Immune-based adverse reactions

Many chemicals (including pharmaceuticals but also environmental and occupational chemicals) are known to stimulate the immune system in a way that autoimmune diseases occur [61]. However, because of its multifactorial nature, the occurrence of autoimmune-like (including drug allergic) diseases is rare if considered on a compound-by-compound base. But, in some cases (e.g., in case of HIV or Herpes virus-infected individuals), adverse reactions occur at a higher rate [65, 66]. 

Immunogenicity concerns are based on a number of potential safety concerns. Adverse reactions can be based on the formation of immune complexes that can give rise to renal toxicity, complement activation, and, as recently reported, the induction of autologous antibodies that cross-react with the patient s own endogenous protein [23-28]. 

Clinical immunization safety assessment centers The National Immunization Program of the Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA, is trying to set up a network of Clinical Immunization Safety Assessment Centers (CISA). Based on standardized clinical evaluation protocols the centers will assist health care providers in evaluating patients who may have had an adverse reaction after immunization. Furthermore, the centers will evaluate newly hypothesized syndromes or events identified through the routine VAERS (28). 

AUergy is a much misused term. The well entrenched and widely accepted term hypersensitivity is reserved here for immune-based reactions. Some nonimmune reactions such as adverse reactions to NSAIDs and contrast media are referred to as sensitivities or intolerances. 

Hypersensitivity. Hypersensitivity reactions, considered to be vaccine-related based on the timing and specificity of the reactions, were reported to the United States Vaccine Adverse Event Reporting System (VAERS) following vaccination for Lyme disease and subsequently evaluated (Burmester et al., 1995 Lathrop et al., 2002). Other reported immune system-related events to vaccines included rheumatoid arthritis, immune system disorders, detection of antinuclear antibodies, lupus syndrome, and lymphocytosis (Zhou et al., 2003). These were very rare events, with each condition comprising 0.2% or fewer of the total reports. Anaphylactic responses to vaccines were also rare and were estimated at less than one case per miUion administered vaccine doses (Bohlke et al., 2003). A number of studies evaluated anaphylactic responses to the measles-mumps-rubella (MMR), hepatitis B, diphtheria or tetanus vaccines with similar findings (Dobson et al., 1995 D Souza et al., 2000 Patja et al, 2000 Pool et al., 2002). However, some of the vaccine-induced hypersensitivity reactions are attributed to components of the formulation, such as gelatin or egg, rather than the antigen itself (Patja et al., 2001 Pool et al., 2002). 

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