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Naïve CD4+ T cells coordinate the immune response by acquiring an effector phenotype in response to cytokines. However, the cytokine responses in memory T cells remain largely understudied. Here we use quantitative proteomics, bulk RNA-seq, and single-cell RNA-seq of over 40,000 human naïve and memory CD4+ T cells to show that responses to cytokines differ substantially between these cell types. Memory T cells are unable to differentiate into the Th2 phenotype, and acquire a Th17-like phenotype in response to iTreg polarization. Single-cell analyses show that T cells constitute a transcriptional continuum that progresses from naïve to central and effector memory T cells, forming an effectorness gradient accompanied by an increase in the expression of chemokines and cytokines. Finally, we show that T cell activation and cytokine responses are influenced by the effectorness gradient. Our results illustrate the heterogeneity of T cell responses, furthering our understanding of inflammation., Cytokines critically control the differentiation and functions of activated naïve and memory T cells. Here the authors show, using multi-omics and single-cell analyses, that naïve and memory T cells exhibit distinct cytokine responses, in which an ‘effectorness gradient’ is depicted by a transcriptional continuum, which shapes the downstream genetic programs.

Multiple sclerosis is a neurodegenerative, autoimmune disease characterized by inrreversible neurological disability. The age at onset of multiple sclerosis is an objective and influential predictor of the evolution of multiple sclerosis independent of disease duration. Little is known about the mechanisms contributing to variation in onset age of multiple sclerosis, though HLA-DRB1*15:01, the predominant risk variant, confers an earlier onset. Here we present an age at onset genome-wide association analysis for 9.2 million variants, including gene-based and pathway enrichment analyses, for 3,495 cases who were non-Latinx white with onset ≥18 years. We investigated whether a higher burden of multiple sclerosis risk variants conferred an earlier age at onset for combinations of HLA-DRB1*15:01 alleles and quintiles of a genetic risk score for 200 risk variants that reside outside the major histocompatibility complex. The study population had a mean age at onset of 32 years, 29% was male, and 46% were HLA-DRB1*15:01 carriers. HLA-DRB1*15:01 carriers were on average one year younger at onset than non-carriers (pp-8). Those in the highest genetic risk score quintile (n=717) were on average 2.5 years younger at onset than those in the lowest quintile (n=698; p=1.2×10-7). For those with the greatest genetic risk burden (highest genetic risk score quintile with two HLA-DRB1*15:01 alleles) were on average five years younger at onset (p=0.002) than those with the lowest genetic risk burden (lowest genetic risk score quintile with no HLA-DRB1*15:01 alleles). There was an apparent inverse relationship between the genetic multiple sclerosis risk burden and age at onset of multiple sclerosis (p-8). We did not observe any individual variants reaching genome-wide significance in the genome-wide association analysis of age at onset. The most significantly associated independent genic loci (p-6) were located within HLA-DQB1, COL21A1, LINC01484, UBR3, and CSMD1. At the gene-level, the most significant associations (p-5) were for SSB, TRAFD1, HECTD2, MMP8, NAA25 and UBR3. There was an enrichment of genes involved in adaptive and innate immunity, specifically genes in the complement pathway, and genes involved in synapses and collagen biosynthesis. In summary, we demonstrated a significant gradient between elevated genetic risk burden and an earlier onset of multiple sclerosis.

Identifying biological correlates of late life cognitive function is important if we are to ascertain biomarkers for, and develop treatments to help reduce, age-related cognitive decline. Here, we investigated the associations between plasma levels of 90 neurology-related proteins (Olink® Proteomics) and general fluid cognitive ability in the Lothian Birth Cohort 1936 (LBC1936, N = 798), Lothian Birth Cohort 1921 (LBC1921, N = 165), and the INTERVAL BioResource (N = 4451). In the LBC1936, 22 of the proteins were significantly associated with general fluid cognitive ability (β between −0.11 and −0.17). MRI-assessed total brain volume partially mediated the association between 10 of these proteins and general fluid cognitive ability. In an age-matched subsample of INTERVAL, effect sizes for the 22 proteins, although smaller, were all in the same direction as in LBC1936. Plasma levels of a number of neurology-related proteins are associated with general fluid cognitive ability in later life, mediated by brain volume in some cases., Late-life cognitive dysfunction is common, but the biological substrates are largely unknown. Here, the authors examined a panel of 90 neurology-related protein biomarkers and show that plasma levels of 22 of these proteins are associated with general fluid cognitive ability in later life.

