Increase of macrophage migration inhibitory factor in sera of patients with iridocyclitis

Macrophage Migration Inhibitory Factor -173GC Variant Might Increase the Risk of Behçet's Disease

OBJECTIVE

The aim of the present study was to investigate any possible association between the macrophage migration inhibitory factor (MIF) -173GC variant and Behçet's disease (BD) in a group of Turkish patients.

SUBJECTS AND METHODS

A total of 111 patients with BD and 100 healthy controls were enrolled in this study. Genomic DNA was extracted from peripheral lymphocytes. The MIF -173GC variant was genotyped using polymerase chain reaction restriction fragment length polymorphism. The allele and genotype frequencies of patients and controls were compared using the χ2 test.

RESULTS

A statistically significant difference in the distribution of the genotype was observed between BD patients and healthy controls. The homo-genotype CC was more prevalent in the patient group compared to the control group (p = 0.008, OR: 0.24, 95% Cl: 0.05-0.78). A significant association was observed when the patients were compared with the controls according to GG + GC versus CC ge-notypes (p = 0.003, OR: 1.21, 95% CI: 0.06-0.063). Allele frequencies of the MIF -173GC variant did not show any statistically significant difference between patients and controls.

CONCLUSION

In this study, we conclude that the CC ge-notype of the MIF -173GC variant may be a risk factor in the pathogenesis of BD in the Turkish population. However, further studies with larger samples are needed to address the exact role of this variant in BD.

MIF Inhibitor ISO-1 Protects Photoreceptors and Reduces Gliosis in Experimental Retinal Detachment

Photoreceptor death and retinal gliosis underlie the majority of vision threatening retinal diseases including retinal detachment (RD). Although the underlying pathobiology of vision limiting processes in RD is not fully understood, inflammation is known to play a critical role. We conducted an iTRAQ proteomic screen of up- and down-regulated proteins in a murine model of RD to identify potential targetable candidates. Macrophage migration inhibitory factor (MIF) was identified and evaluated for neurotoxic and pro-gliotic effects during RD. Systemic administration of the MIF inhibitor ISO-1 significantly blocked photoreceptor apoptosis, outer nuclear layer (ONL) thinning, and retinal gliosis. ISO-1 and MIF knockout (MIFKO) had greater accumulation of Müller glia pERK expression in the detached retina, suggesting that Müller survival pathways might underlie the neuroprotective response. Our data show the feasibility of the MIF-inhibitor ISO-1 to block pathological damage responses in retinal detachment and provide a rationale to explore MIF inhibition as a potential therapeutic option for RD.

Association of macrophage migration inhibitory factor gene polymorphisms with Behçet's disease in a Han Chinese population

OBJECTIVE

To examine whether polymorphisms of the macrophage migration inhibitory factor (MIF) gene are associated with Behçet's disease (BD) in a Han Chinese population.

DESIGN

Case-control study.

PARTICIPANTS

A total of 600 patients with BD and 600 age-, sex-, and ethnically matched healthy controls were enrolled.

METHODS

Two single nucleotide polymorphisms (SNPs), rs755622 and rs2096525, were genotyped using a polymerase chain reaction (PCR) restriction fragment length polymorphism assay. Allele and genotype frequencies were compared between patients and controls using the chi-square test. The expression of MIF was examined by real-time PCR.

MAIN OUTCOME MEASURES

Association of SNPs in MIF with BD.

RESULTS

Significantly decreased frequencies of the rs755622 genotype GG and G allele were found in patients with BD compared with controls. The frequencies of the genotype TT and T allele of the SNP rs2096525 were significantly lower in patients with BD compared with controls. Stratification analysis showed that the frequencies of rs755622 genotype GG in the oral aphthae, genital ulceration, or hypopyon subgroups were significantly decreased compared with controls (all P(c) < 0.05). A significantly lower frequency of the G allele of rs755622 was observed in the oral aphthae, genital ulceration, hypopyon, and arthritis subgroups compared with controls (P(c) < 0.05). The frequencies of the rs2096525 genotype TT and T alleles were also decreased in the oral aphthae, genital ulceration, hypopyon, and skin lesion subgroups compared with the controls (P(c) < 0.01). The results also showed that the expression of MIF mRNA in individuals carrying the CC genotype of rs755622 was 1.78- and 1.92-fold higher than in those carrying the GC or GG genotype.

