A Novel Microbiome Signature in Gastric Cancer: A Two Independent Cohort Retrospective Analysis.

OBJECTIVE: The microbiome is hypothesized to have a significant impact on cancer development. In gastric cancer (GC), Helicobacter pylori is an established class I carcinogen. However, additional organisms in the intratumoral microbiome play an important role in GC pathogenesis and progression. In this study, we characterize the full spectrum of the microbes present within GC and identify distinctions among molecular subtypes. METHODS: A microbiome bioinformatics pipeline that is generalizable across multiple next-generation sequencing platforms was developed. Microbial profiles for alpha diversity and enrichment were generated for 2 large, demographically distinct cohorts: (1) internal Memorial Sloan Kettering Cancer Center (MSKCC) and (2) The Cancer Genome Atlas (TCGA) cohorts. A total of 520 GC samples were compared with select tumor-adjacent nonmalignant samples. Microbiome differences among the GC molecular subtypes were identified. RESULTS: Compared with nonmalignant samples, GC had significantly decreased microbial diversity in both MSKCC and TCGA cohorts ( P <0.05). Helicobacter , Lactobacillus , Streptococcus , Prevotella , and Bacteroides were significantly more enriched in GC samples when compared with nonmalignant tissue ( P <0.05). Microsatellite instability-high GC had distinct microbial enrichment compared with other GC molecular subtypes. CONCLUSION: Distinct patterns of microbial diversity and species enrichment were identified in patients with GC. Given the varied spectrum of disease progression and treatment response of GC, understanding unique microbial signatures will provide the landscape to explore key microbial targets for therapy.

Genome-wide CRISPR screens of T cell exhaustion identify chromatin remodeling factors that limit T cell persistence.

T cell exhaustion limits antitumor immunity, but the molecular determinants of this process remain poorly understood. Using a chronic stimulation assay, we performed genome-wide CRISPR-Cas9 screens to systematically discover regulators of T cell exhaustion, which identified an enrichment of epigenetic factors. In vivo CRISPR screens in murine and human tumor models demonstrated that perturbation of the INO80 and BAF chromatin remodeling complexes improved T cell persistence in tumors. In vivo Perturb-seq revealed distinct transcriptional roles of each complex and that depletion of canonical BAF complex members, including Arid1a, resulted in the maintenance of an effector program and downregulation of exhaustion-related genes in tumor-infiltrating T cells. Finally, Arid1a depletion limited the acquisition of exhaustion-associated chromatin accessibility and led to improved antitumor immunity. In summary, we provide an atlas of the genetic regulators of T cell exhaustion and demonstrate that modulation of epigenetic state can improve T cell responses in cancer immunotherapy.

Immune Checkpoint Inhibitors for Cancer Therapy in the COVID-19 Era.

The potential immune intersection between COVID-19 disease and cancer therapy raises important practical clinical questions and highlights multiple scientific gaps to be filled. Among available therapeutic approaches to be considered, immune checkpoint inhibitors (ICI) seem to require major attention as they may act at the crossroads between cancer treatment and COVID-19 disease, due to their profound immunomodulatory activity. On the basis of available literature evidence, we suggest guidance to consider for treating physicians, and propose areas of clinical and preclinical investigation. Comprehensively, although with the necessary caution, ICI therapy seems to remain a suitable therapeutic option for patients with cancer during the COVID-19 pandemic.

Impact of Prophylactic Levofloxacin on Rates of Bloodstream Infection and Fever in Neutropenic Patients with Multiple Myeloma Undergoing Autologous Hematopoietic Stem Cell Transplantation.

Few studies have evaluated the role of antibacterial prophylaxis during neutropenia in patients with multiple myeloma undergoing autologous hematopoietic stem cell transplantation (HSCT). At our center, levofloxacin prophylaxis was initiated in June 2006 in patients with myeloma who were undergoing autologous HSCT. We compared the incidence of bloodstream infection (BSI) and fever and neutropenia (FN) within 30 days of transplantation before (January 2003 to May 2006) and after (June 2006 to April 2010) the initiation of levofloxacin prophylaxis in patients undergoing autologous HSCT for myeloma. We also compared rates of BSI and FN during the same time periods in autologous HSCT recipients with lymphoma who did not receive antibacterial prophylaxis during either time period. After the initiation of levofloxacin prophylaxis, the BSI rate decreased from 41.2% (49 of 119) to 14.7% (23 of 156) and the rate of FN decreased from 91.6% to 60.9% in patients with myeloma (P < .001, for each). In contrast, rates of BSI (43.1% versus 47.3%; P = .50) and FN (98.8% versus 97.1%; P = .63) did not change in patients with lymphoma. Levofloxacin prophylaxis was independently associated with decreased odds of BSI (odds ratio, .27; 95% confidence interval, .14 to .51; P < .001) and FN (odds ratio, .18; 95% confidence interval, .09 to .36; P < .001) in multivariate analysis. Patients with myeloma had a nonsignificant increase in the risk of BSI due to levofloxacin-resistant Enterobacteriaceae (5% versus 1%, P = .08) and Clostridium difficile infection (7% versus 3%, P = .12) after the initiation of levofloxacin prophylaxis but did not have higher rates of BSI due to other resistant bacteria. Levofloxacin prophylaxis is associated with decreased risk of BSI and FN in patients with myeloma undergoing autologous HSCT.

