Aging Clin. Exp. Res. 4: 135-137, 1992
Plasma lactoferrin as a marker of infection in elderly individuals E.O. Adeyemi*, c. D'Anastasio**, M.G. Impallomeni**, and H.J.F. Hodgson* *Gastroenterology Unit and **Geriatric Unit , Department of Medicine , Royal Postgraduate Medical School, Hammersmith Hospital, London, Great Britain ABSTRACT To assess lactoferrin as a marker of infection , plasma lactoferrin (LF) levels were determined in elderly in-patients with infection and compared with age- and sexmatched healthy and hospital controls and young healthy blood donors. The median LF level in infection (800 nglmL) was significantly higher than in healthy elderly living in old people's home (300 nglmL) or elderly hospital controls (298 nglmL) (p < 0.01 in each case). Plasma LF correlated significantly with elastase alpha-l-proteinase inhibitor complex (EPIC) (R, = 0.8, p < 0.01) and C-reactive protein (CRP) (R; = 0.45, p < 0.02), but not with erythrocyte sedimentation rate (ESR) or white blood cell counts. We conclude that plasma LF, like CRP and EPIC, is a marker of infection in elderly individuals. (Aging Clin. Exp. Res. 4: 135-137, 1992) INTRODUCTION We recently showed that polymorphonuclear leucocyte (PMNL) elastase, which is stored in the azurophil granules, is elevated in the blood of elderly patients with various forms of infection (1). Lactoferrin (LF), another plasma protein stored predominantly in specific granules of PMNLs, was reported to increase uptake and killing of intracellular forms of trypanosoma cruzi by murine peritoneal macrophage and human blood monocytes (2). The aim of this study was to quantitate plasma
LF levels in elderly individuals with infection, as a measure of innate immune response, and a marker of infection in the elderly. HEALTHY CONTROLS AND PATIENTS Thirty-one individuals from the geriatric wards of the Hammersmith Hospital with infection (group I), and 20 individuals in each of the following groups, elderly in-patients without infection (group In, healthy residents in old people 's homes (group III), and young adult blood donors (group IV) , form the basis of this study. The patients and control groups were described elsewhere (1). Elderly patients with infection were selected according to the following criteria: a) clinical and/or radiological chest findings indicating acute infection; b) abnormal urine sediment on microscopy with or without tenderness in the renal angle and lumbar region ; c) presence of fever with or without increased white blood cell count (> 10 x 10 9IL); d) deterioration of general well-being; and e) identification of the offending organism in (a) , (b) or (c). Four subgroups were identified : I) 19 patients, in whom the offending organisms were cultured, referred to as culture-positive individuals; II) 12 patients in whom the microorganisms were not cultured, referred to as culture-negative individuals;
Key words: C-reactive protein , elastase-proteinase-inhibitor complex, elderly, infection, lactoferrin. Correspondence: Dr. Edward O. Adeyemi, Department of Medicine, Royal Postgraduate MedicalSchool, Hammersmith Hospital, 150 Du Cane Road, London W12 OHS , Great Britain. Received June 29 , 1990; accepted October 1, 1991.
Aging Clin. Exp. Res., Vol. 4, N. 2 135
E.O. Adeyemi, C. D'Anastasio, G. Impallomeni, et al.
III) 14 patients with urinary tract infection (UTI); and IV) 12 patients with chest infection.
5000 4000
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MATERIALS AND METHODS
Enzyme-linked immunosorbent assays (ELISA) were used to determine lactoferrin, C-reactive protein (CRP) and elastase, measured as alpha-1proteinase inhibitor-bound elastase (EPIC), and were described elsewhere (3, 4).
Statistics Non-parametric tests of significance were used to test the level of significance (Mann-Whitney) and the degree of interdependence between data groups (Spearman).
