Association of TNFRSF1A and IFNLR1 Gene Polymorphisms with the Risk of Developing Breast Cancer and Clinical Pathologic Features.

Several genes have been associated with breast cancer (BC) susceptibility. The tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A), and interferon lambda receptor 1 (IFNLR1) genes encode receptors that mediate the action of inflammatory cytokines. Previous studies have demonstrated the association of the variants rs1800693 (TNFRSF1A) and rs4649203 (IFNLR1) with some inflammatory diseases. The present study aimed to verify a possible association of these variants with BC, its clinical pathologic features, as well as epidemiological data in a Brazilian population. A total of 243 patients and 294 individuals without history of BC were genotyped for these polymorphisms through TaqMan® SNP genotyping assays by qPCR. For the TNFRSF1A gene, no significant results were found. For IFNLR1, the AA genotype (p = 0.008) and the A allele (p = 0.02) were significantly associated with a lower risk of developing BC. When analyzing the age, it was observed that each increase of one year contributes to the development of BC (p < 0.001). Also, the smoking habit (p < 0.001) and body mass index (p = 0.018) increase the risk of disease development. Analyzing progesterone receptor factor an association was found with the AA genotype of the IFNLR1 (p = 0.02). The findings suggest that polymorphism in the immune-related IFNLR1 gene contribute to BC susceptibility in a Brazilian population. These findings can contribute to the further understanding of the role this gene and pathways in BC development.

Interferon III-related IL28RA variant is associated with rheumatoid arthritis and systemic lupus erythematosus and specific disease sub-phenotypes.

BACKGROUND: The interferon pathways have been commonly implicated in autoimmune disease development but the identity of the genes involved has not yet been fully clarified. Variation in genes involved in interferon pathways is expected to have a role in the etiology of these diseases. METHODS: The potential association of a polymorphism in the IL28RA gene, involved in these pathways, with susceptibility to systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and disease-related phenotypes was investigated in 603 Brazilian individuals (354 well-characterized SLE and RA patients, and 249 controls). IL28RA (rs4649203) variant was genotyped by TaqMan assay. Statistical analysis was performed including both diseases and a comprehensive list of patient clinical manifestations. RESULTS: The rs4649203-G (minor) allele was associated with SLE and RA occurrence and was shown to be a risk factor for serositis and anemia among SLE patients as well as a protective factor for rheumatoid vasculitis and rheumatoid nodules in RA patients, suggesting an association with a milder form of the disease. CONCLUSIONS: The IL28RA gene may contribute to SLE and RA susceptibility and to specific clinical manifestations of the diseases.

[Disseminated infection by M. tuberculosis complex in patient with IFN-γ receptor 1 complete deficiency]. / Infección diseminada por complejo M. tuberculosis en paciente con deficiencia completa del receptor 1 de interferón-γ.

BACKGROUND: Several mutations have been described leading to impaired immunity in the IL-12/IFN-γ axis and, they confer susceptibility to mycobacterial infections. One of the more serious clinical phenotypes is secondary to mutations at IFN-γ receptor 1 gene, characterized by an early onset and more severe disease. CLINICAL REPORT: We present a 3-month-old female patient with systemic M. tuberculosis complex who has a homozygous mutation, it affects the splicing site at IFNGR1 c.201-1G> T. At time of this report, she is with antimycobacterial treatment in the protocol of pluripotent hematopoietic cell transplantation (TCHP). CONCLUSION: It has been reported that antiphimic treatment should be maintained until the immune system is restored by the TCHP. If patients receive THCP before the age of 1 year old, they have a better prognosis. Diminish the levels of IFN-γ in plasma before the procedure is associated to better results.

