Leukocyte Adherence Inhibition Research Articles

Evaluating Non-IgE-Mediated Allergens’ Immunoreactivity in Patients Formerly Classified as “Intrinsic” Asthmatics with Help of the Leukocyte Adherence Inhibition Test

Background: The ancient concept of “intrinsic” and “extrinsic” asthma has evolved in line with growing scientific knowledge and the use of new clinical diagnostic tools. Objective: The present study aims to evaluate the non-IgE-mediated immunoreactivity against common allergens, in asthmatic patients without evidence of IgE-mediated hypersensitivity against these allergens. Methods: A group of 127 “intrinsic” asthmatic outpatients, were submitted to ex vivo Leukocyte Adherence Inhibition Tests (LAIT) with extracts of Dermatophagoides pteronyssinus, Hevea brasiliensis latex, dog dander, cat dander, cow’s milk proteins, beekeeping pollen and a mixture of fungal extracts. Results: Cascade graphs were assembled according to the distribution of the LAIT results among the range of results of Leukocyte Adherence Inhibition (LAI) inside each group. A column graph was plotted with the mean LAI results for each antigen. The non-parametric Wilcoxon-Mann-Whitney U-test performed between the results of each test was significant only between the results of the LAIT performed with the dog extract and the mixed fungal extract (U = 1,179.5; the z-score was -2.64109; the p-value was 0.0083). All other Wilcoxon-Mann-Whitney U-test calculations between LAIT performed with the other allergens were not significant at p < 0.01. Conclusion: The evidence of non-IgE-mediated immunoreactivity in allergic patients has been reported in the medical literature since the beginning of the 19th century and has been increasing since then. This descriptive article presents the contribution of the LAIT as a tool to quantify the overall non-IgE-mediated cellular/humoral immunoreactivity against common allergens in patients formerly classified inside the “intrinsic” asthma endotype.

Evaluating Non-IgE-mediated Allergens’ Immunoreactivity in Patients with “Intrinsic” Persistent Rhinitis with Help of the Leukocyte Adherence Inhibition Test

Background: The non-IgE-mediated immunoreactivities against common allergens are little understood conditions, especially in patients suffering from allergic respiratory disorders such as persistent rhinitis. Objective: The present study aims to evaluate the non-IgE-mediated immunoreactivity against common allergens, in allergen-reactive patients clinically diagnosed with persistent rhinitis without evidence of IgE-mediated hypersensitivity against these allergens. Methods: A group of 533 outpatients diagnosed with non-IgE-mediated allergen-reactive persistent rhinitis, were submitted to ex vivo Leukocyte Adherence Inhibition Tests (LAIT) with extracts of Dermatophagoides pteronyssinus, Hevea brasiliensis latex, dog dander, cat dander, cow’s milk proteins, beekeeping pollen and a mixture of airborne fungal extracts. Results: Cascade distribution column graphs were assembled according to the LAIT results among six ranges of Leukocyte Adherence Inhibition (LAI) of each allergen group. A column graph was plotted with the mean LAI results for each antigen for comparison. Conclusion: The LAIT is a potential tool to quantify the overall non-IgE-mediated cellular/humoral immunoreactivity against common allergens in patients clinically diagnosed with persistent rhinitis. Most studies must be done to evaluate the potential of the LAIT as a screening ex vivo provocation test to select the more reactive allergens to perform the diagnostic in vivo provocation tests.

Leukocyte Adherence Inhibition Test to the assessment of Immunoreactivity Against Cow’s Milk Proteins in Non—IgE-Mediated Gastrointestinal Food Allergy

Background: The non—IgE-mediated food allergy syndromes are a group of conditions diagnosed mostly by clinical criteria and Oral Food Challenge tests (OFC).
 Objective: To evaluate the feasibility of the Leukocyte Adherence Inhibition Test (LAIT) to discriminate antigen-specific immunoreactivity in a group of patients with non—IgE-mediated cow’s milk allergy diagnosed by OFC and clinical criteria.
 Methods: Ex vivo challenge tests performed with cow’s milk proteins extracts were monitored by LAIT in two groups: A) the active group consisting of 38 patients presenting non—IgE-mediated gastrointestinal lactose-free cow’s milk hypersensitivity; B) the control group consisting of 29 cow’s milk tolerant individuals
 Results: The mean Leukocyte Adherence Inhibition (LAI) of the control group was 5.48%, and the mean LAI of the active group was 54.18%. The non-parametric Wilcoxon-Mann-Whitney U test showed p < α = 0.05.
 Conclusion: The Leukocyte Adherence Inhibition Test is an ex vivo immunoassay able to predict individual non—IgE-mediated immunoreactivity against cow’s milk allergens and to act as a triage test to select food allergens to be prescribed in exclusion diets to perform OFC in patients with suspected non—IgE-mediated food allergies.

