Immune System Disorders - Summary of PCB Effects

Immune system disorders may be cause by PCB chemical exposure.

Please give page time to load

Summary of Results

23 Studies of PCB Effects and Human Immune System Disorders

(Each entry represents one finding in a study --- unless otherwise noted. Some studies had multiple findings.)

All 23 studies summarized below showed some aspect of immune system disorders caused by PCB exposure. Keep in mind that not all studies are equal in size or quality. Some examine the effects of old PCB commercial mixtures (which had variable composition), or just one or two individual types of PCBs (out of 209 possible.) This accounts for some of the varying results. It’s clear that not all PCBs have the same effects and only some are immunotoxic. Some of the studies are from the 1970s when scientists were just learning about immune effects. Some studies use high and some use low doses of PCBs. In some cases, the exact PCB dose was unknown. The types of PCBs which have lingered in our area and accumulated in Fox River and Green Bay fish are likely to be the more toxic and persistent PCB types.

background levels of PCB/dioxin exposure influences the human fetal and neonatal immune system. (2 studies)
background levels of organochlorine compounds through the breast milk influences the human neonatal immune system (3 studies)
chlorinated dioxins and related chemicals from the breast milk correlated negatively with the percentages of CD8 positive lymphocytes
increase in the total number of T cells
increase in the number of TcR gamma delta+ T cells
increased in the number of CD8+ (cytotoxic), TcR alpha beta+, and TcR gamma delta+ T cells
lower monocyte and granulocyte counts
no relationship between pre- and postnatal PCB/dioxin exposure and upper or lower respiratory tract symptoms or humoral antibody production
PCBs are linked to long-term immune effects (decades after poisoning)
autoantibodies in patients with Yusho PCB poisoning are frequent --- (which may make them vulnerable to autoimmune disorders)
45.6% of PCB poisoned patients showed antinuclear antibodies, 12.7% rheumatoid (arthritis) factor and 11.1% thyroglobulin antibodies
serum levels of immunoglobulin A(IgA), immunoglobulin G(IgG) and immunoglobulin M(IgM) were elevated in 12.7%, 24.1% and 8.9% respectively in PCB poisoned patients
thyroglobulin antibody was detected in 19.5% of people with higher PCB exposures
mean absolute density of CD4 positive lymphocytes was higher
increased levels of dioxins and related compounds (PCBs) correlate with negative changes in lymphocyte subpopulations and CD4+/CD8+ biomarkers
dioxin and related compounds may be related to immunopathy, such as atopic dermatitis
PCB poisoned children suffer increased rates of bronchitis, respiratory tract and ear infections, and influenza attacks
suppressed immunity was not demonstrated with serum immunologic marker analyses
immune functional tests may be necessary to detect changes (such as delayed hypersensitive skin reaction, in vitro lymphocyte proliferation, and antibody synthesis following immunization)
impaired immune functioning may result in neuropsychological impairment (brain damage)
non-Hodgkin’s lymphoma (NHL) risk increases in humans with immune deficiencies or autoimmune disorders
non-Hodgkin’s lymphoma has been associated with PCB exposure (2 studies)
