Comparison of anti-desmoglein antibodies titres and anti-M3 muscarinic acetylcholine receptor antibody titres as biomarker for potential pemphigus between subjects who are occupationally exposed and not exposed to pesticides

Background The pathogenesis of pemphigus is multifactorial, and pesticides have been implicated as one of the triggering factors due to their interaction with acetylcholine receptors. Aim The aim of this study was to observe the effect of exposure to pesticides (by blood pesticide levels) on serological markers of pemphigus (anti-Dsg1, anti-Dsg3, and anti-M3 ACh receptor antibodies) amongst healthy individuals involved in pesticide use. Methods This was an observational, cross-sectional pilot study performed in Punjab. The study subjects were 45 couples (husband and wife) wherein the husband was involved in activities like spraying and handling pesticides, and the wife was considered a non-genetically related control (not occupationally exposed to pesticides). Clinical data were collected by a structured questionnaire, and venous blood was collected to test blood pesticide levels. Gas chromatography - mass spectroscopy (GC-MS) and enzyme-linked immunosorbent assay (ELISA) were used for anti-Dsg-1, anti-Dsg-3, and anti-M3Ach receptor antibody level detection. Results Pesticides were detected in both husband and wife. There was no correlation between the duration of pesticide exposure and their blood levels. Chlorpyrifos was most frequently detected in husbands and β- endosulfan in wives. The levels of anti-Dsg-1 and anti-Dsg-3 titres were below the diagnostic cut-off values (20 RU/mL) for pemphigus in all participants. Husbands had significantly higher anti-Dsg3 values (p=0.029). There was no statistically significant association between the presence of pesticides and anti-Dsg-1, anti-Dsg-3, and anti-M3 ACh receptor antibodies in the sera. Anti-Dsg-1 antibodies had a significant positive correlation with chlorpyrifos serum levels (r= 0.3, p=0.005). Limitation Determining aspects like expression of adhesion proteins on keratinocyte cell lines, long term follow up of healthy subjects and correlation with pesticide levels with cases of pemphigus was not done as it is cost intensive. Conclusion The exposure to pesticides did not significantly increase any of the biomarkers above clinical cut-off levels in any of the healthy participants. Considering the rarity of clinically manifest pemphigus, many healthy subjects need to be studied with the current study design. Alternatively, the expression of adhesion proteins or their adhesion function can be assessed in keratinocyte cell lines upon incubation with varying concentrations of pesticides.