Hypersensitivity to tetanus toxoid

Retrospective anti-tetanus antibody responses of zoo-based Asian elephants (Elephas maximus) and rhinoceros (Rhinocerotidae)

Tetanus toxoids (TT) commercially available for use in horses and livestock are commonly used to vaccinate elephants and rhinoceros that are in human care. Although recommendations for booster intervals have changed in human and horse protocols to reduce the risks associated with hyper-immunity (i.e. B-cell anergy and hypersensitivity reactions) these have generally not been adopted in zoo protocols. Additionally, there is no evidence to demonstrate commercial TT immunogenicity in rhinoceros. In this study, a preliminary analysis of rhinoceros antibody responses to TT was conducted, in addition to an exploration of the impact of various booster frequencies on antibody responses in elephant. Retrospective analysis of archived serum samples was conducted for 9 Asian elephants (Elephas maximus), 7 southern black (Diceros bicornis minor), one southern white (Ceratotherium simum simum), and two greater one-horned (Rhinoceros unicornis) rhinoceros. Pre-vaccination (baseline) samples and those following priming vaccination (rhinoceros only), annual and non-annual boosters were targeted. A commercially available competitive ELISA kit was used to quantify serum anti-TT antibodies. Average baseline and post-vaccination anti-tetanus antibody concentrations were greater in elephant (92 mg/L ± 42, n = 3, N = 3; 125 ± 76, n = 82, N = 9) than in rhinoceros (47 mg/L ± 39, n = 8, N = 8; 44 mg/L ± 37, n = 16, N = 7). Rhinoceros antibody concentrations did not differ markedly following vaccinations from their naturally acquired high pre-vaccination concentrations. Eight elephants demonstrated antibody maintenance for 3-5 years without a tetanus booster. Additionally, although five out of nine elephants developed local reactions consistent with delayed type IV hypersensitivity following some boosters, there was no association between high antibody concentrations and increased incidence of adverse reactions. In addition, no decrease in antibody concentrations was detected as a result of annual vaccination in elephants, though this does not entirely rule out potential for B-cell anergy.

The vaccines-associated Arthus reaction

The Arthus reaction is a rare adverse reaction that usually occurs after vaccination with large and more severe local reactions, belonging to type Ⅲ hypersensitivity reaction. This reaction is characterized by pain, swelling, induration (Tissue that becomes firm) and edema, even accompanied by severe necrosis or ulceration at the injection sites. However, most of mild cases generally can be cured without treatment, and only severe cases need to be treated with anti-allergy. Therefore, this adverse reaction is often ignored by people.We searched PubMed, Web of Science and Chinese database (CNKI database and Wan Fang database) for published studies using the terms "Arthus reaction" or "Arthus phenomenon", combined with "vaccine", with no date or language restrictions for all publications before January 28, 2019. Only 30 cases of Arthus reaction were found, of which only one case died.4 cases of Arthus reaction post-dose-1 were reported in the review. The proportion of Arthus reaction occurred after the first, second and third injections in those case reports was 13.3%, 50.0%, and 23.3%, respectively. Arthus reaction was determined according to the clinical symptoms (The symptoms which were observed by the researchers, such as red, swelling and painful with itching at or around the injection sites). The specific causes of Arthus reaction after one dose of vaccination are not described in detail in literatures. Therefore, it could be hypothesized that the case has a pre-existing specific IgG (Such as pre-existing antibody, etc.) to cause the Arthus reaction.And 17 reported cases were observed in children younger than 6 y. In addition, we collected only 18 cases of bacterial vaccine-induced Arthus reaction and 12 cases of viral vaccines. However, there are no other data (Such as the total number and incidence rate of vaccination) in literatures, so we cannot compare statistically significant differences. At presents, no previous reviews of vaccine-induced Arthus reaction have been found. Thus, a systematic review about vaccine-associated Arthus reaction is urgently needed to deepen people's understanding and concern of this phenomenon. In this manuscript, we retrospectively reviewed the description of the discovery process and mechanisms of Arthus reaction, a description of the characteristics of Arthus reaction cases, reporting the Arthus reaction cases in China during 2010-2015, diagnostic criteria and general treatment, preventive measures of Arthus reaction, and challenges remaining to be investigated in the future.

Vaccine allergy

Overdiagnosis of vaccine allergy is considered a major public health problem. This article discusses the different types of allergic reactions after immunization based on the timing (immediate vs nonimmediate) and the extent of the reaction (local vs systemic). The vaccine components potentially responsible for an allergic reaction are discussed, as well as the management of patients with a history of reaction to a specific vaccine and those with a history of allergy to one of the vaccine components.

