Immunohistochemical antigenic expression and in vivo tumor uptake of monoclonal antibodies with specificity for tumors of the gastrointestinal tract.

Two monoclonal antibodies with specificity for carcinoembryonic antigen and Ca 19-9 gastrointestinal tract tumor associated antigens were infused after iodination with 125I and 131I, respectively, in six patients 3 days and in one patient 4 days before radical surgery for colon or rectal carcinoma. Biopsy specimens from tumor, normal colon, fat, muscle, and skin along with a blood sample were excised at surgery and counting was performed for gamma emission. Fragments were then studied by two independent pathologists for immunohistochemical expression of corresponding antigens using the avidin-biotin peroxidase complex. A correlation study was thereafter performed between the amount of antibody bound in vivo, expressed as the percentage of injected dose per gram of tissue and the quantitative expression of tumor associated antigens, taking into account both the percentage of cells expressing the antigen and intensity of staining. For this limited number of patients a good correlation was found between amount of targeted antibodies and amount of expressed antigens. For carcinoembryonic antigen, r values were 0.69 and 0.90 for each pathologist (with an r value of interobserver correlation of 0.74); for Ca 19-9, values of 0.78 and 0.84 were obtained for each observer, with an interobserver r value of 0.97. Based on this limited study, it may be assumed that the possibility of imaging a given tumor is in part correlated to intensity of antigenic expression at the tumor site; other parameters, like tumor vascularization and blood flow for instance, are, however, to be considered for accessibility of antibodies to corresponding antigens.

Immunoscintigraphy using 111In-labeled F(ab')2 fragments of anticarcinoembryonic antigen monoclonal antibody for detecting recurrences of medullary thyroid carcinoma.

The only current possibility for curing medullary thyroid carcinoma (MTC), especially recurrences, is total surgical removal. Early positive diagnosis of recurrences is now possible by monitoring tumor markers such as thyrocalcitonin and carcinoembryonic antigen (CEA). However, preoperative topographic diagnosis of such recurrences remains an unresolved problem. Immunoscintigraphy (IS) using an anti-CEA monoclonal antibody is a new approach that complements morphological imaging, i.e. ultrasonography, computerized tomography, and magnetic resonance imaging. In this study, IS by means of an 111In-labeled anti-CEA monoclonal antibody F(ab')2 was performed nine times in eight patients. True positives were obtained five times (one case of cervical involvement confirmed by surgery, three cases of mediastinal involvement confirmed by computerized tomography, magnetic resonance imaging, and surgery, and one case of bone metastasis, one of them was revealed neither by x-ray nor by conventional bone scan). The remaining four tests gave a false positive, a true negative, a probably false negative, and one unconclusive result. We conclude that IS is helpful in diagnosing sites of MTC recurrence and should accompany other examinations in the evaluation of lesions.

Reproducibility of image interpretation in immunoscintigraphy performed with indium-111- and iodine-131-labeled OC125 F(ab')2 antibody injected into the same patients.

An important criterion for the clinical use of a new imaging technique is the correct reproducibility of interpretation. Forty-six paired immunoscintigraphic examinations were performed on 43 patients with suspected ovarian carcinoma recurrence using F(ab')2 fragments of OC125 antibody labeled first with indium-111 and then with iodine-131. Planar scintigraphy (PS) and emission computed tomography (ECT) images were interpreted blindly and separately by three observers, and reproducibility was evaluated by a kappa concordance index. Intra- and interobserver reproducibility were generally satisfactory (kappa values of 0.6 and 0.7, respectively). Binomial analysis of kappa values for ECT showed the superiority of indium-111 for intraobserver (p = 0.035) and interobserver (p = 0.0039) study. However, for PS there was no significant difference in reproducibility with the two radionuclides.

Evaluation of indium-111-labeled antifibrin monoclonal antibody for the diagnosis of venous thrombotic disease.