Antecedentes: Se han descrito diversas mutaciones que llevan a inmunidad alterada en el eje interleucina 12/interferón gamma (IL-12/IFN-γ) y confieren susceptibilidad a infecciones por micobacterias. Uno de los fenotipos clínicos más graves es secundario a mutaciones en el gen del receptor 1 de IFN-γ, caracterizado por su inicio a temprana edad y mayor gravedad. Caso clínico: Paciente femenina de 3 meses de edad, con afección sistémica por complejo M. tuberculosis, en quien se identificó una mutación homocigota que afecta el sitio de splicing a nivel de IFNGR1 c.201-1G>T. Al momento de este reporte es manejada con antifímicos en un protocolo de trasplante de células hematopoyéticas pluripotenciales. Conclusión: Se ha informado que el tratamiento antifímico debe mantenerse hasta que se restaure el sistema inmunológico mediante trasplante de células hematopoyéticas pluripotenciales, cuyo mejor pronóstico se asocia con edad del receptor menor a un año y reducción de los niveles plasmáticos de IFN-γ.

Altered immune parameters correlate with infection-related hospitalizations in children with Down syndrome.

In addition to previously studied immunological variables, the relative expression of IFNGR2, IFNAR1, CD18, and CD275 (all encoded in chromosome 21) on circulating leucocytes and multifunctional T cells (evaluated by an intracellular cytokine/proliferation assay) were compared between children with Down syndrome (DS) and healthy controls (HC). As previously reported, numbers of lymphocytes, CD4(+) T cells, Treg cells, B cells, and levels of serum IgM were decreased, and levels of IgG and IgA were increased in children with DS. Moreover, the relative expression of CD18 on T and B cells (previously and not previously reported, respectively) were elevated in DS children (p⩽0.01). Age and numbers of B and Treg cells moderately correlated with retrospectively identified infection related hospitalizations (rho: 0.300-0.460, p⩽0.003). Age and the numbers of Treg cells also correlated with prospectively identified infection related hospitalizations. Future studies are necessary to clarify the role of these parameters in the immunity of DS patients.

Taenia crassiceps infection and its excreted/secreted products inhibit STAT1 activation in response to IFN-γ.

It is well understood that helminth infections modulate the immune responses of their hosts but the mechanisms involved in this modulation are not fully known. Macrophages and dendritic cells appear to be consistently affected during this type of infection and are common target cells for helminth-derived molecules. In this report, we show that macrophages obtained from chronically Taenia crassiceps-infected mice displayed an impaired response to recombinant murine IFN-γ, but not to recombinant murine IL-4, as measured based on the phosphorylation of STAT1 and STAT6, respectively. These macrophages expressed high levels of SOCS3. However, the inhibition of phosphatase activity by orthovanadate restored the IFN-γ response of these macrophages by increasing STAT1 phosphorylation without affecting SOCS3 expression. Therefore, we aimed to identify the phosphatases associated with IFN-γ signaling inhibition and found that macrophages from T. crassiceps-infected mice displayed enhanced SHP-1 expression. Interestingly, the exposure of naïve macrophages to T. crassiceps excreted/secreted products similarly interfered with IFN-γ-induced STAT1 phosphorylation. Moreover, macrophages exposed to T. crassiceps excreted/secreted products expressed high levels of SOCS3 as well as SHP-1. Strikingly, human peripheral blood mononuclear cells that were exposed to T. crassiceps excreted/secreted products in vitro also displayed impaired STAT1 phosphorylation in response to IFN-γ; again, phosphatase inhibition abrogated the T. crassiceps excreted/secreted product-altered IFN-γ signaling. These data demonstrate a new mechanism by which helminth infection and the products derived during this infection target intracellular pathways to block the response to inflammatory cytokines such as IFN-γ in both murine and human cells.

Association of genetic variants of membrane receptors related to recognition and induction of immune response with Helicobacter pylori infection in Ecuadorian individuals.

