A new approach in the management of urothelial tumors using GM-CSF on marker lesions: an ultrastructural and immunohistochemical study on the macrophage population in bladder mucosa

Our purpose was to investigate a new therapeutic model, GM-CSF-targeted immunomodulation on transitional cell carcinoma (TCC) marker lesions and to evaluate the immunologic response of the bladder mucosa. Eleven patients with pTa or pT1 bladder cancer were eligible for the study. All lesions were removed by transurethral resection (TUR) except for a marker lesion. All patients received 8 weekly instillations of 300 microg of GM-CSF, after which cystoscopy with bladder biopsies +/- TUR was repeated on adjacent urothelium or tumor or both. Paraffin-embedded sections were immunohistochemically stained with CD68, which labels monocytes and macrophages. The CD68+ cell population was evaluated as 1+ to 3+. Comparable specimens were routinely processed for ultrastructural analysis. Complete response was observed in 6 patients (55%), persistent tumor occurred in 4 patients (approximately 36.4%), and 1 patient (8.6%) showed recurrence. Immunohistochemically, an at least twofold increase in the number of the CD68+ cells was observed in all responders. Submicroscopically, migration of macrophages to the surface layer occurred. Macrophages showed an extensive lysosomal system and pseudopodia. This study indicates that the prophylactic treatment of TCC with GM-CSF may induce immunomodulatory effects on macrophage activities, which could be associated with the clinical evolution of the disease.

Natural killer (NK) cell assay within bladder mucosa of patients bearing transitional cell carcinoma (TCC) after interferon (IFN) therapy: an immunohistochemical and ultrastructural study

The authors studied the number and the ultrastructural evidence of NK cell activation in the non-involved urothelium in patients with transitional cell carcinoma (TCC) of the urinary bladder, before and after transurethral resection (TUR) and interferon (IFN) therapy. Eight male patients, free of recurrence 1 year after TUR and IFN-a2b therapy, were studied. Each patient received 22 instillations of 50MU of IFN-a2b over a period of 1 year. Two specimens from the non-involved urothelium, one adjacent to and another away from the tumour, were obtained before and after therapy, for immunohistochemical and ultrastructural studies. The number of NK cells was evaluated immunohistochemically in paraffin sections with the CD57 monoclonal antibody, and their activation was detected by routine electron microscopy processing. Before treatment, few NK cells were randomly found in the lamina propria. At the end of therapy, however, their number increased and NK cells were found to infiltrate the urothelium, a finding that was not observed before treatment. The number of NK cells did not correlate with the degree of the inflammatory infiltrate of the mucosa. Moreover, the ultrastructural study revealed activation of NK cells with enhanced cytolytic activity. IFN therapy increases the number and promotes the activation of NK cells within the bladder mucosa. This finding could be of clinical significance in the prevention of tumour recurrence, given that NK cells enhance the immunological defense mechanisms of the bladder.

Ultrastructural study of the urothelial lysosomal system in patients with transitional cell carcinoma after transurethral resection and interferon therapy

The epithelial cells of human bladder urothelium contain a prominent lysosomal system on the surface layer which involves autophagic, phagocytotic and excretory processes. The noninvolved urothelium of tumor-bearing patients, however, does not contain this well-developed lysosomal system. Interferon restores the differentiation of the urothelium. Its action on the lysosomal system, however, has not been investigated. We studied ultrastructurally the noninvolved urothelium of eight patients with transitional cell carcinoma who after transurethral resection and intravesicular interferon instillations for 2 years did not develop recurrence. We noted that the number and size of lysosomes increased, being most numerous within the cells of the surface layer. Characteristic large lysosomes with the morphology of multivesicular bodies were also evident. These multivesicular bodies were almost entirely filled with small vesicles containing a dense core. Our findings show that after 2 years of interferon administration a re-appearance of a highly developed lysosomal system of the noninvolved urothelium was evident. This restoration to the normal morphology with reappearance of the lysosomal system, which could be partly attributed to interferon therapy, may be of clinical significance for prevention of tumor recurrence.

Ultrastructural study of the noninvolved urothelium of tumor-bearing patients after two years of intravesical interferon therapy

OBJECTIVE

Seventeen patients with transitional cell carcinoma of the urinary bladder were studied. Twelve patients did not have a recurrence 2 years after a transurethral resection (TUR) followed by interferon (IFN)-alpha 2b treatment. This observation led us to study the ultrastructural morphology of the noninvolved urothelium in 8 of the above 12 patients.

METHODS

All patients had a primary solitary grade I or II tumor. Topical therapy was started after TUR. Each patient received a total of 22 instillations of 50 MU IFN-alpha 2b in 12 months according to the standard procedure. After the first year, a repetitive dose of 50 MU IFN-alpha 2b was administered every 2 months for a period of 1 more year.

RESULTS

At the end of therapy, certain ultrastructural modifications were observed indicating a partial restoration of the urothelium: the existence of asymmetric unit membrane, a well-developed Golgi apparatus and an increase of the filaments. The cells were joined to each other with well-developed tight junctions. Tubuloreticular inclusions were also observed.

CONCLUSIONS

Prevention of recurrence by restoring the morphology of the noninvolved urothelium in response to IFN treatment deserves further examination.