The potential advantage of using 111In-antifibrin (111In-AF) monoclonal antibody for the diagnosis of deep venous thrombosis (DVT) was studied in 44 patients with suspected DVT (27 underwent heparin therapy before 111In-AF injection). All patients had contrast venography (considered as the gold standard) and 111In-AF scintigraphy within 24 hr. Two to 3 mCi of 111In-AF were injected intravenously, and planar scintigraphy of the limbs was recorded within 10 min (17 times), 3 hr (44 times), and 18 hr (39 times). Indium-111-AF images were then interpreted without knowledge of the results of the other examinations. The DVT diagnostic accuracy of 111In-AF was greater when interpretation was based on images recorded at different time periods after injection. Indium-111-AF sensitivity for diagnosis of DVT was 85% (29/34) and was not apparently decreased by heparin therapy. None of the 10 patients with negative contrast venography had a positive 111In-AF scan. The results demonstrate the importance of recording serial images and the excellent accuracy of 111In-AF for diagnosing DVT.

Radioimmunodetection of medullary thyroid cancer using a bispecific anti-CEA/anti-indium-DTPA antibody and an indium-111-labeled DTPA dimer.

Two-step radioimmunotargeting using a bispecific anti-CEA/anti-in-DTPA monoclonal antibody and an 111In-labeled DTPA dimer (diDTPA-TL) was evaluated nine times in eight patients with medullary thyroid cancer (MTC). Immunoscintigraphy was performed 5 and 24 hr after injection of 111In-diDTPA-TL. For five patients, radioimmunoguided surgery (RIGS) was performed using a hand-held gamma probe (sodium iodine), and a biodistribution study was performed 48 hr (four times) and 24 hr (one time) after injection of 111In-diDTPA-TL. Mean tumor uptake (%ID/kg in tumor) was 39 (range 2.75-139). In these five patients, immunoscintigraphy visualized all known tumors and detected unknown foci (US and CT were negative) in the neck (once) and neck and liver (once). Immunoscintigraphy, performed four times in search of a recurrence, detected unknown localizations in the mediastinum and neck (twice) and was negative twice. There were no false-positives. In three of five patients who had surgery, RIGS localized tumor foci not detected by the surgeon. RIGS failed to detect two small lesions (10 x 10 mm) corresponding to sites of fibrosis and microscopic cancer infiltration. Bispecific anti-CEA/anti-In-DTPA mediated targeting of 111In-diDTPA-TL provided elevated tumor uptake and tumor-to-normal tissue ratios. Radioimmunodetection of small MTC lesions is thus possible even when morphological imaging techniques prove negative.

Immunoscintigraphy of recurrences of gynecologic carcinomas.

In a first, retrospective study, 15 patients with known ovarian carcinoma were injected with 131I-OC 125 F(ab')2 monoclonal antibody (MAb). The sensitivity of immunoscintigraphy based on the number of the tumor sites was 67% (12/18). In a second, prospective study, 29 patients with gynecologic carcinoma were injected with 131I-OC 125 F(ab')2 (24) or 131I-19-9 F(ab')2 (5) MAbs according to the histologic type. Based on the number of tested anatomic sites, sensitivity was 72% and specificity 86%. In two patients injected with both 131I-OC-125 F(ab')2 and 125I-NS F(ab')2 (nonspecific immunoglobulin) 1 and 4 days before tumor resection, tumor uptake of the specific antibody was 2.2 and 4.5 times greater than that of NS. Immunoscintigraphic results were complementary with those of ultrasonography and computed tomography. Finally, in one patient injected successively with 131I-OC 125 F(ab')2 and 111In-DTPA-OC 125 F(ab')2, the recurrent tumor was visualized with both radionuclides, with 111In providing better abdominal tumor contrast but causing much greater liver radioactivity than 131I.

Two-step immunoscintigraphy for non-small-cell lung cancer staging using a bispecific anti-CEA/anti-indium-DTPA antibody and an indium-111-labeled DTPA dimer.

