Clinicopathological digital image analyses before and after thermal stimulation subdivide acquired idiopathic generalized anhidrosis into inflammatory and non-inflammatory type.

BACKGROUND

Acquired idiopathic generalized anhidrosis (AIGA) manifests varying degrees of syringotropic inflammation.

OBJECTIVE

To better understand the basis of inflammation in AIGA.

METHODS

Changes in the extent of cell infiltration around the sweat gland/duct and the difference in the expression level of immune privilege (IP)-related/sweat gland markers before and after thermal stimulation were assessed in AIGA. We also adopted a semi-quantitative digital image analysis of sweating as detected by the starch-iodine method. The changes in sweating before and after treatment was defined as the improvement index.

RESULTS

Nine AIGA cases were analyzed. Two cases with minimal inflammation were defined as non-inflammatory type (non-inf)AIGA, while others with evident cell infiltration were defined as inflammatory type (inf)AIGA. MHC class I was significantly upregulated with downregulation of macrophage migration inhibitory factor and alpha-melanocyte-stimulating hormone exclusively in the sweat duct of infAIGA after thermal stimulation (p < 0.05). Furthermore, the extent of inflammation and the ductal dermcidin expression prior to thermal stimulation were inversely correlated (r = - 0.807), while that and the ductal claudin-1 expression after thermal stimulation was positively correlated (r = 0.875). The improvement index positively correlated with the degree of inflammation after thermal stimulation implying possible contribution of inflammation in AIGA pathophysiology. In addition, interferon-induced protein 10 and claudin-1 expression level in the sweat duct before thermal stimulation respectively correlated with the improvement index (r = 0.750, and 0.762).

CONCLUSION

The pathophysiology of AIGA may be subcategorized into two groups: IP-collapse possibly play some roles in infAIGA, while ductal dysfunction may exist in non-infAIGA.