Chemotactic heterogeneity of eosinophils in Kimura's disease

Kimura disease forming a human polyomavirus 6–negative parotid gland nodule with prominent squamous metaplasia in a young female: A case report

A case of an asymptomatic 19-year-old woman with Kimura disease presenting with a nodule in the right parotid gland is presented. She had a medical history of atopic dermatitis and noticed a mass on her right-side neck. Cervical lymphadenopathy was clinically diagnosed. The initial management plan was to observe the lesion, which had enlarged from 1 cm to 2 cm in diameter 6 months later. An excisional biopsy was performed, and the pathology confirmed an eosinophil-containing inflammatory parotid gland lesion with many squamous nests and cysts, mimicking a parotid gland tumor. High serum immunoglobulin E levels, peripheral blood eosinophilia, and pathological and genetic diagnoses confirmed Kimura disease. The lesion tested negative for human polyomavirus 6. No recurrence was observed 15 months after the biopsy. The prognosis of Kimura disease without human polyomavirus 6 infection may be favorable; however, further validation of this hypothesis is required as only 5 or 6 cases of Kimura disease have been evaluated for this viral infection. Proliferative squamous metaplasia occurring in parotid gland lesions of Kimura disease is rare and may complicate the diagnostic imaging and pathological diagnosis.

Apoptotic response of eosinophils in chronic eosinophilic pneumonia

To clarify the pathogenesis of chronic eosinophilic pneumonia (CEP), the apoptosis of eosinophils from bronchoalveolar lavage (BAL-Eos) was compared with that of eosinophils from peripheral blood (PB-Eos) in six cases of CEP. The survival rate of eosinophils and the percentage of apoptotic cells of both types of eosinophils were examined, and the effects of interleukin 5 (IL-5) were evaluated. The role of Fas expression in apoptosis of these eosinophils was also studied. The survival rate of BAL-Eos on the third day of culture was significantly higher than that of PB-Eos (p < 0.01). This was associated with a lower proportion of apoptotic cells in BAL-Eos than in PB-Eos; the percentages of apoptotic cells in PB-Eos and BAL-Eos after 24 h of incubation were 21.7 +/- 3.4% and 10.6 +/- 1.7% respectively. IL-5 suppressed apoptosis and increased the survival rate of both PB-Eos and BAL-Eos. It was found that the apoptotic character of BAL-Eos differed from that of PB-Eos in at least three ways. Firstly, the positive rate of Fas expression on PB-Eos was increased after 24 h of incubation, whereas that on BAL-Eos did not change. Secondly, the expression of Fas on PB-Eos was suppressed by IL-5 (18.5 +/- 4.2% - 8.3 +/- 3.2%, p < 0.05), whereas IL-5 failed to suppress Fas expression on BAL-Eos (3.3 +/- 1.6% - 3.6 +/- 1.0%). Lastly, binding of antibody to Fas antigen induced apoptosis of PB-Eos, but not of BAL-Eos. These data suggested that Fas seemed to be involved in the apoptosis of PB-Eos, whereas BAL-Eos were Fas-resistant in chronic eosinophilic pneumonia. In conclusion, apoptosis of eosinophils might be suppressed by proinflammatory cytokines such as IL-5 leading to their accumulation in the lung. Chronic stimulation of eosinophils in the alveolar space with IL-5 may play a crucial role chronic eosinophilic disorders.