Immunogenicity of two accelerated hepatitis B vaccination protocols in liver transplant candidates

OBJECTIVE

It is common practice to immunize patients against hepatitis B virus infection prior to orthotopic liver transplantation (OLT). We compared the seroprotection rates of two accelerated schedules with a recombinant hepatitis B vaccine in patients awaiting OLT.

DESIGN AND METHODS

Patients were prospectively recruited and vaccinated with either 20 micrograms (group 1, n = 14) or 40 micrograms (group 2, n = 20) hepatitis B surface antigen per dosage. Thirty-nine healthy volunteers served as a historical control group. Patients in all groups were vaccinated with an accelerated schedule (0, 7 and 21 days). All patients underwent clinical and laboratory examinations (HBs antibodies, CD4/CD8 ratio, transaminases).

RESULTS

The accelerated hepatitis B vaccination schedules were well tolerated. Eight weeks after the third injection, no significant differences in seroprotection rates were observed between group 1 (31%) and group 2 (26%). There was no correlation with respect to seroconversion rates and gender, smoking habits or CD4/CD8 ratio.

CONCLUSION

These data suggest that accelerated vaccination schedules with a recombinant hepatitis B vaccine are safe and well-tolerated, but only achieve poor seroconversion rates in OLT candidates. Increasing the vaccine dose to 40 micrograms hepatitis B surface antigen per injection did not result in a higher response rate. Because of the low risk of acquiring de novo hepatitis B infection after transplantation, it should be questioned whether routine hepatitis B vaccination with standard recombinant vaccines prior to liver transplantation should be recommended any longer.

The presence of Müllerian inhibiting substance binding sites in human sperm

PURPOSE

The binding of Müllerian inhibiting substance (MIS) to human sperm was investigated using immunohistological techniques.

MATERIALS AND METHODS

Sperm from 5 normal donors and 6 subfertile men were studied. Whole or thin-sectioned sperm were incubated without or with recombinant human MIS (0.5 microg./ml.). MIS binding was identified under light microscopy (LM) using rabbit anti-human MIS antibodies tagged with goat IgG-horseradish peroxidase and diaminobenzidine as substrate, or by scanning and transmission electron microscopy (SEM and TEM) using gold labeled goat IgG. Intracellular MIS binding in sperm sections was examined by TEM. Antibodies were omitted in the controls.

RESULTS

Under LM, DAB staining was present on sperm incubated with or without MIS and absent on controls. Using SEM, gold particles were found primarily on the surfaces of the sperm head with less binding to the tail. With TEM, the clustering of gold particles around the head of sperm represents MIS binding, but very few or no gold particles could be found associated with the sperm tail. MIS binding was also found associated with intracellular structures, but only within the head of the sperm. Overall, less gold particle binding was present in subfertile compared with normal sperm.

CONCLUSIONS

These results suggest that MIS is bound to the sperm surface and sperm from normally fertile men have increased MIS binding. The function of MIS in sperm is unknown, but the presence of MIS binding suggests a direct role(s) in sperm function.

Interleukin-8 suppresses the toxicity and antitumor effect of interleukin-2

The clinical application of interleukin-2 (IL-2) for the treatment of certain human malignancies has shown promise. However, the use of IL-2 in immunotherapeutic protocols has been limited due to its associated toxicities. The administration of therapeutic doses of IL-2 results in a vascular leak syndrome with associated multiple system organ edema, hypotension, and respiratory, renal, and hepatic dysfunction. Previous studies suggest that the mechanism of these toxicities involves the activation of both immune effector cells and the microvascular endothelium with resultant leukocyte-vessel wall interaction, endothelial cell injury, and subsequent invasion of normal tissues by activated leukocytes. Recently it has been demonstrated that interleukin-8 (IL-8) will inhibit leukocyte adherence to an activated endothelium. Thus, we hypothesized that IL-8 would ameliorate IL-2-evoked detrimental effects. We also investigated the influence of IL-8 on IL-2-induced antitumor efficacy. Four groups of nontumored, female, C57BL/6 mice and four groups of C57BL/6 mice with pulmonary metastases from a 3-methylcholanthrene-induced fibrosarcoma (MCA-105) were treated every 6 hr for 4 days by intraperitoneal injections of IL-2 alone, IL-2 and IL-8, IL-8 alone, or an equal volume of saline which served as our control. Upon completion of therapy, we found that IL-8 suppressed many of the IL-2-induced effects including multiple organ edema, hepatic dysfunction, leukopenia, and lymphocytic infiltration of normal organs. When the number of pulmonary metastases were counted 20 days after the cessation of therapy. IL-8 was also found to significantly ablate the IL-2-elicited antitumor efficacy.(ABSTRACT TRUNCATED AT 250 WORDS)

Pentoxifylline inhibits interleukin-2-induced toxicity in C57BL/6 mice but preserves antitumor efficacy

Interleukin 2 (IL-2) mediates the regression of metastatic cancer but clinical use has been limited due to associated toxicities. Tumor necrosis factor (TNF) is an important mediator of IL-2 toxicity and may have a limited role in IL-2 antitumor efficacy. Because pentoxifylline (PTXF) inhibits TNF production, we hypothesized that PTXF would ameliorate IL-2 toxicity without compromising antitumor efficacy. Four groups of female C57BL/6 mice with pulmonary metastases from a 3-methylcholanthrene-induced fibrosarcoma (MCA-105) and four groups of nontumored mice were treated every 6 h for 4 d by intraperitoneal injections of either IL-2 alone, IL-2 and PTXF, PTXF alone, or equal volumes of saline. Upon completion of therapy, we found that PTXF suppressed many of the IL-2-induced effects including TNF production, lymphocytic infiltration of multiple organs, multiple organ edema, hepatic dysfunction, leukopenia, and thrombocytopenia. Tumor response was determined 21 d after cessation of therapy by quantitating the number and surface area of pulmonary metastases. PTXF preserved antitumor efficacy while reducing the morbidity and mortality caused by IL-2 treatment. These data strongly support the use of PTXF in extending the therapeutic index of IL-2 in the treatment of cancer.