Tube Leukocyte Adherence Inhibition Research Articles

The Leukocyte Adherence Inhibition Test (LAI) in Preoperative Diagnosis of Epithelial Ovarian Cancer

One hundred two women admitted for evaluation of an adenexal mass were tested prior to surgery by the computerized tube leukocyte adherence inhibition (LAI) assay. The test was positive in 24/35 (69%) patients, diagnosed after surgery as epithelial ovarian cancer while 50/67 (75%) of those diagnosed as benign masses were negative. Only 2/38 (5%) of normal control subjects showed a false-positive result. The LAI test described in this report showed a sensitivity of 88% and a specificity of 75% in stage I ovarian cancer; thus it may be useful for early diagnosis of ovarian malignancy.

Allergen-specific leukocyte adherence inhibition (LAI) assay: sensitivity, specificity and mechanism

An allergen-specific tube leukocyte adherence inhibition (LAI) assay has been developed in order to study the mechanism by which leukocytes lose their normal property of adherence to glass. Peripheral blood leukocytes (PBL) from 27 individuals allergic to Dermatophagoides farinae (DF), 10 with seasonal rhinitis not induced by DF and 49 non-allergic healthy volunteers were challenged in vitro with DF and a non-relevant allergen, Artemisia vulgaris (AV) and then assayed for the ability to adhere to glass tubes. Challenge by DF, but not by AV, resulted in loss of adherence by PBL from patients allergic to DF, but not in those of normal controls. The specific LAI response was dose-dependent and occurred only when a critical dose of 0.5 × 10 3 was employed. Following in vitro challenge with DF, radioimmunoassay using an antiserum to LTC 4 detected immunoreactive material in supernatants of PBL from DF-allergic individuals. When highly enriched mononuclear cells from non-allergic individuals were armed with cytophilic allergen-specific IgE and challenged with the specific allergen, they lost the property of glass adherence and released a substance that was immunoreactive with LTC 4. The results suggest that the chain of events leading to the LAI response in PBL from allergic individuals involves primary recognition of the allergen by specific IgE antibodies bound to receptors on mononuclear cells. The cells are thus triggered to synthesize cysteinyl-containing leukotrienes which mediate the LAI phenomenon. The results suggest that this assay may be used to study allergen—antibody interaction and the subsequent events leading to the clinical picture of atopic diseases.

Inhibition of sensitized leukocyte's in vitro reactivity by circulating immune complexes in prostate cancer.

Circulating immune complexes in the sera of patients with confirmed histological diagnosis of carcinoma of the prostate, were found to interfere in the sensitized leukocyte's in vitro reactivity to prostate cancer associated antigen as evaluated by tube leukocyte adherence inhibition assay, thereby suggesting an inhibitory role of such serum factors in host's anti tumor cell mediated immune responses.

Leukocyte adherence inhibition in patients with nonmalignant disorders of the colon and colorectal cancer.

The tube leukocyte adherence inhibition (LAI) technique was used to investigate the antitumor immunity in two groups of patients generally considered to be at "high risk" of developing colorectal cancer. The first group comprised 21 patients with colorectal polyps and the second 12 patients with various forms of colitis. Also 29 patients with histologically confirmed colorectal cancer were tested. The tube LAI assay was performed using peripheral blood leukocytes from individual patients and crude extracts of colorectal and breast cancers. Positive LAI reactions were observed in 18 out of 29 (62%) patients with colorectal cancer, in 1 out of 21 (5%) patients with colorectal polyps and in 1 out of 12 (8%) patients with colitis. The results indicate that in confirmed cases of malignancies, sensitization to colon tumor-associated antigens could be detected in the tube LAI test, whereas, premalignant sensitization to these antigens in "high risk" groups of patients could not be demonstrated.

Leukocyte activation in advanced cancer as an explanation for absent leukocyte adherence inhibition to cancer extracts and chemoattractant

