rs3850641 — TNFSF4 TNFSF4 (OX40L) Intron 1 Variant

Intronic variant in TNFSF4 (OX40 ligand); homozygous G carriers show approximately 2-fold increased myocardial infarction risk in some populations

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OX40 Ligand and the Immune Gate of Atherosclerosis

TNFSF4 encodes OX40 ligand (OX40L, also called CD252), a co-stimulatory molecule of the TNF superfamily that serves as the key amplifier of T-cell activation in inflammatory settings. OX40L is expressed on antigen-presenting cells — particularly macrophages, dendritic cells, and vascular endothelial cells — and engages OX40 on activated CD4+ T cells to extend their survival, promote cytokine secretion, and drive clonal expansion. Within atherosclerotic plaques, OX40L expression is markedly elevated compared to healthy vascular tissue, driven by oxidized LDL and other inflammatory mediators.

The Mechanism

Anti-OX40L antibody blockade in LDL receptor-deficient mice11 Anti-OX40L antibody blockade in LDL receptor-deficient mice
Guo et al., Arterioscler Thromb Vasc Biol 2007 — anti-OX40L antibody reduced atherosclerotic lesion area by approximately 53% in Ldlr−/− mice by attenuating Th2-mediated responses and preserving anti-oxLDL IgM antibodies attenuated atherogenesis.

Elevated soluble OX40L (sOX40L) in circulation — released primarily from activated platelets — correlates with acute coronary syndrome severity, plaque instability, and elevated matrix metalloproteinase (MMP-9, MMP-3) levels, reinforcing OX40L as a biomarker of active plaque inflammation.

The Evidence

The variant was first implicated by Wang et al. in Nature Genetics 200522 Wang et al. in Nature Genetics 2005
Positional identification of TNFSF4, encoding OX40 ligand, as a gene that influences atherosclerosis susceptibility, which used positional cloning from the murine atherosclerosis susceptibility locus Ath1 to identify TNFSF4 as a human candidate gene. The rs3850641 G allele was significantly more frequent in MI cases than controls in two independent Swedish cohorts.

A Chinese Han case-control study (Li et al. Oncotarget 2018, PMID 29921578 — 454 cases, 512 controls)33 (Li et al. Oncotarget 2018, PMID 29921578 — 454 cases, 512 controls) found that homozygous GG carriers had significantly elevated MI risk (crude OR 2.00, 95% CI 1.04–3.86, P=0.039; adjusted OR 2.29, 95% CI 1.20–4.69, P=0.023), while the AG heterozygous genotype conferred no significant independent risk under additive or dominant models.

However, larger meta-analyses show overall null results in aggregate populations. A meta-analysis of 9 studies (Fu et al. 2016, PMID 27008001)44 meta-analysis of 9 studies (Fu et al. 2016, PMID 27008001) found allelic OR 1.10 (95% CI 0.96–1.27, P=0.174), and a systematic review of 11 studies covering 3,865 cases and 6,344 controls (Lu et al. 2018, PMID 29424751)55 systematic review of 11 studies covering 3,865 cases and 6,344 controls (Lu et al. 2018, PMID 29424751) found OR 1.02 (95% CI 0.89–1.17) for the G allele — no overall association. These null findings likely reflect population stratification (original signal primarily in European women), heterogeneity across disease definitions (CHD vs. MI specifically), and statistical power limitations for the rare GG genotype (only ~2% of individuals).

Evidence is classified as moderate — no established clinical guidelines and significant heterogeneity across populations.

Practical Actions

For GG homozygotes, the elevated MI risk under the recessive model (OR ~2) warrants proactive cardiovascular monitoring. Tracking inflammatory biomarkers such as hs-CRP and sOX40L alongside standard lipid panels provides the most relevant picture of vascular inflammatory burden for this genotype.

Interactions

rs2205960 and other upstream TNFSF4 promoter region SNPs (rs10912580, rs12039904, rs1234317) form a distinct haplotype block associated with systemic lupus erythematosus susceptibility, illustrating that TNFSF4 haplotypes have different disease consequences depending on which part of the regulatory region they tag.

Individuals carrying both rs3850641 GG and cardiovascular-risk variants in classical inflammatory pathways (e.g., IL-6 signaling genes, CRP variants) may have compounded atherosclerotic risk through synergistic immune activation in the vascular wall — an interaction that has not been formally studied but is mechanistically plausible given the T-cell co-stimulatory nature of the OX40L pathway.

Genotype Interpretations

What each possible genotype means for this variant.

AA Common Genotype Normal

Common genotype — no elevated OX40L-pathway risk

You carry two copies of the A reference allele at rs3850641, the most common genotype globally (approximately 74% of people). In population studies, the AA genotype is the reference group against which risk allele effects are measured. Meta-analyses of over 10,000 individuals find no elevated coronary heart disease or myocardial infarction risk for AA carriers compared to the general population at this locus.

AG G Allele Carrier Intermediate

One G allele — mildly elevated OX40L haplotype risk

Aggregate meta-analyses (>10,000 individuals) find no overall elevated CHD risk for the G allele across all genotypes combined, suggesting heterozygosity alone is insufficient to produce a detectable population-level risk signal. The sex-specific enrichment in women observed in the SCARF cohort is biologically plausible — estrogen signaling modulates OX40L expression on vascular endothelial cells, creating a sex-specific interaction.

GG Homozygous Risk High Risk

Two G alleles — elevated myocardial infarction risk under recessive model

The GG-specific OR of ~2 for MI was observed in the recessive model in a Chinese Han cohort.

Aggregate meta-analyses across all genotypes find no overall CHD association for the G allele.

The G allele is rarest in African populations (~8%) and most common in South Asian populations (~22%), affecting the GG frequency substantially across groups.