Branched PFOS (Sm-PFOS): Understanding the Marker in PFAS Testing Branched PFOS (Sm-PFOS), also known as Perfluorooctane sulfonic acid isomers, is one of the specific PFAS (Forever Chemicals) measured in the PFAS (Forever Chemicals) 9 Panel by Quest Diagnostics. Branched PFOS refers to the non-linear, isomeric forms of PFOS (Perfluorooctane sulfonic acid), which differs from the linear form (n-PFOS) by having a different molecular structure. This chemical, like other PFAS compounds, is persistent in the environment and the human body due to its strong carbon-fluorine bonds. What is Branched PFOS (Sm-PFOS)? Branched PFOS (Sm-PFOS) is a variation of PFOS, which is widely used in various industrial and consumer applications, such as water- and stain-resistant fabrics, firefighting foams, nonstick cookware, and certain food packaging materials. Sm-PFOS differs from the linear PFOS form due to the branching of the carbon chain, which results in several isomers that share similar chemical properties but have different molecular structures. Although linear PFOS is often more commonly detected in environmental studies, branched PFOS forms are also present and can contribute to overall PFOS exposure. Why is Branched PFOS Tested? Branched PFOS (Sm-PFOS) is included in the PFAS 9 Panel because it is an important marker of PFAS exposure. Both linear and branched forms of PFOS are common in industrial and consumer products, and measuring Sm-PFOS levels helps assess overall exposure to PFAS chemicals. These isomers, while chemically similar, can have different environmental behaviors and persistence, making it important to track their presence in the body, especially for individuals who may have been exposed to PFOS through contaminated water, food, or products. Health Implications of Branched PFOS Research into the health effects of Branched PFOS (Sm-PFOS) is ongoing, but like other PFAS compounds, elevated levels of this chemical may be associated with several potential health risks, including: Immune System Disruption: Branched PFOS has been shown to suppress immune function, which can make individuals more vulnerable to infections and less responsive to vaccinations. Cholesterol Imbalances: High levels of Sm-PFOS may contribute to unhealthy cholesterol levels, particularly increased LDL ("bad" cholesterol), which is associated with a higher risk of cardiovascular diseases. Developmental and Reproductive Health: Exposure to Branched PFOS may affect fetal development, leading to potential issues such as low birth weight and developmental delays. Additionally, exposure to PFOS has been linked to reduced fertility in both men and women. Cancer Risk: Some studies have indicated that long-term exposure to PFOS, including Sm-PFOS, may increase the risk of certain cancers, particularly kidney and testicular cancer. However, more research is needed to confirm these links. Why Branched PFOS Is Important in PFAS Testing Both linear and branched forms of PFOS are found in environmental samples and human blood, but Branched PFOS (Sm-PFOS) can have different behaviors compared to the linear form. As branched isomers can be more difficult to break down, tracking their levels helps researchers and healthcare providers better understand the total burden of PFAS in the body. Elevated levels of Sm-PFOS are often indicative of significant exposure to PFAS, which could be linked to health risks mentioned above. Interpreting Branched PFOS Test Results If your Branched PFOS (Sm-PFOS) test results show elevated levels, it likely indicates exposure to PFAS chemicals, either through contaminated water, consumer products, or environmental contamination. While the direct health effects of elevated Sm-PFOS levels are still being studied, it is essential to assess potential health risks, especially in individuals with prolonged exposure to PFAS. What to Do If Your Branched PFOS Levels Are Elevated Consult a Healthcare Provider: If your Branched PFOS levels are elevated, it is important to discuss the results with a healthcare provider. A doctor can help interpret the test results, assess potential health risks, and recommend any further tests or monitoring needed to track any health issues. Reduce Exposure to PFAS: Reducing further