On the long-term effects of methyl isocyanate on cell-mediated immunity in Bhopal gas-exposed long-term survivors and their offspring

Abstract

Methyl isocyanate (MIC) is a toxic industrial chemical that is documented as a potent respiratory toxicant. We investigated cell-mediated immunity (CMI) in the MIC-exposed long-term survivors and their offspring born after the Bhopal gas-leak tragedy in 1984. Several earlier reports show inconsistency in the assessment of immunological effects of MIC on the human population. In these studies, important factors including lifestyle attributes were overlooked. We incorporated these factors also in our study of the basic cell-mediated immune function in the Bhopal MIC-affected population. Twenty-seven years after exposure, we assessed the circulating T-lymphocyte frequency using E-Rosette assay. A total of 46 MIC-exposed healthy long-term survivors and their offspring were studied vis-a-vis parallel gender-age group-matched unexposed controls from Bhopal and various other regions of India. The influence of several lifestyle variabilities (smoking, alcohol intake, and tobacco chewing) on T-lymphocyte frequency was also taken into consideration. Our observations suggest that Erythrocyte-Rosette-forming cell (E-RFC) distribution frequency is largely insignificant in the MIC-affected population as compared to controls ( p > 0.05). In the MIC-affected tobacco chewers, there was a trend of suppression in CMI (relative decrease = 10.3%) as compared to nonchewers. Overall, our results show negligible long-term effect of MIC on CMI measured in terms of E-RFC frequency. These observations are not in agreement with earlier findings that immunosuppressive effects of MIC exposure persist in the T-cells of the affected population. However, atypical lymphocytes were frequently observed as E-RFC in the exposed females when compared to all other subgroups. Hematopoietic disorders (atypical lymphocytosis) in the MIC-affected population along with previous reports on the cytogenetic and humoral immune system linking cancer risk and chronic obstructive pulmonary disease (COPD) are important.

Computational Study of the Reactions of Chlorine Radicals with Atmospheric Organic Compounds Featuring NHx–π-Bond (x = 1, 2) Structures

“…This prediction is consistent with the corresponding experimental product identification performed by Barnes et al, which in turn verifies that the revealed reaction mechanisms that proceed via the H-abstraction pathways to form C-center radicals for the two amides under study are reliable. It deserves mentioning that isocyanic acid and methyl isocyanate are compounds that are potentially hazardous to human health. − Therefore, the transformation of formamide and N -methylformamide initiated by ·Cl will increase the environmental risk of formamide and N -methylformamide. We noted that the NH 2 CO· formed via H abstraction from the −CHO group is the exclusive product for the reaction of formamide with ·OH, ·CONHCH 3 via H abstraction from the −CHO group is the major product, and HCONHCH 2 · is a minor product for the reaction of N -methylformamide with ·OH. , Thus, the reaction mechanism of these two amides with ·OH is similar to that with ·Cl.…”

Susceptibility of the Bhopal–methyl isocyanate (MIC)–gas–tragedy survivors and their offspring to COVID-19: What we know, what we don’t and what we should?

“…Our studies with immunological parameters showed a negligible long-term effect of MIC on cell-mediated immunity in BMAP 14 . In contrast, significant alterations in the circulating proteins, particularly the suppression of α 1 -globulin corresponding to α 1 -antitrypsin (a key inflammatory regulator in the human airway) deficiency, which in turn may contribute to chronic airway obstruction suggests a long-term depreciatory effect of MIC on the humoral immunity of BMAP (Unpublished data).…”

“…Subsequently, a prospective cohort study monitored the immune system and cancer susceptibility of MIC-exposed healthy long-term survivors and their offspring vis-à-vis gender-age-groupmatched unexposed healthy controls from Bhopal and various other regions of India, after rigorously incorporating several lifestyle attributes and dietary habits demonstrated the high occurrence of atypical lymphocytes 12 . It was almost a regular observation in the exposed females (EF) 14 .…”

New Occupational Exposures with Respiratory Effects

“…One of the most disheartening examples of unregulated industrial hazards is the Bhopal gas tragedy caused by the leakage of a dangerous industrial chemical, methyl isocyanate (MIC), that took the life of more than 16,000 people until now and affected over half a million 3,4 . It also caused epigenetic defects in the survivors and their future generations, leading to haematopoietic disorders, cancer, and lung diseases 5 . In today's developing countries, most of the workers are still exposed to hazardous industrial substances.…”