MELISA

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A MELISA (Memory Lymphocyte Immunostimulation Assay) test is a blood test that detects Type-IV allergy to metals, chemicals, environmental toxins and molds from one single blood sample. It can also identify active Lyme disease (Lyme Borreliosis). The test does not measure toxicity-that is to say, it will not measure the amounts of a harmful substance in the patient's blood. It measures if the patient is allergic to it.

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[edit] How the MELISA test works

A MELISA test measures a so-called Type-IV delayed hypersensitivity reaction. In contrast to a Type-I allergy, which is mediated by IgE antibodies and is often tested using an ELISA test, a Type-IV allergic reaction is mediated by T-lymphocytes (or memory lymphocytes) that have had prior contact with a given allergen.[1] In genetically predisposed individuals, an ongoing everyday exposure to allergens can induce the Type-IV hypersensitivity with a resulting allergic reaction[2].

The test procedure is a cell culture and requires live memory lymphocytes. Lymphocytes are isolated and cultured in an incubator for five days. A portion of the blood is kept intact (unexposed to allergens) to serve as a negative control. A second portion is exposed to a universal allergen, such as Pokeweed, to serve as a positive control. Finally, the third portion of the blood is exposed to the suspected allergen in several different concentrations, to ensure that the conditions in vitro are as similar as possible to the ones in vivo.

As an example, if a patient has a suspected allergy to dental amalgams, then the allergens tested for will be the metals most commonly used in dental amalgams, such as mercury, silver, tin, copper and so on[3][4][5]. If a patient has a suspected contact allergy to nickel then the test can be used to test for nickel allergy [6]. This is especially useful in individuals who have clinical symptoms (contact dermatitis) but a negative patch test[7][8]. The lymphocyte reaction to such an allergen is measured by two separate technologies: one based on the uptake of a radioactive isotope by dividing lymphocytes (proliferation); the other by classical microscopy evaluation (transformation). The level of reactivity is measured as a Stimulation Index (SI), against the naïve lymphocytes from the unexposed sample (negative control). Viability and reactivity is determined by cell count as well as reaction to the positive control[9][10].

[edit] How the MELISA test is used

[edit] Occupational medicine

The MELISA test is used in occupational medicine and environmental health. It has been used to screen workers exposed to metals, chemicals or other allergens in their workplace. This is what the test was developed for originally, at the Astra (now Astra-Zeneca) laboratories in Stockholm, Sweden. In the U.S., a similar technique (LTT) is routinely used to screen for Beryllium allergy in asymptomatic workers exposed to Beryllium dust[11][12]. Other occupations that use sensitivity testing include construction work, mining, electrical work, rubber/wood/ paper/textile industry work, dentistry, hairdressing, and painting[13]. The MELISA test is used to screen, diagnose and monitor the immune response of susceptible or affected individuals. It also helps patients suffering from Multiple Chemical Sensitivity or Sick Building Syndrome identify what causes their reactions.

[edit] Dentistry

In Europe, the test is commonly used in dentistry to test for allergy to dental restorative materials, braces and prostheses[14]. Mucosal changes such as oral lichen, or persistent “cold sores” may be due to an allergic reaction to the metal content in amalgam fillings or dental implants[15]. In a sensitive patient, replacement with non-metallic materials, such as zirconium or ceramics, often leads to disappearance of symptoms. Symptoms may not always be local but can be systemic and include inflammation in different body parts. Metals are potential allergens because their ions bind to cellular proteins (enzymes, surface antigens). Research suggests that this can alter the activity of these enzymes or the presentation of these antigens and induce systemic symptoms characteristic of allergic reactions or autoimmune diseases.

[edit] Surgery and orthopedics

In surgery or orthopedics, the MELISA test is used to identify an existing allergy prior to surgery or diagnose a suspected one afterwards. Since implants come in many varieties, it is possible to test several metal panels and choose the implant that is best compatible with the patient. This applies to hip joints, knee prosthesis, screws, pacemakers, cochlear implants, cervical spine plates and dental implants. In the majority of patients, these implants are biocompatible and cause no symptoms at all. On the contrary, they save lives, alleviate symptoms and often dramatically increase the quality of life. However, in genetically predisposed patients (recent research suggests between 5-10% of all patients, depending on ethnicity and previous exposure), the implants may induce side effects such as pain, dermatitis, swelling, impaired wound healing, aseptic bone infections, and implant loosening[3]. Apart from mercury and beryllium, research has also identified nickel[16], cobalt, aluminium, and chromium[17] as known metal allergens. In rare cases, allergy to niobium, molybdenum, and copper has also been seen.

