Human Neutrophil Lipocalin Research Articles

A host-protein signature is superior to other biomarkers for differentiating between bacterial and viral disease in patients with respiratory infection and fever without source: a prospective observational study

Bacterial and viral infections often present with similar symptoms. Etiologic misdiagnosis can alter the trajectory of patient care, including antibiotic overuse. A host-protein signature comprising tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interferon gamma-induced protein-10 (IP-10), and C-reactive protein (CRP) was validated recently for differentiating bacterial from viral disease. However, a focused head-to-head comparison of its diagnostic performance against other biomarker candidates for this indication was lacking in patients with respiratory infection and fever without source. We compared the signature to other biomarkers and prediction rules using specimens collected prospectively at two secondary medical centers from children and adults. Inclusion criteria included fever > 37.5 °C, symptom duration ≤ 12 days, and presentation with respiratory infection or fever without source. Comparator method was based on expert panel adjudication. Signature and biomarker cutoffs and prediction rules were predefined. Of 493 potentially eligible patients, 314 were assigned unanimous expert panel diagnosis and also had sufficient specimen volume. The resulting cohort comprised 175 (56%) viral and 139 (44%) bacterial infections. Signature sensitivity 93.5% (95% CI 89.1–97.9%), specificity 94.3% (95% CI 90.7–98.0%), or both were significantly higher (all p values < 0.01) than for CRP, procalcitonin, interleukin-6, human neutrophil lipocalin, white blood cell count, absolute neutrophil count, and prediction rules. Signature identified as viral 50/57 viral patients prescribed antibiotics, suggesting potential to reduce antibiotic overuse by 88%. The host-protein signature demonstrated superior diagnostic performance in differentiating viral from bacterial respiratory infections and fever without source. Future utility studies are warranted to validate potential to reduce antibiotic overuse.

Species-Wide Genome Mining of Pseudomonas putida for Potential Secondary Metabolites and Drug-Like Natural Products Characterization

The gram negative bacteria species of Pseudomonas putida (P. putida) are important for heterologous expression of diverse biosynthetic pathways and numerous secondary metabolites biosynthesis. The genes code for such secondary metabolites biosynthetic proteins are organized in microbial genomes as clusters to bring the concerted expression of entire biosynthetic machinery. The complete and whole genome sequences of more than fifty different strains available in public DNA sequences databases provide an excellent opportunity to investigate the genetically encoded secondary metabolites potential of ecologically diverse P. putida strains. We implement the advance bioinformatics resources to annotate the so far available P. putida strains genomes for biosynthetic gene clusters (BGCs) and underlie secondary metabolites chemical scaffolds. The P. puida strains are found to harbor genomic signatures coding the molecular machinery for diverse secondary metabolites biosynthesis. The corresponding BGCs of these metabolites are found to be uniquely distributed across different P. putida strains speculate their role toward strain's ecological competency acquirement. The chemoinformatics dereplication and DrugBank database searching revealed the chemical mimicry of one putative metabolite with 2, 3, Dihydroxybenzoylserine, that mediates an antibiotic iron depletion along with human neutrophil lipocalin during innate immune response.

Distinction between bacterial and viral infections by serum measurement of human neutrophil lipocalin (HNL) and the impact of antibody selection

The distinction between acute infections of bacterial or viral causes is clinically important, but often very difficult even for experienced doctors. Previous studies indicated that serum measurements of HNL (Human Neutrophil Lipocalin) might be a superior diagnostic means in this regard, but also indicated that the antibody conformation of the HNL assay might have an impact on the diagnostic performance. The aim of the present report was to examine this further. MethodsSeveral different (n=24) HNL ELISA assays were developed using different combinations of monoclonal and polyclonal HNL antibodies. Sera were collected from healthy persons (n=188) and from 155 patients with acute infections before any antibiotics treatment. The patients were diagnosed as having bacterial (n=69) or viral causes (n=86) of their infections. Plasma and serum were also examined by Western blotting using HNL-specific polyclonal antibodies. ResultsThe optimal assay format for the distinction between bacterial and viral infection resulted in an area under the receiver operating characteristics curve (AuROC) for S-HNL of 0.98.(95% CI 0.94–1.00) as compared to 0.83 (0.76–0.88) for blood neutrophil counts and 0.69 (0.61–0.76) for S-CRP. Results also showed that different assay formats of HNL identified monomeric and dimeric HNL differently, the monomeric HNL being elevated in viral infections and the dimeric HNL being elevated in bacterial infections. ConclusionWe conclude that serum measurement of HNL is a superior diagnostic means to distinguish between acute infections caused by bacteria or virus. For optimal clinical performance the immunoassay should address conformational epitopes in the dimeric HNL.

