Serum ferritin in juvenile chronic polyarthritis

Nutritional Aspects of Juvenile Idiopathic Arthritis: An A to Z for Dietitians

Juvenile idiopathic arthritis (JIA) represents a chronic, autoimmune, rheumatic musculoskeletal disease with a diagnosis before 16 years of age. Chronic arthritis is a common manifestation in all JIA subtypes. The nature of JIA, in combination to its therapy often results in the development of nutrition-, gastrointestinal (GI)- or metabolic-related issues. The most-common therapy-related nutritional issues involve methotrexate (MTX) and glucocorticosteroids (GCC) adverse events. MTX is a folic acid antagonist, thus supplementation with folic acid in required for improving GI side effects and correcting low serum levels. On the other hand, long-term GCC administration is often associated with hyperglycemia, insulin resistance and growth delay. This relationship is further aggravated when more joints are affected and greater doses of GCC are being administered. Apart from stature, body mass index z-scores are also suboptimal in JIA. Other signs of malnutrition include decreased phase angle and muscle mass, especially among patients with polyarthritis JIA. Evidence also points to the existence of an inverse relationship between disease activity and overweight/obesity. Specific dietary patterns, including the anti-inflammatory diet, might confer improvements in selected JIA outcomes, but the level of available research is yet insufficient to draw safe conclusions. The majority of patients exhibit suboptimal vitamin D status; hence, supplementation is recommended. Collectively, the evidence indicates that, due to the age of onset and the complexity of the disease, along with its pharmacotherapy, children with JIA are prone to the development of several nutritional problems, warranting expert monitoring. Vitamin deficiencies, oral and GI-problems limiting dietary intake, faltering growth, overweight and obesity, physical inactivity, or impaired bone health are among the many nutritional issues in JIA requiring dietitian support.

Anaemia in juvenile chronic arthritis

Anaemia is a common manifestation of juvenile rheumatoid arthritis (JCA). We have evaluated 26 JCA patients with anaemia and compared their laboratory parameters to those without anaemia. In the patients with anaemia, activation criteria such as erythrocyte sedimentation rate (ESR) and CRP were significantly higher than in those without anaemia. Anaemia was present in all systemic JCA patients and was present in 42% and 78% of the oligoarticular and polyarticular types, respectively. Serum iron levels and transferrin saturations were low in all, whereas serum iron-binding capacities of the patients were normal. Mean ferritin level was 249pg/l (range 8.46-1000pg/l). There was a significant correlation between ferritin levels and CRP and ESR (r = 0.48 and r = 0.55 respectively) (both p < 0.05). Epo levels were normal. Twelve (60%) of the bone marrow aspiration specimens stained positive for iron whereas 40% stained negative; there were also changes suggestive of myelodysplasia. Sideroblasts were also decreased in number. Thus, in these patients iron is not sufficiently transferred to the erythroid series and/or cannot be used by erythroblasts, accompanied by a possible absolute iron deficiency. Thus we suggest that the iron in JCA tends to be stored in the form of ferritin, not in an accessible form and impaired metabolism along with other factors are effective in the anaemia of JCA.

Relationship between serum ferritin, iron stores and disease activity in rheumatoid arthritis

Bone marrow aspirate from the sternum of 40 patients with active or inactive rheumatoid arthritis (RA) was stained with Perls' Prussian blue for iron determination. In these patients serum ferritin concentrations were correlated with other indices of iron stores and disease activity. In patients with active RA and without bone marrow iron stores, serum ferritin was significantly lower than in patients with either active or inactive RA and iron stores. In patients with bone marrow iron stores, serum ferritin was directly correlated with erythrocyte sedimentation rate (ESR), Ritchie index, alpha 1-antitrypsin, alpha 1-acid glycoprotein and desferrioxamine (DFO)-induced sideruria, while an inverse correlation of serum ferritin with hemoglobin and serum iron was observed. In all patients serum ferritin was significantly correlated only with DFO-induced sideruria and unsaturated iron-binding capacity (UIBC). Thus, serum ferritin is an index of iron stores also in rheumatoid arthritis. In active disease, higher than expected values of serum ferritin are probably due to a shifting of iron from the circulating pool to the reticuloendothelial cells of the synovial membrane.

Ferritinemia as an indicator of systemic disease activity in children with systemic juvenile rheumatoid arthritis

Twenty children with systemic juvenile rheumatoid arthritis, aged 0.9-13.7 years, were studied with regard to their serum ferritin concentration at diagnosis and during follow-up, ranging from 2 to 9 years. At diagnosis, during fever, the concentration was extremely high. The median value was 935 micrograms/l. The values were unrelated to other manifestations of the disease or laboratory findings. During glucocorticoid treatment, the serum ferritin concentrations normalized rapidly, usually within a few weeks. The rate of normalization reflected the response of the fever to treatment. Later, subnormal concentrations were found, which were unrelated to the activity of the arthritis. Thus, serum ferritin is a useful guide when tapering glucocorticoid dosage.

