Plasma cell infiltration of the small bowel: lack of evidence for a non-secretory form of alpha-heavy chain disease.

Eight patients with diffuse plasma cell infiltration of the small bowel who had the clinical features of immunoproliferative small intestinal disease (IPSID), but whose serum was negative for free alpha-heavy chains, were investigated for evidence of a non-secretory form of alpha-chain disease (alpha-CD). Molecular sieving and immunoblotting of serum, immunoperoxidase staining of biopsy specimens, and in vitro protein synthesis studies utilising an immunoprecipitation technique and polyacrylamide gel electrophoresis, failed to detect any new cases of alpha-CD. Four of the eight cases were found to have diffuse intestinal lymphoma. The remaining four patients, who were unsuccessfully investigated for evidence of a significant abnormality in cellular immunity, have not developed detectable alpha-CD protein or lymphoma over a mean of 143 months. Despite continuing exposure to possible environmental stimuli, it is concluded that not all cases of IPSID elaborate detectable alpha-CD protein or evolve to lymphoma.