Tube leukocyte adherence inhibition (LAI) measures human immunity by antigen-binding leukocytes releasing chemoattractant-like mediators that are the ultimate inhibitors of adherence by bystander leukocytes. We determined whether the absent LAI responses to cancer extracts for patients with large body burdens of bladder cancer was related to a defect in antigen binding or chemoattractant responsiveness. Leukocytes from patients with small body burdens of bladder cancer gave positive LAI responses of a similar extent to either bladder cancer extracts or chemoattractant [ n-formyl- l-methionylleucylphenylalanine (FMLP)]. Of the adherent leukocytes, about 20–30% became non-adherent with a positive LAI response: monocytes, neutrophils and lymphocytes responded. In the control tubes, leukocytes from patients with large body burdens of bladder cancer were more non-adherent and about 15% less adherent than leukocytes from controls or patient with early cancer. They showed no further decrease in adherence, or conversely increase in non-adherence, with either extracts of bladder cancer or FMLP. The leukocytes also failed to transduce transmembrane signals to the same stimuli. The defect was reversible since PGE 2 restored the adherence of leukocytes to normal, and subsequently they exhibited membrane potential changes and about 34% non-adherence to either bladder cancer extracts or FMLP. From these results we conclude that chemoattractant LAI-responsive leukocytes from patients with large body burdens of bladder tumor are activated in vivo, probably by mediators from inflammatory cells.

Leukocyte adherence inhibition assay in the diagnosis and follow-up of colorectal cancer patients.

Antitumor immune response to colorectal cancer extract was tested by the tube leukocyte adherence inhibition (LAI) assay. Of 70 colorectal cancer patients, 38 (54%) were LAI-positive. In contrast, 15 of 159 (9%) healthy individuals and 2 of 28 (7%) patients with nonmalignant diseases were positive. The LAI activity disappeared a few months after surgery and remained negative in patients with no evidence of disease as well as in patients with disseminated progressed disease. A change of LAI from negative to positive during the follow up period correlated in some cases with the recurrence of the disease, but was observed also in cases with no clinical evidence of disease.

Diagnostic value of the computerized tube leukocyte adherence inhibition (LAI) assay for human colorectal, breast and lung cancers.

We have tested by the computerized tube leukocyte adherence inhibition (LAI) assay, 319, 100 and 342 patients and controls for the presence of antitumor immunity to colorectal, breast and lung cancers. The assay was standardized and its sensitivity increased by using, as a challenging antigen, spent medium of human carcinoma cell lines and by the addition of prostaglandin E2 (PGE2). By large, the sensitivity of the assay (after the addition of PGE2) was inversely related to tumor burden, namely, it was 82.7, 78.9, and 88.6% as compared to 57.1, 33.3, and 29.6% for the early and late stages of colorectal, breast and lung cancers, respectively. Calculating the frequency of disease in the population studied and in comparison with known frequencies of the same in the general population, the positive and negative predicting values (PVpos, PVneg) were obtained. Our results demonstrate that the LAI assay cannot be applied for mass screening since its low PVpos would impair its effectiveness. However, its application to a population at high risk for developing a particular malignancy or as a second-line modality to more conventional screening methods would increase its cost-effectiveness and favor its applicability.

Leukocyte adherence inhibition (LAI) in rats bearing transplantable syngeneic tumors of different immunogenicity

The tube leukocyte adherence inhibition (LAI) assay was used to follow the LAI response in inbred BN rats with subcutaneously (s.c.) transplanted syngeneic liposarcoma (LS 175) tumor and in inbred WAG rats with s.c. transplanted syngeneic colon (CC 531) and skin ( 1618) tumors. Initially, the tube LAI assay was used to follow the LAI reactivity of peripheral blood leukocytes (PBL) from BN rats bearing tumor LS 175. Sporadic LAI reactivity was observed in the PBL of these rats when incubated with a specific crude tumor extract for either 2 or 20 hr. No definite conclusion regarding the lack of significant tumor-specific LAI reactivity could be drawn since LS 175 is a non-immunogenic tumor. Therefore additional LAI studies were performed with the weakly immunogenic tumor CC 531 and the highly immunogenic tumor 1618 in WAG rats. Surprisingly, only sporadic LAI reactivity was observed in the PBL of rats bearing either the CC 531 or the 1618 tumors using both the 2 and 20 hr LAI assays. This absence of tumor-specific LAI reactivity was particularly remarkable in the highly immunogenic 1618 tumor-bearing rats, since it would suggest that the antigen(s) responsible for its high immunogenicity could not evoke any consistent LAI reactivity. Since oxidative metabolites of arachidonic acid have been shown to be the final mediators of chemoattractant-induced LAI, the adherence inhibition effect of leukotriene B 4 (LTB 4) on the PBL of BN and WAG rats was also investigated in order to exclude the possibility that the lack of consistent LAI reactivity was due to a lack of responsive cell population in the PBL. PBL of both BN and WAG rats showed a significant increase in the adherence inhibition in the presence of LTB4, suggesting that the sporadic LAI reactivity was not due to a lack of responsive cell population.