Serum ferritin and the assessment of iron deficiency in rheumatoid arthritis

In order to evaluate the diagnostic and pathogenetic importance of s-ferritin and p-lactoferrin in the anemia of rheumatoid arthritis (RA), 38 patients were examined. Twenty-one out of 38 randomly selected anemic patients with classical or definite RA had iron deficiency, as estimated from the iron content in stained bone marrow aspiration. S-ferritin concentrations below 60 micrograms per litre had sensitivity and a specificity for iron deficiency of 86% and 88%, respectively, which was much better than such commonly used variables as s-iron, p-transferrin, MCV, and MCHC. Although this cut-off level is higher than in patients without inflammatory disease, s-ferritin was not correlated to disease activity. In 7 out of 8 patients, the s-ferritin level rose during iron therapy. P-lactoferrin values were within the normal range and did not vary with the anemia or with disease activity. Thus p-lactoferrin appears to be of no pathogenetic importance in the anemia of RA.

Serum ferritin and iron uptake by peripheral blood leucocytes in patients with active rheumatoid arthritis

Rheumatoid arthritis is a systemic disease in which anaemia is common. The origin of the anaemia is usually multifactorial. Iron deficiency, a defect of release of iron from the reticulo-endothelial system is discussed. Ferritin content of monocytes, lymphocytes and polymorphs is found altered and mostly elevated in monocytes affected by serum iron deficiency. In all cell types iron uptake is related to transferrin saturation. Alterations against normal subjects in iron uptake, ferritin synthesis and iron incorporation into ferritin are mostly found in patients with serum iron deficiency.

Assessment of iron stores in inflammation by assay of serum ferritin concentrations

A serum ferritin concentration of below 15 microgram/l is accepted as indicating diminished iron reserves in an otherwise normal person. In patients with inflammatory disease this lower limit of normality may be inappropriate as inflammation may directly stimulate the production of ferritin protein. Results obtained in a survey of 150 patients with early inflammatory joint disease suggest that a ferritin concentration of 55 microgram/l is a more appropriate lower limit of normality.

Relationship between serum ferritin, anemia, and disease activity in acute and chronic rheumatoid arthritis

The assessment of anemia in patients with rheumatoid arthritis may be difficult, especially when iron deficiency and the anemia of chronic disease coexist. The development of a radioimmunoassay for serum ferritin concentration has aided the detection of reduced body iron stores in uncomplicated iron deficiency, but its use is compromised in clinically active rheumatoid arthritis by the tendency of serum ferritin to behave as an acute phase reactant. In this latter role it correlated well with disease activity in the patients we studied. Followed serially, serum ferritin levels fell in patients whose disease activity improved after institution of appropriate therapy. In anemic patients with clinically inactive disease, supplemental iron was associated with a significant rise in hemoglobin when compared to untreated patients. Serum ferritin levels behaved independently of hemoglobin levels. Therefore even in clinically inactive rheumatoid arthritis, serum ferritin does not accurately reflect an iron deficiency.

Plasma ferritin concentrations: their clinical significance and relevance to patient care

In healthy persons the plasma ferritin concentration is a sensitive index of the size of body iron stores. It has been successfully applied to large-scale surveys of the iron status of populations. It has also proved useful in the assessment of clinical disorders of iron metabolism. A low plasma ferritin level has a high predictive value for the diagnosis of uncomplicated iron deficiency anemia. It is of less value, however, in anemia associated with infection, chronic inflammatory disorders, liver disease and malignant hematologic diseases, for which a low level indicates iron deficiency and a high level excludes it, but intermediate levels are not diagnostic. Measuring the plasma ferritin concentration is also useful for the detection of excess body iron, particularly in idiopathic hemochromatosis, but again it lacks specificity in the presence of active hepatocellular disease. If iron overload is suspected in these circumstances determination of the iron content of a percutaneous liver biopsy specimen is required. In families with idiopathic hemochromatosis the combined determination of the plasma ferritin concentration and the transferrin saturation is a sufficient screen to identify affected relatives; however, estimation of the hepatic iron concentration is required to establish the diagnosis.

Serum ferritin in assessment of iron nutrition in healthy infants

We followed up 238 infants on 7 occasions during their first year of life. The diets of the infants were systematically either supplemented or not supplemented with iron. Developmental changes in serum ferritin were determined from a group with adequate intake of iron and without evidence of iron deficiency by three laboratory criteria: hemoglobin, mean corpuscular volume and transferrin saturation. The data indicate that the average level of serum ferritin correlates well with iron nutrition within groups of infants since the developmental changes are in accordance with the known changes in storage iron, the level of serum ferritin correlates with iron intake, and low ferritin levels are associated with lower transferrin saturation. The usefulness of serum ferritin as the sole criterion of iron deficiency in individual infants is limited, suggesting the use of more than one indicator to refine the diagnosis of iron deficiency without anemia.