Palladium dichloride

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published paper. No standard guideline available, but data appear scientifically acceptable.

Data source

Reference

Reference Type:

publication

Title:

Occupational hypersensitivity to metal salts, including platinum, in the secondary industry.

Author:

Cristaudo A, Sera F, Severino V, De Rocco M, Di Lella E and Picardo M.

Year:

2005

Bibliographic source:

Allergy 60, 159-164

Materials and methods

Type of sensitisation studied:

respiratory

skin

Study type:

survey

Test guideline

Qualifier:

no guideline required

Deviations:

not applicable

Principles of method if other than guideline:

To determine the prevalence and clinical characteristics of hypersensitivity (skin prick tests and patch tests) to palladium dichloride (and other platinum group elements) among 153 workers in a catalyst production plant.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Palladium dichloride

EC Number:

231-596-2

EC Name:

Palladium dichloride

Cas Number:

7647-10-1

Molecular formula:

Cl2Pd

IUPAC Name:

palladium dichloride

Details on test material:

- Name of test material (as cited in study report): palladium chloride (PdCl2)
- Analytical purity: >99.2%

Method

Type of population:

occupational

Ethical approval:

not specified

Subjects:

- Number of subjects exposed: 153
- Sex: 137 men; 16 women
- Age: 21 to 60 years, average of 34.
- Race: no data
- Demographic information: Workers employed at a large industrial complex in the outskirts of Rome.
- Other: Length of employment ranged from 1 to 360 months.

Clinical history:

- History of allergy or casuistics for study subject or populations: Forty subjects (about 26%) had positive skin prick tests to common inhalants (mostly pollens and house dust mites)
- Symptoms, onset and progress of the disease: Clinical symptoms of the employees included conjuctivitus, rhinitis, asthma, urticaria and eczema.
- Exposure history: Eleven workers were described as white collar employees (with no exposure to PGEs), 105 as low exposure to PGEs (including palladium dichloride), and 37 with high exposure.
- Aggravating factors both in home and workplace: no data
- Family history: no data.
- Medical history (for respiratory hypersensitivity): Clinical symptoms of employees included rhinitis and asthma
- Any other allergic or airway disorders: no data
- Smoking history: Of the workers (n=142) with either low or high prior exposure to PGEs, 69 were non-smokers and 73 were smokers.

Controls:

Eleven white collar workers (office personnel)

Route of administration:

dermal

Details on study design:

TYPE OF TEST(S) USED: patch test (epicutaneous test) and skin prick test;

ADMINISTRATION
- Type of application: Patch test
- Description of patch: Patch tests were carried out with “Al-test on Leukotest”.
- Vehicle / solvent: aqueous solutions
- Concentrations: (10-3 M).
- Volume applied: 15 ul
- Testing/scoring schedule: A first reading was carried out after 25 minutes in subjects with urticaria, and then at day 2.
- Removal of test substance: no data

EXAMINATIONS
- Grading/Scoring system: Readings were scored following international guidelines (no further details)
- Statistical analysis: A contingency table of outcome (allergy to platinum group elements) versus the k levels of the independent variable was produced. In addition to the chi-square test, the investigators estimated the prevalence odds ratio (with 95% confidence intervals) using the level with lower prevalence as the reference group.

TYPE AND DETAILS OF TEST(S) USED
- Skin prick test: Were performed by placing a small amount of freshly prepared aqueous solution of palladium dichloride (10-3-10-6 M) on the volar surface of the forearm and passing a disposable hypodermic needle through the drop and into the epidermal surface. Readings were scored after 25 minutes and two days according to international guidelines.

Results and discussion

Results of examinations:

NO. OF PERSONS WITH/OUT REACTIONS COMPARED TO STUDY POPULATION
- Number of subjects with positive reactions: Positive skin prick tests to platinum group elements (PGEs) at various concentrations was seen in 22 (14%) of 153 workers. Of these 22 subjects, none had positive skin prick reactions to palladium dichloride, although one had a positive skin patch test result. This subject had been pre-diagnosed with work-related asthma and eczema, and also rhinitis, bit there was no clinical history of urticaria.
- Number of subjects with negative reactions: 153/153 workers did not have positive reactions following skin prick tests to palladium dichloride. 152/153 workers did not have a positive reaction fallowing patch tests with palladium dichloride.
- Number of subjects with irritating reactions: no data

OTHER RESULTS: No positive reactions to rhodium trichloride (or any of the other tested PGEs) were seen in the white collar workers

Applicant's summary and conclusion

Conclusions:

Skin patch tests produced a positive reaction to palladium dichloride in one worker out of 142 with prior exposure to PGE. No positive reactions were seen following skin prick tests with palladium dichloride in these 142 workers, and no positive skin reactions (following prick tests or patch tests) to palladium dichloride were seen in eleven office personnel with no prior exposure to PGEs.

Executive summary:

In an attempt to determine the prevalence and clinical characteristics of hypersensitivity to certain platinum group elements (PGEs), 153 workers employed at a catalyst production plant in Rome were skin prick tested and patch tested with palladium dichloride (and also certain platinum, iridium and rhodium chlorides). Eleven of these workers were described as “white collar” employees (office personnel with no prior PGE exposure), 105 with low prior exposure to PGEs, and 37 with high prior exposure to PGEs. Prick test and patch test readings were scored according to international guidelines, 25 minutes and two days after skin testing.

Positive skin prick tests to PGEs at various concentrations were seen in 22 (14%) of the 153 workers. Of these 22 subjects with positive reactions, none reacted to skin prick tests with aqueous solutions of palladium dichloride (10 -3 -10 -6M), but one gave a positive skin patch test result (to palladium dichloride at 10 -2M). This subject had been pre-diagnosed with work-related asthma and eczema, and also rhinitis (suggesting possible work-related skin and respiratory sensitization). There was no history of urticaria. 

Skin patch tests produced a positive reaction to palladium dichloride in one worker out of 142 with prior exposure to PGE. No positive reactions were seen following skin prick tests with palladium dichloride in these 142 workers, and no positive skin reactions (following prick tests or patch tests) to palladium dichloride were seen in eleven office personnel with no prior exposure to PGEs.