Interference with Ca(2+) release activated Ca(2+) (CRAC) channel function delays T-cell arrest in vivo.

Entry of lymphocytes into secondary lymphoid organs (SLOs) involves intravascular arrest and intracellular calcium ion ([Ca(2+)]i) elevation. TCR activation triggers increased [Ca(2+)]i and can arrest T-cell motility in vitro. However, the requirement for [Ca(2+)]i elevation in arresting T cells in vivo has not been tested. Here, we have manipulated the Ca(2+) release-activated Ca(2+) (CRAC) channel pathway required for [Ca(2+)]i elevation in T cells through genetic deletion of stromal interaction molecule (STIM) 1 or by expression of a dominant-negative ORAI1 channel subunit (ORAI1-DN). Interestingly, the absence of CRAC did not interfere with homing of naïve CD4(+) T cells to SLOs and only moderately reduced crawling speeds in vivo. T cells expressing ORAI1-DN lacked TCR activation induced [Ca(2+)]i elevation, yet arrested motility similar to control T cells in vitro. In contrast, antigen-specific ORAI1-DN T cells had a twofold delayed onset of arrest following injection of OVA peptide in vivo. CRAC channel function is not required for homing to SLOs, but enhances spatiotemporal coordination of TCR signaling and motility arrest.

Mitochondrial and plasma membrane pools of stomatin-like protein 2 coalesce at the immunological synapse during T cell activation.

Stomatin-like protein 2 (SLP-2) is a member of the stomatin-prohibitin-flotillin-HflC/K (SPFH) superfamily. Recent evidence indicates that SLP-2 is involved in the organization of cardiolipin-enriched microdomains in mitochondrial membranes and the regulation of mitochondrial biogenesis and function. In T cells, this role translates into enhanced T cell activation. Although the major pool of SLP-2 is associated with mitochondria, we show here that there is an additional pool of SLP-2 associated with the plasma membrane of T cells. Both plasma membrane-associated and mitochondria-associated pools of SLP-2 coalesce at the immunological synapse (IS) upon T cell activation. SLP-2 is not required for formation of IS nor for the re-localization of mitochondria to the IS because SLP-2-deficient T cells showed normal re-localization of these organelles in response to T cell activation. Interestingly, upon T cell activation, we found the surface pool of SLP-2 mostly excluded from the central supramolecular activation complex, and enriched in the peripheral area of the IS where signalling TCR microclusters are located. Based on these results, we propose that SLP-2 facilitates the compartmentalization not only of mitochondrial membranes but also of the plasma membrane into functional microdomains. In this latter location, SLP-2 may facilitate the optimal assembly of TCR signalosome components. Our data also suggest that there may be a net exchange of membrane material between mitochondria and plasma membrane, explaining the presence of some mitochondrial proteins in the plasma membrane.

Self-reactive human CD4 T cell clones form unusual immunological synapses.

Recognition of self-peptide-MHC (pMHC) complexes by CD4 T cells plays an important role in the pathogenesis of many autoimmune diseases. We analyzed formation of immunological synapses (IS) in self-reactive T cell clones from patients with multiple sclerosis and type 1 diabetes. All self-reactive T cells contained a large number of phosphorylated T cell receptor (TCR) microclusters, indicative of active TCR signaling. However, they showed little or no visible pMHC accumulation or transport of TCR-pMHC complexes into a central supramolecular activation cluster (cSMAC). In contrast, influenza-specific T cells accumulated large quantities of pMHC complexes in microclusters and a cSMAC, even when presented with 100-fold lower pMHC densities. The self-reactive T cells also maintained a high degree of motility, again in sharp contrast to virus-specific T cells. 2D affinity measurements of three of these self-reactive T cell clones demonstrated a normal off-rate but a slow on-rate of TCR binding to pMHC. These unusual IS features may facilitate escape from negative selection by self-reactive T cells encountering very small amounts of self-antigen in the thymus. However, these same features may enable acquisition of effector functions by self-reactive T cells encountering large amounts of self-antigen in the target organ of the autoimmune disease.