Leukocyte Adherence Inhibition to Myelin Basic Protein by Cancer Patients' T-Lymphocytes in Association With Class II Major Histocompatibility Antigens on Monocytes<xref ref-type="fn" rid="FN2">2</xref>

Patients' leukocytes were shown to react consistently in tube leukocyte adherence inhibition (LAI) assays with myelin basic protein (MBP) at optimal concentration, whereas control leukocytes were nonreactive. Mononuclear cells from patients with cancer gave positive LAI reactions with MBP, but separated T-lymphocytes, monocytes, and neutrophils did not. The mononuclear cell LAI responses were blocked by monoclonal antibody (MAb) to monomorphic determinant of class II major histocompatibility complex (MHC) antigens and to T4+ (Leu-3a+) and T3+ (Leu-4+) T-cell differentiation antigens but not by antibody to class I MHC antigens or T8+ (Leu-2a+) antigens. MBP was thus recognized by helper T-cells, requiring presentation in association with class II MHC determinants on monocytes. MAb to class I and class II MHC antigens and to T8+ (Leu-2a+), T4+ (Leu-3a+), and T3+ (Leu-4+) differentiation antigens did not negate LAI mediated by peripheral blood lymphocytes to organ-specific cancer neoantigens (OSN) of crude extracts of allogeneic cancer, which had previously been shown to react with cytophilic antibody on allogeneic monocytes. When membrane OSN and leukocytes were autologous, T8+ (Leu-2a+) phenotypic T-cells also mediated LAI that was blocked by anti-T8 (Leu-2a) and anti-T3 (Leu-4). LAI induced by MBP was also negated by drugs that antagonize thromboxane-leukotriene biosynthesis, indicating that, in common with other LAI reactions, the terminal mediators of nonadherence are oxidative metabolites of arachidonic acid. In addition to clarifying the role of MBP in the cellular in vitro immunoreactivity of cancer patients, the present observations have important implications for theories of LAI. Sensitized leukocytes have different mechanisms for the recognition of antigens in different forms, and the antigen-stimulated leukocytes produce mediators that in a final common pathway induce nonadherence of surrounding cells through leukotriene-like metabolites.

Regulation of leukocyte glass adherence and tube leukocyte adherence inhibition (LAI) reactivity by serum factors in dogs with progressing or spontaneously regressing canine transmissible venereal sarcoma (CTVS).

We examined the regulation of leukocyte glass adherence and tube leukocyte adherence inhibition (LAI) reactivity by serum factors in dogs with regressing or progressing canine transmissible venereal sarcomas (CTVS). Both regressor and progressor peripheral blood leukocytes (PBL), draining and non-draining lymph node cells (LNC), and splenic leukocytes were significantly responsive to CTVS antigen extract in tube LAI. In contrast, a significant decrease in basal glass adherence of progressor PBL, draining and non-draining LNC, and splenic leukocytes was observed. Normal glass adherence was restored to progressor leukocytes by extensive washing with warm serum-free media, while significant tube LAI responsiveness to CTVS antigen extract was maintained. Preincubation of regressor PBL and LNC with progressor sera in two-stage tube LAI decreased the basal glass adherence of treated leukocytes. This effect of progressor sera was heat labile, a characteristic of CTVS antigen. Collectively, these findings suggest that progressor leukocytes and progressor sera treated regressor leukocytes were activated by interaction with serum CTVS antigen and thus behaved in tube LAI as stimulated cells, even in the absence of CTVS antigen. Regressor but not progressor sera were shown to contain anti-CTVS IgG with specific arming activity for normal dog PBL, but not LNC in two-stage tube LAI. The nonadherent response of peripheral blood neutrophils in two-stage tube LAI was proportional to the concentration of arming IgG, whereas no change was observed in glass adherence of PBL. The results of this study define the role of progressor and regressor serum factors in the mechanism of tube LAI and demonstrate a relationship between leukocyte glass adherence and the clinical course of CTVS. These findings show that tube LAI is a simple and reproducible measure of active factors in the immune response to a tumor.

