Ultrastructural study of two cases of alpha-chain disease.

Intestinal biopsies of two patients with alpha heavy-chain disease were examined by electron microscopy. Except for a few differences, cells involved by the malignant neoplasia of the small intestine were similar and belonged to the plasma cell line and were, in fact, more like the cells observed in typical multiple myeloma. It is not surprising to find such cells in a disease which is characterized by the presence of alpha heavy chain in the serum since plasma cells are considered to be the main source of immunoglubulins. Moreover, the association of an intestinal plasmacytic neoplasia with the heavy chain of the immunoglobulin A in the serum agree with what is known of the normal synthesis by most of the plasma cells of the digestive tract of this immunoglobulin. Since lymphocytes can synthesize immunoglobulins and plasma cells probably originate from lymphocytes, too great an importance should not be attributed to morphological classification. Only an obvious, functional characteristic seems really useful for differentiation.