Functional anatomy of T cell activation and synapse formation.

T cell activation and function require a structured engagement of antigen-presenting cells. These cell contacts are characterized by two distinct dynamics in vivo: transient contacts resulting from promigratory junctions called immunological kinapses or prolonged contacts from stable junctions called immunological synapses. Kinapses operate in the steady state to allow referencing to self-peptide-MHC (pMHC) and searching for pathogen-derived pMHC. Synapses are induced by T cell receptor (TCR) interactions with agonist pMHC under specific conditions and correlate with robust immune responses that generate effector and memory T cells. High-resolution imaging has revealed that the synapse is highly coordinated, integrating cell adhesion, TCR recognition of pMHC complexes, and an array of activating and inhibitory ligands to promote or prevent T cell signaling. In this review, we examine the molecular components, geometry, and timing underlying kinapses and synapses. We integrate recent molecular and physiological data to provide a synthesis and suggest ways forward.

Galectin-3 negatively regulates TCR-mediated CD4+ T-cell activation at the immunological synapse.

We have investigated the function of endogenous galectin-3 in T cells. Galectin-3-deficient (gal3(-/-)) CD4(+) T cells secreted more IFN-gamma and IL-4 than gal3(+/+)CD4(+) T cells after T-cell receptor (TCR) engagement. Galectin-3 was recruited to the cytoplasmic side of the immunological synapse (IS) in activated T cells. In T cells stimulated on supported lipid bilayers, galectin-3 was primarily located at the peripheral supramolecular activation cluster (pSMAC). Gal3(+/+) T cells formed central SMAC on lipid bilayers less effectively and adhered to antigen-presenting cells less firmly than gal3(-/-) T cells, suggesting that galectin-3 destabilizes the IS. Galectin-3 expression was associated with lower levels of early signaling events and phosphotyrosine signals at the pSMAC. Additional data suggest that galectin-3 potentiates down-regulation of TCR in T cells. By yeast two-hybrid screening, we identified as a galectin-3-binding partner, Alix, which is known to be involved in protein transport and regulation of cell surface expression of certain receptors. Co-immunoprecipitation confirmed galectin-3-Alix association and immunofluorescence analysis demonstrated the translocation of Alix to the IS in activated T cells. We conclude that galectin-3 is an inhibitory regulator of T-cell activation and functions intracellularly by promoting TCR down-regulation, possibly through modulating Alix's function at the IS.

T cell antigen receptor signaling and immunological synapse stability require myosin IIA.

Immunological synapses are initiated by signaling in discrete T cell antigen receptor microclusters and are important for the differentiation and effector functions of T cells. Synapse formation involves the orchestrated movement of microclusters toward the center of the contact area with the antigen-presenting cell. Microcluster movement is associated with centripetal actin flow, but the function of motor proteins is unknown. Here we show that myosin IIA was necessary for complete assembly and movement of T cell antigen receptor microclusters. In the absence of myosin IIA or its ATPase activity, T cell signaling was interrupted 'downstream' of the kinase Lck and the synapse was destabilized. Thus, T cell antigen receptor signaling and the subsequent formation of immunological synapses are active processes dependent on myosin IIA.

The coreceptor CD2 uses plasma membrane microdomains to transduce signals in T cells.

The interaction between a T cell and an antigen-presenting cell (APC) can trigger a signaling response that leads to T cell activation. Prior studies have shown that ligation of the T cell receptor (TCR) triggers a signaling cascade that proceeds through the coalescence of TCR and various signaling molecules (e.g., the kinase Lck and adaptor protein LAT [linker for T cell activation]) into microdomains on the plasma membrane. In this study, we investigated another ligand-receptor interaction (CD58-CD2) that facilities T cell activation using a model system consisting of Jurkat T cells interacting with a planar lipid bilayer that mimics an APC. We show that the binding of CD58 to CD2, in the absence of TCR activation, also induces signaling through the actin-dependent coalescence of signaling molecules (including TCR-zeta chain, Lck, and LAT) into microdomains. When simultaneously activated, TCR and CD2 initially colocalize in small microdomains but then partition into separate zones; this spatial segregation may enable the two receptors to enhance signaling synergistically. Our results show that two structurally distinct receptors both induce a rapid spatial reorganization of molecules in the plasma membrane, suggesting a model for how local increases in the concentration of signaling molecules can trigger T cell signaling.