non-Hodgkin’s lymphoma may result from a combination of chemical immunosuppression and virus infection
eliminating PCB exposures could help prevent non-Hodgkin’s lymphoma
organochlorines have been reported to adversely affect the human immune system, reducing defenses against cancer
immune damage combined with estrogenic qualities (as with PCBs) have been linked to breast cancer
prenatal organochlorine exposure could be a risk factor for increased ear infections in infants
higher incidence of bacterial infections in babies of PCB exposed mothers
increased respiratory symptoms correlated with PCB exposure in poisoned humans, along with viral or bacterial infections
immunoglobulin-A and immunoglobulin-M levels were decreased, while immunoglobulin-G level was increased
PCB caused suppression of cellular immunity such as the delayed-type skin response to streptokinase and streptodornase
changes of lymphocyte subpopulations may be responsible for immune deficiency due to PCBs
percentages of total T cells, active T cells and Tmu cells decreased (2 studies)
decreased concentrations of IgA and IgM but not that of IgG (2 studies)
ratios of CD4+ to CD8+ T cells showed significant increasing tendency correlated with organochlorine exposure
decreased concentration of IgM and IgA but not of IgG
decreased percentage of total T-cells, active T-cells, and helper T-cells
normal percentage of B-cells and suppressor T-cells
suppression of delayed type response to recalling antigens
enhancement of lymphocyte spontaneous proliferation
significantly lower PHA and ConA lymphocyte stimulation values
release of soluble CD23 (Fc epsilon RII) was higher
thrombocyte aggregation, serotonin release and 12-HETE formation
weekly intake of fatty fish correlated negatively with proportions of natural killer (NK) cells
significant negative correlations between numbers of NK cells and blood levels of PCB 126
secretory immunoglobulin A is strongly affected
increased readiness for allergic respiratory disease, through the proof of hyperreactive mucous membranes
PCB 104 induced DNR fragmentation and killed human monocytic cells (parts of the immune system) through an unknown mechanism independent of the arylhydrocarbon (Ah) receptor
PCB 104 decreased cell viability and induced cellular morphologic features characteristic of cell death such as chromatin aggregation and apoptotic bodies
PCB 126 (dioxin-like PCB) did not kill monocytes, but potently induced CYP 1A1 in human hepatoma Hep G2 cells
thymic atrophy
reduced thymocytes
it should be possible to develop dioxin Toxic Euivalency Factors (TEFs) for PCBs causing immune system damage
inhibition of glucose uptake in human leukocytes by PCB Aroclor-1254 appears to be independent of adenosine-triphosphatase inhibition
certain PCB types had no effects on mitogen-induced DNA synthesis and immunoglobulin synthesis by lymphocytes
interference with E-rosette formation and human T-lymphocyte function
direct action on lymphocytes, for example, interference with epitopes of the CD 2-receptor or specific membrane function
PCB immune effects were consistent with the delayed type of hypersensitivity reaction seen in humans
PCB commercial mixture Aroclor 1254 inhibits uptake of lymphocyte DG and monocyte DG (2 types of leukocytes)
research methods have been developed to study PCB impacts on human leukocytes
tests have been created to selectively identify and quantify PCBs 77, 126 and 169