Leukocyte adherence inhibition (LAI) for detecting specific tumor immunity in colorectal cancer

Immunity to colorectal cancer antigen was tested by the tube leukocyte adherence inhibition (LAI) assay, using spent medium of human carcinoma cell lines as a source of antigen. The assay was positive in 18 out of 43 patients (41%) with colorectal tumor in comparison to only 2 out of 34 (5.8%) of colorectal cancer patients clinically free of disease, and to 4 out of 150 (2.6%) healthy subjects. The frequency of positive results correlated negatively with the tumor burden, 16 out of 29 (55.1%) patients with Dukes' A, B and C being positive compared to only 2 out of 14 (14.2%) patients with Dukes' stage D disease. Addition of PGE 2 enhanced the sensitivity of the assay without affecting its specificity. The number of positive assays increased from 18 to 32 (41.8% to 74.4%) in the whole group of 43 colorectal cancer patients without altering significantly the frequency of positive results in the control group. The results with all groups of patients were influenced similarly by the addition of prostaglandins, the frequency of positive assays increasing from 55.1% to 82.7% and from 14.1% to 57.1% in early and advanced disease, respectively. These results lend further support to the value of the LAI assay in diagnosis and monitoring of the immune response in human colorectal cancer.

Evaluation of leukocyte adherence inhibition (LAI) test in primary and secondary hepatic malignancies.

Leukocyte adherence inhibition (LAI) has been demonstrated to be a simple, rapid, and reliable technique in the diagnosis of various malignancies including hepatocellular carcinoma. The LAI test was carried out employing modified tube LAI technique in patients with primary hepatocellular carcinoma (HCC) and secondary carcinomas of liver. Positive LAI response to HCC antigen was obtained in all six (100%) cases of hepatocellular carcinoma tested. None of the control cases, which included 8 healthy subjects and 16 cases of benign liver diseases, gave positive LAI response. Two out of 19 cases of secondary carcinoma gave a positive LAI reaction to HCC antigen. In secondary carcinomas, 19 out of 21 cases (90.48%) gave positive LAI reaction to secondary adenocarcinoma antigen. There were two false positives in controls (1 each of cirrhosis and amebic liver abscess), and 1 out of 8 cases of HCC also gave positive response to secondary carcinoma antigen. Thus, LAI test was found to be useful in the diagnosis of hepatic malignancies.

Amplification of lymph node cell tube leukocyte adherence inhibition (LAI) reactivity by leukocyte adherence inhibition factor (LAIF)

This investigation examines the immunologic basis for specific antigen-induced tube leukocyte adherence inhibition (LAI) reactivity of draining lymph node cells (LNC) from dogs with canine transmissible venereal sarcoma (CTVS). CTVS regresser LNC, macrophage-depleted LNC, and enriched T lymphocyte fractions, but not enriched B lymphocyte fractions, were specifically reactive to CTVS antigen extract in direct tube LAI. In addition, regressor LNC amplified tube LAI responses by generating supernatants with leukocyte adherence inhibition factor (LAIF) activity for normal dog indicator LNC and enriched peripheral blood mononuclear cells (PBMC) in an indirect tube LAI assay. However, macrophage-depleted LNC and enriched T lymphocyte fractions failed to generate supernatants with LAIF activity, suggesting that macrophage accessory cells play a central role in the amplification of tube LAI. Interestingly, CTVS regressor peripheral blood leukocytes (PBL) and PBMC, which were specifically reactive in direct tube LAI, also failed to generate supernatants with LAIF activity. These findings demonstrate a distinction between LAIF-mediated amplification and direct tube LAI reactivity, and suggest that leukocyte populations with differing cellular proportions and from different immunologic compartments may participate in tube LAI via different mechanisms.

Cell-Mediated Immunity in Prostatic Cancer and its Diagnostic Relevancy

Cell-mediated immunity (CMI) in prostatic cancer patients to presumptively identified prostatic tumour-associated antigens (TAA) was further evaluated in this study by tube leukocyte adherence inhibition in 504 patients with and without prostatic cancer. Peripheral blood leukocytes from 210 of 312 (67%) prostatic cancer patients possessed significant reactivity to extracts of malignant prostate. However, significant reactivity to malignant prostate was also observed in 89 of 192 (46%) controls comprised of patients with other than carcinoma of the prostate [including 91 patients with benign prostatic hypertrophy of which 46 (51%) possessed significant reactivity to malignant prostate] and healthy adults. With the exception of a significant difference in the reactivity between stage A vs stage C patients, there was no significant correlation between the level of reactivity to malignant prostate and the stage of disease. Had CMI to presumptively identified prostatic TAA been employed as an adjunctive diagnostic criterion to detect prostatic cancer, 191 (38%) of the 504 patients in this study would have been incorrectly diagnosed. The results of this study emphasize the critical need in attempting to delineate tumour-directed immunity from possible concomitant sensitization to tissue- and species-specific antigens for the identification, isolation and physicochemical characterization of what previously have been referred to as presumptively or putatively identified prostatic TAA.