Contribution of the Leukocyte Adherence Inhibition Test for the Evaluation of Immunoreactivity against Gluten Extracts in Non—IgE-Mediated / Non-Autoimmune Gluten-Related Disorders

Background: The Non-Celiac Gluten Sensitivity (NCGS) is a category inside the Gluten-Related Disorders (GRD) that groups the patients with unidentified mechanisms responsible for their symptoms.
 Objective: To evaluate the opportunity of an ex vivo challenge immunoassay, the Leukocyte Adherence Inhibition Test (LAIT), to discriminate non—IgE-mediated gluten-specific immunoreactivity in patients with NCGS.
 Methods: Ex vivo challenge tests performed with gluten latex extract, monitored by LAIT, were assayed in an asymptomatic control group of 30 individuals and a group of 52 patients with GRD not related to any identifiable immune mechanism (NCGS).
 Results: The mean Leukocyte Adherence Inhibition (LAI) of the control group was 10.9%. The mean LAI of the NCGS patients’ group was 54.9%. The non-parametric Wilcoxon-Mann-Whitney U test comparing the control group with the NCGS patient’s group showed significance with a p-value < 0.00001.
 Conclusion: The LAIT is an ex vivo challenge test able to discriminate gluten-sensitive and gluten-tolerant individuals, suggesting the participation of an immune Non—IgE-mediated hypersensitivity reaction in patients with the clinical diagnosis of NCGS.

Contribution of the Leukocyte Adherence Inhibition Test to the Evaluation of Cellular Immunoreactivity against Latex Extracts for Non—IgE-Mediated Latex-Fruit-Pollen Syndrome in Allergic Candidates to Exclusion Diets and Allergic Desensitization

Background: Due to the lack of standardized laboratory procedures able to demonstrate specific non—IgE-mediated immune responses against latex allergens, these conditions are diagnosed mostly by clinical criteria based on empiric exclusion prescriptions monitored by in vivo challenge tests.
 Objective: To evaluate the opportunity of an ex vivo challenge immunoassay, the Leukocyte Adherence Inhibition (LAI) Test (LAIT), to discriminate non—IgE-mediated latex-specific immunoreactivity.
 Methods: Ex vivo challenge tests performed with Hevea Brasiliense’s latex extract, monitored by LAIT, were assayed in an asymptomatic control group and a group of patients with diverse respiratory and cutaneous non—IgE-mediated allergic conditions, clinically diagnosed by a certified allergologist.
 Results: The mean LAI of the control group was 8.3%. The mean LAI of the complete patients’ group was 41.1%. The non-parametric Wilcoxon-Mann-Whitney U (WMWU) test comparing the control group with the whole patient’s group showed significance with a p-value < 0.00001. The WMWU test comparing the control group with each other patient’s group showed significance with a p-value < α = 0.05 for all comparisons. The WMWU test comparing the patients’ groups between each other did not show any significant p-value.
 Conclusion: Several patients from the diverse non—IgE-mediated allergic phenotypes presented variable immunoreactivity against the latex extract, as demonstrated by the LAIT, which proved to be an easy, quick, and inexpensive ex vivo immunoassay with the potential to predict individual immunoreactivity against Hevea brasiliensis latex allergens in real-world patients with non—IgE-mediated allergies.

Immunoreactivity against Dermatophagoides pteronyssinus Assessed by the Leukocyte Adherence Inhibition Test in Patients with Intrinsic Atopic Dermatitis and Correlated “Intrinsic” Non–IgE-mediated Allergic Conditions

