Evaluation of activatory and inhibitory natural killer cell receptors in non-segmental vitiligo: a flow cytometric study

Background Recent observations established the role of altered cellular immunity and autoimmune hypothesis in the pathogenesis of vitiligo. There have been several reports discussing T‐cell and natural killer (NK) cell populations, but NK cell receptors were not evaluated in vitiligo. Objective The purpose of this investigation was to assess the role of T and NK cells as well as activatory and inhibitory NK cell receptor alterations in the pathogenesis of vitiligo and whether any aberrations were correlated with clinical findings of the disease. Patients/methods Fifty‐three patients with non‐segmental vitiligo and 45 age‐ and sex‐matched healthy controls were enrolled in the study. The percentages of lymphocytes, granulocytes, monocytes and CD3, CD4, CD8, CD14, CD16, CD56, CD45, CD45RA, CD54RO, CD28, CD80, CD94, CD158a, KIR3DL‐1 receptors as well as CD94, CD158a, KIR3DL‐1 receptors on CD16⁺ cells were detected by using flow cytometry. The patient and control groups were compared in terms of the results of flow cytometric analysis, and the results were assessed regarding the type and activity of vitiligo. Results The percentages of CD16⁺CD56⁺, CD3⁺CD16⁺CD56⁺, CD8⁺ and CD45RO⁺ cells were significantly increased in vitiligo group compared with the controls. No difference was detected between the patients and control groups in percentages of CD3⁺, CD4⁺, CD3^?CD16⁺CD56⁺, CD28⁺, CD45⁺, CD45RA⁺, CD94⁺, CD158a⁺ and KIR3DL‐1⁺ cells. The percentage of CD16⁺CD158a⁺ cells was significantly decreased in a randomized selected group of vitiligo patients. There were no differences in percentage expression of studied cell surface antigens between patients in the active or stable period. CD3⁺ cells were significantly increased in generalized form, and CD45RO⁺ cells were significantly increased in acral/acrofacial form when compared with the other types of vitiligo. Conclusions These results indicate further evidence for T and NK cell abnormalities in non‐segmental vitiligo. The present data show that NK cell activation may be responsible in the pathogenesis of vitiligo in conformity with decreased inhibitory and increased activatory NK cell receptors.     

Immunohistochemical study of human rabies

Rabies is a communicable disease that is almost always fatal. In its classic form, rabies is well recognized, but cases presenting with a paralytic illness mimic Landre's Guillain–Barre syndrome and in such cases the diagnosis remains in doubt. This problem is further compounded when the history of dogbite is not forthcoming. At autopsy rabies can be diagnosed by subjecting fresh tissue to virologic investigations or examining formalin‐fixed paraffin‐embedded tissue sections for the presence of characteristic inclusions; that is, the Negri bodies. However, these inclusions are not present in all cases. Hence, the need arises for a better method for diagnosis. The present study utilized immunohistochemistry as a diagnostic tool using both monoclonal and polyclonal antirabies antibodies in 20 cases of rabies encephalomyelitis. The diagnosis of rabies could be confirmed in 17 cases (85%) based on neuropathologic findings alone. In contrast, immunohistochemistry yielded positive results in all cases. Moreover, the amount of rabies viral antigen was much more abundant than could be expected from the histopathologic findings. Thus immunohistochemistry is a rapid, safe, sensitive and specific technique for the diagnosis of rabies.