Vaccine allergies

Currently, the increasing numbers of vaccine administrations are associated with increased reports of adverse vaccine reactions. Whilst the general adverse reactions including allergic reactions caused by the vaccine itself or the vaccine components, are rare, they can in some circumstances be serious and even fatal. In accordance with many IgE-mediated reactions and immediate-type allergic reactions, the primary allergens are proteins. The proteins most often implicated in vaccine allergies are egg and gelatin, with perhaps rare reactions to yeast or latex. Numerous studies have demonstrated that the injectable influenza vaccine can be safely administered, although with appropriate precautions, to patients with severe egg allergy, as the current influenza vaccines contain small trace amounts of egg protein. If an allergy is suspected, an accurate examination followed by algorithms is vital for correct diagnosis, treatment and decision regarding re-vaccination in patients with immediate-type reactions to vaccines. Facilities and health care professionals should be available to treat immediate hypersensitivity reactions (anaphylaxis) in all settings where vaccines are administered.

Quantifying monocyte infiltration in response to intradermal tetanus toxoid injection

Aims: To characterize monocyte response in a delayed-type hypersensitivity reaction to intradermal tetanus toxoid (TT) injection. Materials & methods: Men with positive serum anti-tetanus titers were stratified by last TT vaccination. Subjects were administered three intradermal injections of TT and one saline control on the same side of the back. Skin biopsies were taken post-injection. After 2 weeks, the procedure was repeated on the contralateral side. Results: Men who received TT booster vaccination 1 month before the study showed greater reproducibility and lower variability in monocyte responses than those who were not revaccinated. Monocyte concentration in subjects re-vaccinated within 1 month of study start appeared maximal at 48 h post-injection. Conclusion: This assay represents a novel approach that allows for quantification of dermal monocyte/macrophage influx. This clinical methodology has potential utility in the pharmacodynamic evaluation of therapies targeting inflammatory disorders, which involve monocyte tissue recruitment, like the delayed-type hypersensitivity response.

Use of granulocyte-macrophage colony-stimulating factor to reverse anergy in otherwise immunologically healthy children

BACKGROUND

T-cell anergy, as measured by delayed hypersensitivity skin testing, is associated with increased susceptibility to infection. Because the repertoire of effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) includes enhancement of antigen processing and presentation by antigen-presenting cells, GM-CSF has been used to augment immune function in human immunodeficiency virus-induced and other viral illness-induced immune dysfunction and to affect positively immune function in a wide variety of disorders.

OBJECTIVE

To attempt reversal of T-cell anergy using GM-CSF in 3 otherwise immunologically healthy children with severe recurrent and persistent viral respiratory tract infections and in one child with recurrent bacterial sepsis.

METHODS

After written informed consent and baseline data were obtained, the study participants were administered 3 two-week cycles of GM-CSF. Delayed hypersensitivity skin testing and laboratory tests were repeated 2 weeks after the third cycle and subsequently as clinically indicated.

RESULTS

All 4 children developed delayed hypersensitivity by skin testing, and all demonstrated markedly decreased number and severity of infection. Improvement persisted in all patients for at least 1 year. A single cycle of additional treatment in 2 patients reestablished delayed hypersensitivity and decreased infection, both of which persisted throughout the follow-up period of 4 or more years.

CONCLUSIONS

GM-CSF treatment reversed T-cell anergy in 4 children. Reestablishment of delayed hypersensitivity was associated with a significant decrease in infection. Although further studies will be needed, use of GM-CSF should be considered as an immune modulator in patients with T-cell anergy and recurrent infections.

Assessment of nine candidate DTP-vaccines with reduced amount of antigen and/or without adjuvant as a fourth (booster-) dose in the second year of life

BACKGROUND

The incidence of local reactions to diphtheria-, tetanus and acellular pertussis (DTaP-) vaccines in infants and toddlers increases with each subsequent dose, and entire thigh swellings (ETS) have been reported. Lowering the amount of antigen or of adjuvant may decrease the reactogenicity of DTaP while maintaining a protective immune response.

OBJECTIVES

Following priming with three doses of a DTaP vaccine during infancy, the safety, reactogenicity and immunogenicity of nine different candidate DTaP-vaccines with reduced amounts of antigen and/or adjuvant given as fourth (booster) dose were evaluated.

