02334nas a2200361   4500000000100000008004100001260001300042653001300055653002000068653002700088653001900115653002800134653001100162653002900173653001200202653002000214653000900234653002300243100001300266700001300279700001500292700001400307700001300321700001600334700001100350700001200361700001300373245016100386300001000547490000800557520139300565022001401958       2006                            d  c2006 Aug10aAluminum10aCentral America10aEnvironmental Exposure10aForeign Bodies10aGranuloma, Foreign-Body10aHumans10aLeishmaniasis, Cutaneous10aleprosy10aSilicon Dioxide10aSkin10aVolcanic Eruptions1 aConvit J1 aUlrich M1 aCastillo J1 aDe Lima H1 aPérez M1 aCaballero N1 aHung J1 aArana B1 aPérez P00aInorganic particles in the skin of inhabitants of volcanic areas of Central America: their possible immunomodulatory influence in leishmaniasis and leprosy.  a734-90 v1003 a<p>We have evaluated biopsies from patients with atypical nodular and typical ulcerated lesions of cutaneous leishmaniasis, from leishmanin reactions and skin from normal individuals from Nicaragua, Honduras and Guatemala for the presence of inorganic particles using confocal microscopy with a polarised light source and conventional histopathological techniques. Analysis by semiquantitative confocal microscopy permitted the demonstration of significantly larger numbers of particles in atypical lesions. Silica and aluminium, important components of these particles, were less abundant in particles from normal skin. The histology of these atypical lesions, characterised by 'naked' sarcoidal granulomas with epithelioid differentiation but very few lymphocytes, was very similar to the histological reaction observed after 14 days in persisting inflammation at leishmanin skin test sites. The presence of these unusual lesions in areas of Central American countries characterised by the presence of large amounts of volcanic ash, as well the unexpectedly low prevalence of leprosy in Central America, suggest that environmental factors may contribute significantly to the frequency and clinical manifestations of these infections. Among possible environmental features, the presence of inorganic particles with immunomodulatory properties in the skin may be a significant factor.</p>  a0035-9203