Cell-mediated immunity in prostatic cancer and its diagnostic relevancy

Cell-mediated immunity (CMI) in prostatic cancer patients to presumptively identified prostatic tumour-associated antigens (TAA) was further evaluated in this study by tube leukocyte adherence inhibition in 504 patients with and without prostatic cancer. Peripheral blood leukocytes from 210 of 312 (67%) prostatic cancer patients possessed significant reactivity to extracts of malignant prostate. However, significant reactivity to malignant prostate was also observed in 89 of 192 (46%) controls comprised of patients with other than carcinoma of the prostate [including 91 patients with benign prostatic hypertrophy of which 46 (51%) possessed significant reactivity to malignant prostate] and healthy adults. With the exception of a significant difference in the reactivity between stage A vs stage C patients, there was no significant correlation between the level of reactivity to malignant prostate and the stage of disease. Had CMI to presumptively identified prostatic TAA been employed as an adjunctive diagnostic criterion to detect prostatic cancer, 191 (38%) of the 504 patients in this study would have been incorrectly diagnosed. The results of this study emphasize the critical need in attempting to delineate tumour-directed immunity from possible concomitant sensitization to tissue- and species-specific antigens for the identification, isolation and physicochemical characterization of what previously have been referred to as presumptively or putatively identified prostatic TAA.

A Study of the Immune Response to the Organ-Specific Neoantigen of Human Bladder Cancer

The antitumor immune response of monocytes armed with cytophilic antitumor antibody to an organ-specific neoantigen of human bladder cancer was measured by the tube leukocyte adherence inhibition assay. Of 29 patients with Stage A bladder cancer, 27 had positive tests, whereas of 11 patients with Stage B, C and D bladder cancer, 2 had positive tests. If the leukocytes from advanced bladder cancer patients were preincubated briefly with prostaglandin E2, the negative response was converted to positive. Of 189 patients with diseases of other organs, 2 had positive tests. Patients with acute or chronic cystitis had negative tests. The sensitivity of the assay was 88 per cent; specificity was 95 per cent. The bladder cancer extracts prepared from metastatic tissue or the tissue-cultured cell line, T24, had similar activity in the assay. Normal bladder tissue did not share the bladder cancer organ-specific neoantigen nor did cancers of other organs. Bladder epithelial cells expressed the OSN before they acquired invasive properties since patients with dysplastic bladder epithelium or in-situ cancer had positive tests. Antitumor immunity was often detectable before a recurrence became obvious by cystoscopy or cytology of urine and became undetectable quickly after removal of the bladder cancer. Of 100 patients with prior bladder cancer without evidence of exophytic tumor, 18 had positive tests; the possibility must be considered seriously that some had precancerous changes which formed no visible gross abnormalities. The results suggested that antitumor immunity to bladder cancer was a sensitive indicator of precancerous or cancerous changes existing in epithelial cells.

Predictive value of tube leukocyte adherence inhibition (LAI) assay for breast, colorectal, stomach and pancreatic cancer.

The tube LAI assay measures accurately antitumor immunity in patients with early cancer but fails to detect up to 75% of patients with advanced cancer due to excess circulating organ-specific neoantigen (OSN). Substances such as prostaglandin E2 (PGE2) or aminophylline, which increase intracellular nucleotides in leukocytes of patients with advanced cancer reversed this nonreactivity and greatly increased the sensitivity of the assay without any loss of specificity. Antitumor immunity can now be detected in advanced cancer, and a combination of the two assays gives prognostic potential to the assay: a positive test with PGE2 and negative test without indicates the patient has a large tumor burden. The specificity of the assay for each cancer was high and in most instances was greater than or equal to 95%. The PGE2 stimulated assay retained the high specificity. The sensitivity of the regular tube assay was often low, 33-56% because of the many advanced cancer patients tested, whereas the PGE2 stimulated assay showed almost a two-fold increase in sensitivity, 67-93%. The diagnostic value of the assay was estimated by calculating the predictive value for different prevalences of cancer. It was found that at low prevalences of cancer as found in the general population, the assay had a low diagnostic value since few patients with a positive test would have the cancer tested for. With prevalences of cancer of 5% or greater as might be found in a tertiary care clinical setting, the assay would seem to have diagnostic value since one half or more patients with a positive test would have the cancer tested for. Most false positives, but not all, are found in patients who have lesions that are often considered to increase their risk for cancer: severe dysplasia of the breast, colon adenomas, chronic atrophic gastritis and chronic pancreatitis, suggesting that the assay predicts oncogenesis.