Helicobacter pylori (Hp) has a worldwide distribution showing its higher prevalence of infection in developing countries. Toll-like receptors (TLRs) and C-type lectin receptors (CLRs) are proteins that recognize pathogen-associated molecular patterns (PAMPs) and initiate an innate immune response by promoting growth and differentiation of specialized hematopoietic cells for host defense. Gastric infections led by Hp induce a Th-1 cellular immune response, regulated mainly by the expression of IFN-γ. In this retrospective case-control study, we evaluated the TLR1 1805T/G, TLR2 2029C/T, TLR4 896A/G, CD209 -336A/G and IFNGR1 -56C/T polymorphisms and their relationship with susceptibility to Hp infection. TLR1 1805T/G showed statistical differences when the control (Hp-) and infected (Hp+) groups (P = 0.041*) were compared; the TLR1 1805G allele had a protective effect towards infection (OR = 0.1; 95% CI = 0.01-0.88, P = 0.033*). Similarly, the IFNGR1 -56C/T polymorphism showed statistical differences between Hp+ and Hp- (P = 0.018*), and the IFNGR1 -56TT genotype exhibited significant risk to Hp infection (OR = 2.9, 95% CI = 1.27-6.54, P = 0.018*). In conclusion, the pro-inflammatory TLR1 1805T and IFNGR1 -56T alleles are related with susceptibility to Hp infection in Ecuadorian individuals. The presence of these polymorphisms in individuals with chronic infection increases the risk of cellular damage and diminishes the cellular immune response efficiency towards colonizing agents.

Association study of SNPs of genes IFNGR1 (rs137854905), GSTT1 (rs71748309), and GSTP1 (rs1695) in gastric cancer development in samples of patient in the northern and northeastern Brazil.

Cancer is a multifactorial disease with a high mortality rate in Brazil and worldwide. Gastric cancer (GC) is considered the fourth type of malignancy more frequent in the population worldwide and the second leading cause of death. This work aimed to evaluate single nucleotide polymorphisms (SNPs) of IFNGR1, GSTT1, and GSTP1 genes samples in gastric cancer. We analyzed 60 samples of gastric cancer, 26 diffuse and 34 intestinal types, totaling 120 alleles for each SNP. The results were obtained by PCR and allele-specific PCR. Statistical analyzes performed using BioEstat 5.0 software, applying the Fisher's exact test and chi-square. Only the SNP gene GSTP1 (rs1695) were significantly associated with gastric cancer in the samples analyzed (χ(2) = 8.73, P < 0.05). Our results suggest that the GSTP1 gene SNP (rs1695) can be considered a risk factor associated with gastric carcinogenesis.

Expression of interferon-γ, interferon-α and related genes in individuals with Down syndrome and periodontitis.

BACKGROUND: Recently, attenuation of anti-inflammatory and increase of pro-inflammatory mediators was demonstrated in individuals with Down syndrome (DS) in comparison with euploid patients during periodontal disease (PD), suggesting a shift to a more aggressive inflammation in DS. AIM: To determine the influence of DS in the modulation of interferons (IFNs) signaling pathway in PD. MATERIALS AND METHODS: Clinical periodontal assessment was performed and gingival tissue samples obtained from a total of 51 subjects, including 19 DS individuals with PD, 20 euploid individuals with PD and 12 euploid individuals without PD. Expression levels of interferon-gamma (IFNG) and interferon-alpha (IFNA), and their receptors IFNGR1, IFNGR2, IFNAR1 and IFNAR2, the signaling intermediates Janus kinase 1 (JAK1), signal transducer and activator of transcription 1 (STAT1) and interferon regulatory factor 1 (IRF1) were determined using real time quantitative polymerase chain reaction (qPCR). RESULTS: Clinical signs of periodontal disease were markedly more severe in DS and euploid patients with PD in comparison to euploid and periodontally healthy patients. There was no difference on mRNA levels of IFNA, IFNG, INFGR2, IFNAR1 and IFNAR2 between DS and euploid individuals, even though some of these genes are located on chromosome 21. STAT1 and IRF1 mRNA levels were significantly lower in DS patients in comparison with euploid individuals with PD. In euploid individuals, PD was associated with an increased expression of IFNGR1, IFNGR2, IFNAR1, STAT1 and IRF1. CONCLUSIONS: Reduced expression of STAT1 and IRF1 genes indicate an impaired activation of IFNs signaling in individuals with DS and PD. Expression of IFNA, IFNG and IFN receptors was not altered in DS patients, indicating that indirect mechanisms are involved in the reduced activation of IFN signaling.