UNLABELLED: Immunoscintigraphy (IS) using anti-CEA F(ab')2 monoclonal antibody (MAb) is useful for improving mediastinal staging of nonsmall cell lung cancer (NSCLC), but the technique was limited because of an insufficient contrast between tumor and normal tissues. The aim of this study was to determine if the method could be improved by a two-step method which uses a bispecific anti-CEA/anti-di-DTPA antibody (Bs-MAb) and 111In-labeled di-DTPA-tyrosyl-lysine bivalent hapten. METHODS: Twelve patients were intravenously given a 30 min Bs-MAb infusion (0.1 mg/kg). Four days later, they were injected intravenously with 0.1 microgram/kg hapten labeled with 185 MBq 111In (5 mCi). Images were recorded immediately and 6 and 24 hr after hapten injection. A pharmacokinetic analysis was performed. Surgery was performed 3 days after 111In-hapten injection, and samples of tumor and normal tissues were collected for immunohistochemical and biodistribution studies. IS results were classified as true-positive (TP), false-positive (FP), true-negative (TN) or false-negative (FN) according to the surgical data. RESULTS: Primary tumors were visualized in nine patients. The contrast was excellent, generally higher than that obtained with direct labeling of anti-CEA. In the mediastinum, IS results were (after surgery) five TN, two TP and one FP. One case remains undetermined. The FP result was due to a Bs-MAb uptake in intrapulmonary lymph nodes. IS was in agreement with preoperative staging in six of these nine patients and discordant in three. CONCLUSION: Our study confirmed that the two-step method with a bispecific antibody could greatly improve the performances of IS for lung cancer staging.

Bispecific antibody and iodine-131-labeled bivalent hapten dosimetry in patients with medullary thyroid or small-cell lung cancer.

UNLABELLED: The purpose of this study was to estimate the dose delivered to tumor targets and normal tissues after two-step injection of an anti-CEA/anti-DTPA-In (F6-734) bispecific antibody and a 131I-labeled di-DTPA in-TL bivalent hapten in patients with medullary thyroid carcinoma (MTC) and small-cell lung cancer (SCLC). METHODS: Five patients with persistent disease or recurrences of MTC and five patients with primary SCLC or relapse were studied. In a first step, 0.1 to 0.3 mg/kg of F6-734 bispecific antibody was injected intravenously. Four days later, 6 nmole (5.8 to 9.8 mCi) of 131I-labeled di-DTPA in-TL bivalent hapten were injected. Quantitative imaging was performed during one week after the second injection. RESULTS: All 5 patients with MTC showed positive immunoscintigraphy (IS). In the smallest visualized and resected tumor (0.8 g), the fraction of injected activity per gram (% ID/g) was 0.1% at Day 3. IS was positive in 4 of the 5 patients with SCLC. The volume of the smallest visualized SCLC tumor was estimated at 11 +/- 2 ml, and tumor uptake was about 0.009% ID/g. Tumor dose estimates ranged from 4.2 to 174 cGy/mCi in patients with MTC and from 1.7 to 8 cGy/mCi in patients with SCLC. CONCLUSION: High absorbed dose values were calculated for small MTC recurrences. For SCLC recurrences the values were smaller but in the same range as those obtained by other investigators with the one-step technique in lymphoma.

Radioimmunodetection of medullary thyroid carcinoma using indium-111 bivalent hapten and anti-CEA x anti-DTPA-indium bispecific antibody.

UNLABELLED: Pretargeting labeled bivalent hapten with bispecific antibodies has proven feasible in the clinic, and our earlier results have suggested the technique may be very sensitive for detecting small recurrences and metastases. Medullary thyroid carcinoma (MTC) is an example where this technique may be the most useful since local recurrences and isolated metastases are removed surgically when detected, and thyrocalcitonin provides a specific and sensitive tumor marker. In our current study, we evaluated pretargeted immunoscintigraphy in a larger number of MTC patients. METHODS: Anti-carcinoembryonic antigen (CEA) x anti-diethylenetriaminepentaacetic acid (DTPA) indium bispecific antibody and 111In-labeled bivalent DTPA hapten were administered sequentially (4-5 days apart) to 44 patients with elevated circulating calcitonin after resection of primary MTC. Immunoscintigraphy was performed 2, 5 and 24 hr after hapten injection and, when necessary, at longer time intervals. When available, a handheld gamma probe was used during surgery. RESULTS: Fifteen patients had known tumor sites before immunoscintigraphy. Tumors were imaged in 12 (80%) of these patients, including 3 with liver metastases. Five unknown tumor sites were detected. For the 29 patients with occult disease, immunoscintigraphy detected high-activity uptake sites in 21 patients (72%), including 5 in the liver. Twelve were confirmed by surgery, 1 by guided morphologic imaging and 1 by venous catheterization. There were 2 false-positive patients. The other 5 patients have not yet been confirmed. All detected liver metastases were high-activity uptake areas. Radioimmunoguided surgery was used in 14 patients. It was considered helpful by the surgeon in 12 patients, including 4 patients where it determined the resection of small, not palpable nor visible, tumor-involved lymph nodes. Surgical resection resulted in a significant decrease (8 patients) or normalization (1 patient) of circulating calcitonin and CEA. CONCLUSION: This technique affords high sensitivity and specificity for detecting small tumor lesions including liver metastases. Its use for immunoscintigraphy and guided surgery should improve the therapeutic management of recurrent MTC.

