Distinction between coeliac disease and refractory sprue: A simple immunohistochemical method

We recently showed that refractory sprue is distinct from coeliac disease, the former being characterized by abnormal intraepithelial T-lymphocytes expressing a cytoplasmic CD3 chain (CD3c), lacking CD3 and CD8 surface expression, and showing TCRγ gene rearrangements. To take advantage of the abnormal phenotype of CD3c+ CD8- intraepithelial lymphocytes (IEL) in refractory sprue we developed a simple method to distinguish coeliac disease from refractory sprue. Comparative immunohistochemical studies using anti-CD3 and anti-CD8 antibodies were applied on paraffin-embedded and frozen biopsy specimens in refractory sprue (n = 6), coeliac disease (n = 10), healthy controls (n = 5) and suspected refractory sprue (n = 6). Comparable results were obtained on fixed and frozen biopsy specimens. In four of the six patients with suspected refractory sprue, abnormal CD3c+ CD8- IEL and TCRγ gene rearrangements were found, as in refractory sprue; the remaining two patients had normal (CD3+ CD8+) IEL and no TCRγ gene rearrangements. Both patients had coeliac disease, as one failed to comply with a gluten-free diet, while the other was a slow responder. This simplified immunostaining method using anti-CD3 and anti-CD8 antibodies on paraffin sections can distinguish active coeliac disease from refractory sprue and should prove useful in clinical practice.