A novel internalization motif regulates human IFN-γ R1 endocytosis.

This study tested the hypothesis that the IFN-γ R1 287-YVSLI-91 intracellular motif regulates its endocytosis. IFN-γ exerts its biological activities by interacting with a specific cell-surface RC composed of two IFN-γ R1 and two IFN-γ R2 chains. Following IFN-γ binding and along with the initiation of signal transduction, the ligand and IFN-γ R1 are internalized. Two major types of consensus-sorting signals are described in receptors, which are rapidly internalized from the plasma membrane to intracellular compartments: tyrosine-based and dileucine-based internalization motifs. Transfection of HEK 293 cells and IFN-γ R1-deficient fibroblasts with WT and site-directed, mutagenesis-generated mutant IFN-γ R1 expression vectors helped us to identify region IFN-γ R1 287-YVSLI-291 as the critical domain required for IFN-γ-induced IFN-γ R1 internalization and Y287 and LI290-291 as part of a common structure essential for receptor endocytosis and function. This new endocytosis motif, YxxLI, shares characteristics of tyrosine-based and dileucine-based internalization motifs and is highly conserved in IFN-γ Rs across species. The IFN-γ R1 270-LI-271 dileucine motif, previously thought to be involved in this receptor endocytosis, showed to be unnecessary for receptor endocytosis.

Genetic polymorphisms in mediators of inflammation and gastric precancerous lesions.

Chronic inflammation induced by Helicobacter pylori is a key process in gastric carcinogenesis. We hypothesized that genetic polymorphisms in important mediators of H. pylori-induced inflammation may influence the risk of developing various grades of precancerous lesions. We studied the associations between single nucleotide polymorphisms (SNPs) in cyclooxygenase 1 and 2 (PTGS1 and PTGS2), inducible nitric oxide synthase (NOS2A), interferon gamma (IFNG) and its receptor (IFNGR1), and risk of gastric precancerous lesions in a Venezuelan population characterized by high rates of H. pylori infection. We found no association of precancerous lesions with SNPs in PTGS1 and in IFNG. A nonsynonymous SNP of NOS2A (Ser608Leu) and an SNP located in the promoter of IFNGR1 (C-56T) were associated with higher risk of atrophic gastritis [odds ratio (OR)=1.37, 95% confidence interval (CI)=1.01-1.86, and OR=1.49, 95% CI=1.01-2.19, respectively]. Two SNPs of PTGS2 were associated with risk of dysplasia (OR=1.60, 95% CI=1.01-2.54, and OR=0.66, 95% CI=0.43-0.99). We conclude that genetic variability in the genes we studied does not play a major role in the early stages of gastric carcinogenesis.

Gangliosides of the stroma layer participate in the interferon-gamma receptor-dependent controls of myelopoiesis.

Stroma-mediated myelopoiesis depends upon growth-factors and an appropriate intercellular microenvironment, whose polarity is relevant for granulocyte-macrophage colony stimulating factor (GM-CSF) mediated myeloid cell proliferation. Here we have studied qualitative and quantitative aspects of ganglioside participation in controls of the microenvironment required to sustain myelopoiesis. We analysed ganglioside synthesis, expression and shedding by two primary liver stromal cell cultures isolated from wild type and interferon-gamma (IFNgamma) receptor knockout mice. The latter one has a higher capacity to sustain myelopoiesis. FDC-P1 myeloid growth factor-dependent cell line was used as the reporter system, monitoring the cell survival and proliferation that reflect the bio-availability and the activity of GM-CSF. Although the two stromal cells synthesised the same gangliosides their relative content was quite different. FDC-P1 proliferation decreased in cultures in which ganglioside synthesis was inhibited in the stroma, as well as in presence of stroma cell supernatants in which GM3 was neutralised by the anti-GM3 monoclonal antibody. Addition of exogenous GM3 reverted the inhibition and sustained proliferation of FDC-P1 cells. FDC-P1 cells do not accumulate GM3, but they are able to take up the stroma-produced sphingolipids. Thus, stroma has a double role in sustaining myelopoiesis, providing both growth factor(s) and ganglioside(s) required for the optimal stimulation of the myeloid cell proliferation, and the IFNgamma mediated stroma-dependent controls of myelopoiesis are determinant for this cell interaction.