Background: Due to the lack of standardized laboratory procedures able to demonstrate specific immune responses against the culprit allergens, the non—IgE-mediated allergy syndromes are a group of conditions diagnosed mostly by clinical examination and exclusion criteria.
 Objective: To evaluate the opportunity of the Leukocyte Adherence Inhibition Test (LAIT) to discriminate specific immunoreactivity against Dermatophagoides pteronyssinus (Dp) in a group of patients with non–IgE-mediated chronic allergic conditions.
 Methods: Ex vivo challenge tests performed with Dp were monitored by LAIT in patients presenting diverse non–IgE-mediated allergic conditions: intrinsic Atopic Dermatitis (iAD), intrinsic Allergic Rhinitis (iAR), intrinsic Ocular Allergy (iOA), intrinsic Chronic Pharyngitis (iCP), and intrinsic Asthma (iAS).
 Results: The mean LAI of the control group was 7%; the mean LAI of the iAR group was 34%; the mean LAI of the iCP group was 44%; the mean LAI of the iAS group was 45%; the mean LAI of the iOA group was 47%; the mean LAI of the iAD group was 55%. The non-parametric Wilcoxon-Mann-Whitney U test comparing the control group with each other group showed significance with p-value < α = 0.05 for all groups.
 Conclusion: The Leukocyte Adherence Inhibition Test is an easy, quick, and inexpensive ex vivo immunoassay with the potential to predict individual immunoreactivity against HDM allergens in real-world patients with non–IgE-mediated allergies.

Assessment of Immunoreactivity against Therapeutic Options Employing the Leukocyte Adherence Inhibition Test as a Tool for Precision Medicine

Background: The Precision Medicine’s approach employs the endotype concept as a central feature to personalize medical treatment. Individual immunoreactivity, alongside characteristics such as genetics, environment, and diet, is one of the factors that differentiates the therapeutic-driven endotypes.
 Objective: To evaluate the opportunity of the Leukocyte Adherence Inhibition test to differentiate the immunoreactivity between two similar therapeutic agents employed on Allergen Immunotherapy.
 Methods: Side by side Leukocyte Adherence Inhibitions tests were performed with ovalbumin and carbamylated ovalbumin on a population of 33 self-reported egg-allergic individuals.
 Results: The results showed two endotypes inside the immune response of the studied groups: The first endotype was defined by the 16 individuals that presented a significant decrease in ovalbumin’s immunoreactivity after carbamylation (mean of differences = 35%; p = 0.002). The second endotype was defined by 17 individuals that presented a significant increase in ovalbumin’s immunoreactivity after carbamylation (mean of differences = 32%; p = 0.001).
 Conclusion: The Leukocyte Adherence Inhibition test was able to differentiate two distinct immunoreactivity patterns when comparing two similar therapeutic agents suggesting, as proof of concept, a potential role to be employed as a Precision Medicine tool.

The Plasma Preincubation with Papain Before the Assay Suggests that a Gell and Coombs Type II Reaction is Been Demonstrated by the Leukocyte Adherence Inhibition Test

The Leukocyte Adherence Inhibition Test (LAIT) is an ex vivo challenge test used to testimony specific...

A Novel Utility for an Old Method: The Leukocyte Adherence Inhibition Test Is an Easy Way to Detect the Immunoreactive Interference of the Collection Tube Anticoagulant on Cellular Immunoassays

The leukocyte adherence inhibition (LAI) test was designed to evaluate the presence of cellular immunoreactivity against specific antigens and is highly sensitive to analytical interference. To compare the performance of the LAI test among plasmas obtained with different anticoagulants, 36 blood samples of allergic subjects were divided into three tubes with heparin, sodium citrate, and EDTA. The adherence was assessed with the hemocytometer technique. The mean adherence of each group was compared as well as the number of tests with inappropriate adherence (<25%). Of the 36 tests, there were 4, 9, and 21 with inappropriate adherence in the groups of heparin, citrate, and EDTA, respectively. Of these last, 5 samples also did not demonstrate proper adherence with sodium citrate and 1 sample did not show proper adherence with any anticoagulant. The anticoagulant in the collection tube can elicit a specific immune response, becoming an interferent for the LAI test. In this case, there is the possibility of redoing the test using another anticoagulant. Performed with different anticoagulants, the LAI test may be used as a preanalytical tool for choosing the less immunoreactive anticoagulant for more complex immunoassays.