CONCLUSIONS

This study identified a strong association of the 2 SNPs, rs755622 and rs2096525, in the MIF gene with BD and suggests that the involvement of MIF in BD may be through regulation of its mRNA expression.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Autoimmune diseases: MIF as a therapeutic target

IMPORTANCE OF THE FIELD

Autoimmune inflammatory diseases occur commonly in developed countries. The treatment of these diseases is usually non-curative and is aimed at suppressing inflammatory end-organ damage. Macrophage migration inhibitory factor (MIF) is a multipotent cytokine that has been implicated in the pathogenesis of numerous autoimmune inflammatory disorders. The selective targeting of MIF with either anti-MIF antibody or specific MIF antagonists may offer new therapeutic avenues for these diseases.

AREAS COVERED IN THIS REVIEW

Our aim is to discuss MIF-directed therapies as a novel therapeutic approach. The review covers literature from the past 10 years.

WHAT THE READER WILL GAIN

MIF inhibition has been shown to be efficacious in many experimental and pre-clinical studies of autoimmune inflammatory diseases. The close regulatory relationship between MIF and glucocorticoids makes therapeutic antagonism of MIF a potential steroid-sparing therapy in patients with refractory autoimmune diseases.

TAKE HOME MESSAGE

We expect that MIF antagonism by either small-molecule- or antibody-based approaches will find wide application in the treatment of autoimmune inflammatory diseases. Such therapy also may be informed by the MIF genotype of affected patients.

Elevation of surfactant protein D, a pulmonary disease biomarker, in the sera of uveitis patients with sarcoidosis

PURPOSE

Surfactant protein D (SP-D) is found in the epithelial cells of multiple mucosal surfaces. It is commonly used to diagnose and screen for pulmonary diseases. In the present study, serum levels of SP-D were measured in patients with uveitis to ascertain whether SP-D is a clinically useful laboratory parameter to diagnose sarcoidosis.

METHODS

Sera were obtained from 81 patients with sarcoidosis, 16 patients with Behçet disease, 40 patients with HLA-B27 associated uveitis, 50 patients with Vogt-Koyanagi-Harada (VKH) disease, and 33 healthy volunteers. Serum SP-D levels were quantified with an SP-D enzyme immunoassay kit.

RESULTS

In the healthy control subjects, the average serum SP-D level was 39.70 ng/ml; in the uveitis patients with sarcoidosis, the mean serum SP-D level was 57.0 ng/ml, and in the uveitis patients with other etiologies the mean levels were 38.63 ng/ml for Behçet disease, 38.18 ng/ml for HLA-B27 associated uveitis, and 31.32 ng/ml for the VKH patients. The average serum SP-D levels of patients with sarcoidosis were significantly higher than those of patients with any other uveitis etiologies or healthy controls (P < 0.01).

CONCLUSIONS

SP-D may be a less invasive and less expensive laboratory examination for sarcoidosis screening. SP-D should be considered as a new laboratory parameter for the diagnosis of uveitis and sarcoidosis.

High expression of macrophage migration inhibitory factor in the murine lacrimal gland

PURPOSE

To report the expression of macrophage migration inhibitory factor (MIF) in murine lacrimal glands.

METHODS

Six lacrimal glands from 3 female 8-week-old CBA/J mice were analyzed using a gene microarray method (Oligo GEArray mouse inflammatory cytokines and receptors, Catalog No. OMM-011, SuperArray Bioscience) and immunofluorescent staining for MIF. Nine lacrimal glands from 8-week-old CBA/J mice, 9 lacrimal glands from 8-week-old C57BL/6 mice, and 7 lacrimal glands from 8-week-old BALB/c mice were analyzed using real-time reverse transcription-polymerase chain reaction. Five spleens, 5 livers, and 5 serum samples from 5 female 8-week-old CBA/J mice were analyzed using enzyme-linked immunosorbent assay.