Type I IFNs stimulate nitric oxide production and resistance to Trypanosoma cruzi infection.

The participation of type I IFNs (IFN-I) in NO production and resistance to Trypanosoma cruzi infection was investigated. Adherent cells obtained from the peritoneal cavity of mice infected by the i.p. route produced NO and IFN-I. Synthesis of NO by these cells was partially inhibited by treatment with anti-IFN-alphabeta or anti-TNF-alpha Abs. Compared with susceptible BALB/c mice, peritoneal cells from parasite-infected resistant C57BL/6 mice produced more NO (2-fold), IFN-I (10-fold), and TNF-alpha (3.5-fold). Later in the infection, IFN-I levels measured in spleen cell (SC) cultures from 8-day infected mice were greater in C57BL/6 than in infected BALB/c mice, and treatment of the cultures with anti-IFN-alphabeta Ab reduced NO production. IFN-gamma or IL-10 production by SCs was not different between the two mouse strains; IL-4 was not detectable. Treatment of C57BL/6 mice with IFN-I reduced parasitemia levels in the acute phase of infection. Mice deprived of the IFN-alphabetaR gene developed 3-fold higher parasitemia levels in the acute phase in comparison with control 129Sv mice. Production of NO by peritoneal macrophages and SCs was reduced in mice that lacked signaling by IFN-alphabeta, whereas parasitism of macrophages was heavier than in control wild-type mice. We conclude that IFN-I costimulate NO synthesis early in T. cruzi infection, which contributes to a better control of the parasitemia in resistant mice.

Defects in the interferon-gamma and interleukin-12 pathways.

The interferon-gamma (IFN-gamma)/interleukin-12 (IL-12) pathway is a pivotal player in the immune system and is central to controlling mycobacterial infections. We highlight the most recent and relevant advances in understanding this pathway and their repercussions on basic and clinical science. Human mutations in IFN-gamma receptor-1 (IFN-gammaR1), IFN-gammaR2, IL-12p40, IL-12 receptor-beta1, signal transducer and activator of transcription-1, and nuclear factor-kappaB essential modulator are analyzed in the context of genetic susceptibility to mycobacterial diseases. A diagnostic and therapeutic approach is described. The IFN-gamma/IL-12 pathway is central in immune control of both environmental and autochthonous challenges, as reflected in human mutations and animal models. Besides being crucial for mycobacterial control, the IFN-gamma/IL-12 pathway is also involved in the pathogenesis of autoimmune disease as well as tumor development and control. Genotype-phenotype correlations have been established for certain genes in this pathway, some of which have therapeutic implications.

Hematopoietic stem cell transplantation for complete IFN-gamma receptor 1 deficiency: a multi-institutional survey.

OBJECTIVES: To evaluate the outcome of hematopoietic stem cell transplantation (HSCT) in a series of patients with inherited complete IFN-gamma receptor 1 (IFNgammaR1) deficiency. STUDY DESIGN: We report 8 patients who received altogether 11 HSCT from family donors, including 10 HLA-identical (5 siblings and 5 relatives) and 1 HLA-haplo-identical donors. Five grafts were T-cell depleted, and conditioning regimens varied in intensity. RESULTS: Four patients died within 8 months after HSCT. Two of these deaths were due to specific complications related to mycobacterial infection. There was no or very low (2%) donor cell engraftment in 2 survivors. Only 2 patients are in full remission of mycobacterial disease 5 years after HSCT. These are the only patients who received non-T-cell-depleted grafts from an HLA-identical sibling after a fully myeloablative conditioning regimen. CONCLUSIONS: HSCT can lead to prolonged remission of mycobacterial disease in children with complete IFNgammaR1 deficiency. However, optimal control of mycobacterial infection before HSCT and the use of a non-T-cell-depleted transplant from an HLA-identical sibling after a fully myeloablative conditioning regimen are recommended.