ASSESSMENT OF CLINICAL-IMMUNOLOGICAL EFFECTIVENESS OF COMPLEX THERAPY OF INFANT ATOPIC DERMATITIS

The work is aimed at assessment of clinicalimmunological effectiveness of diet therapy based on hypoallergenic formula used for infants with atopic dermatitis. 167 infants with atopic dermatitis associated with cow’s milk protein allergy have been put included under outpatient observation. 52 infants of from the first group were being fed on whole goat milk’s formula, 56 infants of from the the second group — cows’ milk protein hydrolysate and 59 infants of the from the third groupsoy’s isolate formula. The age of infants was 2, 5—9 months. The duration of observation was 3—12 months. Complex therapy has been conducted over the infants and it contained antiallergenic treatment and diet therapy with hypoallergenic baby formula. The majority of patients showed improvement due to applied treatment. The first group’s infants with positive clinical dynamic showed decrease of specific IgG and IgE to cow’s milk protein, casein, β-LH and soy’s protein. The infants of the second and third groups also showed decrease of specific IgG and IgE to cow’s milk protein, casein, β-LH, soy’s protein and goat’s milk at clinical remission. All the infants with positive clinical effect showed trend to decrease of IL12, IL13, sICAM1 and sEselectin’s concentration in the blood stream, that can indicate on leukocyte adherence inhibition and cell migration to the area of inflammation. Based on the results of research, we can conclude that replacement of one product with another one by taking into account their clinicalimmunological effectiveness as the method of treatment the of atopic dermatitis patients let us optimize infant diet therapy.

In search of a tolerance-induction strategy for cow’s milk allergies: significant reduction of beta-lactoglobulin allergenicity via transglutaminase/cysteine polymerization: Allergoid generation by polymerization

OBJECTIVE:To explore the use of β-lactoglobulin polymerized using microbial transglutaminase and heating to identify whether protein polymerization could reduce in vivo allergenicity and maintain in vitro and ex vivo immunoreactivity for use in tolerance-induction protocols.METHODS:Based on previous protocols applied in mice and children, we performed in vivo challenges (using a skin prick test) with native and polymerized β-lactoglobulin in adult patients with an IgE-mediated allergy to β-lactoglobulin. In vitro humoral immunoreactivity was analyzed using immunoblotting. Cell-mediated immunoreactivity was analyzed using ex vivo challenges with native and polymerized β-lactoglobulin and monitored by leukocyte adherence inhibition tests.RESULTS:The skin tests demonstrated that there was a significant reduction in immediate cutaneous reactivity after polymerization. Polymerization did not decrease the immunoblotting detection of s-IgE specific to β-lactoglobulin. Cell-mediated immunoreactivity, as assessed by ex vivo challenges and leukocyte adherence inhibition tests, did not exhibit significant differences between leukocytes challenged with native versus polymerized β-lactoglobulin.CONCLUSIONS:The polymerization of β-lactoglobulin decreased in vivo allergenicity and did not decrease in vitro humoral or ex vivo cell-mediated immunoreactivity. Therefore, we conclude that inducing polymerization using transglutaminase represents a promising technique to produce suitable molecules for the purpose of designing oral/sublingual tolerance induction protocols for the treatment of allergies.

Ovarian cancer: evaluation of the leukocyte adherence inhibition assay.

The Leukocyte Adherence Inhibition (LAI) assay has been evaluated for clinical use in the management of patients with ovarian cancer. Studies on the tube method included determination of the optimal concentration of cells used and the type, or presence or absence, of serum supplement utilised; also the effect on LAI of various specific and non-specific crude antigen preparations. A refined assay was used to compare data from 21 patients with epithelial ovarian cancer, a miscellaneous group of other types of cancer and control groups of healthy pregnant and non-pregnant women of reproductive age. Positive LAI responses were produced in some patients with ovarian cancer, but there were no significant differences between the groups. It was concluded that lack of reactivity in patients with widespread disease, early loss of reactivity in remission, and moderation of the LAI index by concurrent therapy would limit the practical use of this assay to monitor the host response of patients with ovarian cancer.

Purification and part of physico-chemical characterization as well as biological activity for immuno-globulin ribonucleic acid of anti-rabies

Objective To explore the preparation of specific immune RMA(iRNA) on anti-rabies and further study immunotherapy of rabies virus exposure. Methods Horses were immunized with the rabi-es virus and their livers were isolated from the horse of antiserum, from which total RNA was extracted and purified by sodium lauryisulfonate, phenol, chloroform, ethyiene glycol monomethyl ether, cetyltrimethyam-moniumbromide and alcohol. Results Pure preparation physico-chemical characterization was analyzed, and it's weight was 0.15% of weight of liver. The RNA contained 2.86% DNA and 1.16% protein. The iRNA with a maximum UV absorbance at 258 nm and A_(258/280) about 2.0. The test of RNA was positive, which had a relative molecular mas of 13.7×10~3 by high performance liquid chromatography(HPLC), and its hy-perchromic effect was 50.67%. The vesults of biological activity was showed that the rate of leucocyte adher-ence inhibition(LAI) was 41.73%, The protective rate was 50% and prolonging the life was 31.62%. Conclusion The results obtained with the practical value were identical and provide a basis on medicines of anti-rabies. Key words: Anti-rabies; Immunoglobulin ribonucleic; Purification; Physico-chemical character-ization; Biological activity