Prostaglandin E2 Affects the Tumor Immune Response in Prostatic Carcinoma

Antitumor immunity to prostatic carcinoma was assayed by the tube leukocyte adherence inhibition assay. Peripheral blood leukocytes from 37 patients with prostatic carcinoma and 128 patients without prostatic carcinoma were incubated separately with extracts from prostatic carcinoma and from an unrelated control cancer, and the non-adherence index was calculated. The number of patients with prostatic carcinoma who had a positive response (non-adherence index greater or equal to 30) was small. Nevertheless, the mean non-adherence index (11) of the patients with prostatic carcinoma was statistically different (p less than 0.02) from the mean non-adherence index (2) of the subjects without prostatic carcinoma. Of patients with prostatic carcinoma 14 per cent (5 of 37) had positive leukocyte adherence inhibition responses, compared to 1.5 per cent of control subjects (2 of 128) (p less than 0.05). Sixty patients diagnosed clinically as having benign prostatic hyperplasia were screened by the leukocyte adherence inhibition test and the non-adherence index results then were evaluated with the histopathological diagnosis of the surgical specimen. Of the patients with benign prostatic hyperplasia 3 (5 per cent) had stage A prostatic carcinoma, and 1 of these 3 patients (33 per cent) had a positive leukocyte adherence inhibition test.After in vitro treatment of the peripheral blood leukocytes with 10–6 M. prostaglandin E2 11 of 18 patients with prostatic carcinoma (61 per cent) and 1 of 35 subjects without prostatic carcinoma (3 per cent) had positive leukocyte adherence inhibition responses. The ability of prostaglandin E2 to heighten the leukocyte adherence inhibition response of the peripheral blood leukocytes from patients with prostatic carcinoma suggests that there is a functional defect in the antitumor response of the peripheral blood leukocytes, possibly caused in part by an excess of circulating tumor antigen. In fact, this is supported by the high mean non-adherence index (19) in patients with prostatic carcinoma who had serum prostatic acid phosphatase within normal limits, while patients with an elevated prostatic acid phosphatase had a low mean non-adherence index (0.2). Therefore, patients with prostatic carcinoma are expressing an antitumor response to prostatic carcinoma but this response is weak even when the clinical stage of the disease seems to be early.

Inhibition of leukocyte adherence by 3 M potassium chloride extracts of human malignant melanoma

The tube leukocyte adherence inhibition (LAI) assay was performed using 3 M KCl extracts of malignant melanoma materials and leukocytes taken from 24 malignant melanoma patients. Of these patients, 21 participated in sequential studies which employed a minimum of 3 time points. An increasing non-adherence index (NAI) was found in 5 of 6 patients who exhibited a favorable disease course. In 5 of 6 patients with an unfavorable disease course, NAI values decreased. In 8 of 9 patients with stable disease, the NAI also was stable. These results indicate that the trend of sequential LAI studies reflects the clinical course of malignant melanoma patients.

A Coded Study of Antitumor Immunity to Human Lung Cancer Assayed by Tube Leukocyte Adherence Inhibition

The present study was undertaken to evaluate the specificity of antitumor immunity to human lung cancer, measured by an in vitro assay–tube leukocyte adherence inhibition (LAI). We standardized and monitored the putative tumor antigen activity of the extracts by testing leukocytes from controls and patients with lung cancer in the Montreal General Hospital. A specific antitumor response to a lung cancer antigen was detected with coded leukocytes from 56% (20 out of 36) of patients with epidermoid lung cancer. By contrast, 4% (2 out of 53) of patients with inflammatory lung disease and none of 46 other patients with cancer metastatic to the lung or with other diagnoses had an LAI-positive result. The LAI response was inversely related to the extent of cancer: 80% (8 of 10) with Stage I, 66% (2 of 3) with Stage II, 54% (6 of 11) with localized Stage III, and 33% (4 of 12) with widespread Stage III were LAI positive. Leukocytes from patients with epidermoid, adenocarcinoma, or small cell lung cancer reacted to a common tumor antigen shared by extracts of epidermoid and small cell lung cancer. This study with coded samples from a remote hospital confirms the results of other investigators that the LAI measures an antitumor immune response to human organ-specific neoantigens.