The aim was to analyze humoral immune response againstGM1 ganglioside expressed on the surface of melanocytic cells, and thepossible correlation between the level of antibodies against GM1 IgGand IgM class and melanoma progression. The study included 128 adultpatients with malignant melanoma, without paraneoplastic neurologicdisorders, 48 adults with dysplastic nevi and 48 healthy volunteers. Thepresence of IgM and IgG antibodies against GM1 was demonstrated byImmunodot method. Automatic evaluation of strips marked with GM1 antigenwas performed by EUROLineScan software. Lactate dehydrogenase(LDH) activity was evaluated by spectrophotometry. Serum concentrationof gangliosides was determined using the method with resorcinol-HCl. IgGantibodies against GM1 gangliosides were identified in six patients withmelanoma (4.68%) and in none of the subjects from other groups. AntiGM1IgM class were observed in 20 (15.63%) melanoma patients, three (6.25%)dysplastic nevi patients and one healthy volunteer. No statistically significantdifference was observed when serum profile of GM1 IgM antibodies inpatients with localized melanoma was compared with that of other studysubjects. The levels of IgM antibodies varied with clinical stage of tumorand histopathologic features. Moreover, a statistically significant positivecorrelation was found between IgM antibodies and LDH (r=0.87; p=0.01;IC=95%). In conclusion, antibodies against GM1 ganglioside are frequentin patients with melanoma. Dysplastic nevi and early melanoma cannot bedifferentiated using the antiGM1 antibody profile. The synthesis of theseantibodies is characteristic for advanced stages of melanoma.</span
