MELISA (Memory Lymphocyte Immunostimulation Assay) is a blood test that detects type IV hypersensitivity to metals, chemicals, environmental toxins and molds.
Finally, the blood is exposed to the suspected allergen/s in several different concentrations, to ensure that the conditions in vitro are as similar as possible to those in vivo.
The level of reactivity is measured as a Stimulation Index (SI), against the naïve lymphocytes from the unexposed sample (negative control).
[3] MELISA is an optimised, standardised version of the lymphocyte transformation test (LTT) which was developed in the early 1960s to help identify allergies to drugs, metabolites and metals.
[6][7][8][9] The frequency of metal-induced lymphocyte responses was examined in 3,162 dental patients in three European laboratories using the MELISA test.
After consultation with a dentist, a subgroup of 111 patients who showed allergy to their dental metals replaced their restorations with non-metallic materials.
[22][30] The test is also used to determine whether metal allergy is a contributing factor in the development of chronic diseases such as CFS (Sterzl, et al., 1999) and multiple sclerosis.
The authors hypothesize that if the immune system is constantly displaying an allergic reaction to a metal present in the body, this will alert the HPA axis inducing fatigue-like symptoms.
Performing the LTT under optimised stimulating conditions might be a useful additional tool for the diagnosis of hypersensitivity (Ständer, et al., 2017) (FDA, 2019).
The clinical relevance of the test has been shown by the decrease of patient-reported metal-specific responses following the removal of the allergy-causing metals (however the trial did not have a placebo control).