Detection of lung and bone infection with anti-granulocyte monoclonal antibody BW 250/183 radiolabelled with 99Tcm.

Twenty-four patients with suspected infection (eight bone, 16 lung) were studied using monoclonal antibody BW250/183 which recognizes epitopes present on the surface of granulocytes. Bronchofibroscopic samples (microbiological studies and alveolar cell counts) were obtained from 14/16 patients with lung disease. Bronchofibroscopy isolated a micro-organism nine times. In two other cases, the diagnosis of infection was based on clinical course data. Infection was confirmed by surgical biopsy in the eight patients with bone pathology. Scans were performed 2 and 24 h after injection of 1 mg BW 250/183 labelled with 99Tcm. For lung disease, immunoscintigraphy was positive six times (five true positive, one false positive) and negative 10 times (six false negative, four true negative). Immunoscintigraphy was false negative when the lung infection was not systematized or no granulocytes were mobilized in the infectious site. Immunoscintigraphy was falsely positive when noninfectious lung disease mobilized granulocytes. It was positive in all patients with bone infection. Images recorded at 24 h had better sensitivity (five false negative) than those at 2 h (eight false negative).

Comparison of technetium-99m aerosol and krypton-81m in ventilation studies for the diagnosis of pulmonary embolism.

A new method of producing aerosols (technegas) in which 99Tcm is bound to carbon atoms (99Tcm-C) was evaluated by comparing 99Tcm-C images with those obtained with 81Krm in the same patients. Twenty-five patients with suspected pulmonary embolism (PE) were studied. Immediately after the last 99Tcm-C view, the patients remained in supine position and inhaled 81Krm at tidal volume. Immediately after the 81Krm ventilation views were recorded, 4-7 mCi of MAA were injected IV. The same four views (ant, lop, rop, post) were recorded after inhalation of 99Tcm-C and 81Krm (200 kcounts) and 99Tcm MAA injection (400 kcounts). The mean penetration index of 99Tcm-C (0.91) was lower than that of 81Krm (1.04) (P less than 0.03). The apex to base lung distribution of 99Tcm-C and 81Krm appeared to be similar. The mean heterogeneity of 99Tcm distribution was 23, greater than that of 81Krm (14) (P = 10(-4)). The 99Tcm-C ventilation image quality was considered very good for 16 patients and good for 6 others. Significant foci of high bronchial uptake were infrequent. Interpretation of the examinations performed after inhalation of 99Tcm-C and 81Krm was concordant in all cases. No patient had an 81Krm/99Tcm MAA examination suggestive of PE when 99Tcm-C/99Tcm MAA indicated a low probability of PE, and vice versa. 99Tcm-C aerosols enable good quality ventilation images to be obtained in nearly all cases. Thus 99Tcm-C aerosols could be used in preference to 81Krm in ventilation studies for the diagnosis of PE.

Anti-beta HCG abdominopelvic immunoscintigraphy in patients with resistant gestational trophoblastic disease.