Neuromyelitis optica (NMO) is a rare autoimmune disease that affects the optic nerve and spinal cord. Most NMO patients ( > 70%) are seropositive for circulating autoantibodies against aquaporin 4 (NMO-IgG+). Here, we meta-analyze whole-genome sequences from 86 NMO cases and 460 controls with genome-wide SNP array from 129 NMO cases and 784 controls to test for association with SNPs and copy number variation (total N = 215 NMO cases, 1244 controls). We identify two independent signals in the major histocompatibility complex (MHC) region associated with NMO-IgG+, one of which may be explained by structural variation in the complement component 4 genes. Mendelian Randomization analysis reveals a significant causal effect of known systemic lupus erythematosus (SLE), but not multiple sclerosis (MS), risk variants in NMO-IgG+. Our results suggest that genetic variants in the MHC region contribute to the etiology of NMO-IgG+ and that NMO-IgG+ is genetically more similar to SLE than MS., Neuromyelitis optica (NMO) is a rare autoimmune condition characterized by inflammation and demyelination of the optic nerve and the spinal cord. Here, Estrada et al. identify NMO susceptibility variants in the MHC region and find that autoantibody-positive NMO genetically overlaps with lupus.

CLEC16A, a putative immunoreceptor, was recently established as a susceptibility locus for type I diabetes and multiple sclerosis. Subsequently, associations between CLEC16A and rheumatoid arthritis (RA), Addison’s disease and Crohn’s disease have been reported. A large comprehensive and independent investigation of CLEC16A variation in RA was pursued. This study tested 251 CLEC16A single-nucleotide polymorphisms in 2542 RA cases (85% anti-cyclic citrullinated peptide (anti-CCP) positive) and 2210 controls (N = 4752). All individuals were of European ancestry, as determined by ancestry informative genetic markers. No evidence for significant association between CLEC16A variation and RA was observed. This is the first study to fully characterize common genetic variation in CLEC16A including assessment of haplotypes and gender-specific effects. The previously reported association between RA and rs6498169 was not replicated. Results show that CLEC16A does not have a prominent function in susceptibility to anti-CCP-positive RA.

Background: Previous linkage studies have shown that chromosome 12 harbors susceptibility genes for late-onset Alzheimer disease (LOAD). However, association studies of several candidate genes on this chromosome region have produced ambiguous results. A recent study reported the association between the glyceraldehyde-3-phosphate dehydrogenase ( GAPD ) gene on chromosome 12p and the risk of LOAD. Methods: The authors conducted family-based and case-control association studies in two independent LOAD data sets on 12 single-nucleotide polymorphisms (SNPs) in the GAPD gene and its paralogs. Results: No association was found of the GAPD gene with LOAD in the family-based data set, but marginal evidence of association was seen in the later-onset subgroup when age at onset was stratified. The SNP rs2029721 in one GAPD pseudogene was also found to be associated with risk for LOAD in the unrelated case-control data set ( p = 0.003). Conclusions: The GAPD gene and its pseudogene may play a role in the development of late-onset Alzheimer disease. However, the effect, if any, is likely to be limited.

Alzheimer disease (AD) is a progressive neurodegenerative disorder of later life with a complex etiology and a strong genetic component. Several genomic screens have suggested that a region between chromosome 12p13 and 12q22 contains at least one additional locus underlying the susceptibility of AD. However, localization of this locus has been difficult. We performed a 5 cM microsatellite marker screen across 74 cM on chromosome 12 with 15 markers in 585 multiplex families consisting of 994 affected sibpairs and 213 other affected relative pairs. Analyses across the entire data set did not reveal significant evidence of linkage. However, suggestive linkage was observed in several subsets. In the 91 families where no affected individuals carry an ApoE varepsilon4 allele, an HLOD score of 1.55 was generated at D12S1042. We further examined the linkage data considering the proposed linkages to chromosome 9 (D9S741) and chromosome 10 (alpha-catenin gene). There was a modest (P=0.20) increase in the LOD score for D12S368 (MLOD=1.70) when using the D9S741 LOD scores as a covariate and a highly significant (P0.001) increase in the MLOD score (4.19) for D12S1701 in autopsy-confirmed families (n=228) when using alpha-catenin LOD scores as a covariate. In both cases, families with no evidence of linkage to D9S741 or alpha-catenin demonstrated most of the evidence of linkage to chromosome 12, suggesting locus heterogeneity. Taken together, our data suggest that the 16 cM region between D12S1042 and D12S368 should be the subject of further detailed genomic efforts for the disease.

