.

RESULTS

After the 4-week period of nutritional recovery, the weight and length indicators and the four immunologic assays showed significant increase (P < 0.005).

CONCLUSION

The study demonstrated that a 4-week nutritional recovery period with a starting infant formula and 0.8 kcal/mL energy density favorably affected the natural and cell-mediated immune response in infants with severe protein-energy malnutrition.

Severe anorexia nervosa associated with osteoporotic-linked femural neck fracture and pulmonary tuberculosis: a case report

We report a case study of a 38-year-old woman who had been suffering from anorexia nervosa (AN) since the age of 26. Before admittance to our clinic, she weighed 23.8 kg (at a height of 164 cm, 8.8 body mass index [BMI]) but still carried out strenuous physical activities. After good psychotherapeutic response and weight gain (34.4 kg), she accidentally fell and broke her femoral neck-favored as it was by osteoporosis. The X-ray taken before dynamic hip screw implantation coincidentally showed signs of pulmonary tuberculosis (TB), which could then be proven by computed tomography (CT) scans and cultures from a bronchoscopy. Other than lack of appetite and loss of weight, which we attributed to AN, there were no other clinical or biochemical indicators which could have pointed to an earlier TB diagnosis. As a result, the need for screening procedures is discussed. The manifestation of TB during the first weight gain after 12 years of severe malnutrition, during which there were no serious infections, seems to endorse former observations that AN patients appear to be "resistant" to some extent against infectious diseases, a "protection" which may be lost with convalescence and weight gain.

Immunodeficiency associated with anorexia nervosa is secondary and improves after refeeding

Several studies have addressed the question of starvation effects on immune function by means of changes in lymphocyte subsets, cytokine induction or lymphocyte activation. Anorexia nervosa (AN) patients are severely malnourished and contradictory results have been obtained regarding the accompanying immunodeficiency, including its assignation as a part of the primary nervous disorder. In the present work, an extensive immunological function examination was carried out on 40 AN patients who were compared with a control group of 14 healthy girls. The AN patients were also classified according to their nutritional status (by the Body Mass Index: BMI), this being critical for a better understanding of these secondary immunodeficiency bases. Moreover, another immune system study was performed on five patients after refeeding. Lymphocyte subsets and function, cytokine induction and peripheral blood concentrations, and innate as well as humoral immunity were evaluated. Deregulation in the cytokine network, owing to the interaction of the central nervous (CNS) and immune systems, seems to be the initial immune alteration in AN immunodeficiency but it has not been disproved that the immunodeficiency is a direct consequence of the original psychiatric perturbation. Spontaneous high levels of circulating interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha) have been observed; this is probably one of the causes of the anomalies found in the T-cell subpopulations (mainly the naive CD4+CD45RA+ reduction and the cytotoxic CD8+ increase) and T-cell activation status (mainly the down-regulation of the CD2 and CD69 activation pathways). This finally leads to an impairment, not only in T-cell function but also in T-cell to B-cell co-operation. The AN specificity of these results is confirmed by the fact that these immune alterations improve after refeeding and when nutritional status becomes less critical, which also suggests that AN immunodeficiency is indeed secondary to malnutrition.

The immune system in eating disorders: an overview

Eating disorders, such as anorexia nervosa and bulimia nervosa, are becoming more and more common in our society. Although they are psychiatric illnesses, there are many factors involved, including abnormal food behavior. Nutrients play an important role in the development and functionality of immunocompetent cells. An impaired immunocompetence has been shown to be an important causal factor in the increased susceptibility of malnourished individuals to infectious disease. Therefore, studies on the immune system are of great interest when assessing the extent to which the nutritional status of these patients could be affected. However, the literature in this field is controversial, and the mechanisms are not yet completely defined, although some hypotheses try to clarify the disturbances caused in the organism under these bizarre circumstances. In spite of the fact that the immune system is altered by distorted food behaviors, such as in eating disorders, the awareness of characteristics of other systems involved, and therefore altered, by these pathologies would be very helpful for understanding the mechanisms triggered in these syndromes. In fact, the interactions among the immune and other systems in eating disorders are beginning to be studied. Finally, the main goals are to limit the evolution of these illnesses through early diagnosis, and to devise a long-lasting, definitive cure for these patients through appropriate therapy.

