Measurement of fecal lactoferrin as a marker of fecal leukocytes

Abstract

While diarrheal illnesses are extremely common in communities and hospitals throughout the world, an etiologic diagnosis may be expensive and cost-ineffective. Although the presence of fecal leukocytes are helpful in the diagnosis and specific therapy of inflammatory diarrheas, this requires prompt microscopic examination of fecal specimens (preferably obtained in a cup rather than a swab or diaper) by a trained observer. We developed a simple, sensitive test for the detection of leukocytes in fecal specimens using antilactoferrin antibody. Whereas radial immunodiffusion detected 0.02 micrograms of lactoferrin (LF) per microliter or greater than or equal to 2,000 leukocytes per microliter, latex agglutination (LA) readily detected greater than or equal to 0.001 micrograms of LF per microliter or greater than or equal to 200 leukocytes per microliter added to stool specimens. Despite the destruction or loss of morphologic leukocytes on storage for 1 to 7 days at 4 degrees C or placement of specimens on swabs, measurable LF remained stable. Initial studies of stool specimens from six patients with Salmonella or Clostridium difficile enteritis were positive and those from three controls were negative for LF by LA. Of 17 children in Brazil with inflammatory diarrhea (greater than or equal to 1 leukocyte per high-power field), 16 (94%) had LF titers of greater than 1:50 by LA, whereas only 3 of 12 fecal specimens with less than 1 leukocyte per high-power field on methylene blue examination and none of 7 normal control specimens had an LF titer of greater than 1:50 by LA. Of 16 fecal specimens from patients with C. difficile diarrhea (cytotoxin titers, >/= 1:1,000), 95% (n = 15) had detectable LF by LA (in titers of 1:100 to 1: 800). Finally, of 48 fecal specimens from healthy adult U.S. volunteers before and after experimental shigellosis and of 29 fecal specimens from children with documented shigellosis and hospitalized controls in northeastern Brazil, fecal LF titers ranged from 1:200 to >/= 1:5,000 in 96% (25 of 26) samples from patients with shigellosis (and reported positive for fecal leukocytes), while 51 controls consistently had fecal LF titers of </= 1:200. We conclude that fecal LF is a useful marker for fecal leukocytes, even when they are morphologically lost swab specimens or when they are destroyed on transport or storage or by cytotoxic fecal specimens.

Comparison of 4 Neutrophil-Derived Proteins in Feces As Indicators of Disease Activity in Ulcerative Colitis

“…Lf is an iron-binding glycoprotein that is secreted by most mucosal membranes. [6][7][8] It is a major component of the secondary granules of PMNs, which are a primary component of the acute inflammatory response. 9 Fecal Lf has proven useful in the discrimination of inflammatory conditions in inflammatory bowel disease (IBD) from several noninflammatory conditions including irritable bowel syndrome or healthy subjects and in patients with ileal pouch-anal anastomosis.…”

A longitudinal study of Giardia lamblia infection in north‐east Brazilian children

“…Specimens were examined for ova and parasites (including Giardia lamblia ) using Lugol’s iodine stain of both fresh and concentrated stool (formalin‐ethyl acetate, Fecal Parasite Concentrator, Evergreen Scientific, Los Angeles, CA, USA) at 400×. Stools were examined for Cryptosporidium oocysts using modified acid‐fast and auramine stains, and for faecal leucocytes using both microscopy (gram stain) and a latex agglutination assay for the detection of lactoferrin (Guerrant et al . 1992) ( LEUKO ‐TEST, Techlab, Blacksburg, VA, USA).…”

Prospective evaluation of faecal neutrophil‐derived proteins in identifying intestinal inflammation: combination of parameters does not improve diagnostic accuracy of calprotectin

“…3,4 During intestinal inflammation, PMN infiltrate the mucosa, resulting in an increase in the concentration of lactoferrin in the faeces and its presence is proportional to neutrophil translocation to the gastrointestinal tract. 5 Calprotectin, also known as L1 protein, MRP-8 ⁄ 14, calgranulin and cystic fibrosis antigen, is a 36 kDa calcium-and zinc-binding protein found in neutrophils and comprises up to 60% of their total cytosolic protein content. The protein is a heterocomplex protein consisting of two heavy chains and one light chain, which are non-covalently linked.…”