Hydrocarbons, C5-8

Immunotoxicity

Administrative data

Endpoint:

immunotoxicity

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Data source

Reference

Title:

No information

Author:

Kirkeleit, J, Ulvestad, E, Riise, T, Bratveit, M and Moen, BE. (2006) Acute suppression of serum IgM and IgA in tank workers exposed to benzene. Scand J Immunol 64, 690-698.

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Benzene

EC Number:

200-753-7

EC Name:

Benzene

Cas Number:

71-43-2

Molecular formula:

C6H6

IUPAC Name:

benzene

Results and discussion

Any other information on results incl. tables

Mean benzene exposure of the tank workers (geometric mean was 0.15ppm  (n=26) over the 3-day study period was.  

The geometric mean concentration of benzene in blood and urine was  significantly higher in tank workers than in referents at all sample  periods (pre-shift, post-shift, pre-next shift):

	Blood		Urine
	Pre-shift	Post-shift	Post-shift
Tank workers	1.4	12	27
Referents	0.7	0.9	0.7
Comment: numerical data for other time-points not reported

Baseline serum IgM for the tank workers (0.70 g/l) was significantly  lower than that of the referents (0.98 g/l), with a further 4.9% decrease  (significant) at the post-shift sampling time.  

Serum IgA was numerically (but not significantly) lower in pre-shift  samples from tank workers (1.91 g/l) compared to referents (2.18 g/l) but  declined by 5% (significant) in the benzene-exposed population at the  post-shift point. In contrast, mean levels of IgM and IgA for the  referents increased (5.1% and 0.6%, respectively) during the same period

There was no significant difference between the exposed and referent  groups for the other immune parameters included in the study.

IgM and IgA were found to be negatively correlated (Pearson correlation  coefficient; r) with benzene exposure in the tank worker group (no  correlation for IgE and IgG):  

	Time in tank	Benzene exposure	Post shift in blood	benzene in urine
IgM
Change post-shift	-0.45*	-0.42	-0.45*	-0.36
Change pre-next shift	-0.53*	-0.27	-0.52*	-0.42
IgA
Change post-shift	-0.20	-0.06	-0.01	-0.01
Change pre-next shift	-0.65**	-0.36	-0.54*	-0.53*

There were no exposure-related alterations in total lymphocytes however  the concentration of CD4 T cells declined significantly from baseline to  post-shift and from post-shift to pre-next shift in tank workers. The  change in total CD4 T cells from baseline to post-shift (but not in  post-shift to pre-next shift) was significantly correlated with the  benzene exposure.
Remark: The use of respirators among tank workers was not monitored and  varied between the subjects.

Applicant's summary and conclusion

Conclusions:

The authors conclude that relatively low exposure to benzene was linked with significant decreases in serum IgA, IgM and CD4 T cells in this study but recognise that the population size was small and the exposures within the tanks potentially complex.