Immune responses during recovery from protein-energy malnutrition

Protein-energy malnutrition (PEM) is a worldwide problem. Infants and children from developing countries and elderly people from all around the world are the two main groups suffering from PEM. PEM induces profound immunodeficiency, characterized mainly by decreased cell-mediated immunity, and also by decreased humoral and non-specific immunity. Non-specific immune deficiency is of particular importance for defences against infections and its decrease in PEM may further deteriorate nutritional and immune status, pushing patients into a vicious and dramatic circle. Refeeding such patients and the restoration of their nutritional status lead to improvement in all immune responses: a strong association between the evolution of these two responses is always observed during refeeding. The need for specific nutrients to restore immune functions during refeeding of PEM patient has been extensively studied in the past years. This review describes the pathophysiological mechanisms of immune consequences of PEM and of immune restoration with refeeding, and in addition focuses upon some nutrients of particular importance, namely glutamine, zinc and vitamin E. Particular attention is directed at the elderly patients with PEM, a growing population for which the importance of undernutrition on prognosis is not yet fully recognized.

Deficient induction of the immune response to oral immunization with cholera toxin in malnourished rats during suckling

Malnourished rats during suckling were orally immunized with cholera toxin (CT) after different periods of refeeding. Intestinal fluids, sera, and supernatant fluids from cultured mesenteric lymph node (MLN) cells were obtained after rats were given three doses of CT and analyzed by enzyme-linked immunosorbent assay (ELISA) to evaluate the specific antibody response. Serum-specific immunoglobulin G (IgG), IgA, and IgM were severely diminished in malnourished rats immunized with three doses of CT after 1 week of refeeding when compared with those of controls. Also, a decreased IgA ELISA titer of the intestinal fluids and abrogation of the capacity to neutralize the CT in the intestinal ligated loop test were found. When a booster was given at 113 days of age, the immune response continued to be affected in the serum and the intestinal fluid. The results from the analysis of the supernatant fluids from cultured MLN cells were coincident with those mentioned above. When one dose of CT was administered into Peyer's patches (PP) after 1 week of refeeding, an impaired immune response was found in the intestinal fluid of malnourished rats during suckling compared with that of controls. This result together with the analysis of supernatant from MLN and PP cell cultures suggests that antigen triggering in the PP was affected. When the refeeding period was extended to 30 days and then the first dose of CT was administered, the antibody immune responses in intestinal fluid serum and supernatant fluid approached control values. These observations reinforce the fact that the gut-associated lymphoid tissue immaturity of the rats when they received the first CT dose (at 28 days old) was the main reason for the decreased immune response observed in the experimental group.

Anorexia nervosa and tuberculosis: case reports and a review of immune mechanisms

A pair of identical twins living together and with a long-standing history of anorexia nervosa were admitted to restore weight. In the course of their admission one of them was found to be suffering from pulmonary tuberculosis and the other developed tuberculosis after 1 year. We seek to highlight factors that can lead to a delay in case detection and discuss issues relating to the immune mechanisms in tuberculosis and anorexia nervosa.

Low lymphocyte interferon-gamma production and variable proliferative response in anorexia nervosa patients

Interferon-gamma (IFN-gamma) production by peripheral blood mononuclear cells (PBMC) in 14 patients with anorexia nervosa (AN) was significantly lower than in 14 age-matched healthy controls. Follow-up samples in four patients displayed low levels, except in two when they recovered the IFN-gamma production as the hormonal cycles were restored. A large interindividual variation for the lymphocyte proliferative response was observed in 30 AN patients. DNA synthesis of PBMC was normal in 8 patients (27%), significantly increased in 6 (20%) (P < 0.001), and significantly decreased in 16 (53%) (P < 0.001). IFN-gamma inhibition was reversed by culturing a control lymphocyte population with monocytes from patients with AN. This was not observed in cultures of control monocytes and AN lymphocytes. IL-2 receptor (TAC subunit) was assessed and no difference was found in the number of TAC-positive cells between patients and controls. These results point out impaired production of the immunomodulator cytokine IFN-gamma as a major functional defect of AN peripheral lymphocytes.

Spleen and thymus cell subsets modified by long-term morphine administration in protein-undernourished mice--I

Severe infections in intravenous drug abusers could be the consequence of morphine-induced damage on the immune system. To evaluate the long-term effect of in vivo morphine administration on the immune system we developed an experimental model where we studied the combined effects of morphine treatment and protein malnutrition. We treated protein-undernourished mice daily for 11 weeks with increasing doses of morphine. Morphine treatment produced a decrease in body weight and spleen cell number. The changes observed were partially independent of the nutritional status of the host. Saline-injected mice showed a decrease in the percentage of Thy 1+ cells in the spleen. Morphine treatment induced a decrease in the total number of cells and therefore in the absolute number of T-(Thy 1, CD4, CD8), B- and Mac 1+ (macrophages) cells in protein-undernourished mice. Saline-injected mice showed a decrease in the percentage of Thy 1+ cells and an increase in the percentage of B- and Ia(+)-cells in the spleen. We conclude that morphine altered the immune system by down-regulating splenocyte proliferation. We also studied the effects of i.p. administered morphine on expression of thymocyte phenotype in well-nourished and protein-undernourished mice. In well-nourished mice, morphine treatment reduced the number of Thy 1+, CD4+ and CD8+ cells per thymus to 30% of that found in untreated mice and to 40% of the cells in those saline-treated controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Splenocyte subsets in normal and protein malnourished mice after long-term exposure to cocaine or morphine