RESULTS

Microarray analysis revealed that MIF is highly expressed in the murine lacrimal gland. Lacrimal acinar cells stain strongly with anti-MIF antibodies. Real-time reverse transcription-polymerase chain reaction revealed that the MIF mRNA expression level is lower in lacrimal glands of CBA/J mice compared with C57BL/6 and BALB/c mice when normalized against the expression of beta-actin mRNA. Enzyme-linked immunosorbent assay revealed that MIF level was higher in lacrimal glands and spleens compared with livers and sera.

CONCLUSION

The murine lacrimal gland expresses high levels of macrophage MIF without any evidence of lacrimal gland inflammation.

Increase in macrophage migration inhibitory factor levels in lacrimal fluid of patients with severe atopic dermatitis

BACKGROUND AND AIMS OF THE STUDY

Atopic dermatitis is a chronic inflammatory skin disorder that often involves some ophthalmic features. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is associated with the generation of cell-mediated immune responses. Although serum MIF levels may be elevated in severe atopic dermatitis, the quantity of MIF in regional ocular fluid remains unknown. We measured MIF levels in tears (lacrimal fluid) of patients with atopic dermatitis.

PATIENTS AND METHODS

Tear samples were collected from 16 patients with atopic dermatitis, 10 patients with allergic conjunctivitis, and 15 healthy control subjects. The clinical severity of atopic dermatitis was evaluated according to the Scoring Atopic Dermatitis (SCORAD) index. The index was calculated by summing the following scores: extent criteria, intensity criteria, and subjective symptoms. Macrophage migration inhibitory factor levels were determined by a human MIF enzyme-linked immunosorbent assay. All comparisons were two-tailed, and P values <0.01 were considered as statistically significant.

RESULTS

The mean MIF concentration in lacrimal fluid collected from healthy control subjects was 0.69+/-0.2 ng/ml. The mean tear MIF levels were 17.87+/-6.3 ng/ml in moderate-to-severe atopic dermatitis (SCORAD> or =15, P=0.002), 0.93+/-0.08 ng/ml in mild atopic dermatitis (SCORAD<15), and 2.76+/-0.86 ng/ml in allergic conjunctivitis (P=0.008).

CONCLUSIONS

A proinflammatory cytokine MIF level was elevated in tears as well as serum in cases of severe atopic dermatitis. These results suggest that MIF may play an important role in the induction or enhancement of ophthalmic features related to severe atopic dermatitis.

Usefulness of quantifying serum KL-6 levels in the follow-up of uveitic patients with sarcoidosis

BACKGROUND

KL-6 is a human glycoprotein secreted by type II alveolar cells in the lung, and its serum levels increase in pneumonia of various causes. We previously reported that serum KL-6 levels in uveitis patients with sarcoidosis were significantly higher than those of other uveitis patients and healthy controls. Additionally, the combined measurement of serum KL-6 and angiotensin converting enzyme (ACE) was useful for screening uveitic patients to diagnose sarcoidosis. The purpose of the present study was to investigate the clinical usefulness of quantifying serum KL-6 levels for following-up the patients with sarcoidosis.

METHODS

Sera were obtained from 36 uveitic patients diagnosed with sarcoidosis and the same number of healthy volunteers. To examine the influence of systemic medication, we also collected blood samples from four more sarcoidosis patients, who were systemically treated with corticosteroid or angiotensin converting enzyme (ACE) inhibitor, an anti-hypertensive drug. The serum concentration of KL-6 was measured by a human KL-6 electrochemiluminescence immunoassay (ECLIA).

RESULTS

The mean KL-6 concentrations of sarcoidosis patients and healthy controls were 449.3+/-66.3 (mean+/-SE) and 192.1+/-11.3, respectively. The average levels of serum KL-6 were significantly elevated in sarcoidosis patients compared with healthy control subjects (P<0.001), and there were significant correlations between serum KL-6 and ACE levels in the patients with sarcoidosis (r=0.70 and P<0.0001). Moreover, serum KL-6 concentrations were less affected by systemic corticosteroid, and unaffected by ACE inhibitory drugs in contrast to ACE levels.