Human Neutrophil Lipocalin as a Superior Diagnostic Means To Distinguish between Acute Bacterial and Viral Infections

The distinction between causes of acute infections is a major clinical challenge. Current biomarkers, however, are not sufficiently accurate. Human neutrophil lipocalin (HNL) concentrations in serum or whole blood activated by formyl-methionine-leucine-phenylalanine (fMLP) were shown to distinguish acute infections of bacterial or viral cause with high accuracy. The aim was therefore to compare the clinical performance of HNL with currently used biomarkers. Seven hundred twenty-five subjects (144 healthy controls and 581 patients with signs and symptoms of acute infections) were included in the study. C-reactive protein (CRP), the expression of CD64 on neutrophils, procalcitonin (PCT), and blood neutrophil counts were measured by established techniques, and HNL concentrations were measured in whole-blood samples after activation with fMLP. All tested biomarkers were elevated in bacterial as opposed to viral infections (P < 0.001). CRP, PCT, and CD64 expression in neutrophils was elevated in viral infections compared to healthy controls (P < 0.001). In the distinction between healthy controls and patients with bacterial infections, the areas under the receiver operating characteristic (ROC) curves were >0.85 for all biomarkers, whereas for the distinction between bacterial and viral infections, only HNL concentration in fMLP-activated whole blood showed an area under the ROC curve (AUROC) of >0.90 and superior clinical performance. The clinical performance of HNL in fMLP-activated whole blood was superior to current biomarkers and similar to previous results of HNL in serum. The procedure can be adopted for point-of-care testing with response times of <15 min.

Human neutrophil lipocalin in fMLP-activated whole blood as a diagnostic means to distinguish between acute bacterial and viral infections

The distinction between causes of acute infections is a major clinical challenge. Current biomarkers, however, are not sufficiently accurate. Human neutrophil lipocalin (HNL) in serum distinguishes acute infections with high accuracy, but in the emergency setting the assay time should be <15–20min, which excludes the use of serum samples. The aim was therefore to develop a novel rapid assay principle and test its clinical performance. MethodsSerum and neutrophils obtained from 84 infected and 20 healthy subjects were used in the experimental study. 725 subjects (144 healthy controls and 581 patients with signs and symptoms of acute infections) were included in the clinical study. HNL was measured in EDTA-plasma by ELISA or in heparinized whole blood after fMLP activation by a prototype point-of-care assay. ResultsIncreased release of HNL from neutrophils after activation with fMLP was seen already after 5min incubation. The release of HNL from purified neutrophils after 15min incubation with fMLP was significantly correlated to the HNL concentrations in serum obtained from the same patient (r=0.74, p<0.001). In the distinction between healthy controls and patients with bacterial infections, the areas under the ROC-curves were 0.95 (95% CI 0.91–0.97) and 0.88 (95% CI 0.84–0.91) for HNL in fMLP-activated whole blood and EDTA-plasma, respectively, (p<0.001) and in the distinction between bacterial and viral infections 0.91 (95% CI 0.86–0.95) and 0.76 (95% CI 0.70–0.81), respectively (p<0.001). ConclusionThe clinical performance of HNL in fMLP-activated whole blood was superior to HNL in EDTA-plasma and similar to HNL in serum. The procedure can be adopted for point-of-care testing with response times of <15min.

