BackgroundHirschsprung’s disease (HD) is an anomaly characterized by the absence of myenteric and submucosal ganglion cells (GC) in the distal alimentary tract. Diagnosis of HD is made by the absence of GC and missing out on even a single ganglion cell can be very devastating. Acetylcholinesterase (AChE) histochemistry, done on frozen sections is said to be a very useful ancillary technique in the diagnosis and in aiding the operative procedures of HD.MethodsTo assess this, 73 samples from 42 suspected/known cases of HD were subjected to frozen section analysis with rapid haematoxylin and eosin, toluidin blue stain along with AChE histochemistry. The remnant sample was paraffin embedded for routine haematoxylin and eosin staining.ResultsOn frozen section analysis, 33 samples showed absence of ganglion cells, AChE histochemistry showed a positive staining pattern in 17 samples and paraffin embedded routine, H&E stained sections showed absence of ganglion cells in 19 samples. Sensitivity and specificity of both tests ie frozen section rapid H&E/AChE histochemistry in the diagnosis of HD, were calculated taking paraffin embedded H&E stained sections as the gold standard. Sensitivity of frozen section rapid H&E in the diagnosis of HD is 57.57 % and specificity is 79.10 %. The p-value is <0.0001, which is significant. The sensitivity of AChE histochemistry in the diagnosis of HD is 90.47 % and specificity is 96.36 %. The p-value is <0.0001, which is significant.ConclusionsAcetylcholineesterase (AChE) histochemistry is a very useful ancillary technique in the diagnosis and in aiding the operative procedures of HD. It acts as a double check in the diagnosis of HD.

Thymic stromal lymphopoietin is a general responder to disrupted skin homeostasis and may have a role in triggering the alarm system of the skin. TSLP induction is rapid, transient and driven by a mechanism that does not involve TNF-α, but partially relies on the evolutionarily ancient IL-1 system. The irritated skin secretes TSLP into the circulatory system. TSLP regulation varies between species.

Summary Background Thymic stromal lymphopoietin (TSLP) mediates proallergic T helper 2‐type responses by acting on leucocytes. Endogenous pathways regulating TSLP production are poorly defined. Objectives To uncover the mechanisms by which skin barrier disruption elicits TSLP production and to delineate the level at which individual mechanistic components may converge. Methods A combination of primary keratinocytes, skin explants and in vivo strategies was employed. Murine skin was tape stripped in the presence of neutralizing antibodies or antagonists. Cells and explants were stimulated with interleukin (IL)‐1 and protease‐activated receptor 2 agonist (PAR‐2‐Ag). TSLP levels were quantified by enzyme‐linked immunosorbent assay and real‐time quantitative polymerase chain reaction. Chromatin immunoprecipitation and promoter reporter assays were used to examine recruitment and functional activity of nuclear factor kappa B (NF‐κB) at the TSLP promoter. Results TSLP induction in mouse skin occurred in a PAR‐2‐ and IL‐1‐dependent manner. This scenario was duplicated by exogenous IL‐1 plus PAR‐2‐Ag vs. each stimulus alone. Joint activity of PAR‐2 and IL‐1 was also observed in human keratinocytes. The TSLP promoter was identified as the target of PAR‐2/IL‐1, whereby PAR‐2 activation augmented the recruitment of NF‐κB and transcriptional activation over IL‐1 alone. Combined treatment showed activity at concentrations of IL‐1 unable to elicit NF‐κB activity on their own. Conclusions Skin barrier disruption activates the IL‐1 and the PAR‐2 pathways, which act in concert to activate the TSLP promoter and possibly other inflammatory genes. Awareness of this combined activity may permit a more flexible clinical management by selective targeting of either pathway individually or collectively. What's already known about this topic? Thymic stromal lymphopoietin (TSLP) is rapidly induced upon skin perturbation and mediates proallergic T helper 2‐type responses by acting on leucocytes. Endogenous control of TSLP expression is poorly understood, but interleukin (IL)‐1 is one regulator in the cutaneous environment In addition to IL‐1, protease‐activated receptor 2 (PAR‐2) organizes central inflammatory pathways in the skin. What does this study add? IL‐1 and PAR‐2 pathways cooperate in driving TSLP production in mice and humans. Pathway integration occurs at the level of the TSLP promoter through enhanced recruitment and transcriptional activation of nuclear factor kappa B. When PAR‐2 is co‐stimulated, very low IL‐1 levels (inactive by themselves) can induce biologically meaningful responses in the skin environment. What is the translational message? Physical skin irritation results in robust TSLP production by simultaneous activation of PAR‐2 and IL‐1 pathways.

Our data indicate that the expression of barrier genes and proteins was normalized following treatment with alitretinoin in patients with CHE. The change in expression levels of these genes correlated with the clinical efficacy, suggesting that alitretinoin exhibits a disease-modifying activity. TSLP is upregulated in CHE and seems to counteract filaggrin expression in the skin.

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