The neuroendocrine thymus: coexistence of oxytocin and neurophysin in the human thymus.

Immunoreactive oxytocin and neurophysin were identified and measured by radioimmunoassay in human thymus extracts. Serial dilutions of extracts paralleled the appropriate standard curves. Thymus-extracted oxytocin and neurophysin eluted in the same positions as reference preparations on Sephadex G-75. Authenticity of oxytocin was confirmed by biological assay and high-performance liquid chromatography analysis. In most instances, thymus contents of oxytocin and neurophysin were far greater than those expected from known circulating concentrations and declined with increasing age. The molar ratio of oxytocin to neurophysin in thymus was similar to that found in the hypothalamo-neurohypophyseal system, which strongly suggested with the other data a local synthesis of oxytocin. These findings indicate the presence of neurohypophyseal peptides in the human thymus and further support the concept of a neuroendocrine function integrated in an immune structure.

Unusually restricted anti-isotype human immune response to OKT3 monoclonal antibody.

The unusual anti-mouse immunoglobulin (Ig) sensitization of a renal allograft recipient who was treated prophylactically with the anti-T cell monoclonal antibody OKT3 (IgG2a) is reported. Whereas in most patients, the injection of OKT3 (5 mg/day, i.v. for 13 days) induces the rapid appearance of neutralizing anti-OKT3 antibodies, the patient reported here did not show the signs of conventional anti-OKT3 sensitization. High levels of circulating OKT3 persisted and no OKT3+ lymphocytes reappeared during the whole treatment period. Moreover, no IgG or IgM anti-OKT3 antibodies were detected at any time, using a specific enzyme-linked immunosorbent assay. However, an atypical anti-isotype response was evidenced in this subject whose Ig were shown by indirect fluorescence to bind to normal T cells coated with OKT3 or with other anti-T cell murine monoclonal antibodies carrying the IgG2a isotype (no reactivity was observed with IgG1 or IgG2b molecules). The patient's Ig did not bind to normal T cells coated with F(ab')2 fragments of OKT3 and did not inhibit the binding of OKT3 to its target antigen indicating that they reacted with the Fc fragment of the OKT3 molecule. Additionally, and probably explained by this unusual anti-OKT3 response, the patient's Ig were shown to inhibit the phytohemagglutinin-induced proliferation of normal lymphocytes, to bind under selected in vitro conditions to normal T cells and lastly to enhance the antigenic modulation induced in vitro by OKT3 on its membrane receptor.

Restriction of the human in vivo immune response against the mouse monoclonal antibody OKT3.

The murine monoclonal antibody OKT3 (IgG2a) was administered prophylactically to 17 renal allograft recipients (5 mg/day, i.v.), either alone or in association with corticosteroids (0.25 mg/kg/day) and azathioprine (3 mg/kg/day). In all patients the kinetics of the IgM and IgG anti-OKT3 response was monitored by means of immunofluorescence and ELISA. All patients treated with OKT3 alone showed a rapid and strong sensitization that completely neutralized the therapeutic effectiveness of the monoclonal antibody. The anti-OKT3 sensitization was manifested by accelerated OKT3 clearance and abrupt reappearance of circulating OKT3+ cells before the end of treatment. This immune response was significantly delayed and reduced in its incidence and intensity in patients receiving low dose corticosteroids and azathioprine in association to OKT3; mainly IgM anti-OKT3 antibodies that did not accelerate OKT3 clearance were then observed. The fine specificity of the antibodies produced was studied, using patients whole sera and various mouse IgG2a-affinity chromatography-purified serum fractions. The results obtained showed that the anti-OKT3 response was remarkably restricted to two main categories of antibodies: a) anti-idiotypic antibodies that inhibited OKT3 binding to T cells and abrogated its therapeutic activity and b) anti-mouse IgG2a (anti-isotypic) antibodies that did not neutralize OKT3 immunosuppressive activity. These results suggest that OKT3-immunized patients might still be sensitive to the immunosuppressive effect of other anti-T cell monoclonals that do not share the OKT3 idiotype and possibly isotype.

Human in vivo antigenic modulation induced by the anti-T cell OKT3 monoclonal antibody.

The anti-pan T cell monoclonal antibody OKT3 was administered daily for 2 weeks in four human renal allograft recipients. The antibody induced a dramatic and immediate depletion of peripheral T cells followed by an in vivo antigenic modulation of the OKT3-defined membrane antigen: after three injections, OKT3-treated patients showed a limited but significant number of OKT3- cells of T cell nature (as defined by OKT4 and OKT8) which recovered the OKT3 receptor after an overnight in vitro incubation in the absence of the monoclonal antibody.

