In vitro study of lymphocyte antiproliferation and cytogenetic effect by occupational formaldehyde exposure

Critical airway induced by formalin injection: case report

Background:

Formalin is a saturated aqueous solution comprising 37–40 per cent formaldehyde. It is often used in histopathology laboratories as a tissue preservative. The ingestion or injection of formalin has an immediate, powerful and destructive impact on humans. This paper reports a case of formalin injection and reviews the relevant world literature.

Case report:

A 36-year-old male attempted suicide by injecting formalin into the right side of his neck, resulting in a critical airway situation. An endotracheal tube was inserted and a tracheostomy was then performed to secure his airway. After receiving medical treatment, including antibiotics and N-acetyl cysteine, the status of the patient's airway improved.

Conclusion:

When examining patients who have injected substances into their neck, the possibility of deep neck inflammation with airway compromise should be considered. Immediate management, which should include establishment of a definitive airway and prophylactic infection control, is crucial.

Effects of formaldehyde exposure on human NK cells in vitro

Natural killer (NK) cells play a pivotal role in human immunologic surveillance. Formaldehyde (FA), a ubiquitous environmental contaminant, has been classified as a carcinogen to humans. Although it is known that immune cells are sensitive to FA, so far little is known about how it's affecting the activity of human NK cells. To probe it, the primary human NK cells were treated with different concentrations of FA (3200, 1600, 800, 400, 200, 100, 50, and 0 μM) in vitro. The morphology, viability, apoptosis, cytotoxicity (killing tumor cell activity) and cytokine and cytolytic proteins secretion of NK cells were evaluated respectively. Our results reveal that FA could induce NK cells death obviously in a concentration-dependent manner. With the decreased concentrations of FA from 3200 μM to 800 μM, accordingly, the viability of NK cells increased from 65. 2 ± 12.1% to 78.48 ± 10.3% (p<0.05), and the cytotoxicity of NK cells recovered from 29.2 ± 8.5% to 63.9 ± 5.9% (p<0.05). The secretion of perforin was affected significantly by FA, whereas the secretion of IFN-γ and granzyme-B altered slightly. It is concluded that human NK cell is sensitive to FA, 800 μM may be a critical concentration of FA inhibiting the activity of human NK cell.