Modulation of T cell activation by stomatin-like protein 2.

T cell activation through the Ag receptor (TCR) requires sustained signaling from signalosomes within lipid raft microdomains in the plasma membrane. In a proteomic analysis of lipid rafts from human T cells, we identified stomatin-like protein (SLP)-2 as a candidate molecule involved in T cell activation through the Ag receptor. In this study, we show that SLP-2 expression in human primary lymphocytes is up-regulated following in vivo and ex vivo activation. In activated T cells, SLP-2 interacts with components of TCR signalosomes and with polymerized actin. More importantly, up-regulation of SLP-2 expression in human T cell lines and primary peripheral blood T cells increases effector responses, whereas down-regulation of SLP-2 expression correlates with loss of sustained TCR signaling and decreased T cell activation. Our data suggest that SLP-2 is an important player in T cell activation by ensuring sustained TCR signaling, which is required for full effector T cell differentiation, and point to SLP-2 as a potential target for immunomodulation.

TNFA-308G>A polymorphism influences the TNF-alpha response to altered vaginal flora.

OBJECTIVE: To investigate the association between a tumor necrosis factor-alpha (TNF-alpha) gene polymorphism, vaginal TNF-alpha level, and microbial flora in pregnant women. METHODS: Vaginal samples from 203 women at 18-22 weeks' gestation were analyzed for microflora. TNFA-308G>A polymorphism was analyzed by polymerase chain reaction and restriction endonuclease analysis and TNF-alpha concentration was determined by ELISA. Outcome data were subsequently obtained. RESULTS: The vaginal TNF-alpha concentration was elevated in TNFA-308A carriers only in the presence of abnormal vaginal flora. A median TNF-alpha level of 10.94 pg/ml in TNFA-308A carriers with bacterial vaginosis (BV) was significantly higher than that of 1.77 pg/ml in TNFA-308A carriers without BV (P=.02), and 1.72 pg/ml in TNF-308G homozygotes with BV (P=.01). CONCLUSION: The TNFA-308G>A polymorphism influences the local TNF-alpha response to altered vaginal microflora. This suggests that the nature of the host response to microbial invasion in the lower female genital is genetically determined.

Association of a maternal CD14 -159 gene polymorphism with preterm premature rupture of membranes and spontaneous preterm birth in multi-fetal pregnancies.

CD14, the major receptor for bacterial lipopolysaccharide (LPS) as well as other microbial antigens, is a component of the innate immune system. We hypothesized that a single nucleotide C>T polymorphism at position -159 in the CD14 gene that results in elevated CD14 production would influence susceptibility to preterm premature rupture of membranes (PPROM) and spontaneous preterm birth (SPTB) in multi-fetal pregnancies. DNA from 107 mother-twin and three mother-triplet pairs was analyzed. Pregnancy outcomes were obtained after completion of testing. CD14*T homozygosity was present in 39.3% of 28 women whose pregnancies ended with PPROM, as opposed to 18.1% of 72 pregnancies without a SPTB (P=0.03). There was no relation between the fetal CD14 genotype and PPROM. The likelihood ratio (LR) for PPROM was 2.2 for women homozygous for CD14*T. The LR increased to 3.3 and 3.6 if the CD14 polymorphism was present in combination with previously determined maternal polymorphisms in the genes coding for the inducible 70kDa heat shock protein (hsp70-2) and the interleukin-1 receptor antagonist (IL1RN), respectively. Thus, an enhanced maternal pro-inflammatory immune response to LPS may increase susceptibility to PPROM in multi-fetal pregnancies.

Association between fetal interleukin-1 receptor antagonist gene polymorphism and unexplained fetal death.