The major histocompatibility complex (MHC) class II transactivator gene (CIITA) encodes an important transcription factor regulating genes required for human leukocyte antigen (HLA) class II MHC-restricted antigen presentation. Major histocompatibility complex (MHC) genes, particularly HLA class II, are strongly associated with risk of developing rheumatoid arthritis (RA). Given the strong biological relationship between CIITA and HLA class II genes, a comprehensive investigation of CIITA variation in RA was conducted. This study tested 31 CIITA SNPs in 2542 RA cases and 3690 controls (N = 6232). All individuals were of European ancestry, as determined by ancestry informative genetic markers. No evidence for association between CIITA variation and RA was observed after a correction for multiple testing was applied. This is the largest study to fully characterize common genetic variation in CIITA, including an assessment of haplotypes. Results exclude even a modest role for common CIITA polymorphisms in susceptibility to RA.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by autoantibodies to nuclear and cell surface antigens. Although the etiology of SLE remains unknown, evidence for genetic susceptibility is well established. The HLA class II alleles DRB1*1501, *0301, and *0801 and the HLA class I alleles A*01 and B*08 in the major histocompatibility complex (MHC) region are consistently associated with SLE. HLA loci may also influence SLE through additional inherited or noninherited mechanisms. Differences in maternal and paternal transmission rates, or parent-of-origin effects, have not been previously examined in SLE. One potential mechanism influencing disease susceptibility is “genomic imprinting” due to epigenetic modification of the genome. This modification results in unequal transcription of parental alleles and subsequent allele expression, depending on whether alleles were transmitted from the mother or from the father. Increased HLA compatibility between a mother and her offspring is hypothesized to contribute to the risk of autoimmune disease. Maternal–offspring effects can present as excess HLA compatibility between the mother and affected offspring (Figure 1). In mice, HLA similarity between mother and fetus has been shown to promote the persistence of maternal cells in the offspring (maternal microchimerism) following pregnancy (1). Figure 1 Maternal–offspring HLA compatibility relationships. The developing immune system of the fetus is also directly exposed to noninherited maternal antigens (NIMAs) in utero (2). Exposure to NIMAs can have a lifelong influence on the immune system and has been theorized to tolerize or predispose to autoimmune reactions. A tolerogenic effect may explain the longer survival of renal transplants from sibling donors expressing NIMAs versus noninherited paternal HLA. Decreased B cell responses to HLA class I NIMAs in humans have been reported (3). Recent data suggest that fetuses may also develop T cell tolerance to NIMAs in utero through tolerogenic fetal regulatory T cells that are maintained throughout life (4). The aim of this study was to test the hypothesis that the DRB1 locus influences SLE through these novel biologic mechanisms in addition to genetic transmission of particular HLA risk alleles.

Aim: Type 1 diabetes (T1D) is a complex trait for which variation in the classical human leucocyte antigen (HLA) loci within the Major Histocompatibility Complex (MHC) significantly influences disease risk. To date, HLA class II DR-DQ genes confer the strongest known genetic effect in T1D. HLA loci may also influence T1D through additional inherited or non-inherited effects. Evidence for the role of increased maternal–offspring HLA compatibility, and both parent-of-origin (POO) and non-inherited maternal HLA (NIMA) effects in autoimmune disease has been previously established. The current study tested hypotheses that classical HLA loci influence T1D through these mechanisms, in addition to genetic transmission of particular risk alleles. Methods: The Type 1 Diabetes Genetics Consortium (T1DGC) cohort was of European descent and consisted of 2271 affected sib-pair families (total n = 11 023 individuals). Class I genes HLA-A, Cw and B, and class II genes HLA-DRB1, DQA1, DQB1, DPA1 and DPB1 were studied. The pedigree disequilibrium test was used to examine transmission of HLA alleles to individuals with T1D. Conditional logistic regression was used to model compatibility relationships between mother–offspring and father–offspring for all HLA loci. POO and NIMA effects were investigated by comparing frequencies of maternal and paternal transmitted and non-transmitted HLA alleles for each locus. Analyses were also stratified by gender of T1D-affected offspring. Results: Strong associations were observed for all classical HLA loci except for DPA1, as expected. Compatibility differences between mother–offspring and father–offspring were not observed for any HLA loci. Furthermore, POO and NIMA HLA effects influencing T1D were not present. Conclusions: Maternal–offspring HLA compatibility, POO and NIMA effects for eight classical HLA loci were investigated. Results suggest that these HLA-related effects are unlikely to play a major role in the development of T1D.

Alzheimer disease (AD) is heterogeneous and complex with a strong genetic diathesis. It is the most common cause of dementia affecting the elderly. Linkage studies [Kehoe et al., 1999; Hum Mol Genet 8: 237-245]; [Pericak-Vance et al., 2000; Exp Gerontol 35: 1343-1352]; [Myers et al., 2002; Am J Med Genet 114: 235-244]; [Blacker et al., 2003; Hum Mol Genet 12: 23-32] identified chromosome 9q as a region containing a possible AD candidate gene. Functional protein studies [Mah et al., 2000; J Cell Biol 151: 847-862]; [Ko et al., 2002; J Biol Chem 277: 35386-35392] identified the UBQLN1 gene on chromosome 9q that encodes ubiquilin as a likely candidate for a role in late-onset AD pathogenesis. A recent family-based study by [Bertram et al., 2005; N Engl J 352: 884-894] reported genetic association and expression evidence for a putative AD risk allele of an intronic single nucleotide polymorphism (SNP) within the UBQLN1 gene. In this study, we comprehensively assessed whether any of seven polymorphisms located across the UBQLN1 gene are associated with AD in another large family-based data set and an independent case-control data set. We found no significant association of AD risk with any of the seven SNPs genotyped (including those SNPs previously reported by Bertram et al.) in either the family-based or case-control data set. Age-specific analyses and analyses conditional on Apolipoprotein E (ApoE) genotype and sex also revealed no significant associations to AD risk in either data set. Using age at onset (AAO) as a quantitative trait revealed a modest age modifying association; however, the results were inconsistent between the data sets. Our results suggest that UBQLN1 variants do not increase risk for AD in these data.