METHODS

Study participants were healthy infants aged 15-27 months at the time of booster vaccination. Each participant had received three doses of a DTaP vaccine (Infanrixtrade mark, GlaxoSmithKline, Rixensart, Belgium; "reference DTaP") at age 3, 4, and 5 months as part of a previous clinical trial. More than 20,000 children were eligible for participation in the current study protocol at the time. In a first phase at a University hospital-based vaccination study center, nine sequential cohorts of 63-119 study subjects received one of nine different candidate vaccines. Patients and study personal were blinded with regard to which vaccine was currently in use. Reactogenicity was solicited from parents using diary cards. Blood was drawn prior to and 4 weeks after vaccination and immediately centrifuged. The serum was stored at -20 degrees C until serology was performed by ELISA tests. As soon as the first candidate vaccine with adequate reactogenicity and immunogenicity profile was identified in the first study phase, a second study phase was initiated in parallel, to evaluate the safety and reactogenicity of the respective candidate vaccine in private practices in large cohorts (1613-2095 study subjects per group).

RESULTS

In the first study phase, DTaP with no aluminum induced the highest frequency of ETS and fever. All other candidate vaccines caused lower rates of local and general reactions than the reference DTaP. As a general rule, vaccines with less antigen induced fewer reactions, although there was no strict dose-response effect and the difference, e.g. between a one-tenth and a one-fifth DTaP dose (DTaP 1/5; DTaP 1/10) was not clinically relevant. Separate injections of Td and aP caused fewer general reactions than the respective TdaP combination and local reactions were higher at the aP than at the Td injection site. Again, as a general rule, reduced amounts of antigen induced lower antibody concentrations, although all vaccines induced "protective" anti-tetanus and anti-diphtheria antibody responses. A total of 92-100% of children showed seroresponses to pertussis antigens even when vaccinated with reduced amounts of the respective pertussis antigen. Elimination of aluminum from DTaP vaccine induced higher anti-tetanus-antibody concentrations and so did a reduction of the amount of diphtheria antigen. Additional examples for antigen interaction were increased antibody concentrations, observed with injection of Td and aP into different limbs. In the second study phase, all three vaccines evaluated (one with a reduced amount of diphtheria antigen, TdaP; one with reduced amounts of all antigens, tdap; and one with a fifth dose of the reference vaccine (DTaP 1/5)) were safe and had an acceptable reactogenicity profile in a total of 4871 study subjects.

CONCLUSIONS

Local reactions due to DTaP booster doses in the second year of life can be reduced by reducing the amount of antigen in the respective vaccine while an adequate immunogenicity is maintained. Aluminum-free vaccines induced ETS and fever most commonly. Any changes in vaccine composition should lead to a full evaluation of the new product.

Immediate allergy to tetanus toxoid vaccine: determination of immunoglobulin E and immunoglobulin G antibodies to allergenic proteins

BACKGROUND

Adverse reactions to tetanus toxoid (TT) vaccine are mostly mild and limited to the injection site. However, immunoglobulin (Ig)E-mediated reactions may occur, and the incidence of anaphylactic responses to TT immunization is 0.001%. When TT induces an allergic reaction, the potential causative agents can be TT antigens, thimerosal or aluminum phosphate.

OBJECTIVE

We studied four children who developed immediate urticaria after TT vaccine, soon after the reaction and 5 years later.

METHODS

Skin tests were performed separately with TT vaccine and two vaccine components, thimerosal and aluminum phosphate, and the diagnosis was confirmed by provocation test. IgE and IgG antibodies to TT and their specificities were determined. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting were performed to characterize the antigenic proteins.

RESULTS

All four children were immediate skin test-positive to TT, but negative to thimerosal and aluminum phosphate; 3 developed a reaction after intramuscular provocation using increasing doses of TT vaccine; and 1 refused to be tested. All these tests were negative in five controls, all of whom received TT vaccine and developed only local swelling at the site of application 24 hours after vaccine administration. After 5 years the IgG antibodies were still high in all cases and the IgE antibody values fell by 50%. Patients allergic to TT vaccine produced IgE and IgG antibodies, which decreased at different rates but remained for at least 5 years. The pattern of antibody decrease was confirmed by radioallergosorbent test, enzyme-linked immunoadsorbent assay, or immunoblotting assay. IgE and IgG antibodies recognized two proteins derived from TT, of 150 and 50 kDa, corresponding to the intracellular form and to a chain of the extracellular form of the tetanus neurotoxin.

