Specific protein assays in protein-calorie malnutrition

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.

Serum C-reactive protein and C3 complement protein levels in severely malnourished Nigerian children with and without bacterial infections

Bacterial infections are the major determinants of fatality in severe protein-energy malnutrition (PEM). Unfortunately, these infections are difficult to diagnose clinically. C-reactive protein (CRP) levels were determined in 17 infected and 10 non-infected Nigerian children with severe PEM and compared with age/sex-matched apparently healthy controls. The aim was to study the response of this acute phase protein to bacterial infections as well as to assess its value in the diagnosis of infections in severe PEM. C3 complement protein levels were also determined in the same group of subjects. The major organisms isolated in samples from these subjects were S. aureus and the coliforms. Mean CRP level in the non-infected children with severe PEM was 13.8 +/- 6.21 mg/l and rose to 159.83 +/- 124.07 mg/l in the presence of infection. The mean value in healthy non-infected controls was 2.01 +/- 0.96 mg/l. The difference in the mean CRP levels between the infected and non-infected PEM children was statistically significant at p < 0.01. The mean difference between the non-infected and the control subjects was not significant. Using a diagnostic level of 20.00 mg/l of CRP gave a sensitivity of 85.0% and a specificity of 80.0%. This CRP level is a useful index of bacterial infections in severe PEM. C3 complement protein was low in the non-infected malnourished group, but rose significantly in the presence of infection to values similar to that of the healthy controls. C3 protein thus behaves as an acute phase reactant in the presence of infection in severe PEM, and does not appear to be consumed, probably due to a deficiency in the early components of the complement cascade. This suggests a role for C3 measurement in the monitoring of bacterial infections in severe PEM.

Serum lipid concentrations in patients with major depressive disorder

This study compared the serum lipid concentrations in 100 patients with major depressive disorder (MDD) with those from 100 matched healthy controls. It was found that the serum total cholesterol concentration in patients with MDD (5.27 +/- 1.18 mmol/L) was significantly lower than the value (6.63 +/- 1.32 mmol/L) in sex-, age-, and weight-matched healthy controls. This significant decrease in serum cholesterol in patients with MDD was noted in both sexes and in all age groups. Patients with MDD, however, had significantly higher HDL cholesterol than matched controls. There were no statistically significant differences in serum concentrations of triglycerides, apolipoprotein (Apo) A1, Apo B, transferrin, and albumin between patients and controls. Clinical recovery of patients with MDD was accompanied by a significant increase in serum total cholesterol from 5.27 +/- 1.18 mmol/L to 6.12 +/- 1.2 mmol/L. These results suggest an association between low serum total cholesterol and depression in both sexes and at all age groups.

Differential effects of three enteral dietary regimens on selected outcome variables in burn patients

A modular tube feeding recipe (MTF) was designed to meet the unique nutritional needs of burn patients, applying principles previously documented in our burned guinea pig model. MTF, a high-protein, low-fat, linoleic acid-restricted formulation is enriched with omega-3 fatty acids, arginine, cysteine, histidine, vitamin A, zinc, and ascorbic acid. Fifty patients, 3 to 76 years of age with burns ranging from 10 to 89% total body surface area were prospectively randomized into three groups which blindly compared MTF to two enteral regimens widely utilized in the nutritional support of burns. Age, percent total and third-degree burn, resting energy expenditure, and calorie and protein intake were similar in all groups. Data analysis demonstrated significant superiority of MTF in the reduction of wound infection (p less than 0.03) and length of stay/percent burn (p less than 0.02). MTF was also associated with a decreased incidence of diarrhea, improved glucose tolerance, lower serum triglycerides, reduced total number of infectious episodes and trends toward improved preservation of muscle mass, although statistical significance was not achieved. Seventy percent of deaths occurred in the group supported with an inherently large dose of fat and linoleic acid. Combining these observations, it is believed that MTF is effective in modulating an improved response to burn injury.

The measurement of albumin in serum and plasma

This publication was prepared at the invitation of the Analytical Methods Working Party of the Scientific Committee of the Association of Clinical Biochemists, but does not necessarily reflect the views of the Scientific Committee.

Influence of total parenteral nutrition on plasma fibronectin in malnourished subjects with or without inflammatory response

Plasma fibronectin, which is an alpha 2-glycoprotein of importance for the immunodefence, has been reported to decrease after starvation and in severely ill patients with cancer. To evaluate the usefulness of fibronectin as an indicator of nutritional repletion, 18 patients with gastrointestinal disorders were studied over a 2-wk period of total parenteral nutrition (TPN). According to nutritional assessment on admission the patients were divided into well nourished (n = 6) and malnourished (n = 12). For comparison nine patients with anorexia nervosa were also studied over a 3-wk period of TPN. Before and after TPN fibronectin, albumin, prealbumin, transferrin, and two acute-phase reactants, haptoglobin and orosomucoid were measured in plasma. The majority of the malnourished patients had an inflammatory reaction in contrast to only a few of the well-nourished and anorexia nervosa patients. Of the proteins measured, only fibronectin rose significantly in the malnourished patients (malnourished and anorexia nervosa), but not in the well nourished patients during TPN. Our results may indicate the usefulness of fibronectin as an indicator of short-term TPN in malnourished subjects, irrespective of the presence or absence of inflammatory response.

A study of enocrine function in protein-energy malnutrition

Serum concentration of cortisol, growth hormone, thyroxine, thyroid stimulating hormone, follicle stimulating hormone and luteinising hormone, together with triiodothyronine uptake have been measured in Nigerian children with kwashiorkor and marasmus and compared with controls. In both types of malnutrition the cortisol and growth hormone concentrations are raised, whereas those of thyroxine and thyroid stimulating hormone are lowered compared with the controls. Triiodothyronine uptake is lowered in malnutrition but there is no apparent effect on follicle stimulating hormone or luteinising hormone in this age group.