NGAL Can Alternately Mediate Sunitinib Resistance in Renal Cell Carcinoma

Serum NGAL is highly expressed in patients with advanced renal cancer treated with sunitinib. We investigated the role of NGAL in sunitinib resistance in renal cell carcinoma to identify potential tactics to overcome it. NGAL expression was correlated with sunitinib sensitivity. Vascular endothelial growth factor related upstream Ras, Erk1/2 and STAT1 phosphorylation activity in Caki-1 and NGAL transfected Caki-1 cells after sunitinib treatment was analyzed using Western blot. NGAL and vascular endothelial growth factor-A interaction with sunitinib therapeutic efficacy was monitored in renal cell carcinoma tumor xenografted mice by tumor growth inhibition, serum NGAL and vascular endothelial growth factor-a levels, and microscopic examination of tumor microvascular density. Sunitinib cytotoxicity in various renal cell carcinoma cell lines was reversibly related to NGAL expression. Sunitinib showed the lowest 50% inhibitory concentration (5.53 μM) in Caki-1 cells, which had the lowest NGAL expression of these renal cell carcinoma cell lines. After sunitinib treatment adding NGAL inhibited Ras and Erk1/2 phosphorylation but activated STAT1α phosphorylation in Caki-1 cells and Caki-1 cells transfected with NGAL. In a xenograft mouse model sunitinib significantly inhibited tumor growth in Caki-1 mice. NGAL transfected Caki-1 mice had higher serum NGAL and lower vascular endothelial growth factor-A than Caki-1 mice. Microvascular density was decreased in Caki-1 mice with sunitinib treatment. NGAL in tumor cells may show crosstalk with vascular endothelial growth factor-a and alternative activation in stimulating tumor growth during sunitinib treatment. It may become a therapeutic target to reverse sunitinib resistance in renal cell carcinoma.

Human Neutrophil Lipocalin in Early Diagnosis of Neonatal Sepsis

Human Neutrophil Lipocalin in Early Diagnosis of Neonatal Sepsis

Searching for novel intercellular signal-transducing molecules in the kidney and their clinical application

In this review, isolation and characterization of several kidney-derived molecules are described, namely carbonic anhydrase XIV, cysteine-rich protein 61, and kidney-liver-specific immunoglobulin-like protein. Features of neutrophil gelatinase-associated lipocalin (LCN2 or human neutrophil lipocalin) as a kidney differentiation inducer and renal injury biomarker and also as an iron-carrier protein are also summarized. Furthermore, the concepts of forest fire theory and the biology of siderophore-binding proteins are discussed.

Efficacy of two breath condensers

Examination of Exhaled Breath Condensate has been suggested to give information about inflammatory airway diseases. The aim was to compare efficacy and variability in gain of two commercially available exhaled breath condensers, ECoScreen and RTube in an in vitro set up. Test fluids containing myeloperoxidase (MPO) or human neutrophil lipocalin (HNL) in addition to saline and bovine serum albumin were nebulized and aerosols were transferred by a servo ventilator to either of the two condensers. Analyses of MPO, HNL, or chlorine were done by means of ELISA, RIA, or a modified adsorbed organic halogen technique (AOX), respectively. Recoveries of HNL were higher when using ECoScreen than RTube (P<0.05). In contrast, there were no significant differences between the two condensers in recoveries of MPO or chlorine. The spread of data was wide regarding all tested compounds. Variability in gain was large and ECoScreen was more efficacious then RTube in condensing the tested solutes of HNL, but not those of MPO or chlorine.

Assays of urine levels of HNL/NGAL in patients undergoing cardiac surgery and the impact of antibody configuration on their clinical performances

Background Acute kidney injury (AKI) is one of the most serious postoperative complications of cardiac surgery. The lack of early and powerful markers for AKI makes the morbidity and mortality still very high. HNL (Human neutrophil lipocalin)/NGAL (Neutrophil gelatinase-associated lipocalin) was recently shown as a novel biomarker for AKI after cardiac surgery. Methods Serial urine samples from 59 patients undergoing cardiac surgery were analyzed by polyclonal antibody based radioimmunoassay (RIA), monoclonal–polyclonal antibody based enzyme-linked immunosorbent assay (ELISA). Results We found 10 to 100-fold increases in urine HNL/NGAL levels in about half of the patients 2 h after termination of the operation and elevated levels in all patients 72 h post operation. The urine levels of HNL/NGAL showed a weak, but significant relation with kidney function as measured by plasma levels of cystatin C or creatinine. The 2 h-HNL/NGAL levels were positively correlated to extracorporeal circulation time ( p < 0001). The assays were well correlated, but had different clinical performances. Conclusions We confirmed that urine HNL/NGAL may be a useful early biomarker of postoperative kidney injury. The results indicate that the antibody configuration of the assay has an impact on the clinical performance of the assay.