[edit] Titanium

Until recently, titanium was considered to be inert and non-allergenic, which is one of the reasons it has become so widely used. When fashioned into implants, however, the chemical properties of titanium change. Titanium sensitivity is now a recognised medical condition.[18][19]

European and Japanese research shows that in the moist and warm environment of the human body, titanium can also function as a hapten to trigger cellular hypersensitivity[20]. Case reports convey disappearance of symptoms after removal of the implant. Patch testing for titanium allergy, is at present, not a reliable method, with many false negative results.[21] These false negative results occur because titanium dioxide is a large molecule that has significant difficulties penetrating the skin (which is why it is used as a blocking agent in most sun screens).

[edit] Chronic diseases

The test is also used to determine whether metal allergy is a factor behind chronic diseases such as Chronic Fatigue Syndrome[22] and Multiple Sclerosis[23]. If the immune system is constantly staging an allergic reaction to a metal present in the body, this will alert the HPA axis inducing fatigue-like symptoms. A peer-reviewed study[24] of 930 fatigue patients showed 62% testing MELISA-positive to metal allergy. Of those who removed the offending metals, 76% improved. Metal allergy can also be a factor behind demyelination, the symptom behind MS. This happens if the immune system is attacking metal ions which have bound to the myelin sheath.

[edit] Mold

Aside from metals, the MELISA test has been used to detect allergy to mold, including toxic molds such as Aspergillus Nigri, certain types of Penicillium, Claudosporium and Alternaria. These molds can cause respiratory allergies with symptoms that do not respond to traditional treatment. Aspergillus has also been shown to cause neurological symptoms, such as dizziness, short term memory impairment, inability to focus on complex tasks and mood swings. Chronic exposure can lead to neurological damage that may not be fully reversible. By identifying a heightened reaction to mold allergens, the MELISA test can identify whether or not patients are being exposed to molds in their environment.

[edit] Active Lyme disease

Lastly, the MELISA test is used to detect the active form of Lyme disease reliably[25]. Several other tests, including ELISA and the Western Blot, as well as PCR techniques, can detect an existing or previous infection with the Lyme spirochete, but none of these can confirm an active disease. Many people become infected with Borrelia, and have the antibodies to prove it[26]. Only some of these people actually develop active Lyme disease, however. ELISA, Western Blot, PCR and CD59 testing also have a larger incidence of false negatives, false positives and inconclusive test results than does the MELISA test. One reason is that some patients do not produce antibodies to Borrelia Lyme[27]. As MELISA tests for a direct cellular immunological reaction, Lyme Borreliosis is detected even in these patients[28]. Paired with a Western Blot, it is a useful diagnostic tool for detecting active disease and previous exposure.

[edit] Allergy vs. toxicity

As previously noted, the MELISA test does not measure the levels of metals, chemicals or mold in a patient's body; it only measures whether the patient is allergic to them. For example, if a hair sample shows levels of mercury below the official “safe limit”, a highly allergic individual can still become ill and have significant clinical symptoms. For this person, the “normal” blood levels will not explain his or her symptoms.

Another aspect to consider, especially with metals, is that not all metals are conveniently deposited in locales that are easy to access and measure (such as hair, nails and blood). Many heavy and transition metals are deposited in fatty tissue: the myelin sheath around nerves or the fat that encapsulates many of our inner organs. For this reason, an analysis of metal levels in the blood or hair can be misleading. T-lymphocytes, however, circulate through the entire body, and so encounter and remember even these “hidden” metal stores. These T-lymphocytes return to the blood where they are accessible and respond to the analyte in the MELISA test.

