99mTc-CD19 monoclonal antibody is not useful for imaging of B cell non-Hodgkin's lymphoma.

In this study we investigated the applicability of 99mTc-labeled CD19 monoclonal antibody (mAb) for tumor imaging in patients with B cell non-Hodgkin's lymphoma. A 1-mg sample of murine CD19 mAb was labeled with approximately 550 MBq [99mTc]pertechnetate. The labeled mAb was administered i.v. to seven patients, four without and three with pretreatment with 10 mg unlabeled CD19 mAb. The number of circulating B cells was decreased by 44 +/- 5% 1 h after injection of the radiolabeled mAb. Peripheral B cells were coated with CD19, resulting in partial modulation of CD19, most pronounced in the three pretreated patients. Whole-body images were obtained with a gamma camera and compared with results obtained by conventional imaging techniques. Initially, blood-pool activity dominated, whereas 24 h after injection the radioactivity was mainly located in the spleen, kidneys and liver. In two patients, a lesion in the spleen appeared as an unlabeled spot. In one patient, a lesion in the femur, which was detected by computed tomography (CT) and gallium-67 scans, was also seen on the CD19 scan from 1 h after administration of the radioimmunoconjugate onwards. Good imaging of bone marrow infiltration was observed in one of three patients. Lymph node involvement was not observed in any of the patients in whom affected lymph nodes were detected by CT or gallium-67 scan. In conclusion, in the present study radioimmunodetection with 99mTc-labeled CD19 mAb was found to be inferior to CT and gallium-67 scanning in the diagnosis of patients with B cell non-Hodgkin's lymphoma.

Contribution of phagocytic cells and bacteria to the accumulation of technetium-99m labelled polyclonal human immunoglobulin at sites of inflammation.

The purpose of this study was to assess the contribution of phagocytic cells and bacteria to the accumulation of technetium-99m labelled polyclonal human immunoglobulin (HIG) at sites of inflammation. Mice were intraperitoneally injected with Staphylococcus aureus (SA animals), with heat-inactivated newborn calf serum (NBCS, to mimic a non-bacterial inflammation) or with physiological saline (controls); 1 h thereafter they received HIG. At various intervals after the administration of HIG the mice were killed, and the percentages of radioactivity in the peritoneal effluent and attached to the cellular and bacterial fraction thereof were established. Furthermore, the total number of cells and that of bacteria in the fluid were quantitated. The percentage of activity in the effluent in the SA animals was (P < 0.02) higher than those in the NBCS-injected animals and controls from 4 h onwards. In all groups of mice this percentage was highest at 4 h and decreased (P < 0.01) afterwards. The percentage of cell-bound activity and the total number of cells remained fairly constant or increased with time in the SA animals (P < 0.01). The bacteria-bound activity remained rather constant throughout the experiment and ranged between 4% and 6%. In the SA-infected animals the percentage of cell-bound activity was correlated with the total number of cells (macrophages but especially neutrophils) but even more strongly with the number of cell-associated bacteria. In the NBCS-injected animals a correlation was demonstrated between the cell-bound activity and the total number of cells (only neutrophils).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of a local staphylococcal infection in mice with technetium-99m-labeled polyclonal human immunoglobulin.

The purpose of this study was to investigate both the ability of 99mTc-labeled polyclonal human immunoglobulin (HIG) to localize an infection and the modes of action involved in this process. Mice, infected with Staphylococcus aureus ATCC 25923 in a thigh muscle, received HIG intravenously. Scintigrams were made 1, 4, and 24 hr later; subsequently the mice were killed and the activity in several organs and thighs was determined. The radiopharmaceutical demonstrated a time-dependent accumulation at the site of infection. It was found that vascular permeability or Fc binding alone could not account for the mode of action of HIG. Neither the origin of Ig (human versus murine) nor the total amount of protein (0.01-1.0 mg Ig per mouse) affected the target-to-background (T/B) ratios. Ratios were not different for leukocytopenic animals. A correlation (p less than 0.001) was demonstrated between the number of bacteria at the site of infection and the T/B ratio. This was also found after antibiotic treatment (p less than 0.02).

Clumping of labeled leukocyte suspension. A simple measure for avoiding it.

Leukocytes in "mixed" suspensions can clump together, resulting in cell clusters which are responsible for false positive hot spots in lungs of patients, in the case of abscess localization studies using 111In labeled leukocytes. Addition of extra ACD (acid-citrate-dextrose) in those labeled leukocyte suspensions prevented cell clumping and avoided occurrence of focal radioactivity accumulation in lungs. The acidification did not interfere in leukocyte migration under agar.

Comparison of several indium-111 ligands in labeling blood cells: effect of diethylpyrocarbonate and CO2.