exposure to Branched PFOS and other PFAS chemicals is a crucial step in managing your health. This can involve: Using water filters certified to remove PFAS from drinking water. Avoiding products that contain PFOS, such as nonstick cookware, water- and stain-resistant fabrics, and certain cosmetics. If living in an area with known PFAS contamination, taking precautions such as avoiding contaminated water sources. Regular Health Monitoring: Regular check-ups with your healthcare provider can help monitor specific health markers like cholesterol levels, immune function, and kidney health. Monitoring your health over time can help detect any potential issues related to PFAS exposure and guide appropriate actions. Conclusion Branched PFOS (Sm-PFOS) is an important marker in assessing PFAS exposure. Elevated levels of Sm-PFOS indicate significant exposure to PFAS, which could be associated with various health risks such as immune system disruption, cholesterol imbalances, reproductive issues, and cancer. If your Branched PFOS levels are elevated, it is essential to work with a healthcare provider to understand the potential health implications, reduce exposure to PFAS, and monitor your health. Regular testing and proactive health management can help reduce long-term risks associated with PFAS chemicals.
Elevated antibody levels can be clinically significant — while the antibodies themselves don’t destroy anything, they do trigger an inflammatory response that can cause significant destruction of tissue and resulting symptoms. This response is not necessarily dependent on antibody levels. However, an equivocal result may mean you are just beginning to exhibit an immune reaction, so this is an important time to take measures to support the body in damping immune reactivity. How useful is this test? Immunoglobulin G (IgG) food testing is a useful guide for structuring elimination diets for people with many chronic conditions. Individuals with neurological, gastrointestinal, movement, and behavioral disorders often suffer from IgG food sensitivities. People may continue to eat offending foods unaware of their potential adverse effects. The clinical significance of IgG food testing was illustrated in an early article published by an otolaryngologist who reported that the majority of his patients had substantial health improvements after eliminating foods found positive by IgG food allergy testing. The study demonstrated a 71% success rate for all symptoms, achieving at least a 75% relief. Of particular interest was the group of patients with chronic, disabling symptoms, unresponsive to other intensive treatments. Symptoms most commonly improved (75%-100%) on the elimination diets included asthma, coughing, ringing in the ears, chronic fatigue, headaches, gas, bloating, diarrhea, skin rash and itching, and nasal congestion. The most common IgG food allergies were to cow’s milk, garlic, mustard, egg yolk, tea, and chocolate. A recent study reported that 93% of non-celiac, gluten-sensitive patients showed anti-gliadin IgG antibody disappearance after a six-month adherence to a gluten-free diet. The IgG disappearance was closely related to a significant improvement of both gastrointestinal and extra-intestinal symptoms. High IgG antibody levels have frequently been found in children with diabetes mellitus, Crohn’s disease, celiac disease, and in those considered to be obese. IgG versus IgE Symptoms associated with food sensitivities may occur hours or days after the offending food was eaten because IgG food antibodies remain for a much longer time than IgE antibodies. IgE food allergy causes the release of histamine, producing an immediate hypersensitivity reaction. In contrast, IgG food sensitivity is triggered by the binding of complement to IgG food antigen complexes, causing an inflammatory response. This is a delayed hypersensitivity reaction in which symptoms appear anywhere from hours to days after eating the offending food. References: - Anderson S, Wakeley P, Wibberley G, et al. Development and evaluation of a Luminex multiplex serology assay to detect antibodies to bovine herpes virus 1, parainfluenza 3 virus, bovine viral diarrhoea virus, and bovine respiratory syncytial virus, with comparison