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RESULTS
Median plasma LF values in groups I-IV were 800, 298, 300, and 208 ng/mL, respectively (Fig. 1). The median value in the infection group was significantly higher than in each of the other groups (p < 0.01 in each case). There was no significant difference between the median LF values of hospital and healthy control groups (p = 0.34). However, the median LF value of the non-geriatric controls (208 ng/mL) was significantly lower than each of the control groups (p < 0.01 in each case). The median LF values in patients with UTI and chest infection were 885 ng/mL (range 260 4540) and 875 ng/mL (range 500 - 2400), respectively, and the difference was not significant (p = 0.2). There was also no significant difference between the median LF values of culture-positive (800 ng/mL, range 260 - 4540) and culture-negative patients (850 ng/mL, range 330 - 2400) (p = 0.2). LF concentrations correlated significantly with elastase (Rs = 0.8, p < 0.01) and CRP (R, = 0.45, p < 0.02) levels, but not with ESR values (R, = 0.2, p > 0.05). DISCUSSION
This study shows that plasma lactoferrin is elevated in the blood of elderly patients with infection without significant overlap with age- and
136 Aging Clin. Exp. Res., Vol. 4, N. 2
Figure 1 - Plasma lactoferrin levels in elderly hospital inpatients with infection (closed and open circles indicate culture-positive and negative cases of injection respectively), elderly hospital in-patients without infection (hospital controls), healthy residents in old people's home (healthy controls), and young adult controls.
sex-matched healthy controls and young healthy controls. This LF elevation in infection, or significantly higher median level in the elderly than in the young, is similar to that previously reported for elastase (1). This strong correlation between lactoferrin and elastase is not surprising, as lactoferrin is released pari passu with elastase during PMNL activation and degranulation (3). Plasma lactoferrin also correlated significantly with CRP. This agrees with our previous findings in patients with active rheumatoid arthritis (4). Lactoferrin may have some advantages over established markers of inflammation, as it is also a biological chelator of iron. By binding iron, which microorganisms need for growth, it can be bacteriostatic (5) during inflammation. In support of its anti-bacterial activity, lactoferrin was recently shown to accelerate Fe 2+ autoxidation, a process which promotes the for-
Lactoferrin and infection in the elderly
mation of oxygen and hydroxyl radicals in the Haber-Weiss reaction (6). Elastase, on the other hand, does not have iron-binding properties, but probably exerts its anti-bacterial activity by degrading the bacterial cell wall as reported recently (4). Levels of C-reactive protein, the classical acute phase reactant synthesized and released from the liver in response to various cytokines, are elevated in trivial viral infections (7); lactoferrin and elastase reflect PMNL degranulation, and their values are not raised in this situation. Finally, in our laboratory, the cost of processing one hundred specimens in a batch is less than twenty pounds sterling. We conclude that plasma lactoferrin may function as another marker of infection or inflammation in the elderly. Like neutrophil elastase, with which it shares a common source, it reflects neutrophil activation and degranulation. In addition to its ability to bind iron (5), which is essential for bacterial cell growth, it may also enhance host defense against infection, as Lima et al. (2) demonstrated in vitro.
REFERENCES 1. Adeyemi E.O., D'Anastasio C; Impallomeni M., Hodgson H.J.F.: Circulating neutrophil elastase in infectious diseases in geriatric patients. Aging Clin. Exp. Res. 1: 65-70, 1989. 2. Lima M.L, Kierszenbaum F.: Lactoferrin effects on phagocytic cell function. Increased uptake and killing of an intracellular parasite by murine macrophages and human monocytes. J. Immunol. 134: 4176-4183,1985. 3. Adeyemi E.O., Hodgson H.J.F.: Augmented release of human leucocyte lactoferrin (and elastase) during coagulation. J. Clin. Lab. Immunol. 27: 1-4, 1988. 4. Adeyemi E.O., Campos L., Louizo L., Walport M., Hodgson H.J.F.: Plasma lactoferrin and neutrophil elastase in rheumatoid arthritis and systemic lupus erythematosus. Br. J. Rheumatol. 19: 15-20, 1990. 5. Molloy A.L., Winterbourn c.c.: Release of iron from phagocytosed Escherichia coli and uptake by neutrophillactoferrin. Blood 75: 984-989, 1990. 6. Klebanoff S.J., Waltersdorph A.M.: Prooxidant activity of transferrin and lactoferrin. J. Exp. Med. 172: 1293-1303,1990. 7. Adeyemi E.O., Hodgson H.J.F.: Lactoferrin: a correlate of disease activityin inflammatory bowel disease. Eur. J. Gastroenterol. Hepatol. 3: 51-56,1991.
