Do Orthotopic Ileal Diversions Induce Immunological Changes in Retained Urethral Tissue?

BACKGROUND

A second primary tumors of the urethra (urethral recurrence) after radical cystectomy has been reported to be more infrequent in patients with ileal orthotopic (neobladder) compared to incontinent diversions.

OBJECTIVE

To investigate whether an altered immunogenic environment of urethral tissue is induced by urethro-ileal anastomosis.

METHODS

Between 10/2008 and 12/2009 urethral biopsies of 19 patients (9 neobladder patients, 10 control patients without urethra-ileal anastomosis) were evaluated by conventional histopathological examination and immunohistochemistry for T- (CD3/CD5, CD4, CD8) and B-cell markers (CD20/22, CD79a, CD138). After semi-quantitative assessment, relative cell fractions (B vs. T cells) and subclasses (T4-helper vs. T8-killer cells vs. B cell clones, plasma cells) in neobladder vs. control patients were studied. Unpaired t-test was used for statistical analysis.

RESULTS

Of 19 included patients, 16 were eligible for analysis (7x neobladder, 9x controls). All neobladder patients had undergone cystectomy for UBC. Comparing relative fractions of cells positive for T- and B-cell markers in NB and CO patients, no statistical differences were observed. In 4/7 neobladder patients relative fraction of CD79a positive B-cells was higher than relative fraction of CD3/CD5 positive T-cells (B/T-ratio 1.3). B cells were predominantly CD138 positive plasma cells (5/7 NB patients). Relative B-cell fraction was lower than T-cell fraction in 7/9 control patients (B/T-ratio 0.6). Neither CD 138 positive plasma cells nor CD22 positive B cell clones were predominant. T-helper and CD8 positive T-killer cells were equally distributed in both neobladder (CD4/CD8-ratio: 2.1) and control patients (CD4/CD8-ratio: 1.9).

CONCLUSIONS

Comparing neobadder and control patients the distribution of B- and T-cells was statistically not different. However, a trend towards an increased presence of B-cells in urethral tissues of NB patients that could become relevant in a larger study might be suggestive for an immunological response induced by connecting urethral and ileal tissue.