Potential use of mucins as biomaterial coatings. II. Mucin coatings affect the conformation and neutrophil‐activating properties of adsorbed host proteins—Toward a mucosal mimic

In continuation of our recent fractionation and characterization study on mucins of bovine salivary (BSM), porcine gastric (PGM), and human salivary (MG1) origin, this study evaluates the effect of mucin precoating on the conformation and neutrophil-activating properties of host proteins adsorbed to a polyethylene terephthalate-based model biomaterial. Microscopy combined with assays for the neutrophil releases of reactive oxygen species and human neutrophil lipocalin showed that mucin precoating greatly reduced the strong immune-response normally induced by adsorbed immunoglobulin G (IgG) and secretory immunoglobulin A (sIgA), respectively. A similar finding was made for the proinflammatory fibrinogen. Although the total uptakes of these proteins depended on the mucin surface concentration, a detailed composite analysis suggested the fraction of surface-exposed protein to be a stronger determinant of coating performance. The unexpectedly low neutrophil activation showed by composites containing near-monolayer concentrations of exposed IgG and sIgA, respectively, suggested that these act synergistically with mucin on the surface. In support of this hypothesis, quartz crystal microbalance with dissipation monitoring measurements revealed that a preadsorbed BSM layer stabilizes IgG through complexation on a polymeric model surface. Our findings link well to the complex in vivo situation and suggest that functional mucosal mimics can be created in situ for improved biomaterials performance.

Systemic and local eosinophil inflammation during the birch pollen season in allergic patients with predominant rhinitis or asthma

BackgroundThe aim of the study was to investigate inflammation during the birch pollen season in patients with rhinitis or asthma.MethodsSubjects with birch pollen asthma (n = 7) or rhinitis (n = 9) and controls (n = 5) were studied before and during pollen seasons. Eosinophils (Eos), eosinophil cationic protein (ECP) and human neutrophil lipocalin were analysed.ResultsAllergic asthmatics had a larger decline in FEV1 after inhaling hypertonic saline than patients with rhinitis (median) (-7.0 vs.-0.4%, p = 0.02). The asthmatics had a lower sesonal PEFR than the rhinitis group. The seasonal increase in B-Eos was higher among patients with asthma (+0.17 × 109/L) and rhinitis (+0.27 × 109/L) than among controls (+0.01 × 109/L, p = 0.01). Allergic asthmatics and patients with rhinitis had a larger increase in sputum ECP (+2180 and +310 μg/L) than the controls (-146 μg/L, p = 0.02). No significant differences in inflammatory parameters were found between the two groups of allergic patients.ConclusionPatients with allergic asthma and rhinitis have the same degree of eosinophil inflammation. Despite this, only the asthmatic group experienced an impairment in lung function during the pollen season.

Airway hyperresponsiveness, peak flow variability and inflammatory markers in non‐asthmatic subjects with respiratory infections

The aim of this study was to characterise non-asthmatic subjects with asthma-like symptoms during a common cold, particularly in relation to airway hyperresponsiveness (AHR). Subjects with acute respiratory infections and a group of controls (n = 20 + 20), age 20-65 years, underwent bronchial provocations with methacholine, adenosine and cold air. All were non-smokers and had no history of asthma or heart disease. Those with infection had asthma-like symptoms (>2). Measurements of exhaled nitric oxide (eNO), serum levels of eosinophil cationic protein (ECP), eosinophil peroxidase, myeloperoxidase and human neutrophil lipocalin were made at each provocation. A 17-day symptom and peak flow diary was calculated. No differences between the two groups were found, regarding responsiveness to methacholine, adenosine or cold air challenge, as well as the inflammatory markers measured. In the infected group, the mean (standard deviation) ECP was higher in those with AHR to methacholine or cold air [15.7 (6.5) and 11.4 (4.2) microg/L, respectively; P < 0.05]; furthermore, eNO was higher in the infected group [116 (54) and 88 (52) nL/min, respectively; P = 0.055]. The infected group had, at all times, more symptoms and higher peak flow, with a decrease in the symptoms (P = 0.02) and a tendency to change in peak flow variation (P = 0.06). AHR does not seem to be the main cause of asthma-like symptoms in adults with infectious wheezing. Peak flow variation and symptom prevalence during the post-infection period may imply airway pathology different from AHR.

