Halogenated organic compounds and the human immune system: preliminary report on a study in hobby fishermen

Relation of serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) level to hematological examination results in veterans of Operation Ranch Hand

The authors studied indices of hematologic function and exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Vietnam War veterans of Operation Ranch Hand--the Air Force unit responsible for the aerial spraying of Agent Orange and other herbicides in Vietnam. The herbicides were contaminated with TCDD. The authors measured TCDD serum levels in 1987 or later and extrapolated the result to the time of service in Vietnam. The authors studied serum TCDD level in relation to red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, white blood cell count, platelet count, and erythrocyte sedimentation rate at each of 4 physical examinations. Compared with veterans not involved in Operation Ranch Hand, those with the highest TCDD levels in Operation Ranch Hand had mean corpuscular volumes that were about 1% higher and platelet counts that were about 4% higher. These small increases were unlikely to be of clinical significance and may not have been caused by TCDD.

Diesel exhaust particles and carbon black have adjuvant activity on the local lymph node response and systemic IgE production to ovalbumin

The possible adjuvant effect of diesel exhaust particles (DEP) on the response to the model allergen ovalbumin (OA) was studied in BALB/c mice using the popliteal lymph node (PLN) assay. In addition to changes in PLN weight, cell numbers and cell proliferation, specific serum IgE anti-OA antibody levels were measured. OA inoculated together with DEP into one hind footpad gave a significantly augmented response (increase in weight, cell numbers and cell proliferation) in the draining popliteal lymph node as compared to DEP or OA alone. Also, the local lymph node response was of longer duration when DEP were given with the allergen. Experiments in thymus-deficient nu/nu mice indicated that the lymph node response observed in BALB/c mice was of a specific immunologic character and not an unspecific inflammatory reaction. The OA-specific IgE response was increased in mice receiving OA together with DEP as compared to the response in mice receiving OA without DEP. Carbon black (CB) was given with and without OA in some experiments, as a surrogate for the non-extractable core of DEP. CB was found to resemble DEP in its capacity to increase the local lymph node response and serum specific IgE response to OA, but CB appeared to be slightly less potent than DEP. Thus, both DEP and CB had a significant adjuvant effect on the local immune-mediated inflammatory response and on the systemic specific IgE response to allergen. The results indicate that the non-extractable particle core contributes substantially to the adjuvant activity of DEP.