Histochemical and immunohistochemical study of the intrinsic innervation in colonic dysganglionosis.

Defective innervation of the neuromuscular junctions (NMJ) was recently described in intestinal neuronal dysplasia type B (IND B). The aim of the present study was to correlate the alterations in NMJs to other classically described parameters in dysganglionoses and to determine the relationship between NMJ abnormalities in IND B and clinical symptoms. The rectal biopsies and full-thickness colonic biopsy specimens of 17 patients were studied applying histochemical (acetylcholinesterase [AChE], lactic dehydrogenase [LDH], and succinic dehydrogenase [SDH] reactions) and immunohistochemical (neuronal-cell adhesion molecule [NCAM] and SY antibodies) methods. Thirteen patients had Hirschsprung's disease (HD). IND B was diagnosed in 11 (associated with HD in 8 cases, isolated in 2, and associated with hypoganglionosis in 1). In the aganglionic segment of HD there was very intense AChE activity; in contrast, NCAM- and SY-immunoreactive nerve fibers were markedly decreased. A spectrum of abnormalities was observed in IND B, usually more severe in the most distal segments: giant and immature ganglia in the submucous plexus were observed in all cases; heterotopic myenteric ganglia were frequent (72.7%); hyperganglionosis was observed in 6 (54.5%) and was not related to the patients' age; thick and tortuous NCAM- and SY-immunoreactive nerve fibers, irregularly distributed in the colonic wall, were observed in 81.8% of the cases. No relationship was observed between abnormalities of NCAM- and SY-immunoreactive nerve fibers and AChE activity, ganglion-cell maturity, heterotopy, or the clinical symptoms presented by the patients with IND B. In hypoganglionism, low AChE activity and a slight decrease in NCAM- and SY-immunoreactive nerves were observed. Thick and tortuous, irregularly-distributed intrinsic NCAM- and SY-immunoreactive nerves were observed in every colon layer in IND B. Our results do not support IND B as a NMJ disorder.