The clinical utility of abdominopelvic immunoscintigraphy (IS) using anti-beta HCG-labelled monoclonal antibodies was evaluated in six patients with resistant gestational trophoblastic disease and no common pathological site. Five patients with abnormal retrovesical uptake had persistence of uterine trophoblastic disease confirmed on hysterectomy. Four of these patients are now in remission. It is concluded that IS provides a useful indication for surgery when a single abnormal uptake site is found.

Aerosol-perfusion lung scintigraphy: value of ventilation subtraction.

99Tcm-labelled aerosol ventilation and 99Tcm-macroaggregate albumin (99Tcm-MAA) perfusion can be performed in the diagnosis of pulmonary embolism (PE). If both examinations are performed on the same day, the superposition of activity from the first scintigraphic examination might mask defects in the second. In this study, 106 examinations were carried out for suspected PE. Aerosol ventilation was performed first with 20 to 30 mCi 99Tcm-labelled rhenium sulphur (four views, 200,000 counts). Immediately afterwards, with the patient remaining in the same position, 5 to 7 mCi of 99Tcm-MAA were injected (four views, 400,000 counts). After normalization, aerosol activity was subtracted from perfusion images and unprocessed perfusion (UP) and ventilation subtraction perfusion (SP) images were compared. Interobserver diagnostic reproducibility between three readers was calculated both for UP and SP images. Intraobserver reproducibility between UP and SP images was calculated for each reader. Interobserver reproducibility was comparable for SP and UP images. Intraobserver reproducibility was good. Thus, whether ventilation was subtracted or not from perfusion images, there was no appreciable effect on perfusion defect detection. However, some perfusion abnormalities showed up more clearly on SP images. Perfusion can be performed immediately after aerosol ventilation; the images thus obtained are reliable for interpretation, and subtraction of ventilation is not necessary.

Pretargetted imaging of colorectal cancer recurrences using an 111In-labelled bivalent hapten and a bispecific antibody conjugate.

In 11 patients recurrence of colorectal cancer was suspected by a rise in serum carcinoembryonic antigen (CEA) (nine cases), by a subocclusive clinical situation (one case) or by endoscopy (on an anastomosis, one case). Two-step tumour targetting was performed by a first injection of 0.1 mg kg-1 of unlabelled bispecific antibody conjugate (an anti-CEA Fab' fragment chemically coupled to an anti-diethylene triamine pentaacetate (DTPA)-indium fragment) followed 4 to 5 days later by injection of the bivalent DTPA hapten labelled with 5 to 8 mCi 111In. Planar scintigraphy, single photon emission computed tomographic (SPECT) 360 degrees acquisitions and whole-body scans were obtained 4.5 and 24 h after injection of the radiolabelled hapten. Biodistribution was determined for eight patients at 48 h. The final diagnosis was confirmed histologically in nine patients (eight by second-look surgery, one by laparotomy). Overall, results were one true negative (1-year follow-up) and 10 true positive; however, for the three large liver metastases (3 to 6 cm), only the periphery of the metastasis had high uptake compared to normal liver. For pelvic recurrences, immunoscintigraphic (IS) contrast was better for small tumours. The highest tumour uptake was found for a 1 cm diameter pelvic recurrence (7.2% i.d. kg-1). Mean tumour-to-blood ratios were 6.4. Thus, this two-step tumour targetting technique, which uses a bispecific antibody conjugate and an 111In-labelled bivalent hapten injected sequentially without chasing the excess bispecific antibody, provided satisfactory results in this preliminary clinical trial for detection of recurrent colorectal cancers.

99Tcm-labelled anti-fibrin Fab' fragment for evaluating the course of venous thrombosis in the rabbit.

Immunoscintigraphy was performed using the Fab' fragment of 99Tcm-labelled T2G1s anti-fibrin monoclonal antibody in a rabbit experimental model of venous thrombosis of known and increasing age (1, 3 and 7 days). Scans were positive in 3/7 cases for 1-day thrombosis (fibrin-poor network) and in 7/7 cases for 3-day thrombosis (fibrin-rich network). In rabbits with 7-day thrombosis, the scan was positive (2/4 cases) only when connective tissue was not present in the clot. Scintigraphic results were concordant with those of biodistribution studies showing the mean percentage of injected dose per gram 99Tcm-T2G1s present in the thrombosed vein wall (0.043, 0.082 and 0.07 for thrombi at 1, 3 and 7 days, respectively). Mean thrombosed vein wall-to-blood ratios were 1.027, 2.291 and 1.301, respectively. Immunoscintigraphy with T2G1s anti-fibrin monoclonal antibody thus enabled hematological status to be evaluated.

