Effects of rituximab therapy on B cell differentiation and depletion.

Rituximab is a human/murine chimeric anti-CD20 monoclonal antibody. It is largely used to treat B cell malignancies and has become standard in the management of B cell­mediated diseases such as rheumatoid arthritis and granulomatosis with polyangitis. The effects of rituximab need to be monitored by B cell phenotyping. Evaluate possible surface markers for monitoring B cell development in response to rituximab treatment. This review discusses the literature on the B cell surface markers analysed by flow cytometry in patients treated with rituximab. A panel of biomarkers of response to treatment to monitor by flow cytometry is also suggested. B cell phenotyping is useful to predict clinical relapses after rituximab treatment. The proposed panel of biomarkers includes CD38++CD24++IgD+/- immature B cells and IgD-CD38+/- memory B cells. In responders, Th1/Th2 balance and tolerance cells (CD4+CD25+CD127-/low Treg cells and CD19+CD24hiCD38hi Breg cells) tend to be restored after rituximab therapy. Furthermore, in responder patients, indirect depletion of CD19+/-CD27++CD38++ preplasma cells can be proposed as a predictor of response. Flow cytometric analysis of samples from patients treated with rituximab is a useful strategy to stratify patients according to response to treatment. Identification of B cell differentiation stages by means of a specific flow cytometry panel could improve monitoring of rituximab effects and enable non-responders to be distinguished from good responders.

NK and NKT-like cells in granulomatous and fibrotic lung diseases.

ABTRACT: Background The pathogenetic and regulatory roles of natural killer (NK) and natural killer T-like cells in interstitial lung diseases (ILDs), fibrotic and granulomatous of unknown etiology are unclear. Objectives Here we investigated NK and NKT-like cells in peripheral blood (PB) and Bronchoalveolar lavage (BAL) from patients with ILDs. Method 190 patients (94 male mean age 61 ± 14.3 years) and 8 controls undergoing bronchoscopy for ILD diagnostic work-up were enrolled consecutively; 115 patients sarcoidosis, 24 chronic fibrotic hypersensitivity pneumonitis and 43 patients other ILDs [32 idiopathic pulmonary fibrosis (IPF) and 11 non-specific interstitial pneumonia (NSIP)]. PB and BAL were processed by flow cytometry using monoclonal antibodies to differentiate NK and NKT-like cells. Results NK% in BAL was significantly different among ILDs (p = 0.02). Lower NK% was observed in BAL from sarcoidosis than other ILDs (p < 0.05). Similar findings were observed for NKT-like, whereas no differences were found for PB NK%. Difference of NK% was observed between BAL and PB in all groups (p < 0.001). Sarcoidosis patients reported the best area under the curve for NKT-like (AUC = 0.678, p = 0.0015) and NK cells (AUC = 0.61, p = 0.001). In the IPF-NSIP subgroup, NK% cell was inversely correlated with FVC% (r = - 0.34, p = 0.03) and DLCO% (r = - 0.47, p = 0.0044). Conclusions NK and NKT-like were expressed differently in BAL from patients with different ILD and were significantly depleted in sarcoidosis respect to other ILDs. This suggests that these cells may play a protective role in the pathogenesis of sarcoidosis.

Analysis of macrophage migration inhibitory factor (MIF) in patients with idiopathic pulmonary fibrosis.

By proteomic approach we previously characterised bronchoalveolar lavage (BAL) protein profiles of patients with idiopathic pulmonary fibrosis (IPF), sarcoidosis and systemic sclerosis. Among differently expressed proteins we identified macrophage migration inhibitory factor (MIF), a multi-function pleiotropic cytokine. This study was performed to validate our findings by a further proteomic approach and ELISA in a larger population of patients and controls. MIF expression in lung tissue was also evaluated by immunohistochemistry. MIF was identified in all 2-DE gels of IPF patients and it was significantly increased compared to controls (p<0.05). This result was confirmed by ELISA: MIF concentrations were significantly higher in IPF patients than controls (p<0.001) and were directly correlated with neutrophil percentages (p=0.0095). Immunohistochemical analysis revealed enhanced expression in bronchiolar epithelium, alveolar epithelium, and fibroblastic foci. In conclusion, MIF is a pleiotropic cytokine that could be involved in the pathogenesis of IPF, being particularly abundant in BAL of these patients and mainly expressed in the areas of active fibrosis.