Lateral Flow Immunoassay Using Europium (III) Chelate Microparticles and Time-Resolved Fluorescence for Eosinophils and Neutrophils in Whole Blood

A simple point-of-care method for measuring leukocyte counts in a doctor's office or emergency room could be of great importance. We developed a protocol for measuring cell count by disrupting the cell membrane and analyzing specific proteins within the cells and used it to analyze proteins from eosinophils and neutrophils. Lateral immunochromatographic (ICR) assays have been developed for eosinophil protein X (EPX) and human neutrophil lipocalin (HNL) as measures of the concentration of eosinophils and neutrophils. The correlation between the lateral ICR assays and cell counting of eosinophils and neutrophils was performed manually and with an automated cell counter. RIA assays measuring the same analytes were also compared with the results from cell counting and lateral ICR assays. The optimized assays showed analytical detection limits below the clinical ranges of 3.36 microg/L and 2.05 microg/L for EPX and HNL, respectively. The recovery was 114.8%-122.8% for EPX and 94.5%-96.9% for HNL. The imprecision was 3%-17% CV for EPX over the whole range and 5%-16% CV for HNL. The correlation coefficients between manually counted cells and lateral ICR assays were 0.9 and 0.83 for EPX and HNL, respectively. The numbers of eosinophils and neutrophils in small amounts of blood can be estimated in the point-of-care setting by means of fast lateral ICR assays of EPX and HNL.

Induction of Neutrophil Gelatinase-Associated Lipocalin in Vascular Injury via Activation of Nuclear Factor-κB

Neutrophil gelatinase-associated lipocalin (NGAL) has recently emerged as an important modulator of cell homeostasis. Elevated plasma NGAL levels, possibly because of activation of blood leukocytes, are associated with atherosclerosis. However, little is known about induction of NGAL expression in blood vessels. Using a rat carotid artery injury model, we found that NGAL was highly induced in the intima after angioplasty but was attenuated by adenovirus-mediated expression of a dominant-negative mutant of inhibitor of nuclear factor (NF)-kappaB kinase beta (dnIKKbeta). Expression of NGAL mRNA and protein was also up-regulated in an NF-kappaB-dependent manner in rat and human vascular smooth muscle cells (SMCs) in response to interleukin-1beta stimulation. Rat SMC-produced NGAL was present as mono- and homomeric forms in the cytosol and in a complex containing matrix metalloproteinase-9 (MMP-9) after secretion. In agreement with levels of NGAL, proteolytic activity of MMP-9 was markedly high in the intima of injured vessels and in the culture supernatant of activated intimal SMCs but was reduced in the vessels transduced with dnIKKbeta. The present study reveals a previously unrecognized vascular response to an-gioplastic injury, characterized by NF-kappaB-dependent expression of NGAL in vascular SMCs. Further-more, SMC-produced NGAL interacts with MMP-9, a mechanism by which NGAL may modulate MMP-9 proteolytic activity in the vascular repair process.

Myeloperoxidase as a marker of increasing systemic inflammation in smokers without severe airway symptoms

There is increasing evidence of systemic inflammation in patients with chronic obstructive pulmonary disease (COPD), but there is very little information on the development of systemic inflammation in smokers without severe airway symptoms. In this longitudinal study, we examined whether smokers with mild or no airway symptoms develop signs of systemic inflammation by assessing inflammatory markers in blood over a 6-year period. Forty smokers and 28 male never-smokers were investigated in 1995 (year 0) and 6 years later (year 6). At year 6, 11 smokers had stopped smoking (quitters); these subjects were analysed as a separate group. At year 0 and 6, we measured serum levels of myeloperoxidase (MPO), lysozyme and human neutrophil lipocalin (HNL), regarded as markers of activity in neutrophils plus monocyte-lineage cells, monocyte-lineage cells only and neutrophils only. All systemic markers of inflammation (MPO, HNL and lysozyme) were significantly higher in smokers than in never smokers at year 6. For MPO alone, smokers only displayed a unique pattern compared with the other groups; the concentration of MPO in blood increased among smokers during the 6-year period, and this increase was statistically significant compared with that observed in never-smokers. Even though quitters did not display any clear change in MPO, we observed a statistically significant negative correlation between the change in blood MPO and the duration of smoking cessation in this group. For HNL and lysozyme, the changes over time were similar in smokers and never-smokers, with no statistically significant difference compared with quitters. This study provides evidence that male smokers without severe airway symptoms develop an increasing systemic inflammation during a 6-year period. The study forwards both direct and indirect evidence that MPO may be an early marker of this systemic inflammation. However, our study also forwards indirect evidence that ongoing tobacco smoking may "drive" the level of systemic HNL and lysozyme. The origin of the increased MPO and its value as an easily measured predictor for future COPD deserves to be further evaluated.

