The development of mixed cryoglobulinemia in Capillaria hepatica-infected mice is associated with the capillaria antigen-induced selective proliferation of splenic B-1a cells in response to interleukin-5 stimulation

PD-L2 Blockade Exacerbates Liver Lesion in Mice Infected with Capillaria hepatica through Reducing Alternatively Activated Macrophages

Capillaria hepatica is a seriously neglected zoonotic parasite, which infects the liver of mammalian hosts, causing fibrosis or even hepatic failure. At present, the immune responses elicited by C. hepatica are not fully understood, and the role(s) of the programmed death 1 (PD-1) signaling pathway in the context of C. hepatica-induced pathology are not known. In this study, we identify that the late stage of infection with C. hepatica-especially the egg-derived antigens-modulates the host immune responses to promote alternatively activated macrophage (M2) polarization and programmed death ligand 2 (PD-L2) expression. The PD-L2-expressing alternatively activated M2 macrophages play an important role in maintaining Th2-biased regulatory immune responses, which may facilitate the survival of parasitic worms or eggs within the infected liver and reduce the liver pathology caused by the egg granulomas. Treatment with anti-PD-L2 antibody had no effect on the survival of parasitic eggs but deteriorated the pathology of egg granulomas. The obtained results suggest that PD-1/PD-L2 signaling, which is involved in alternative macrophage polarization, determines the immune response pattern and the immunopathology, consequently determining the outcome of the parasitic infection.

A diagnostic score for eosinophilic granulomatosis with polyangiitis among eosinophilic disorders

BACKGROUND

Eosinophilic granulomatosis with polyangiitis (EGPA) is a form of systemic vasculitis with eosinophilic inflammation. However, existing classification criteria are all designed to classify EGPA among vasculitis and there is no established method distinguishing EGPA from other eosinophilic disorders. The aim of the present study was to propose a scoring system to differentiate EGPA among eosinophilic disorders.

METHODS

Non-supervised hierarchical clustering using Ward's method and principal component analysis (PCA) were performed for 19 clinical parameters of 58 patients with eosinophilia-related diseases at a tertiary university hospital. The newly proposed scoring system was externally validated in 40 patients at another tertiary institution.

RESULTS

Two distinct clusters were identified, and clinical features including peripheral neuropathy, asthma, skin involvement, lung involvement, rheumatoid factor (RF) positivity, myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA) positivity, IgE elevation, C-reactive protein (CRP) elevation, and vasculitis pathological findings were predominantly observed in one of these clusters (p < 0.05). Ten features defining the cluster with a high rate of vasculitis were weighted by PCA to create the E-CASE (EGPA classification among systemic eosinophilia) scoring system, on a 16-point scale. Based on the distribution of scores in the primary cohort, we defined an E-CASE score ≥12 as positive, ≤ 8 as negative, and 9-11 as undeterminable. The sensitivity and specificity of the E-CASE score in the validation cohort were 93.3% and 100%, respectively.

CONCLUSIONS

We developed and verified a novel scoring system for differentiating EGPA from other types of eosinophilic disorders.

Subtypes in eosinophilic granulomatosis with polyangiitis classified according to rheumatoid factor

To investigate the relevance of RF in patients with EGPA, we reviewed consecutive patients who were newly diagnosed with EGPA from August 1998 to February 2019 in Keio University Hospital with RF titer at diagnosis available. We divided the patients according to the median level of RF titer of 75 IU/mL and compared clinical features between the two groups. Among 16 patients identified, 8 patients were in the RF high group and the other 8 patients were in the RF low group. All patients in the high RF group were negative for MPO-ANCA, whereas all in the low RF group was positive for MPO-ANCA with a mean titer of 103 IU/mL. The eosinophil count at diagnosis was significantly higher in the RF high group than the RF low group (20001/μL vs 5144/μL, p < 0.01). Gastrointestinal lesion was significantly more frequent in the RF high group, and parenchymal organ lesions, such as heart and renal organ involvement, were frequent in the RF low group. With principal component analysis, RF high and low groups were clearly divided by the combination of eosinophil count, MPO-ANCA titer, gastrointestinal lesions, musculoskeletal symptoms, and disease activity score. Those results suggest EGPA can be divided into two groups in association with RF.Key Points• Our study showed that patients with EGPA can be separated into two groups according to RF titer.• The two subtypes reflect different underlying pathogenesis in EGPA, and the optimal treatment for them may be different.

High IL-1α Production Was Induced in the WBN/Kob-Leprfa Type 2 Diabetes Mellitus Rat Model and Inhibited by Syphacia Muris Infection

The novel WBN/Kob-Lepr^fa (fa/fa) congenic rat strain is considered a useful rat model of type 2 diabetes mellitus (T2DM). Accumulating findings suggest that low-grade inflammation is a causative factor in T2DM and that circulating levels of inflammatory cytokines are associated with insulin resistance. However, inflammatory cytokine profiles and their correlations with T2DM development/ progression in fa/fa rats have not been studied. In this study, we found that the fa/fa rats had considerably high plasma levels of interleukin (IL)-1α. Abundant cecal IL-1α mRNA expression and cecal inflammation with infiltrating IL-1α-producing macrophages was observed in fa/fa rats. Bone marrow derived macrophages from fa/fa rats expressed high levels of IL-1α upon lipopolysaccharide stimulation. Furthermore, Syphacia muris infection, which delays the onset of T2DM, reduced both plasma and cecal IL-1α levels in fa/fa rats. These results suggest that macrophage infiltration and IL-1α secretion comprise an important part of T2DM development and that S. muris infection inhibits pro-inflammatory cytokine expression in fa/fa rats.