THE MODIFIED STEINER STAIN - A NEW USE FOR AN OLD STAIN - STAINING CYTOMEGALOVIRUS-INFECTED CELLS IN GASTROINTESTINAL BIOPSIES

The modified Steiner stain is a non-specific silver stain for identify ing bacteria in formalin-fixed, paraffin-embedded tissues. The princip le behind its use is that bacteria are first sensitized using uranyl n itrate solution, making them able to precipitate silver from a silver nitrate solution. It is used routinely for staining gastric biopsies t o identify Helicobacter pylori. Upon staining a gastric biopsy from a patient with acquired immunodeficiency syndrome (AIDS) and cytomegalov irus gastritis, we recognized that this technique also stains the vira l inclusions of cytomegalovirus-infected cells. We then proceeded to s tain 43 consecutive cytomegalovirus-positive gastrointestinal biopsies from 33 immunocompromised patients based on positive cytomegalovirus immunohistochemistry (DAKO-cytomegalovirus monoclonal antibody, clones DDG9 and CCH2). We also stained eight cytomegalovirus-infected, non-g astrointestinal tissues, including lung, adrenal gland, ovary, skin an d neural tissue, to ensure that the stain was staining the cytomegalov irus-infected cells and not argyrophilic or argentaffin neuroendocrine cells of the gastrointestinal tract. In 40 of the 43 cytomegalovirus- infected gastrointestinal biopsies, we saw positive staining with the modified Steiner stain (93% sensitivity). The cytomegalovirus-infected , non-gastrointestinal tissues all stained positively with the modifie d Steiner stain. Because the modified Steiner stain is frequently used to identify Helicobacter pylori in gastric biopsies, we propose that it be studied further for possible use either as a screen or as a conf irmatory tool, or both, for cytomegalovirus inclusions in gastrointest inal biopsies. (C) 1998 Chapman & Hall.