Normal expression of IFN-gammaR in four patients with uncommon mycobacterial infection phenotypes.

Several primary immunodeficiency diseases affecting the interleukin 12/interferon gamma (IFN-gamma) pathway have been identified, most of them characterized by recurrent and protracted infections produced by intracellular microorganisms, particularly by several species of mycobacteria. In the present study we analyzed the expression of IFN-gamma receptor (IFN-gammaR) and signal transducer and activator of transcription 1 (STAT-1) in 4 children with Mycobacterium tuberculosis infection of uncommon clinical presentation. These molecules were evaluated by flow cytometry and Western blotting in B cells transformed with Epstein-Barr virus and mutations were scanned by single-strand conformational polymorphisms and DNA sequencing. The expression of IFN-gammaR1 was normal in all 4 patients. The genetic analysis of IFN-gammaR1 and IFN-gammaR2 coding sequences did not reveal any mutation. The expression of the STAT-1 molecule was similar in patients and healthy controls; however, when the phosphorylation of this transcription factor in response to IFN-gamma activation was evaluated by Western blot, a significant lower signal was evident in one patient. These data indicate that there are no alterations in the expression or function of the IFN-gammaR chains in these patients. However, the low level of STAT-1 phosphorylation found in one of these patients might be explained by a defect in one of the molecules involved in the signal transduction pathway after IFN-gamma interacts with its receptor. In the other three patients the inability to eliminate the mycobacteria may be due to a defect in another effector mechanism of the mononuclear phagocytes.

HHV-8-associated Kaposi sarcoma in a child with IFNgammaR1 deficiency.

OBJECTIVES: Mediterranean classic Kaposi sarcoma (KS) of childhood is rare and unexplained. Our objective is to describe the case of a child with complete IFNgammaR1 deficiency and severe mycobacterial disease in whom Kaposi sarcoma (KS) developed. RESULTS: Disseminated mycobacterial infection began at the age of 5 months, and at 11 years of age the child had disseminated KS lesions. The histologic appearance of these lesions was typical, with endothelial and spindle cell proliferation. Human herpesvirus-8 (HHV-8)-associated antigens were detected in situ by immunohistochemistry. HHV-8 DNA of K1 molecular subtype A was amplified from tissue lesions, and HHV-8-specific antibodies were detected in the patient's serum. The child died at 12 years of age of disseminated mycobacterial disease and KS. CONCLUSIONS: This is the first identification of a well-defined primary immunodeficiency in a child with KS. Inherited disorders of IFN-gamma-mediated immunity and severe mycobacterial disease may predispose HHV-8-infected children to KS.

Missense mutations of the interleukin-12 receptor beta 1(IL12RB1) and interferon-gamma receptor 1 (IFNGR1) genes are not associated with susceptibility to lepromatous leprosy in Korea