[edit] See also

[edit] References

  1. ^ Stejskal VDM, M Forsbeck, R Nilsson. Lymphocyte transformation test for diagnosis of isothiazalinone allergy in man. J Invest Dermatol 1990; 94:798–802.
  2. ^ Willis CM, E Young, DR Brandon, JD Wilkinson. Immunopathological and ultrastructural fi ndings in human allergic and irritant contact dermatitis. Br J Dermatol 1986; 15:305–316.
  3. ^ Silvennoinen-Kassinen S, A Niinimäki. Gold sensitivity blast transformation. Contact Derm 1984; 11:156–158.
  4. ^ Stejskal VDM, M Forsbeck, KE Cederbrant, O Asteman. Mercury-specific lymphocytes: an indication of mercury allergy in man. J Clin Immunol 1996; 16:31–40.
  5. ^ Marcusson JA. Contact allergies to nickel sulfate, gold sodium thiosulfate and palladium chloride in patients claiming sideeffects from dental alloy components. Contact Derm 1996; 34:320–323.
  6. ^ Everness KM, DJ Gawkrodger, PA Botham, JAA Hunter. The discrimination between nickel-sensitive and non-nickel-sensitive subjects by an in vitro lymphocyte transformation test. Brit J Dermatol 1990; 122:293–298.
  7. ^ Klas PA, G Corey, FJ Storrs, SC Chan, JM Hanfi n. Allergic and irritant patch test reactions and atopic disease. Contact Derm 1996; 4:121–124.
  8. ^ Rietschel RL. Reproducibility of patch-test results. Lancet 1996; 347:1202.
  9. ^ Sachs B, H Merk. Demonstration and characterization of drug-specific lymphocyte reactivity in drug allergies. ACI International 2001; 13:91–98.
  10. ^ Stejskal VDM, K Cederbrant, A Lindvall, M Forsbeck. MELISA – an in vitro tool for the study of metal allergy. Toxicol In Vitro 1994; 8:991–1000.
  11. ^ Mroz MM, K Kreiss, DC Lezotte, PA Campbell, LS Newman. Reexamination of the blood lymphocyte transformation test in the diagnosis of chronic beryllium disease. J Allergy Clin Immunol 1991; 88:54–60.
  12. ^ Newman LS. Signifi cance of the blood beryllium lymphocyte proliferation test. Environment Health Perspect (Suppl 5) 1996; 104:953–956.
  13. ^ Bach FH, K Hirschhorn. Lymphocyte interaction: a potential histocompatibility test in vitro. Science 1964; 143:813–814.
  14. ^ Stejskal VDM, K Cederbrant, A Lindvall, M Forsbeck. MELISA – an in vitro tool for the study of metal allergy. Toxicol In Vitro 1994; 8:991–1000.
  15. ^ Stejskal VDM, Olin RG, Forsbeck M. The lymphocyte transformation test for diagnosis of drug-induced occupational allergy. J Allergy Clin Immunol 1986; 77:411–426.
  16. ^ Regland B, O Zachrisson, V Stejskal, C-G Gottfries. Nickel allergy is found in a majority of women with chronic fatigue syndrome and muscle pain – and may be triggered by cigarette smoke and dietary nickel intake. J Chronic Fatigue Syndrome 2001; 8:57–65.
  17. ^ Räsänen L, H Sainio, M Lehlo, T Reunala. Lymphocyte proliferation test as a diagnostic aid in chromiun contact sensitivity. Contact Derm 1991; 25:25–29.
  18. ^ Lalor PA, Revell PA, Gray AB, Wright S, Railton GT, Freeman MA (1991). "Sensitivity to titanium. A cause of implant failure?". J Bone Joint Surg Br. 73 (1): 25-8. 
  19. ^ The effect of titanium particulate on development ...[Spine. 2002] - PubMed Result
  20. ^ Intolerance and Allergy to Titanium. Author: Muller KE Published in: Lecture at the Symposium on Toxic metals as Key factors in Disease, Sept 2005, Prague.
  21. ^ [1][2]
  22. ^ Sterzl I, J Procházkova, P Hrda, J Bártová, P Matucha, V Stejskal. Mercury and nickel allergy: risk factors in fatigue and autoimmunity. Neuroendocrin Lett 1999; 20:221–228.
  23. ^ Stejskal V, A Danersund, A Lindvall, R Hudecek, V Nordmann, A Yagob, W Mayer, W Bieger, U Lindh. Metal-specifi c lymphocytes: biomarkers of sensitivity in man. Neuroendo Letters 1999; 20:289–298.
  24. ^ Stejskal VD, Danersund A, Lindvall A, Hudecek R, Nordman V, Yaqob A, Mayer W, Bieger W, Lindh U (1999). "Metal-specific lymphocytes: biomarkers of sensitivity in man". Neuro Endocrinol Lett. 20 (5): 289-298. PMID 11460087. 
  25. ^ Dressler F, Yoshinari NH, Steere AC (1991) The T-cell proliferative assay in the diagnosis of Lyme disease. Ann Intern Med 115:533-539.
  26. ^ Bauer Y, Hofmann H, Jahraus O, Mytilineos J, Simon MM, Wallich R (2001) Prominent T cell response to a selectively in vivo expressed Borrelia burgdorferi outer surface protein (pG) in patients with Lyme disease. Eur JImmunol 31:767-776.
  27. ^ Dattwyler RJ, Volkmann DJ, Luft BJ, Halperin JJ, Thomas J, Golightly MG (1988) Seronegative Lyme disease. Dissociation of specific T- and B-lymphocyte responses to Borrelia burgdorferi. N Engl J Med 19:1441-1446.
  28. ^ Dressler F, NH Yoshinari, AC Steere. The T-cell proliferative assay in the diagnosis of Lyme disease. Ann Int Med 1991; 115:533-539.