An experimental model which resembles human drug addiction was developed to study the effect of chronic drug (cocaine or morphine) administration on the immune system. As malnutrition has been associated with drug use, a low protein diet has been evaluated for its contribution to the impairment of the immune system during cocaine/morphine addiction. Female C57BL/6 mice that received a 20% or 4% casein diet were studied. Both drugs were administered intraperitoneally daily for 11 weeks and drugs were administered in increasing daily doses, beginning after 3 weeks of diet consumption. Doses of cocaine began with 5 mg/kg body weight and reached the maximum dose of 40 mg/kg/day at the fourth week. Doses of morphine gradually increased from 10 mg/kg to 75 mg/kg body weight with the maximum dose reached after 5 weeks of treatment. Cocaine administration reduced body weight, particularly in the low protein diet group, and spleen weight in protein malnourished mice. Cocaine as well as saline injected mice showed a decrease in the percentage of CD4+ CD8+ and Mac-1+ cells and an increase in B cells in the spleens of well nourished mice. Morphine-treated mice showed similar results to those observed in cocaine or saline treated mice. These results suggest that cocaine, morphine or saline injection can alter the percentage of cells that express a defined phenotype independently of the nutritional status of the subject. Moreover, the effect appears dependent on a stress mediated process.

Suppression of immune function in growth hormone-deficient children during treatment with human growth hormone

Inasmuch as growth hormone is known to interact with the immune system, we studied immune functions including immunoglobulins, cell surface markers, mitogen responses, and polymorphonuclear cell function in eight children with growth hormone deficiency, ages 1 to 17 years, before and during treatment with human growth hormone for 12 to 16 months. Before treatment immune functions were normal in all children. Treatment with human growth hormone did not significantly affect serum immunoglobulins, polymorphonuclear cell function, or percent T cells. However, percent B cells decreased to subnormal levels in seven of seven patients. T helper/suppressor ratios decreased in all patients, to subnormal values in seven of eight patients; and mitogen responses decreased to below normal in all. The decline of percent B cells was transient in all patients, of T helper/suppressor ratios in seven of eight, and mitogen responses in five of eight patients. In vitro incubation of lymphocytes with growth hormone resulted in no changes in cell surface markers or mitogen responses. Although the depression of immune functions resulted in no increased rate of infections during the observation period, we do not know the possible effects of prolonged treatment and therefore caution against the indiscriminate use of human growth hormone. The effects of biosynthetically obtained growth hormone on immune function remain to be determined.

The influence of dietary protein on the protective effect of BCG in guinea pigs

Specific pathogen-free, Hartley guinea pigs were vaccinated with viable Bacille Calmette-Guerin (BCG) and given isocaloric diets identical in every nutrient except protein (control = 30%; low protein = 10%). A non-vaccinated group was maintained on the control diet. Five weeks later, all animals were infected with an aerosol containing virulent M. tuberculosis H37Rv. On the same day, half of the protein-deficient guinea pigs were transferred to the control diet, while the remainder were maintained on the low protein (10%) diet. Animals from each diet treatment were tuberculin tested and sacrificed 1,2,3 and 4 weeks post-challenge. Protein-deficient guinea pigs exhibited diminished tuberculin reactions and loss of BCG-induced protection against virulent challenge as measured by the number of viable M. tuberculosis recovered from the lung and spleen. Renourished animals expressed normal levels of delayed hypersensitivity within 1 week of initiating the normal diet and were protected as well as vaccinated control guinea pigs against virulent respiratory challenge.

Immunity in esophageal carcinoma

In carcinoma of the esophagus, response to in vivo sensitization with recall antigens and DNCB was markedly depressed with 13% and 16% positivity respectively. Similarly, the number of T-cells was found to be significantly low (24 +/- 14) as compared to normal control (61 +/- 23). Blastogenesis index with PHA was only 1.75 +/- 1.04 in contrast to normal of 6.79 +/- 2.57. This depression was independent of serum albumin level and body weight. Cell-mediated immunity was further depressed following radiotherapy and did not improve following enteral alimentation for 3 weeks. In untreated patients, there was a significant rise in levels of IgA (298 +/- 184 mg/100 ml) as compared to normal (154 +/- 54 mg/100 ml). Levels of IgA did show a downward trend following enteral hyperalimentation. Circulating immune complexes and serum CEA level were elevated in almost 50% of patients. These data confirm the influence of tumor-related impairment of cell-mediated immunity while nutrition appears to affect IgA levels.