Aging Clin. Exp. Res., Vol. 4, N. 2 137
Plasma lactoferrin as a marker of infection in elderly individuals E.O. Adeyemi*, c. D'Anastasio**, M.G. Impallomeni**, and H.J.F. Hodgson* *Gastroenterology Unit and **Geriatric Unit , Department of Medicine , Royal Postgraduate Medical School, Hammersmith Hospital, London, Great Britain ABSTRACT To assess lactoferrin as a marker of infection , plasma lactoferrin (LF) levels were determined in elderly in-patients with infection and compared with age- and sexmatched healthy and hospital controls and young healthy blood donors. The median LF level in infection (800 nglmL) was significantly higher than in healthy elderly living in old people's home (300 nglmL) or elderly hospital controls (298 nglmL) (p < 0.01 in each case). Plasma LF correlated significantly with elastase alpha-l-proteinase inhibitor complex (EPIC) (R, = 0.8, p < 0.01) and C-reactive protein (CRP) (R; = 0.45, p < 0.02), but not with erythrocyte sedimentation rate (ESR) or white blood cell counts. We conclude that plasma LF, like CRP and EPIC, is a marker of infection in elderly individuals. (Aging Clin. Exp. Res. 4: 135-137, 1992) INTRODUCTION We recently showed that polymorphonuclear leucocyte (PMNL) elastase, which is stored in the azurophil granules, is elevated in the blood of elderly patients with various forms of infection (1). Lactoferrin (LF), another plasma protein stored predominantly in specific granules of PMNLs, was reported to increase uptake and killing of intracellular forms of trypanosoma cruzi by murine peritoneal macrophage and human blood monocytes (2). The aim of this study was to quantitate plasma
LF levels in elderly individuals with infection, as a measure of innate immune response, and a marker of infection in the elderly. HEALTHY CONTROLS AND PATIENTS Thirty-one individuals from the geriatric wards of the Hammersmith Hospital with infection (group I), and 20 individuals in each of the following groups, elderly in-patients without infection (group In, healthy residents in old people 's homes (group III), and young adult blood donors (group IV) , form the basis of this study. The patients and control groups were described elsewhere (1). Elderly patients with infection were selected according to the following criteria: a) clinical and/or radiological chest findings indicating acute infection; b) abnormal urine sediment on microscopy with or without tenderness in the renal angle and lumbar region ; c) presence of fever with or without increased white blood cell count (> 10 x 10 9IL); d) deterioration of general well-being; and e) identification of the offending organism in (a) , (b) or (c). Four subgroups were identified : I) 19 patients, in whom the offending organisms were cultured, referred to as culture-positive individuals; II) 12 patients in whom the microorganisms were not cultured, referred to as culture-negative individuals;
Key words: C-reactive protein , elastase-proteinase-inhibitor complex, elderly, infection, lactoferrin. Correspondence: Dr. Edward O. Adeyemi, Department of Medicine, Royal Postgraduate MedicalSchool, Hammersmith Hospital, 150 Du Cane Road, London W12 OHS , Great Britain. Received June 29 , 1990; accepted October 1, 1991.
Aging Clin. Exp. Res., Vol. 4, N. 2 135
E.O. Adeyemi, C. D'Anastasio, G. Impallomeni, et al.
III) 14 patients with urinary tract infection (UTI); and IV) 12 patients with chest infection.
5000 4000
E
MATERIALS AND METHODS
Enzyme-linked immunosorbent assays (ELISA) were used to determine lactoferrin, C-reactive protein (CRP) and elastase, measured as alpha-1proteinase inhibitor-bound elastase (EPIC), and were described elsewhere (3, 4).
Statistics Non-parametric tests of significance were used to test the level of significance (Mann-Whitney) and the degree of interdependence between data groups (Spearman).