CONCLUSIONS

Measurement of serum KL-6 in the uveitic patients may be useful to follow-up the diagnosed sarcoidosis, as well as for diagnosing sarcoidosis, because the serum KL-6 level was well correlated with the ACE level, and less affected by systemic medication than ACE levels.

Macrophage migration inhibitory factor: a regulator of innate immunity

Cytokines are essential effector molecules of innate immunity that initiate and coordinate the cellular and humoral responses aimed, for example, at the eradication of microbial pathogens.

Discovered in the late 1960s as a product of activated T cells, the cytokine macrophage migration inhibitory factor (MIF) has been discovered recently to carry out important functions as a mediator of the innate immune system.

Constitutively expressed by a broad spectrum of cells and tissues, including monocytes and macrophages, MIF is rapidly released after exposure to microbial products and pro-inflammatory mediators, and in response to stress. After it is released, MIF induces pro-inflammatory biological responses that act as a regulator of immune responses.

MIF activates the extracellular signal-regulated kinase 1 (ERK1)/ERK2–mitogen-activated protein kinase pathway, inhibits the activity of JUN activation domain-binding protein 1 (JAB1) — a co-activator of the activator protein 1 (AP1) — upregulates the expression of Toll-like receptor 4 to promote the recognition of endotoxin-expressing bacterial pathogens, sustains pro-inflammatory function by inhibiting p53-dependent apoptosis of macrophages and counter-regulates the immunosuppressive effects of glucocorticoids on immune cells.

As a pro-inflammatory mediator, MIF has been shown to be implicated in the pathogenesis of severe sepsis and septic shock, acute respiratory distress syndrome, and several other inflammatory and autoimmune diseases, including rheumatoid arthritis, glomerulonephritis and inflammatory bowel diseases.

Given its crucial role as a regulator of innate and acquired immunity, pharmacological or immunological modulation of MIF activity might offer new treatment opportunities for the management of acute and chronic inflammatory diseases.

For more than a quarter of a century, macrophage migration inhibitory factor (MIF) has been a mysterious cytokine. In recent years, MIF has assumed an important role as a pivotal regulator of innate immunity. MIF is an integral component of the host antimicrobial alarm system and stress response that promotes the pro-inflammatory functions of immune cells. A rapidly increasing amount of literature indicates that MIF is implicated in the pathogenesis of sepsis, and inflammatory and autoimmune diseases, suggesting that MIF-directed therapies might offer new treatment opportunities for human diseases in the future.

Macrophage migration inhibitory factor is associated with aneurysmal expansion

BACKGROUND

Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine released mainly from macrophages and activated lymphocytes. Both atherosclerosis and abdominal aortic aneurysm (AAA) are inflammatory diseases tightly linked to the function of these cells. The correlation and contribution of MIF to these human diseases remain unknown, although a recent rabbit study showed expression of this cytokine in atherosclerotic lesions.

MATERIAL AND METHODS

MIF immunohistochemistry was performed on tissue sections from five normal aortas, seven atherosclerotic carotids, and six AAAs. A group of 112 men with small AAAs (defined as 3 to 5 cm) was recruited at the time of diagnosis, had serum samples taken, and was followed annually for 1 to 5 years (mean, 2.9 years) and referred for surgery if the AAA exceeded 5 cm in diameter. Of this study group, 98 had serum MIF measured with an enzyme-linked immunosorbent assay and 61 had detectable levels.

RESULTS

In human atherosclerotic and aneurysmal lesions, MIF protein colocalized in macrophages, endothelial cells, and smooth muscle cells, but normal arteries had negligible MIF expression. Furthermore, serum-MIF levels correlated significantly with annual expansion rate (r = 0.28; P =.005), persisting after adjustment for initial AAA size, smoking habits, diastolic blood pressure, ankle blood pressure index, and age. After exclusion of 38 cases with MIF levels below the detection limit, initial AAA size was also significantly correlated with the MIF levels (r = 0.42; P =.001), persisting after adjustment for similar confounders, and the correlation coefficient with expansion rate increased to 0.42 (P =.001).