Cell-Mediated Immunity in Cervical Cancer Evolution

Cell-mediated immunity (CMI) response to different antigens was examined in healthy women, in patients with cervical precancerous lesions, and in patients with cervical cancer. Cervical lesions were diagnosed by cytological (PAP) smears, from examination by colposcopy, and from “punch” biopsy material by histology. CMI response is related to specific processes in healthy and cancer cells. CMI was investigated by leukocyte adherence inhibition (LAI) assay using specific antigen (prepared from cervical carcinoma tissue) and non specific antigen (prepared from blood of mice infected by LDH—lactate dehydrogenase—virus). The CMI responses of healthy women and cancer patients to the antigens used are different: the majority of T lymphocytes display adherence and non adherence, respectively (but the CMI responses elicited by the antigens are not equal and small quantitative differences are observed). Regardless of the CIN (cervical intraepithelial neoplasia) grades, CMI responses correspond either to healthy women or to cervical carcinoma patients (at about similar ratio of cases in all the CIN groups). Effect of non specific antigen suggests that cervical carcinoma transformation may be connected with reduction of mitochondrial activity similar to processes in LDH virus infection.

The Comparison of Methods for Determination of Humoral and Cell-Mediated Immunity in Patients with Breast Cancer

We observed the immunological answer to antigens obtained from the human malignant breast tumor and from the blood of inbred mice strain C3H/H2K infected by LDH virus. We compared the modified ELISA method for humoral immunity with the leukocyte adherence inhibition (LAI) assay for cell-mediated immnunity. The modified ELISA method is suitable for early diagnosing and monitoring antibodies in a malignant breast tumor simultaneously with senological examinations which include mammography and clinical examinations, because the antibodies are determined in a high number of samples by single application.

Exposure to Polycyclic Aromatic Hydrocarbons - Risk Factor for Lung Cancer

P-200 Abstract: Occupational exposure to chemical carcinogens has been associated with high cancer incidence. Lung cancer is the most important cause of cancer death in many industrialized countries. Polycyclic aromatic hydrocarbons (PAH) are included in the group of the substances with increased risk for respiratory tract cancer. Chemical carcinogens -induced lung cancer develops through a secvence of the cellular alterations that have a lung time period of the reversible alterations, after that irreversible malignant transformations take place. Smoking habit is associated with alteration of the bronchial epithelium, reversible a long time period and with changes in the activation state of the inflammatory and immune cells by the respiratory tract. Recent studies associated the effects of the chemical carcinogenes and of the smoking with immune functions. The sensitived leukocytes to the anti-tumor immune factor lose their ability to adherence to glass or plastic surfaces then they are exposed. The aim of this study was to assess the effects of the smoking habit on the health of the 400 occupational exposed workers to the PAH, using radiological, cytological and immunological investigations. A standard questionnaire including informations on occupational exposure, respiratory symptoms, health history, and smoking habit was completed. Concomitantly, two groups of subjects without, one of them including smokers and other including non-smokers, were investigated. The cytological screening of the sputum was performed by Papanicolaou method and the results were included in the 5 types: I—normal; II—slight atypia; III—Moderate atypia; IV—marked atypia; V—cancer cells. Leukocyte adherence inhibition test (LAI test) was performed for the detection of the anti-tumor immune factor in the exposed subjects. PAH- exposed group presented 28% of the cytological examinations with moderate and marked atypia; 78% of them are high smokers. The LAI test disclosed positive responders against the crud tumor extract at the 74% of the subjects with III and IV type of the sputum cytology. 81% of them are high smokers. PAH-exposed workers present an increased risk for respiratory tract cancer. Smoking is a very important risk factor for lung cancer in the plants with exposure to PAH.