Human neutrophil lipocalin (HNL) as a diagnostic tool in children with acute infections: A study of the kinetics

To study the changes in blood of human neutrophil lipocalin (HNL) and C-reactive protein (CRP) during the course of an acute infection in children. Children (n=92) hospitalized with symptoms and signs of acute infections were included and categorized into five groups, i.e. bacterial infection, suspected bacterial infection, viral infection, suspected viral infection and others. Blood was taken at admittance and the following 3-4 d for the measurement of CRP and HNL. Both CRP and HNL were significantly raised at admittance in bacterial infection as compared to viral infection (p<0.001). After 25-48 h, 83% of the children with bacterial infections still had raised CRP levels in contrast to 11% having raised HNL levels. The levels of CRP, but not those of HNL, were significantly correlated to days of symptoms before admission. HNL is a promising diagnostic tool in the distinction of acute infections caused by bacteria or virus. The differences in the kinetics of CRP and HNL make HNL a better marker for monitoring antibacterial treatment, since HNL is probably elevated only when an active bacterial infection is at hand.

Human neutrophil lipocalin (HNL) as a diagnostic tool in children with acute infections: A study of the kinetics

Human neutrophil lipocalin (HNL) as a diagnostic tool in children with acute infections: A study of the kinetics

Cell surface expression of FcγRI (CD64) on neutrophils and monocytes in patients with influenza A, with and without complications

The expression of the Fcgamma-receptor I (FcgammaRI), CD64 on normal neutrophils is up-regulated during bacterial infections. CD64 is a promising diagnostic tool in the diagnosis of acute infections. The aim was to study surface expressions of CD64 on neutrophils and monocytes in patients with influenza A with and without complications and evaluate these as diagnostic tools in comparison with serum levels of HNL (human neutrophil lipocalin). CD64 expression on neutrophils and monocytes was evaluated by flow cytometry. HNL was assayed by a specific radioimmunoassay. 22 patients with influenza A with or without complications were included and the results compared with those of 29 patients with acute bacterial infections and 29 healthy subjects. Neutrophil expression of CD64 was increased in influenza A with raised proportion expressing CD64 in complicated compared to uncomplicated influenza. The expression was significantly higher in bacterial infections compared to both influenza groups. Serum levels of HNL were raised in all infection groups, but significantly more so in the group with bacterial infection. ROC-curve analysis showed that neutrophil expression of CD64 and the serum levels of HNL had similar diagnostic power in the discrimination between acute bacterial infections and influenza A. Monocyte expression of CD64 was raised in all infections with no differences between subgroups. We conclude that neutrophil expression of CD64 and serum levels of HNL are both promising assays in the distinction between infections caused by bacteria or influenza A, whereas CD64 could identify patients with complications of their influenza A infection.

Human neutrophil lipocalin: normal levels and use as a marker for invasive infection in the newborn

To determine the prevalence of lactose malabsorption in young Lithuanian atopic dermatitis children; to evaluate the relationship between lactose malabsorption and the duration of exclusive breastfeeding, and the relationship between lactose malabsorption and cow's milk intolerance in parents and grandparents. 144 children with atopic dermatitis aged 1.5-24 mo (study group) and 32 children without symptoms of allergic diseases aged 1.5-23 mo (control group) were investigated. Lactose and glucose-galactose absorption tests based on serial blood glucose determination, culture of stool, latex agglutination test for rotavirus and microscopic examination of stool for parasites were performed. Lactose malabsorption was determined in 59 (40.9%) and glucose-galactose malabsorption in 17 (11.8%) children with atopic dermatitis. The risk of developing lactose malabsorption was higher in children fed exclusively on breast milk up to 1 mo of age than in children fed exclusively on breast milk for 4 to 6 mo (OR: 2.62; 95% CI: 1.02-6.75). Lactose malabsorption was significantly more frequent in patients whose mothers did not tolerate cow's milk (20/30; 66.7%) than in patients whose mothers were tolerant to it (39/95; 41.1%) (p = 0.02). Lactose malabsorption was determined in 40.9% of Lithuanian atopic dermatitis children aged under 2 y. Lactose malabsorption appeared to be associated with the duration of exclusive breastfeeding up to only 1 mo and mothers' milk intolerance.