28 K in squamous metaplasia of the bladder in patients with spinal cord injury

Antibody to 28 K was used to examine sections of bladder biopsies obtained by cystoscopy from 14 patients with spinal cord injury (SCI). Most of the biopsies were obtained from patients with indwelling catheters during the investigation for possible malignancy. Sections of bladder were stained by the streptavidin procedure. The 28 K in the normal transitional epithelium of the bladder was in the superficial cells (umbrella cells). All the biopsies from patients with indwelling urethral catheters showed areas of squamous metaplasia usually associated with evidence of chronic inflammation. Cystitis cystica glandularis was also seen in one patient. Staining was most marked in the areas of squamous metaplasia with intracellular granular staining. The basal layers were not well stained. With marked squamous metaplasia, there was a superficial hyperkeratotic layer that stained variably and often did not stain at all. Staining was less marked in areas of hyperplasia, regenerating urothelium, and cystitis cystica glandularis. These findings raise the possibility that the presence of 28 K glycoprotein in the tissues or released into the urine may be used as an indicator of squamous metaplasia and chronic inflammation of the bladder.