Induction and measurement of in vivo antibody responses

The capacity of the human immune system to mount an antibody response following in vivo immunization with a protein or polysaccharide antigen is a revealing indication of the overall integrity of both the B and T cell arms of the immune system. As such, in vivo immunization followed by measurement of the antibody response is an appropriate test of immune function in the various acquired and congenital immunodeficiencies and in a host of other conditions affecting the immune system. This unit describes procedures for in vivo immunization and for the measurement of the subsequent immune response using an ELISA technique.

Mosquito bite pathogenesis in necrotic skin reactors

Mosquito bite exposure results in a variety of reactions and secondary complications. Clinical hypersensitivity manifests primarily as local reactions with anaphylaxis being a very rare event. Risk factors for more severe local reactions include immunodeficiency, young children and visitors to an area with new exposure to indigenous mosquitoes. Necrotic skin reactions to mosquito bites have been associated with a newly recognized hemophagocytic syndrome in predominantly oriental populations. Diagnostic and therapeutic agents in the clinical management of mosquito hypersensitivity remain limited, but recent discovery of 3 recombinant proteins (rAed a 1, rAed a 2, rAed a 3) shared by several mosquito species promise to be more specific skin test antigens for the future.

Cell-mediated immune response to tuberculosis antigens: comparison of skin testing and measurement of in vitro gamma interferon production in whole-blood culture

Although delayed-type hypersensitivity skin testing with tuberculin purified protein derivative (PPD) is the standard for tuberculosis screening, its variability suggests the need for a more sensitive, noninvasive test. An in vitro whole-blood assay has been proposed as an alternative. Using health care worker volunteers, we confirmed the correlation between PPD skin test (PPD-ST) results (positive, induration of >15 mm) and a standardized gamma interferon (IFN-gamma) assay, QuantiFERON-TB (Q-IFN), manufactured by CSL Biosciences in Australia, and we evaluated Mycobacterium tuberculosis culture subfractions as potential substitutes for PPD. Twenty healthy volunteers with positive PPD-ST results and 20 PPD-ST-negative controls were enrolled. Whole blood was cultured with human PPD antigens (HuPPD), Mycobacterium avium complex (MAC) PPD, phytohemagglutinin (PHA), and four M. tuberculosis culture subfractions: low-molecular-weight culture, filtrate, culture filtrate without lipoarabinomannan, soluble cell wall proteins, and cytosolic proteins, all developed from M. tuberculosis strain H(37)RV. Secretion of IFN-gamma (expressed as international units per milliliter) was measured by an enzyme immunoassay. The PPD or subculture fraction response as a percentage of the PHA response was used to determine positivity. Sixteen of 20 PPD-ST-positive individuals were classified as M. tuberculosis positive by Q-IFN, and 1 was classified as MAC positive. Sixteen of 20 PPD-ST-negative individuals were M. tuberculosis negative by Q-IFN, 2 were MAC positive, and 2 were M. tuberculosis positive. The tuberculosis culture subfractions stimulated IFN-gamma production in PPD-ST-positive volunteers, and significant differences could be seen between the two PPD-ST groups with all subfractions except soluble cell wall protein; however, the response was variable and no better than the Q-IFN PPD. The agreement between the Q-IFN test and the PPD-ST was good (Cohen's kappa = 0.73). The Q-IFN assay can be a useful tool in further studies of immune responses to M. tuberculosis antigens.

Varicella immunity: persistent serologic non-response to immunization

OBJECTIVE

Varicella-zoster (VZV) infection is an occupational hazard for health care workers. The "gold standard" for assessing protection is a positive antibody titer. We present a case of persistent serologic non-responsiveness following VZV immunization and discuss a management strategy.

METHODS

A 29-year-old woman, immunocompetent pediatric resident was repeatedly removed from her clinical duties because of a negative history of chicken pox and the absence of a VZV antibody titer. She received a total of three doses of the VZV vaccine and continued to have a negative antibody titer as measured by a commercial ELISA assay (Wampole). Subsequently, she had three direct contacts with infectious children and did not develop clinical chicken pox.