CONCLUSIONS

In children with immediate allergic reactions to TT vaccine, antibodies may persist for at least 5 years, requiring evaluation by skin and/or in vitro tests before subsequent treatment.

Arthus reaction to recombinant hepatitis B virus vaccine

A severe, local, inflammatory, late-phase reaction accompanied by skin necrosis occurred after an infant was given an intramuscular injection of recombinant hepatitis B virus vaccine. The clinical course and appearance of the rash were typical of an Arthus reaction. Although not identical to this case, prior reported cases of complement-mediated reactions occurring after hepatitis B virus infection or vaccination provide theoretical support for this diagnosis.

Immediate and longterm effects of immune stimulation: hypothesis linking the immune response to subsequent physical and psychological wellbeing

We hypothesize that antigenic stimuli in susceptible persons during key developmental life stages alters neuroendocrine-immune organization and leads to the development of aberrant immune and neuroendocrine responses to subsequent environmental stressors, with longterm physical and psychological consequences. The release of interleukin-1beta (IL-1beta) and other proinflammatory cytokines associated with the immune response during times when individuals are most vulnerable to the effects of environmental influences activates the hypothalamic-pituitary-adrenal (HPA) axis and leads to maladaptive responses to subsequent stressors. The primed HPA axis is reactivated by proinflammatory cytokines, resulting in the secretion of corticotropin-releasing hormone (CRH) and cortisol, followed by physical and psychological effects that feedback on the HPA axis to produce an array of outcomes affecting general wellbeing. Through the release of histamine and other mediators and their effects on the mast cell-leukocyte cytokine cascade, immune stimuli in susceptible persons increase allergic inflammation and magnify stressors' effects through the release of HPA-axis-activating cytokines, such as IL-1beta, that drive the axis and reinforce the physiological and behavioral effects. Thus, specific proinflammatory cytokines and allergic reactions initiate, promote, and maintain immune-stimulus-associated HPA axis activity, and with CRH and cortisol, participate in a positive feedback loop, resulting in aberrant, maladaptive responses to physical or psychological stressors, with outcomes such as depression, hyperalgesia, and pain-related behavior.

Neonatal tetanus in Peru: risk assessment with modified enzyme-linked immunosorbent assay and toxoid skin test

We used a modified enzyme-linked immunosorbent assay (ELISA) to investigate tetanus immunity in 232 pregnant Peruvian women. One hundred forty-two (61.2%) had protective antitoxin titers (> or = 0.01 IU/mL). Protective titers correlated positively with the number of toxoid doses reported during the current pregnancy. A majority of women reporting no toxoid doses during the current pregnancy had at least one prenatal health care visit. We evaluated a toxoid skin test in 44 of the subjects, but it correlated poorly with the ELISA. The modified ELISA is a useful in vitro method for studying tetanus immunity in the developing world.

Snake venom coagulopathy: use and abuse of blood products in the treatment of pit viper envenomation

Coagulopathies are commonly encountered in victims of pit viper envenomation. In the majority of patients these defects improve with administration of antivenin. However, blood products are often transfused based on arbitrary criteria and with significant risk to the patient. This article documents the effectiveness and risks of antivenin administration and the risks of blood product transfusion. We recommend that blood products not be used except for clearly defined clinical indications.

Detection of tetanus antitoxin using Eu(3+)-labeled anti-human immunoglobulin G monoclonal antibodies in a time-resolved fluorescence immunoassay

Tetanus antitoxin in human sera was detected with solid-phase immunoassays in microtitration modules coated with tetanus toxoid by using Eu(3+)-labeled anti-human monoclonal antibodies on the basis of an exactly calibrated antibody standard. The use of a time-resolved fluorescence immunoassay (TR-FIA) significantly improved the quantitative detection of tetanus antitoxin over that of the enzyme-linked immunosorbent assay (ELISA) technique because of its high sensitivity and its wide measurement range, detecting antibody levels between 0.001 and 12.5 IU/ml with a single serum dilution of 1:100. For the same purpose, two different serum dilutions (1:100 and 1:1,000) were needed in the ELISA technique. TR-FIA is reproducible and can be performed in 3.5 h. A study of 2,630 serum samples was undertaken to examine the age-dependent distribution of titer levels, indicating the decline of sufficient protection in patients older than 60 years. The wide measurement range of TR-FIA enabled fast examination of large numbers of serum samples without the need for repetition, with further sample dilution, as was often necessary in the ELISA procedure.

