Alpha-chain disease without qualitative serum IgA abnormality. Report of two cases, including a "nonsecretory" form.

Two cases of alpha-chain disease (alpha-CD) without detectable amounts of alpha-CD protein in serum are reported. Both patients presented with the usual epidemiologic, clinical and pathologic features of alpha-CD, including a predominantly plasmacytic infiltration of the whole small intestine, alpha-CD Protein was found in the jejunal fluid in one case but not in the other, the latter presenting as a "nonsecretory" form of alpha-CD. In both cases, immunofluorescence study of the small bowel mucosa showed that most of the infiltrating cells were positive for alpha chains and negative for other isotypes, and kappa and lambda light chains. These findings warrant a reevaluation of the prevalence of alpha-CD protein synthesis in immunoproliferative small intestinal disease (IPSID) (including lymphomas previously described as Mediterranean lymphoma) by performing an adequate search for alpha-CD protein in the jejunal juice, and at the cellular level in patients without detectable amounts of this protein in serum.