Table 2.
IL-34 and autoimmune diseases
| Diseases | Major finding related to IL-34 | References |
|---|---|---|
| Bowel Autoimmune Diseases | High IL-34 expression levels in lamina propria compartments in Crohn's disease (CD) and Ulcerative colitis (UC); IL-34 enhances inflammatory response by up-regulation of TNF-α and IL-6 factors |
119 |
| High expression levels of IL-34 in CD than in UC, with IL-34 mainly expressed in the Ileum; TNF-α induces IL-34 production by epithelial cells. |
120 | |
| IL-34 participates in the cross talk between epithelial and immune cells by induction of CCL20 chemokine expression | 121 | |
| IL-34 is highly produced in the fibrotic gut of CD patients and contributes to collagen production by enhancing COL1A1 and COL3A1 expression in a p38MAP kinase-depending mechanism | 122 | |
| Multiple Sclerosis (MS) | IL-34 acts as a neuroprotective factor by inducing microglia differentiation with anti-inflammatory properties | 123 |
| Il-34 expression by neurons contributes to the re-establishment of tight junctions and blood brain barrier by epithelial cells; IL-34 induces microglia differentiation with anti-inflammatory properties | 124 | |
| IL-34 levels do not change in relapsing-remitting MS | 125 | |
| IL-34 induces neuroprotection by expansion of CD11c+ microglia population via CD115 | 126 | |
| IL-34 expression is down regulated in cerebrospinal fluids in MS affected patients | 127 | |
| In children, Vitamin D partially induces IL-34 expression by neurons conferring neuroprotection against MS | 128 | |
| Psoriasis | High levels of IL-34 in serum of patients affected by psoriatic Arthritis correlate with high levels of osteoclast precursors and poor prognosis | 129 |
| Rheumatoid Arthritis (RA) | IL-34 is highly expressed by synovial fibroblast of RA affected patients; IL-34 expression is induced by pro-inflammatory factors IL-1β and TNF-α; High levels of IL-34 correlate with severity and poor prognosis of RA | 111 |
| High levels of IL-34 in synovial fluids of RA patients; IL-34 induces osteoclast differentiation in RA; TNF-α induces IL-34 expression by synovial fibroblast via NFκB and JNK pathways | 130 | |
| IL-34 high levels in serum and synovial fluid of RA patients; IL-34 induces the expression of pro-inflammatory factor IL-17 by circulating mononuclear cells | 131 | |
| High levels of IL-34 in serum of RA patients positively correlate with IL-6, RANKL and anti-cyclic citrullinated peptide (CCP) antibody levels | 132 | |
| High levels of IL-34 in serum and synovial fluids positively correlate with rheumatoid factors (RF), current smoking, erythrocyte sedimentation rate (ESR) and C-reactive protein levels; IL-34 as an independent risk factor for radiographic progression of RA | 133 | |
| High levels of IL-34 in serum of RA patients in stage III of hand R-ray score; IL-34 levels positively correlate with increase of pro-inflammatory factors IL-6, IL-8, MMP-3 and C-reactive protein | 134 | |
| Treatment with TNF-α antagonist reduces levels of IL-34 after 3 months of treatment and correlates with good prognosis of RA | 135 | |
| Simultaneous inhibition of M-CSF and IL-34 cytokines decrease pathology symptoms in RA mouse models and humans | 136 | |
| High levels of IL-34 in serum and synovial fluids of RA patients; IL-34 enhances synovial fibroblast apoptosis resistance by production of miR-21 via STAT3 signaling pathway activation | 137 | |
| BMP2 and TGF-β acts as controllers of inflammatory process in RA by inhibition of IL-34 expression in synovial fibroblast | 115 | |
| High levels of IL34 in serum of RA patients positively correlate with C-reactive protein, ESR, RF and anti-CCP antibody; IL-34 induces the expression of IL-6 cytokine and subsequently promotes Th17 production | 113 | |
| IL-34 plays an essential role in the immune cell cross talk during RA; IL-34/CD115 complex stimulates the expression of ROS in THP-1 cells, inducing IL-6 secretion and Th17 production | 116 | |
| IL-34 participates in the establishment of RA in mice by induction of proliferation, migration and transformation of circulating fibrocytes in fibroblast-like synovial cells in affected joints | 112 | |
| High levels of IL-34 in serum of RA patients positively correlate with RANKL, DAS28-ERS, C-reactive protein, RF and bone erosion score; IL-34 levels can be used as a predictor of bone erosion | 118 | |
| IL-34 participates in local joint destruction and osteoporosis during RA by induction of RANKL expression and inhibition of OPG, partially mediate by IL-17, in sinoviocytes fibroblast and circulating monocytes | 117 | |
| IL-34 may participate indirectly in angiogenesis process in RA by induction of VEGF and HIF-1α factors secretion in RA circulating monocytes | 138 | |
| IL-34 modulates the proliferation and migration of synoviocytes fibroblast in RA | 114 | |
| Sjogren Syndrome (pSS) | IL-34 expression correlates with expansion of pro-inflammatory CD14bright CD16+ monocytes in salivary glands; IL-34 acts as a pathogenic factor in pSS | 139 |
| High levels of IL-34 in serum of pSS patients are positively associated with levels of RF, IgG and γ-globulin; IL-34 induces hyper-activation of B cells and antibodies production | 140 | |
| Systemic Lupus Erythematosus (SLE) | High levels of IL-34 in serum of children with SLE correlate with high SLE Disease Activity Index (SLEDAI), anti-double-stranded DNA antibody (anti-sdDNA) and C-reactive protein | 141 |
| IL-34 levels are detectable in serum of SLE affected patients and correlate with SLEDAI and high IgG; IL-34 as a potential disease activity marker for SLE | 142 | |
| High levels of IL-34 in serum and urine correlate with poor prognosis of SLE patients; IL-34 expression is associated with high expression of CD115 and PTP-ζ and induces differentiation and accumulation of intrarenal macrophages that favors tubular epithelial cell apoptosis | 143 | |
| High levels of IL-34 in serum of children with SLE correlate with high SLEDAI, anti-sdDNA and C-reactive protein, with a more aggressive effect that adult SLE | 144 | |
| High levels of IL-34 in serum of patients affected by lupus nephritis and correlate with SLEDAI, anti-sdDNA and C-reactive protein; IL-34 can be used as surrogate marker for early detection of lupus nephritis diseases | 145 | |
| Systemic Sclerosis (SS) | High levels of IL-34 in serum of SS patients correlate with expansion of M2 and Th17 macrophages and severity of interstitial lung disease | 146 |