Interleukin-12 receptor beta 1 ( IL12RB1), interleukin-12 receptor beta 2 ( IL12RB2), and interferon gamma receptor 1 ( IFNGR1) perform important roles in the host defense against intracellular pathogens such as Mycobacteria. Several mutations within their genes have been confirmed as associated with increased susceptibility to mycobacterial infection. However, the association between mutations of the IL12RB1, IL12RB2, and IFNGR1 encoding genes and lepromatous leprosy has not been studied. This study screened for polymorphisms within IL12RB1, IL12RB2, and IFNGR1 encoding genes in the Korean populations using polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) DNA sequencing assay, and an association study was performed using the missense mutations of 705 A/G (Q214R), 1196 G/C (G378R), 1637 G/A (A525T), and 1664 C/T (P534S) of the IL12RB1, 83 G/A (V14M), and 1443 T/C (L467P) for the IFNGR1 encoding genes. There were no differences in the genotype and allele frequencies of IL12RB1 and IFNGR1 genes between 93 lepromatous leprosy patients and 94 control subjects. In conclusion, missense mutations of 705 A/G (Q214R), 1196 G/C (G378R), 1637 G/A (A525T), 1664 C/T (P534S) of the IL12RB1, 83 G/A (V14 M), and 1443 T/C (L467P) of the IFNGR1 encoding genes have no association with the susceptibility to lepromatous leprosy in the Korean population.

561del4 defines a novel small deletion hotspot in the interferon-gamma receptor 1 chain.

Patients with a dominant small deletion (818del4, hotspot) in the interferon-gamma receptor 1 (IFNGR1) gene (6q23-q24) and increased susceptibility to mycobacterial infections have been recently reported. We describe a female patient homozygous for a 4-bp deletion in exon 5 of IFNGR1 (561del4) who developed postvaccinal disseminated Bacille Calmette-Guerin infection. She was born to unrelated Argentinean parents, each of whom was heterozygous for this mutation. 561del4 has been previously described as a maternally inherited mutation in a compound heterozygous German patient. By single nucleotide polymorphism analysis of the areas surrounding the deletion, we showed the independent inheritance of 561del4 in three heterozygous carriers. Polypurine runs and "direct repeats," previously shown to be associated with areas of recurrent small deletions, were found in the flanking region of 561del4. The independent inheritance of three identical mutational events defines 561del4 as a new hotspot in the IFNGR1 gene.

Endogenous accumulation of IFN-gamma in IFN-gamma-R(-/-) mice increases resistance to B16F10-Nex2 murine melanoma: a model for direct IFN-gamma anti-tumor cytotoxicity in vitro and in vivo.

Syngeneic IFN-gamma(-/-) and IRF-1(-/-) mice are very sensitive to B16F10-Nex2 murine melanoma cells implanted subcutaneously. In contrast, IFN-gamma-R(-/-) (GRKO) mice are remarkably resistant to tumor development. Only 0-30% of these animals, challenged with a high dose of melanoma cells (5 x 10(5)), developed tumors at a late stage. The hypothesis of interferon gamma (IFN-gamma) accumulation and consequent cytotoxicity to implanted tumor cells was confirmed in vitro and ex vivo. IFN-gamma reduced tumor-cell growth in vitro in 60-81%, added alone or with LPS. Splenocytes and peritoneal macrophages from naïve GRKO mice activated with anti-CD3 and interleukin-12 (IL-12), respectively, accumulated IFN-gamma at levels 10-fold those of the wild-type. Supernatants of IL-12-activated macrophages from GRKO mice were toxic to B16F10-Nex2 cells, an effect reversible by anti-IFN-gamma antibody treatment. IL-12-activated macrophages from iNOS(-/-) mice were still highly cytotoxic to B16F10-Nex2 cells, but IL-12-activated macrophages from IFN-gamma-deficient mice were not inhibitory. In vivo, a single injection of anti-IFN-gamma antibody 18 h after tumor-cell challenge in GRKO mice rendered all animals susceptible to B16F10-Nex2 melanoma development. No tumors developed in the untreated GRKO mice during up to 45 days of observation. This model can be useful in understanding immune responses that involve IFN-gamma as a direct cytotoxic factor.

Interferon-gamma receptor deficiency mimicking Langerhans' cell histiocytosis.

Two patients who were initially given a diagnosis of Langerhans' cell histiocytosis on the basis of the clinical, radiologic, and biopsy findings had mycobacterial infection subsequently identified. The correct diagnosis of dominant partial interferon-gamma receptor deficiency was established.