Human nutrition and internal medicine

An abbreviation review explaining partly the role of human nutrition science in medicine shows that this very branch of medicine is not fully covered by dietetics, food hygiene or so-called metabolism as such. It forms on the contrary a special interdisciplinary part of it (such as e. g. clinical pharmacology) with its own methodology and field of research. Its large extent--from e. g. inborn errors of metabolism and their correction to illnesses caused by some substrate deficiency (malnutrition, hypovitaminosis, lack of minerals or microelements) or secondarily induced deficits of some enzymes etc.--can lead to regulatory, structural or functional disturbances in humans' organism. On the other side there is a lot of serious health impairments induced indirectly from overfeeding with energy or some imbalance food pattern as shown in the case of over doses of fat. Many other combinations of different factors (e. g. imbalance of fat and lack of some micronutrient, overdoses of vitamins or minerals) can enter into pathophysiology and should be subjects of further studies.

Cell-mediated immunity in malnourished guinea pigs after Mycobacterium bovis BCG vaccination

Specific-pathogen-free guinea pigs were vaccinated with viable Mycobacterium bovis BCG and maintained on purified, isocaloric diets containing either 30% or 7.5% casein, or commercial chow. At intervals of 4, 5, 6, and 8 weeks postvaccination, groups of guinea pigs from each diet treatment were skin tested with purified protein derivative and killed. Protein-deficient animals exhibited progressive reductions in total serum proteins and albumin. Significantly greater numbers of viable M. bovis BCG were recovered from the vaccination site and inguinal lymph nodes of protein-deficient guinea pigs at all intervals. In contrast, the development of delayed hypersensitivity was markedly retarded in the 7.5% casein group and was also reduced somewhat in the 30% casein group as compared to chow control. Peripheral blood lymphocytes from protein-deficient animals did not respond normally in vitro to a polyclonal T cell mitogen, phytohemagglutinin. These results demonstrate that protein-calorie malnutrition in this model impairs the development of cell-mediated immunity as evidenced by skin test anergy, lymphocyte hyporesponsiveness, and failure to control levels of viable M. bovis BCG after vaccination.

Resistance to bacterial and parasitic infections in the nutritionally compromised host

Over the past few years the relationships and interactions of diet, disease, and immunology are becoming better defined with the development and understanding of host defenses. Nutritional state, immunity, and disease all influence each other in the hospitalized patient, the elderly, and the young. Disease can alter nutritional needs and immune responses to antigens. The roles of both dietary excesses and deficiencies on cellular, secretory, and humoral immune responses are related to diseases and disease incidence in humans and experimental animals. Malnutrition alters incidence and severity of fungal, bacterial, viral, and parasitic pathogens. The mechanisms of altered disease resistance in nutritionally stressed animal models occurs via changes in the lymphoreticular endothelial system. The effects of common nutritional deficiencies, low protein, and low carbohydrate diets on antibody production, macrophage function, secretory IgA synthesis, and T-cell functions. Nutritional supplementation can increase lymphocyte function and decrease growth of some pathogens and tumors. Alternatively, obesity and high fat have roles in infectious disease and immunity.

Host defense mechanisms in protein energy malnutrition

This review has focused on effects of protein energy malnutrition on immune responses in the human host. These studies document major impairment of the T-cell and complement systems in severe PEM, and less profound, but probably significant, effects upon B-cells and immunoglobulins, particularly SIgA. While mild-moderate malnutrition also alters the T-cell system and may predispose to infection, there is less evidence to suggest that complement is similarly affected. Indeed, some data suggest that the host with mild to moderate malnutrition is still able to respond to stress with an acute phase serum protein response and to boost serum levels of complement and complement activity. This may be a functionally significant distinction, serving to separate the more from the less severely ill. Because many other factors alter immune responses, including vitamins, calories, and trace metals, and few clinical studies have examined these parameters, it is uncertain how much of the problem in malnutrition is due to protein, to energy intake, to iron, to other micronutrients and trace minerals, to vitamin E or to other vitamins alone or in combination with deficiencies in protein and energy. Other chapters in this volume attempt to sort out these questions in animal studies, but the relevance of these data for the human situation will remain uncertain until the investigations are carried out in humans as well.