Selection of plasma donors suitable for tetanus boosting

As a result of a comparative trial examining the immunogenicity and clinical reactivity of two tetanus vaccines, 33 donors with high antibody levels were plasmapheresed over 6 months for the collection of tetanus hyperimmune plasma. Serial antibody assay results and the frequency of adverse reactions were analysed to define the donors most suitable for an immune plasma programme. A high proportion of boosted donors were withdrawn from plasmapheresis because of poor persistence of antibody levels. Donors most suitable for boosting appear to be males under 25 years old with a tetanus antibody level of around 8 IU/ml prior to boosting.

A study of the factors influencing tetanus immunity in Israeli male adults

In Israel the immune status of the adult population is largely unknown, because many adults have immigrated from various countries and have no reliable record of immunisation. The Israel Defence Force has implemented a preventive booster immunisation schedule for all its members. The immunity of the adult male population as well as the factors contributing to it were measured and 77.3% found to have sufficient tetanus antibody for protection. The antibody titres in the 3241 subjects studied were found to depend on age. In the older age groups (45-54 years) over one-third had less than 0.01 IU/ml, but even among those of 21-30 years 14% were 'unprotected', if 0.01 IU/ml is taken as the threshold value. Apart from age, the only other contributing factors identified were the occupation as a civilian, education and the number of years since the last immunisation. In our view, the findings call for an immunisation schedule based in each individual country on population serosurveys.

Misuse of tetanus immunoprophylaxis in wound care

We prospectively studied medical personnel compliance with antitetanus prophylaxis in 211 patients with wounds in three emergency departments. The guidelines were incorrectly followed in 13.4% of the patients, with 88.9% of the mistakes resulting from overimmunization. The most common mistake was the practice of giving tetanus and diphtheria toxoid (Td) to a patient with a clean wound who had complete primary immunization and a booster within ten years. This mistake accounted for 63% of the mistakes. The next most common, accounting for 18.5%, was the practice of giving Td and tetanus immune globulin to the never-immunized patient who had sustained a clean wound. Overimmunization increases the possibility of adverse reactions, and undertreatment places the patient at risk for tetanus.

A new rapid semi-quantitative enzyme immunoassay suitable for determining immunity to tetanus

A sensitive enzyme immunoassay for rapidly assessing a patient's state of immunity to tetanus is described. The test, which uses 50 microliter sample of blood, plasma or serum, is done in a capillary tube and, by comparison with two adjacent reference tubes containing standardised sera, places immunity to tetanus in one of three categories--low-negative (less than 0.01 IU/ml), intermediate (0.01-1.28 IU/ml) or high (greater than 1.28 IU/ml). In a study of 90 clinical specimens assayed both by toxin neutralisation bioassay and capillary enzyme immunoassay the enzyme immunoassay accurately assessed the state of immunity to tetanus of the patients concerned.

Delayed cutaneous hypersensitivity in normals: choice of antigens and comparison to in vitro assays of cell-mediated immunity

In 81 normal subjects, ages 19 to 100 yr (mean 52), we studied the prevalence of positive 48 hr skin reactions to six antigens: fluid tetanus toxoid, Candida albicans, SK/SD, Trichophyton, PPD, and coccidioidin. Of these, C. albicans was most frequently reactive (92%); SK/SD (51%) and tetanus (49%) were less so. Each of the remaining three antigens was reactive in less than 42% of the subjects. The minimum number of antigens required to detect delayed hypersensitivity in 100% of subjects was two: C. albicans and tetanus. We found no correlation between skin reactivity at 20 min, 6 hr, and 48 hr for most of the antigens studied, suggesting different mechanisms for reactions occurring at each time. In 60 of the subjects, lymphocyte stimulation index (LSI) with tetanus toxoid and monocyte chemotaxis (MC) assays were done. The natural log of the area of induration at 48 hr after tetanus skin testing (I48) increased as a function of LSI (p less than 0.005) and MC (p less than 0.025) by multiple regression analysis. Skin testing was less sensitive than LSI as a test for cell-mediated immunity in our population. However, because of availability and correlation with LSI, delayed cutaneous hypersensitivity should be tested initially. For this purpose, tetanus toxoid appears to be a useful antigen when used in combination with C. albicans.

