Increased blood group 2 innate lymphoid cells are involved in blood eosinophilia and itching in Kimura disease

Background: Kimura disease (KD) is a rare, chronic inflammatory disorder characterized by blood eosinophilia, general itching, and subcutaneous head and neck mass lesions; however, the etiology of this disease is unknown. We hypothesized that group 2 innate lymphoid cells (ILC2s) in peripheral blood may play an essential role in the pathogenesis of KD. Methods: The prevalence of blood ILC2s and their ability to produce interleukin (IL) -4, IL-5, IL-13, and IL-31 in patients with KD were compared with those in control subjects and in patients with house dust mite (HDM) -induced allergic rhinitis (AR). Changes in blood ILC2 prevalence, blood eosinophilia, and clinical symptoms after surgery and steroid therapy were evaluated. Results: Blood ILC2 prevalence in patients with KD were eight times and six times higher than those in control subjects and in patients with AR, respectively. There was a strong positive correlation between ILC2 prevalence and blood eosinophilia. Patients with KD showed increased serum IL-13 and decreased IL-31 levels. KD patient-derived blood ILC2s produced large amounts of IL-5 and IL-13 in response to prostaglandin (PG) D and leukotriene (LT) D , compared to ILC2s derived from control subjects and patients with AR. Surgery and systemic steroid therapy ameliorated general itching with a concomitant decrease in blood ILC2s and blood eosinophilia. Upon disease recurrence, blood ILC2 prevalence and blood eosinophilia increased concurrently with general itching. Conclusion: Increased blood ILC2s may be involved in blood eosinophilia and general itching through the production of IL-5 and IL-13 in patients with KD.

Correlation between Peripheral Blood Eosinophilia and the Histopathological Changes in Nasal Mucosal in Chronic Rhinosinusitis

Background: Chronic rhinosinusitis(CRS) has emerged as one of the major causes of significant morbidity in otorhinolaryngology, as it is often noted to be refractory to medical management and has a tendency to recur post-surgery. Limited research has shown that peripheral eosinophilia is related to the presence of nasal polyps, the extent of the mucosal disease, the severity of tissue eosinophilia, and the risk of recurrence. Aim: This study aimed to establish the significance of peripheral blood eosinophilia, both differential (EC) and absolute eosinophil counts (AEC) - in adult CRS, to correlate the tissue eosinophilia and peripheral blood eosinophilia, and compare the observations in the two types of CRS with nasal polyp and without nasal polyp. Material and Methods: A total of 50 adult patients with CRS who underwent FESS were included in the study and were divided based on the presence (Group 1) or absence (Group 2) of peripheral blood eosinophilia. Results: There were equal number of cases of chronic rhinosinusitis with nasal polyp (CRSwNP) and without polyp (CRSsNP); 25 each. With regard to clinical features, Group 1 had a higher number of cases with nasal obstruction (p-value = 0.023), post-nasal drip (p-value = 0.035), and hyposmia (p-value = 0.021) when compared to Group 2. On histopathology, Group 1 had more areas of edema (p-value = 0.027), and mucous gland hyperplasia (p-value = 0.013) while Group 2 had prominent lymphoplasmacytic infiltrates (p-value = 0.035), neutrophilia (p-value = 0.047), and tissue infiltration of macrophages (p-value = 0.027). Tissue eosinophilia was present in 32 out of the total cases; 20 (71.43%) in Group 1 and 12 (53.33%) in Group 2. The group with tissue eosinophilia had significantly higher eosinophil count (9.24 ± 4.26% vs 5.32 ± 2.9%; p-value < 0.01) as well as AEC (823.335 ± 434.357/µl vs 485.128 ± 285/µl. 907; p-value < 0.01). Conclusion: The study demonstrated that CRS cases with tissue eosinophilia exhibit an elevated peripheral eosinophil count when compared to non-eosinophilic CRS.

Eosinophilic Chronic Obstructive Pulmonary Disease

Recent therapeutic advances in the management of asthma have underscored the importance of eosinophilia and the role of pro-eosinophilic mediators such as IL-5 in asthma. Given that a subset of patients with COPD may display peripheral eosinophilia similar to what is observed in asthma, a number of recent studies have implied that eosinophilic COPD is a distinct entity. This review will seek to contrast the mechanisms of eosinophilia in asthma and COPD, the implications of eosinophilia for disease outcome, and review current data regarding the utility of peripheral blood eosinophilia in the management of COPD patients.