A plant polyphenol-rich extract restores the suppressed functions of phagocytes in influenza virus-infected mice

Influenza infection was induced in white ICR mice by intranasal (i.n.) inoculation of the virus A/Aichi/2/68 (H3N2). The number, migration and phagocyte indices of alveolar and peritoneal macrophages (pMØ) and of blood polymorphonuclear leukocytes (PMNs), as well as the inhibition of the PMN adherence in the presence of a specific antigen were followed for 9 days after infection. The effect of the i.n. application of a polyphenol-rich extract, designated as polyphenolic complex (PC), isolated from the medicinal plant Geranium sanguineum L., on the inspected immune parameters was studied in parallel with the virological parameters of the infection, e.g. rate of mortality, mean survival time (MST), infectious lung virus titre and consolidation of the lungs. It was found that the application of PC induced a continuous 2- to 2.5-fold rise in the number of both peritoneal and alveolar macrophages (aMØ) in the infected and healthy controls. The migration of both peritoneal and aMØ increased 1.5- to 2-fold in the group of infected PC-treated animals and four to fivefold in the control group, the maximum being on day 9. PC stimulated phagocyte activities of blood PMNs in both infected and healthy mice. The leukocyte adherence inhibition (LAI) index decreased in the infected and PC-treated animals. The restoration of the suppressed functions of phagocytes in influenza virus-infected mice (VIM) was consistent with a prolongation of MST and reduction in mortality rate, infectious virus titre and lung consolidation. The immunoenhancing properties of PC apparently contribute to the overall protective effect of the plant preparation in the lethal murine experimental influenza A/Aichi infection.

Effects of Magnetic Field 0.1 and 0.05 mT on Leukocyte Adherence Inhibition

T lymphocytes taken from healthy humans and cancer patients before and after medical treatment were exposed to the magnetic field 0.1 and 0.05 mT to study response of the cell-mediated immunity. Leukocyte adherence, which is considered to correlate with the cell-mediated immunity, was measured using an in vitro technique—leukocyte adherence inhibition (LAI) assay. Exposure to the magnetic field increases adherence of T lymphocytes especially those from cancer patients before medical treatment. The effects of exposure to the magnetic field 0.1 and 0.05 mT are similar to those of greater magnetic fields in the range of 0.5 to 10 mT. The effects of the AC and DC magnetic fields 0.05 mT do not display large differences attributable to the magnetic field.

Effects of Sinusoidal 0.5 mT Magnetic Field on Leukocyte Adherence Inhibition

Exposure of T lymphocytes to an external 50 Hz and 0.5 mT magnetic field was investigated in vitro using leukocyte adherence inhibition (LAI) assay which is a measure of cell-mediated immunity. Adherence of T lymphocytes taken from healthy humans and from cancer patients before and after medical treatment is enhanced after 1 h exposure to the magnetic field. The experimental findings for the magnetic field 0.5 mT are compared with published data for 1 and 10 mT. The results are consistent with suggestions of magnetic field effects on immune function in humans.

Effect of a fungal Cu/Zn superoxide dismutase on the cell-mediated immune response in Graffi tumor bearing hamsters.

The antibody-dependent cell cytotoxicity (ADCC) of spleen lymphocytes, isolated from hamsters with progressing myeloid Graffi tumor, was studied. The effect of the application of Cu/Zn superoxide dismutase, isolated from the fungal strain Humicola lutea (HL SOD), before and during tumor transplantation on the lymphocyte ADCC was examined. Myeloid Graffi tumor cells as target cells were used. Antibodies from a rabbit hyper-immune anti-tumor Graffi cells serum, or from tumor-bearing hamsters serum were used in the test. The leukocyte adherence inhibition (LAI) in the presence of tumor antigen was examined also during tumor progression. ADCC of the spleen lymphocytes, determined by both, rabbit and hamster anti-tumor antibodies, decreased during tumor progression. The optimum treatment of the animals by HL SOD induced a 20-30% increase of lymphocyte cytotoxicity against myeloid Graffi tumor cells. Cytotoxicity in presence of tumor bearing hamsters serum was twofold lower as compared to that one determined in the presence of rabbit hyper-immune anti-myeloid Graffi tumor cells serum. Leukocyte adherence inhibition (LAI) index in the presence of tumor antigen increased during tumor development in the groups of treated and untreated animals. The LAI indices of HL SOD-treated tumor-bearing hamsters were lower than that of untreated animals with tumors, what can be explained by a higher adherence ability of leukocytes induced by HL SOD treatment (in formula for calculation of LAI index the adherence value is in the denominator). The results show the beneficial effect of HL SOD on the cell-mediated immune response of myeloid Graffi tumor bearing hamsters, what is probably due to the participation of the enzyme in the host's oxidant-antioxidant balance.