OBJECTIVE: In spite of extensive clinical examinations or autopsies, as many as 15% to 40% of stillbirths remain unexplained. A systemic fetal inflammatory response is an independent risk factor for severe neonatal morbidity, mediated by proinflammatory cytokines. As a major anti-inflammatory cytokine, interleukin-1 receptor antagonist (IL-1ra) plays a crucial role modulating the proinflammatory response. The gene coding for IL-1ra (IL1RN) is polymorphic. We hypothesized that fetal possession of a specific allele, IL-1RN*2, associated with increased proinflammatory responses, may increase susceptibility to intrauterine fetal death. STUDY DESIGN: Fetal kidney cells were obtained from paraffin blocks of 27 unexplained stillbirths. DNA was isolated and tested for IL-1RN genotypes by polymerase chain reaction. As a control group, DNA from 302 live births was also tested. RESULTS: There was an enhanced rate of IL-1RN*2 homozygocity, 41%, among unexplained stillbirths compared with the control group, 8.6% (P < .001). Histologic analysis of fetal tissues demonstrated a predominant proinflammatory response in IL-1RN*2 homozygote fetuses. Extensive screening (microbiology, maternal serology, placenta histology) did not identify any specific trigger agent. CONCLUSION: There is an association between unexplained stillbirth and fetal homozygous IL1RN*2 carriage.

Clara cell protein 16 concentration in mid-trimester amniotic fluid: association with fetal gender, fetal G>A +38 CC16 gene polymorphism and pregnancy outcome.

Clara cell protein 16 (CC16) is a major immunomodulatory protein produced in the fetal lung. We hypothesized that the mid-trimester amniotic fluid concentration of CC16 would vary according to a +38 CC16 polymorphism in the fetal genome and that increased levels would be an early indicator of subsequent adverse pregnancy outcome. Mid-trimester singleton amniotic fluids from 244 women were assayed for CC16 by ELISA. DNA from fetal cells in 179 amniotic fluids were tested for the A>G polymorphism at position +38 in exon 1 by PCR. Outcome data were obtained from 233 women after completion of laboratory testing. Median CC16 levels were higher in amniotic fluids containing male fetuses than in those with females (p=0.0005). Median amniotic fluid CC16 levels were higher in Hispanics than in Whites and Asians (p<0.05). CC16*G homozygosity was associated with elevated amniotic fluid CC16 concentrations compared to CC16*A homozygotes (p=0.02). Intraamniotic CC16 levels were highest in pregnancies that subsequently resulted in preterm premature rupture of membranes (PPROM) (p=0.01). We conclude that mid-trimester intraamniotic CC16 concentrations vary by gender, ethnicity and fetal CC16 gene polymorphism. Elevated CC16 levels are predictive of subsequent development of PPROM.

A single nucleotide A>G polymorphism at position -670 in the Fas gene promoter: relationship to preterm premature rupture of fetal membranes in multifetal pregnancies.

OBJECTIVE: The relationship between a polymorphism at position -670 in the Fas gene (TNFRSF6) and preterm premature rupture of membranes (PPROM) in multifetal pregnancies was examined. METHODS: Buccal swabs from 119 mother-infant sets were analyzed for an adenine (A) to guanine (G) substitution at position -670 in the TNFRSF6 promoter. Pregnancy outcome data were subsequently obtained. Analysis was by Fisher exact test. RESULTS: Maternal allele G homozygosity (TNFRSF6*G) was observed in 42.4% of 33 PPROM pregnancies as opposed to 19.5% of 77 with no spontaneous preterm birth (P = .01). Similarly, TNFRSF6*G homozygosity was present in 37.5% of 32 first-born neonates from PPROM pregnancies as opposed to 18.7% of 75 uncomplicated pregnancies (P = .04). PPROM occurred in 8 of 14 (57.1%) pregnancies in which mother and all neonates were TNFRSF6*G homozygotes as opposed to 25 of 105 (23.8%) cases in which uniform TNFRSF6*G homozygosity was not observed (P = .02). CONCLUSIONS: A genetic variant in the Fas gene is associated with an increased rate of PPROM in multifetal pregnancies.

Fetal interleukin-1 receptor antagonist gene polymorphism, intra-amniotic interleukin-1beta levels, and history of spontaneous abortion.