to existing ELISA detection methods. J Immunol Methods 2011;366:79-88. - Gimenez-Lirola LG, Jiang Y-H, Sun D, et al. Simultaneous Detection of Antibodies against Apx Toxins ApxI, ApxII, ApxIII, and ApxIV in Pigs with Known and Unknown Actinobacillus pleuropneumoniae Exposure Using a Multiplexing Liquid Array Platform. Clin Vaccine Immunol 2014;21(1):85-95. - Langenhorst RJ, Lawson S, Kittawornrat A, et al. Development of a fluorescent microsphere immunoassay for detection of antibodies against porcine reproductive and respiratory syndrome virus using oral fluid samples as an alternative to serum-based assays. Clin Vaccine Immunol 2012;19(2):180-9. - Smits GP, van Gageldonk PG, Schouls LM, et al. Development of a BeadBased Multiplex Immunoassay for Simultaneous Quantitative Detection of IgG Serum Antibodies against Measles, Mumps, Rubella, and Varicella-Zoster Virus. Clin Vaccine Immunol 2012;19(3):396-400. - Alpay, K. et al. Diet restriction in migraine, based on IgG against foods: a clinical double-blind, randomised, cross-over trial. Cephalalgia : an international journal of headache 30, 829-837, doi:10.1177/0333102410361404 (2010). - Mitchell, N. et al. Randomised controlled trial of food elimination diet based on IgG antibodies for the prevention of migraine like headaches. Nutrition journal 10, 85, doi:10.1186/1475-2891-10-85 (2011). - Zar, S., Mincher, L., Benson, M. J. & Kumar, D. Food-specific IgG4 antibody-guided exclusion diet improves symptoms and rectal compliance in irritable bowel syndrome. Scandinavian journal of gastroenterology 40, 800-807, doi:10.1080/00365520510015593 (2005). - Atkinson, W., Sheldon, T. A., Shaath, N. & Whorwell, P. J. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut 53, 1459-1464, doi:10.1136/gut.2003.037697 (2004). - Drisko, J., Bischoff, B., Hall, M. & McCallum, R. Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics. Journal of the American College of Nutrition 25, 514-522 (2006). - Bentz, S. et al. Clinical relevance of IgG antibodies against food antigens in Crohn’s disease: a double-blind cross-over diet intervention study. Digestion 81, 252-264, doi:10.1159/000264649 (2010). - Egger, J., Carter, C. M., Soothill, J. F. & Wilson, J. Oligoantigenic diet treatment of children with epilepsy and migraine. The Journal of pediatrics 114, 51-58 (1989). - Pelsser, L. M. et al. Effects of a restricted elimination diet on the behavior of children with attention-deficit hyperactivity disorder (INCA study): a randomized controlled trial. Lancet 377, 494-503, doi:10.1016/S0140- 6736(10)62227-1 (2011). 8b cookbook - Veling, M. & Trevino, R. (2002). Food allergies and hypersensitivities. Alexandria, VA: American Academy of Otolaryngology-Head and Neck Surgery Foundation. - Dixon H, Treatment of delayed food allergy based on specific immunoglobulin G RAST testing relief. Otoloryngol Head Neck Surg 2000;123:48- 54. - Ciao, G. et al, Effect of gluten free diet on immune response to gliadin in patients with non-celiac gluten sensitivity. BMC Gastroenterology 14, 26 (2014) - Kemeny DM, et al Sub-class of IgG in allergic disease. I. IgG sub-class antibodies in immediate and non-immediate food allergy. Clin Allergy. 1986; 16:571-81 - Hofman, T. IgE and IgG antibodies in children with food allergy. Rocz Akad Med Bialymst 40, 468-473 (1995). - Jenmalm, M. C. & Bjorksten, B. Cord blood levels of immunoglobulin G subclass antibodies to food and inhalant allergens in relation to maternal atopy and the development of atopic disease during the first 8 years of life. Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology 30, 34-40 (2000). - Lucarelli, S. et al. Food allergy in cystic fibrosis. Minerva pediatrica 46, 543-548 (1994). - van der Woude, F. J. et al. Do food antigens play a role in the pathogenesis of some cases of human glomerulonephritis? Clinical and experimental immunology 51, 587-594 (1983). - James L.K and Till S.J Potential mechanisms for IgG4 inhibition of immediate hypersensitivity reactions. Current Allergy Asthma Rep. 16:23, 2016 PMID: 26892721 - Caubet J.C. et al. Natural tolerance development in cow’s milk allergic children: IgE and IgG4 epitope binding. European Journal of Allergy and Clinical Immunology, First published: 27 March 2017