Delayed hypersensitivity to tetanus toxoid in man: in vivo and in vitro studies

The frequency of positive delayed hypersensitivity skin test reactions to tetanus toxoid in 47 healthy volunteers was 80%. The frequency of immediate hypersensitivity was low (8%) and there was less discomfort than with streptokinase or PPD. There was good correlation between leukocyte migration inhibition and delayed hypersensitivity skin testing, and a quantitative relationship was demonstrated between diameter of cutaneous reaction and degree of leukocyte migration inhibition. No relationship was demonstrated between any measures of immune responsiveness and the interval from the last booster immunization. It was concluded that tetanus toxoid is a valuable antigen for assessment of delayed hypersensitivity in man.

Delayed hypersensitivity to mumps antigen in humans

Sixty-one subjects, preselected for mumps sensitivity, were entered into a double-blind protocol to standardize Mumps Skin Test Antigen. Four lots of mumps antigen selected on the basis of in vitro potency tests were used. Four other antigens, Histoplasmin, Dermatophytin-O, Dermatophytin, and fluid tetanus toxoid were also tested; positive reactions for these four antigens occurred in 48, 68, 25, and 43% of individuals, respectively. The mumps lots exhibited delayed hypersensitivity with positivity ranging from 63 to 67% at 20 CFU/ml and 77 to 84% at 80 CFU/ml in the acceptable lots. Side effects were primarily local and minor in nature. Mumps Skin Test Antigen is a useful measure of the integrity of the immune system, but lacks complete specificity because of local dermal factors.

Use of tetanus toxoid for testing cell-mediated immunity

Tetanus toxoid was assessed as a skin test antigen for the measurement of cutaneous delayed-type hypersensitivity (DTH) by comparing the responses to intradermal injections of aqueous tetanus toxoid and an extract of Candida albicans in 50 randomly selected healthy adults and 10 adults with immunodeficiency. Of 42 healthy subjects previously immunised with tetanus toxoid, 33 (79%) reacted to tetanus toxoid and 33 (79%) reacted to Candida albicans. Of eight non-immunised subjects, none reacted to tetanus toxoid although five reacted to Candida albicans. Ten immunodeficient adults previously shown to be anergic to a standard panel of five skin test antigens including Candida albicans, and who had received primary immunisation and booster doses of tetanus toxoid, were anergic on current testing with tetanus toxoid and Candida albicans. Tetanus toxoid in previously immunised subjects has certain advantages as a "recall" DTH test antigen over the standard skin test antigens candidin, mumps, trichophyton, tuberculin and streptokinase-streptodornase used to diagnose cell-mediated immuno-deficiency. It is a sensitive measurement of DTH, it recalls a defined immunological event, it has a low incidence of side effects, and it produces a slight but beneficial boosting of serum antibody to tetanus toxoid.

In vivo and in vitro cell-mediated immunity to tetanus toxoid in adults

The purpose of this study was to evaluate tetanus toxoid (TT) as an indicator of cutaneous delayed hypersensitivity (CDH) in adults. Fifty-two normal subjects, aged 25 to 64 yr, were skin tested with TT and streptokinase-streptodornase (SK/SD). Lymphocyte transformation was studied in seven normal TT reactors, four normal TT nonreactors, and seven hospitalized anergic patients. CDH was common with both TT and SK/SD; 90% of the adults, aged 25 to 39 yr, had CDH reactions to TT and 79% had CDH reactions to SK/SD. In adults aged 40 to 64 yr, 75% had DCH reactions to TT and 59% had CDH reactions to SK/SD. Lymphocyte transformation to TT correlated well with TT skin-test results. Punch biopsy specimens of TT reactions 48 hr after skin testing demonstrated DCH. We conclude that TT is an excellent antigen for assessing the presence or absence of CDH in adults aged 25 to 64 yr.

Acute hemolytic anemia related to diphtheria-pertussis-tetanus vaccination

Three infants developed severe hemolytic anemia following the second or third diphtheria-pertussistetanus vaccination. Direct antiglobulin tests were positive, and the infant most severely affected also had reduced serum complement levels, indicating an immunological mechanism for the hemolysis. The presence of IgM on the erythrocytes from 2 of the infants could be demonstrated by antiglobulin tests or immunization experiments. Heat eluates of the erythrocytes from one of the infants contained antibodies to tetanus and diphtheria toxoids, as well as to Bordetella pertussis, suggesting that these antibodies were antigenically bound to the erythrocytes. Virus antibodies or isoagglutinins, present in the serum, were not found in the eluate. No antibodies against the vaccine components could be demonstrated in eluates of erythrocytes from control subjects. In vivo experiments showed that tetanus and diphtheria toxoids were easily bound to human erythrocytes. This finding could help explain the pathogenesis of the autohemolysis.