OBJECTIVE: The purpose of this study was to determine whether fetal carriage of specific alleles of the polymorphic interleukin-1 receptor antagonist gene is associated with variations in intra-amniotic cytokine levels and previous pregnancy outcomes. STUDY DESIGN: Fetal cells in midtrimester amniotic fluid from 189 women were tested for interleukin-1 receptor antagonist intron 2 length polymorphisms. Concentrations of cytokines in amniotic fluid were tested by enzyme-linked immunosorbent assay. Pregnancy history data were obtained subsequently. RESULTS: Homozygosity for interleukin-1 receptor antagonist allele 1 was detected in 13 of 17 fetuses (76.5%) from women whose previous pregnancies all ended in spontaneous abortions, as compared with 33 of 74 fetuses (44.6%) from women with at least 1 previous term birth ( P = .02). Fetal carriage of interleukin-1 receptor antagonist allele 2 was associated with only 1 (5.9%) previous spontaneous abortion, as opposed to 31 pregnancies (41.9%) that were associated with a previous term delivery ( P = .004). A similar relationship between interleukin-1 receptor antagonist allele 1 and spontaneous abortions was observed when pregnancies of white women only were analyzed. Median mid trimester amniotic fluid interleukin-1beta concentrations were higher in women whose previous pregnancies ended in term deliveries (15.7 pg/mL), as opposed to women with 1 to 2 (6.4 pg/mL; P = .04) or > or =3 (4.1 pg/mL; P = .007) previous spontaneous abortions. Fetal carriage of interleukin-1 receptor antagonist allele 2 was associated with elevated intra-amniotic interleukin-1beta levels (16.2 pg/mL), as compared with interleukin-1 receptor antagonist allele 1 homozygotes (10.8 pg/mL; P = .03). CONCLUSION: Fetal carriage of interleukin-1 receptor antagonist allele 1 is associated with reduced intra-amniotic interleukin-1beta concentrations and an increased occurrence of spontaneous abortions in previous pregnancies.

Polymorphism in intron 2 of the interleukin-1 receptor antagonist gene, local midtrimester cytokine response to vaginal flora, and subsequent preterm birth.

OBJECTIVE: This study investigated the association between polymorphism in intron 2 of the interleukin-1 receptor antagonist gene, midtrimester vaginal microflora, vaginal interleukin receptor antagonist and interleukin-1beta levels and subsequent spontaneous preterm birth. STUDY DESIGN: Vaginal samples from 212 women, collected at 18-22 weeks' gestation, were analyzed for the polymorphism in intron 2 of the interleukin-1 receptor antagonist gene by polymerase chain reaction, qualitative and quantitative vaginal microflora, and interleukin-1beta and interleukin-1ra concentrations by enzyme-linked immunosorbent assay. Pregnancy outcome data were subsequently obtained. RESULTS: Carriage of intron 2 of the interleukin-1 receptor antagonist allele 2 (IL1RN * 2) was associated with an elevated vaginal pH in black ( P < .001) and white ( P = .005) women, a reduced interleukin-1beta response to anaerobic Gram-negative rods and/or Gardnerella vaginalis ( P < .01), and a decreased rate of spontaneous preterm deliveries (6% versus 18%, P = .02). In black women, IL1RN * 2 carriage was associated with increased anaerobic Gram-negative rods, Mycoplasma, and Peptostreptococci and decreased Lactobacilli colonization. CONCLUSION: IL1RN * 2 carriage was associated with a blunted proinflammatory interleukin-1beta response to abnormal vaginal flora. This property may decrease susceptibility to infection-related preterm birth.

Polymorphisms in the tumor necrosis factor-alpha gene at position -308 and the inducible 70 kd heat shock protein gene at position +1267 in multifetal pregnancies and preterm premature rupture of fetal membranes.

OBJECTIVE: The purpose of this study was to determine the relationship between preterm premature rupture of membranes, tumor necrosis factor-alpha, and heat shock protein-70 gene polymorphisms in multifetal gestations. STUDY DESIGN: Buccal swabs from 101 mother-neonate pairs of multifetal pregnancies were tested for single nucleotide polymorphisms at position -308 of the tumor necrosis factor-alpha gene and +1267 of the heat shock protein-70 gene. Pregnancy outcome data were obtained subsequently. RESULTS: Tumor necrosis factor-alpha allele 2 carriage by the first-born occurred in 10 of 27 pregnancies (37.0%) that resulted in preterm premature rupture of membranes compared with 6 of 67 pregnancies (9.0%) without preterm premature rupture of membranes ( P = .002). The allele frequency of tumor necrosis factor-alpha allele 2 and heat shock protein-70 allele 2 in the first born was higher in pregnancies that were complicated by preterm premature rupture of membranes (18.5% vs 4.5%; P = .003; and 57.7% vs 41.3%; P = .04, respectively). There was no relationship between tumor necrosis factor-alpha allele 2 or heat shock protein-70 allele 2 carriage by the second fetus or mother and preterm premature rupture of membranes. CONCLUSION: Tumor necrosis factor-alpha allele 2 and/or heat shock protein-70 allele 2 carriage by the first-born fetus is associated with preterm premature rupture of membranes in multifetal pregnancies.