Morphology and structural changes responsible for the chronicity of rhino-scleroma

ABSTRACT

This study aimed to identify the structural changes of the proliferative phase of rhinoscleroma which could be responsible for the chronicity of the disease. Samples of friable tissue taken from the nasal mucosa of nine untreated patients were processed for light and ultrastructural microscopy. The majority of changes contributing to the chronicity of the disease occurred in the subepithelium and followed a three closely related events. [1] Infiltrative; sub-epithelial invasion by the Klebsiella was followed by its active multiplication and proliferation of capillaries, [2] Neutrophilic; a large numbers of neutrophils were delivered into this space. The neutrophils actively phagocytized the Kiebsielia but appeared to die at an accelerated rate without completing digestion of the micro-organisms, and [3] Histiocytic event the histiocytes entered the subepithelium and engaged in unrestrained phagoaytosis of decaying neutrophils, the Klebsiella, and debris. During this process, the histiocytes, phagosomes underwent massive dilation, thus becoming the Mikulicz cells. Mikulicz cells were unable to consistently destroy the Kiebsiella and eventually ruptured, releasing them into the interstitium. Evidence was found that an autophagic process might contribute to phagosome distention and to the rupture of the vacuolar membranes and cell wall. In conclusion, severaic critical changes responsible for the chronicity of rhinoscleroma occur during the proliferative phase of the disease. The majority of these changes take place in the subepithelium and include [1] Factors leading to the transformation of histiocytes into Mikulicz cells, [2] The inability of these cells to consistently destroy the Klebsiella, [3] Their rupture releasing viable Klebsiella, and the intrinsic resistance of the pathogen