[In vivo induction of antigenic modulation in man by an anti-T cell monoclonal antibody (author's transl)]. / Induction in vivo chez l'homme du phénomène de modulation antigénique par un anticorps monoclonal anti lymphocytes T.

The anti-T cell monoclonal antibody OKT3 was administered to renal allograft recipients. A dramatic depletion of peripheral T cells was immediately observed followed, after 2-5 days, by the reappearance of a limited but significant number of or OKT3-4+ or OKT3-8+T cells showing antigenic modulation of the OKT3-defined antigen. These cells recovered the OKT3 receptor after overnight in vitro incubation.

Serum tumor necrosis factor levels in patients with infectious disease and septic shock.

The role of tumor necrosis factor (TNF-alpha) in the pathogenesis of septic shock has been assessed by daily measurements of serum TNF-alpha levels in 60 patients admitted to the medical intensive care unit. All patients in the study had infectious disease and were at risk for the development of sepsis and septic shock. Sepsis was diagnosed in 34 patients, 24 of whom died (six within the first 24 hours). The 26 patients who did not evolve toward sepsis served as a control group. The clinical condition of all patients was monitored by daily APACHE II scoring. Blood was drawn once a day and additional samples were taken in patients whose clinical condition underwent sudden deterioration. TNF-alpha levels were measured with a commercially available immunoradiometric assay. At time of patient admission, TNF-alpha levels were higher in the group with sepsis than in the control group (median 79 iqr 329 vs median 0.5 iqr 5; p less than 0.001). In the group with sepsis, extremely high TNF-alpha levels were found in patients who died within 24 hours. These patients had TNF-alpha levels of 917 iqr 755 pg/ml, whereas the patients who died more than 24 hours after admission had TNF-alpha levels of 58 iqr 59 pg/ml. Survivors had lower TNF-alpha levels (26 iqr 347 pg/ml). APACHE II scores correlated with TNF-alpha levels in the total sepsis group (Spearman rank correlation coefficient 0.477; p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Imipenem/cilastatin versus amikacin plus piperacillin in the treatment of infections in neutropenic patients: a prospective, randomized multi-clinic study.

In this open, controlled, randomized multi-clinic trial, monotherapy with imipenem/cilastatin was compared to amikacin plus piperacillin as empiric antibacterial therapy in 210 neutropenic cancer patients. Of patients randomized, 53 (25%) had bacteriologically documented infections and of those 30 had septicemia. A further 80 patients (38%) were evaluable for clinical efficacy but did not have documented infections. Seventy-seven patients (37%) were non-evaluable due to effective antibiotic treatment before the trial, early institution of other antibiotics during the trial, verified non-bacterial infections, no neutropenia or other reasons. There were no significant differences in terms of efficacy between imipenem/cilastatin and amikacin plus piperacillin but a consistent trend towards higher rates of clinical cure or improvement and of elimination of causative pathogens was noted in the imipenem/cilastatin group. In patients who were severely neutropenic (less than 0.1 x 10(9) granulocytes/l), similar cure rates were obtained in the two treatment groups--again with a tendency towards better results in the imipenem/cilastatin group. Among evaluable patients with septicemia, one patient in the imipenem/cilastatin group had persistent Staphylococcus aureus bacteremia during treatment. Five patients in the amikacin plus piperacillin group had persistent bacteremia during treatment; all but one (a Pseudomonas aeruginosa) caused by strains resistant to amikacin or piperacillin. Clinical and laboratory adverse effects were mild in the imipenem/cilastatin group although nausea was significantly more common than in the amikacin plus piperacillin group. Among patients on amikacin plus piperacillin, one died in renal failure, possibly related to treatment. Drug-related serious adverse events were reported in two additional amikacin plus piperacillin patients; one with drug fever and one with hearing loss. Microbiological adverse effects occurred in similar frequencies in the two groups. It is concluded that imipenem/cilastatin is a promising candidate for monotherapy of bacterial infections in neutropenic cancer patients.

Generation of monoclonal antibodies against HILDA/LIF and their use in the quantitative assay of the cytokine.

An adoptive transfer immunization/fusion protocol in mice has been successfully used to raise a series of monoclonal antibodies directed against the Human Interleukin for DA-1a (HILDA)/Leukemia Inhibitory Factor (LIF) cytokine. These antibodies which were raised using recombinant HILDA/LIF purified from conditioned medium of transfected Chinese Hamster Ovary (CHO) cells also react with natural HILDA/LIF from the HSB2 T lymphoma cell line and unglycosylated HILDA/LIF produced in E. coli. They define four separate epitopes, one of which is involved in receptor binding and induction of biological activity. A sensitive sandwich immunoradiometric assay which is linear up to 5 ng/ml HILDA/LIF and can detect as low as 25 pg/ml of the cytokine has been developed.