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RESULTS
Median plasma LF values in groups I-IV were 800, 298, 300, and 208 ng/mL, respectively (Fig. 1). The median value in the infection group was significantly higher than in each of the other groups (p < 0.01 in each case). There was no significant difference between the median LF values of hospital and healthy control groups (p = 0.34). However, the median LF value of the non-geriatric controls (208 ng/mL) was significantly lower than each of the control groups (p < 0.01 in each case). The median LF values in patients with UTI and chest infection were 885 ng/mL (range 260 4540) and 875 ng/mL (range 500 - 2400), respectively, and the difference was not significant (p = 0.2). There was also no significant difference between the median LF values of culture-positive (800 ng/mL, range 260 - 4540) and culture-negative patients (850 ng/mL, range 330 - 2400) (p = 0.2). LF concentrations correlated significantly with elastase (Rs = 0.8, p < 0.01) and CRP (R, = 0.45, p < 0.02) levels, but not with ESR values (R, = 0.2, p > 0.05). DISCUSSION
This study shows that plasma lactoferrin is elevated in the blood of elderly patients with infection without significant overlap with age- and
136 Aging Clin. Exp. Res., Vol. 4, N. 2
Figure 1 - Plasma lactoferrin levels in elderly hospital inpatients with infection (closed and open circles indicate culture-positive and negative cases of injection respectively), elderly hospital in-patients without infection (hospital controls), healthy residents in old people's home (healthy controls), and young adult controls.
sex-matched healthy controls and young healthy controls. This LF elevation in infection, or significantly higher median level in the elderly than in the young, is similar to that previously reported for elastase (1). This strong correlation between lactoferrin and elastase is not surprising, as lactoferrin is released pari passu with elastase during PMNL activation and degranulation (3). Plasma lactoferrin also correlated significantly with CRP. This agrees with our previous findings in patients with active rheumatoid arthritis (4). Lactoferrin may have some advantages over established markers of inflammation, as it is also a biological chelator of iron. By binding iron, which microorganisms need for growth, it can be bacteriostatic (5) during inflammation. In support of its anti-bacterial activity, lactoferrin was recently shown to accelerate Fe 2+ autoxidation, a process which promotes the for-
Lactoferrin and infection in the elderly
mation of oxygen and hydroxyl radicals in the Haber-Weiss reaction (6). Elastase, on the other hand, does not have iron-binding properties, but probably exerts its anti-bacterial activity by degrading the bacterial cell wall as reported recently (4). Levels of C-reactive protein, the classical acute phase reactant synthesized and released from the liver in response to various cytokines, are elevated in trivial viral infections (7); lactoferrin and elastase reflect PMNL degranulation, and their values are not raised in this situation. Finally, in our laboratory, the cost of processing one hundred specimens in a batch is less than twenty pounds sterling. We conclude that plasma lactoferrin may function as another marker of infection or inflammation in the elderly. Like neutrophil elastase, with which it shares a common source, it reflects neutrophil activation and degranulation. In addition to its ability to bind iron (5), which is essential for bacterial cell growth, it may also enhance host defense against infection, as Lima et al. (2) demonstrated in vitro.
REFERENCES 1. Adeyemi E.O., D'Anastasio C; Impallomeni M., Hodgson H.J.F.: Circulating neutrophil elastase in infectious diseases in geriatric patients. Aging Clin. Exp. Res. 1: 65-70, 1989. 2. Lima M.L, Kierszenbaum F.: Lactoferrin effects on phagocytic cell function. Increased uptake and killing of an intracellular parasite by murine macrophages and human monocytes. J. Immunol. 134: 4176-4183,1985. 3. Adeyemi E.O., Hodgson H.J.F.: Augmented release of human leucocyte lactoferrin (and elastase) during coagulation. J. Clin. Lab. Immunol. 27: 1-4, 1988. 4. Adeyemi E.O., Campos L., Louizo L., Walport M., Hodgson H.J.F.: Plasma lactoferrin and neutrophil elastase in rheumatoid arthritis and systemic lupus erythematosus. Br. J. Rheumatol. 19: 15-20, 1990. 5. Molloy A.L., Winterbourn c.c.: Release of iron from phagocytosed Escherichia coli and uptake by neutrophillactoferrin. Blood 75: 984-989, 1990. 6. Klebanoff S.J., Waltersdorph A.M.: Prooxidant activity of transferrin and lactoferrin. J. Exp. Med. 172: 1293-1303,1990. 7. Adeyemi E.O., Hodgson H.J.F.: Lactoferrin: a correlate of disease activityin inflammatory bowel disease. Eur. J. Gastroenterol. Hepatol. 3: 51-56,1991.
Aging Clin. Exp. Res., Vol. 4, N. 2 137