Summary of 45 Study Reviews

(Each entry represents one finding in a study --- unless otherwise noted. Some studies had multiple findings.)

All but one of the 45 reviews listed below indicate that PCBs are believed to be toxic to at least some portions of the human immune system.

extensive evidence has accumulated over 20 years showing immune systems of several species are a target for PCB toxicity
there is no "safe" level of PCB exposure --- any PCB exposure could carry risk, no matter how small the exposure
dioxins and dioxin-like chemicals (like PCBs) are present in the environment, food chain and body tissues at doses at or near levels supposed to cause harm to public health
background exposure levels of PCBs may change the T-cell population
non-cancer effects of chemical exposure may occur at low concentrations
to achieve human consumption levels close to zero-PCBs would require prohibition of important foods, such as fish
political judgements are made to balance public health protection with the need to prevent "excessive losses of food" (ie: fish consumption warnings are weaker than a pure public health warning would require)
dioxin is the common name for a series of 75 dibenzodioxins, 135 dibenzofurans and 209 PCBs.
PCBs are one of the 12 worst Persistent Organic Pollutants (POPs) identified by the United Nations Environment Program as requiring urgent regulatory attention
POPs are known to play a role in immune system dysfunction and greater susceptibility to disease
All of the POPs are closely related Chlorinated Organic Compounds
immune system changes occur at dioxin doses one-tenth to one-hundredth of the cancer-causing dose (certain PCBs are dioxin-like)
environmental chemicals that modify the immune functions may also interact with chemical carcinogens
the immune system can provide significant deterrants to cancer
immune suppression may increase the risk of tumors or cancer
some chemicals promote tumors indirectly by altering the functions of the immune system
PCBs promote tumors by this method
PCBs have been shown to alter tumor transplantation resistance
PCBs and dioxins may affect primary antibody response
alterations in lymphocyte subpopulations
one biomarker (test) for this effect measures the CD4/CD8 ratio (a measure of certain lymphocytes)
immune system damage is more dramatic and persistent for PCB exposed fetuses and babies, as opposed to PCB exposed adults (2 studies)
autoimmune and hypersensitivity disorders diseases may be linked to early exposure to immunotoxicant chemicals
PCBs are associated with autoimmunity and immune enhancement
immunosuppression and immunodepression equal decreased resistance to viral, bacterial, fungal, and other infectious agents or increased susceptibility to cancer
immunoenhancement equals increased risk of autoimmune reactions or allergic reactions
children exposed prenatally to PCBs and furans suffer increased respiratory disease
atrophy of major lymphoid organs
apoptotic cell death may lead to altered T-B cell ratios, and loss of regulatory cells in critical numbers leading to perturbations in immune function
disruption of the immune system could disrupt other vital systems, during early development in the womb or infancy
immune disruption may alter reproductive functions
chemical regulatory programs should be reevaluated to address concerns about non-cancer effects
immunotoxicity is one of the 3 main PCB effects used for risk assessment
it is not known how all these effects are related to functional impairment of the immune system
PCBs are potent inducers of certain cytochrome enzymes
the PCB composition of a commercial mixture is different from the PCB composition of the mixtures which humans will be exposed to, especially from food
Aroclor PCB commercial mixtures have been shown to produce immunosuppressive effects
humans accidentally poisoned with PCBs suffered compromised immune system function
laboratory animals show immunotoxic effects and thymus atrophy
the immune system is perhaps one of the most sensitive indicators for adverse PCB-induced health effects
certain PCBs bind to the body’s Ah receptor, which links to the immune system
immunotoxicity of one chemical can sometimes be modified by a second chemical
the fetus appears to be particularly vulnerable
different PCBs cause different effects
the immune systems of humans are not affected by PCBs (1993)
with the exception of sensitization, most of the PCB effects observed in animals have not yet been observed in humans (1988)
the effect of many chemicals or their metabolites on immune function are due to their direct effects or on lymphoid tissues.
a single assay of immune function may not be appropriate to detect chemical induced immune dysfunction
in 1974, scientists already had evidence of PCBs causing immune system damage
immunotoxicity is one of the most significant health effects of dioxins
a number of PCBs (the planar and the mono-ortho planar PCBs) cause effects corresponding with those of the 2,3,7,8-PCDDs (dioxins) and PCDFs (furans)
immunotoxicity studies produce variable results, using a wide variety of measures
a broad database of normal human immunological endpoints needs to be established for use in immunotoxicity assessments
chemical exposures may lead to immunosuppression, immunopotentiation, hypersensitivity or perturbed innate host resistance
No one infectious model has yet emerged as a routine screening tool to detect and assess the subtle effects that may occur in immune responses
effects on the immune system have been demonstrated in the low dose range but clear dose-effect relationships are lacking
immunological effects have been demonstrated in humans but data so far do not allow any quantitative conclusions to be drawn. Due to the lack of quantitative data from studies in humans, risk assessments have to be based on experimental animal data
observed immune changes are usually slight and do not allow firm predictions of health effects
the capacity of chemicals to trigger autoimmune diseases in humans is poorly studied because of basic research method difficulties
non-invasive tests of humans are limited
responses in the human population are heterogenous (we each have different genetic susceptibilities, so we each respond differently)
exposure levels are often low (which may make effects more subtle, infrequent or difficult to detect)
workplace exposures to toxins affecting the blood-forming and immune systems are of basic importance
immunotoxicity of PCBs is a concern in silicone oil used in eye operations
more studies are needed

Other pages in this Immunity section:

PCB Human Health Risks

Fox River Watch

Site Index

Make a Donation