CONCLUSION

Highly expressed MIF in macrophages, endothelial cells, and smooth muscle cells in lesions from atherosclerosis and AAA and significant association between serum MIF level and AAA initial size and AAA expansion rate in a group of patients with AAA suggest a potential involvement of this proinflammatory cytokine in the pathogenesis of these cardiovascular diseases.

Macrophage migration inhibitory factor in human pregnancy and labor

PROBLEM

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in reproduction. Presently there is no information on the possible involvement of MIF in the onset of labor.

METHODS

Macrophage migration inhibitory factor was assayed, by enzyme-linked immunosorbent assay (ELISA), in maternal serum (MS) and amniotic fluid (AF) both, at midtrimester and at term, as well as in cord serum (CS) at birth. Extraembryonic membranes were analyzed by immunohistochemistry.

RESULTS

Amniotic fluid MIF concentrations were significantly higher at term (median 62.10 ng/mL) than at midtrimester (median 20.07 ng/mL) and reached a peak in term labor (median 258.80 ng/mL). The AF/MS ratio varied from a median of 4.34 at midtrimester and 33.7 at term labor. The MS/CS ratio was 0.4. Migration inhibitory factor immunoreactivity was found in different cell layers of the extraembryonic membranes.

CONCLUSIONS

The increased secretion of MIF in AF at term, particularly at term labor, suggests that MIF contributes to the inflammatory events leading to labor.

Macrophage migration inhibitory factor evaluation compared with prostate specific antigen as a biomarker in patients with prostate carcinoma

BACKGROUND

Cytokines are polypeptides that constitute a class of chemical mediator molecules that modulate cell growth by inducing specific target gene expression. The objective of this study was to evaluate the clinical usefulness of serum evaluation of the cytokine macrophage migration inhibitory factor (MIF) in patients undergoing routine prostate specific antigen (PSA) screening.

METHODS

In this preliminary, retrospective study, the authors report the development of an enzyme-linked immunosorbent assay (ELISA) for MIF determination in serum samples. A polymerase chain reaction (PCR)-based assay investigated associations between MIF expression and prostate carcinoma (CaP). The authors developed a relative quantitative reverse transcriptase-PCR assay to determine MIF mRNA amounts within laser-capture microscopy (LCM)-dissected prostate epithelial cells.

RESULTS

A comparison of serum MIF levels and total PSA levels identified a positive correlation (correlation coefficient [r2] = 0.61; P < 0.001; n = 509 patients), suggesting an association between elevated serum concentrations of these proteins and CaP. A correlation of serum MIF levels with a diagnosis of CaP demonstrated that patients with a previous CaP diagnosis had significantly elevated serum MIF concentrations (mean +/- standard deviation, 6.8 +/- 0.87 ng/mL; P < 0.001). To associate altered serum MIF levels with MIF mRNA expression within prostate epithelial cells, LCM-dissected prostate epithelial cells (formalin fixed biopsies from three different patients) were used to determine MIF mRNA amounts by PCR analysis. On average, MIF mRNA amounts were 6.5 times higher in CaP epithelial cells that were invasive to the margin compared with MIF mRNA amounts in normal prostate epithelial cells within the same biopsy specimen.

CONCLUSIONS

The ELISA data from the current study suggested an association between increased MIF expression and CaP and suggested that serum MIF concentration may serve as a prognostic marker for CaP.

High-dose corticosteroid administration induces increase of serum macrophage migration inhibitory factor in patients with Vogt-Koyanagi-Harada's disease

To investigate the influence of corticosteroid administration on the serum level of macrophage migration inhibitory factor (MIF), sera obtained from 9 patients with Vogt-Koyanagi-Harada's disease who had been treated with high-dose corticosteroid were analyzed. The serum MIF levels of most patients were prominently increased on day 7 and/or day 14 after corticosteroid treatment. No TNF-alpha was detected in the sera. The average serum MIF level of nine patients at the highest stages after corticosteroid administration was significantly higher than that before the corticosteroid treatment. It seems that MIF is a unique cytokine and acts together with corticosteroid to regulate inflammation and immunity.