Is IgA nephropathy induced by hyperproduction of interferon-α?

Hydroxychloroquine alleviates persistent proteinuria in IgA nephropathy

PURPOSE

Dendritic cells, Toll-like receptor (TLR), interleukin-6 (IFN-α), interferon-alpha (IFN-α) and tumor necrosis factor-alpha (TNF-α) play an important role in the pathogenesis of IgA nephropathy (IgAN). Hydroxychloroquine (HCQ) is an antimalarial agent and had a notable impact on immune activation by the reduction of circulating activated immune cells that including decreased TLR-expressing cells, reduced IFN-secreting DCs, reduced production of cytokines including IFN-α,IL-6 and TNF-α. We evaluated the efficacy of HCQ in reducing proteinuria in patients with IgAN.

METHODS

Twenty-eight IgAN patients with persistent proteinuria (0.5-2.0 g/24 h) despite treatment with losartan for 3 months were matched to receive HCQ and losartan (group 1) or continue losartan therapy (group 2) for 24 weeks. The primary end point of this prospective, paired case-control study was reduction of proteinuria by 50% or more over entry level.

RESULTS

Six patients (42.9%) in group one versus two patients (14.3%) in group 2 reach the primary end point (P = 0.004). By 24 weeks, the mean urinary protein excretion was 65.9 ± 25.5% (P = 0.002) and 95.3 ± 30.0% (P = 0.791) that of the corresponding baseline value in group 1 and group 2, respectively. Baseline proteinuria and histologic grades, blood pressure control and changes in serum creatinine and eGFR were not different between the two groups.

CONCLUSIONS

In selected patients with IgAN, HCQ is effective in ameliorating proteinuria.

A pig tonsil cell culture model for evaluating oral, low-dose IFN-α treatments

Oral, low-dose IFN-α treatments proved effective in several models of viral infections and immunopathological conditions. Also, they do not give rise to the serious side effects observed after parenteral inoculation of high doses (10(5)U/kg b.w. and higher). There is convincing evidence that such treatments work through an early, effective interaction with oral lymphoid tissues before the IFN-α molecules are rapidly destroyed by gut enzymes. Yet, the paucity of detailed information about these crucial interactions and the lack of recognized in vitro models hamper the development of proper administration protocols. On the basis of a previous study, we developed an in vitro model of interaction between different types of human and porcine IFNs-α at low/moderate concentrations and pig tonsil cells. The IFNs-α under study showed different properties with respect to three fundamental control actions: (1) IgA release in culture, (2) release of natural antimicrobial compounds, and (3) homeostatic regulation of the inflammatory response. This was checked in pig intestinal epithelial cells (IPEC-J2 cell line) treated with supernatants of control and IFN α-treated tonsil cell cultures, respectively, in terms of inflammatory cytokine and chemokine responses. Some IFNs-α caused a significant inhibition of IL-8 (protein release and gene expression) and beta-defensin 1 (gene expression) probably through second messengers released by IFN α-treated tonsil cells. Interestingly, a human lymphoblastoid IFN-α under study caused the decrease of polyclonal IgA release by pig tonsil cells and significantly stimulated the in vitro recall antibody response of swine PBMC to Foot-and-Mouth Disease virus. The modulation of IgA and antibacterial compounds was accompanied by an anti-inflammatory control action at the same, low to moderate IFN-α concentrations (1-100 U/ml). This highlights the very foundation of the homeostatic control actions performed by Type I IFNs: to promote an effective host response to infectious and non-infectious stressors and to turn off noxious inflammatory responses associated with tissue damage and waste of metabolic energy. The described tonsil cell model in vitro can be conducive to a further development of oral cytokine treatments in humans and animals in the "one health" conceptual framework.

Enrichment of the Basic/Cationic Urinary Proteome Using Ion Exchange Chromatography and Batch Adsorption

Anionic or acidic proteins are the main compositions of normal urinary proteome. Efforts to characterize human urinary proteome, thus, have focused mainly on the anionic compartment. The information of cationic or basic proteins present in the normal urine is virtually unknown. In the present study, we applied different methods to enrich cationic urinary proteome. Efficacies of these methods were compared using equal volume (1 L) of urine samples from the same pool obtained from 8 normal healthy individuals. Cation exchange chromatography using RESOURCE-S column provided the least amount of the recovered proteins, whereas batch adsorption using SP Sepharose 4 Fast Flow beads equilibrated with acetic acid (pH 4.8) provided the greatest yield of protein recovery. The recovered proteins were then resolved with 2-DE (pI 7-11) and identified by peptide mass fingerprinting using MALDI-TOF MS. There were several isoforms of immunoglobulin heavy and light chains enriched by these methods. In addition, three isoforms of interferon alpha-3 (IFNalpha3) and six isoforms of eosinophil-derived neurotoxin (EDN), were also enriched. The enrichment of IFNalpha3 and EDN was particularly effective by batch adsorption using SP Sepharose 4 Fast Flow beads equilibrated with acetic acid (pH 6.0). Initial depletion of anionic components using DEAE batch adsorption reduced the recovery yield of these two proteins and did not improve recovery of any other cationic urinary proteins. We conclude that batch adsorption using SP Sepharose Fast Flow beads equilibrated with acetic acid (pH 6.0) is the method of choice to examine the basic/cationic urinary proteome, as this protocol provided the satisfactory yield of protein recovery and provided the greatest amount as well as maximal number of IFNalpha3 and EDN isoforms. Our data will be useful for further highly focused study targeting on cationic/basic urinary proteins. Moreover, the techniques described herein may be applicable for enrichment of cationic proteomes in other body fluids, cells, and tissues.