Experimental venous thrombosis: what animal model?

A new experimental venous thrombosis model is described and its role relative to other models is defined. Previous models are not satisfactory for all types of investigation. Opposite, present model based on the three classic thrombogenic factors is suitable for venous scintigraphy and evaluation of different forms of therapy for venous thrombosis of the limbs. So this model permits research on diagnosis and therapy of thromboembolic disease.

Bifunctional antibodies for radioimmunotherapy.

In two-step targeting technique using bifunctional antibodies, a nonradiolabeled immunoconjugate with slow uptake kinetics (several days) is initially injected, followed by a small radiolabeled hapten with fast kinetics (several hours) that binds to the bispecific immunoconjugate already taken up by the tumor target. In patients with colorectal or medullary thyroid cancer, clinical studies performed with an anti-CEA/anti-DTPA-indium bifunctional antibody and an indium-111-labeled di-DTPA-TL bivalent hapten showed that tumor uptake was not modified compared to results for F(ab')2 fragments of the same anti-CEA antibody directly labeled with indium-111, whereas the radioactivity of normal tissues was significantly reduced (3- to 6-fold). The fast tumor uptake kinetics (several hours) and high or very high tumor-to-normal tissue ratios obtained with the bifunctional antibody technique are favorable parameters for efficient radioimmunotherapy.

MIBG scintigraphy of a patient with pheochromocytoma on labetalol therapy.

A patient with pheochromocytoma was studied by MIBG scintigraphy while on labetalol therapy, which has been reported to interfere with imaging. Serial imaging was performed at 2, 18, 25, and 90 hours to obtain time/activity curves. Blood samples were taken at each imaging study to determine activity counts. Tumor activity per gram of tissue (surgery 116 hours after injection) was compared with blood activity. Tumor and blood activity decreased concurrently, whereas the decrease in peritumoral activity was faster, thus providing transiently improved contrast on 18- and 25-hour images. The diagnostic implications of these results are discussed.

[Pelvic phlebitis presenting as paradoxical arterial embolism]. / Phlébite pelvienne révélée par une embolie artérielle paradoxale.

The authors report the case of a 24-year-old woman with paradoxical embolism of the right arm subsequent to childbirth. Patent foramen ovale was diagnosed by right cardiac catheterization and contrast echocardiography. On the basis of clinical, immunoscintigraphic and radiologic data, the pelvic region was the only possible origin of the embolic process. The main interest of this case is that arterial ischemic signs were indicative of an embolic process of pelvic origin diagnosed by scintigraphy using radiolabeled antifibrin antibody.

[Finger plethysmography for studying the blood rheological and hemodynamic components of an acrosyndrome]. / L'apport de la pléthysmographie digitale pour l'étude des composantes hémorhéologiques et hémodynamiques d'un acrosyndrome.

Digital plethysmography allows investigation of maximum digital pulse (M.D.P.) after immersion of hands at 45 degrees C over three minutes. It is correlated with digital arterial blood flow. Reactivity to cold is determined from the ratio M.D.P./digital pulse after local and body cooling over 3 minutes. Tests were performed on 65 controls, 69 patients with idiopathic Raynaud's syndrome, 12 with scleroderma, 10 with digital arteritis and 15 with Raynaud's phenomenon secondary to hemorheologic affections. Maximum digital pulse was significantly decreased in patients with digital arteritis and scleroderma. The M.D.P. was normal in controls and patients with idiopathic Raynaud's syndrome, and was significantly increased in patients with a rheologic Raynaud's phenomenon. Digital artery reactivity differentiates the populations studied: it was maximum in patients with scleroderma, moderate in controls and patients with isolated digital arteritis and marked in patients with idiopathic Raynaud's disease and those with rheologic Raynaud's phenomena.