The effect of oxine sulfate, oxine sulfonate, tropolone, and Merc (2 mercaptopyridine-1-oxide) were compared with oxine, with respect to their capability of labeling blood cells when complexed to indium-111 (111In). Indium-111 oxine sulfate performed similarly to [111In]oxine with regard to cell labeling capability. Indium-111 oxine sulfonate had no labeling ability. Indium-111 tropolone and Merc were not superior to [111In]oxine as cell labeling agents. Carbon dioxide (CO2) and a CO2 generating compound, diethyl pyrocarbonate, dramatically improved the cell labeling ability in plasma of [111In]tropolone and Merc. In the case of oxine, this improvement was less distinct. Theoretical aspects of the CO2 cell labeling stimulating effect are discussed in terms of intra- and extracellular transferrin and lactoferrin iron (indium) binding capacity. Indium-111 tropolone behaved favorably with respect to inhibition of leukocyte migration, compared with oxine and Merc. Combined with the property of easy cell labeling and good solubility in water, also in the complexed state, tropolone must be regarded as the most suitable cell labeling ligand.

111In-tropolonate labelled platelets; studies in normals and in patients with thrombocytopenia.

Human platelets were labelled with aqueous 111In-tropolonate in comparison with 111In-oxinate. In normals the labelling efficiency with 111In-tropolonate was higher (93% +/- 2%) than with 111In-oxinate (67% +/- 8%) (P less than 0.05). In cases of severe thrombocytopenia, lower labelling efficiencies were obtained. In six normals a mean platelet life of 9 days +/- 3 days and an initial recovery of 59% +/- 15% were obtained. In twelve patients with thrombocytopenia the mean platelet life was 4 days +/- 4 days and the initial recovery was 58% +/- 20%. The absolute uptake of radioactivity in spleen and in liver in both groups are reported.

A motility test of leukocytes under agar.

A migration test under agar for leukocytes was developed. Leukocytes moved quite a distance under anaerobic Blood Agar Base (blood agar), a Gibco product. Migration on stained and coloured plates was visualized by projection with a profile projector, making the use of a light microscope superfluous. A migration index was defined. Reproducibility was good enough to allow paired comparisons of leukocyte populations subjected to different treatments. Migration was the result of spontaneous and chemotactically directed migration. Cell-labelling complexes as 111In-oxinate and 111In-tropolonate--ligand concentration 3.5 micrograms/mL in the ultimate cell preparation--did not affect leukocyte migration. 111In-pyrithionate (mercapto pyridine-N-oxide) significantly impaired cell motility. The motility test described could be used as retrospective analysis in abscess localization studies using 111In labelled leukocytes.

Comparison of indium-111 oxinate labelled autologous granulocytes with indium-111 oxinate and indium-111 chloride as abscess scanning agents. An experimental study in an animal model.

Bacterial abscesses were evoked in goats. Imaging of these abscesses was obtained by means of labelling autologous granulocytes with 111In oxinate, reinjection of the cells into the animal, and scintigraphy by gamma camera one day later. Comparable imaging results, however, were obtained after intravenous injection of 111In oxinate or of 111In chloride. The gamma camera images were supported by tissue distribution studies. In the case of administration of 111In oxinate to the goats, the radioactivity accumulated in the cell fraction of the blood to a significant extent. This did not occur in the case of plain 111In chloride. It remained unexplained why such different accumulation in cells did not result in differences in the scintigraphic studies. Blood clearance studies supplied conclusive evidence that the granulocytes stayed in the circulation for several days following labelling with 111In oxinate and reinjection of the cells into the animals.

Procedure for a normalised thyroxine determination in small sephadex columns.

A rapid simple test for measuring normalised serum thyroxine is described in detail, using small Sephadex columns. A small portion of test serum is reintroduced into the test system at the competitive binding stage, so that corrected T4 values are obtained when the concentrations of thyroxine binding globulin are variable. Only 125 microliter serum is required for the whole test. Values obtained by the present method correlated well with the product of thyroxine concentration and radioactive T3 uptake (T4--RT3U index) and with a commercially available method for normalized thyroxine (T4N). Day-to-day variation was CV=6%.

Radioimmunoassay for normalized thyroxine with use of Sephadex columns.

We describe a reproducible radioimmunoassay, with use of Sephadex columns, for measuring normalized thyroxine. In comparison with a competitive protein-binding procedure, the present method is more specific because antibody rather than thyroxine-binding globulin is responsible for the competition between endogeneous and tracer thyroxine. In barbital buffer, various concentrations of thyroxine binding pre-albumin and albumin had no influence on the results. Values obtained by the present method correlated well with those by the free thyroxine index and a generally accepted thyroxine normalized method.

A radioimmunoassay for thyroxine on Sephadex columns. Investigations on the influence of some buffers on the binding of thyroxine to serum proteins.

A thyroxine radioimmunoassay procedure (T4RIA) based on incubation and separation on Sephadex columns is presented. The assay is rapid and easily to perform; if necessary columns may be regenerated. The raising of antibodies against thyroxine in goats is described in detail. The specificity of the antiserum towards the coupling of several compounds related to thyroxine has been tested. Influence of some buffers on the binding of thyroxine to serum proteins has been investigated. The results of T4RIA in patient sera were in agreement with those obtained by a competitive binding method. The within-day variation was approximately 4% (coefficient of variation, C.V.); day-to-day variation was 7% C.V.