RESULTS

A lymphocyte proliferation assay was performed using inactivated varicella vaccine and tetanus antigens. The patient's varicella and tetanus stimulation index (SI) were 46.5 and 42, respectively. The SI for the positive control (a patient recently recovered from a wild type infection) were 144 (varicella specific), and 114 (tetanus). The SI secondary to VZV antigens reported in the literature is 30.5 +/- 9.1. We reassessed the varicella antibody titer using more sensitive assays: fluorescent antibody to membrane antigen and latex agglutination. Both tests verified the presence of VZV specific IgG at a titer of 1:8 in our patient.

CONCLUSION

This case illustrates that in a subgroup of individuals the antibody response to VZV vaccine may be low despite an adequate cell-mediated response. Commercial VZV ELISA assays were designed to measure higher titers associated with natural infection rather than the lower titer induced by the vaccine. Repeated immunizations plus more sensitive measures of VZV-specific IgG should be used to validate protection rather than the current commonly utilized ELISA screening. Clinicians should be aware of the variability in VZV-specific antibody assays when assessing post VZV vaccine titers prior to determining protection in health care workers.

Probenecid hypersensitivity in AIDS: a case report

BACKGROUND

Cidofovir plus probenecid is a new therapeutic alternative for refractory cytomegalovirus and acyclovir-resistant herpes infections in AIDS patients. Probenecid is used in conjunction with the antiherpetic medication (cidofovir) in order to reduce the incidence of nephrotoxicity by cidofovir.

OBJECTIVE

To present therapeutic alternatives for successful administration of probenecid to AIDS patients who develop a hypersensitivity reaction to the medication.

METHODS AND RESULTS

We describe a patient with AIDS who was being treated with the cidofovir/probenecid combination for a peri-anal acyclovir-resistant herpetic infection. The patient subsequently developed a cutaneous hypersensitivity reaction to probenecid alone. A pretreatment regimen consisting of prednisone, H1 and H2 blockers was administered before the dosing of probenecid in order for the patient to continue with the antiviral therapy.

CONCLUSION

Cutaneous hypersensitivity reactions to probenecid may be seen more frequently with the increasing use of cidofovir in AIDS patients. Our pre-treatment protocol is one therapeutic alternative to be considered in order to continue with probenecid.

Immediate hypersensitivity to human recombinant granulocyte-macrophage colony-stimulating factor associated with a positive prick skin test reaction

BACKGROUND

Recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF), also known as sargramostim, is used to accelerate myeloid recovery following bone marrow transplantation or cytotoxic chemotherapy. "Anaphylactic" reactions to sargramostim have been reported on a limited basis and are poorly characterized.

OBJECTIVE

It is the purpose of this report to describe an adverse reaction to sargramostim treatment involving palmar itching, urticaria, angioedema, and throat tightness and to demonstrate the utility of prick skin testing to determine type I sensitization.

METHODS

Prick skin testing with 100 and 250 micrograms/mL sargramostim and 300 micrograms/mL rhu G-CSF (filgrastim) was performed in the patient and four control subjects.

RESULTS

The patient experienced an immediate wheal and flare reaction with both concentrations of sargramostim while the control subjects demonstrated no reaction. There was also no reaction with filgrastim (rhu G-CSF) in either group and the patient subsequently tolerated filgrastim therapy.

CONCLUSION

Prick skin testing with rhu GM-CSF and rhu G-CSF may be useful to demonstrate type I sensitization. Additional studies are needed to determine the incidence and prevalence of skin test reactions in larger numbers of patients with cytokine therapy exposure.

Practice parameters for the diagnosis and management of immunodeficiency. The Clinical and Laboratory Immunology Committee of the American Academy of Allergy, Asthma, and Immunology (CLIC-AAAAI)

In this brief review, only the most useful immunologic tests available for defining host defects that lead to susceptibility to infection have been emphasized. It should be pointed out that those evaluations and tests ordered by the physician will rule out the vast majority of the currently recognized defects. Finally, it is important that any patients identified as abnormal by these screening tests be characterized as fully as possible in centers specializing in these diseases before therapy is initiated, since what may appear to be a simple diagnosis on the surface may be an indicator of more complex underlying problems.

Tannic acid's effect on bird antigen

BACKGROUND

Birds have been associated with many diseases including hypersensitivity pneumonitis and allergic diseases such as asthma and rhinitis. Bird antigen from homes of patients with hypersensitivity pneumonitis persists long after the bird is removed from the home. This may account for the persistence of symptoms, signs, and bird-specific IgG in patients with hypersensitivity pneumonitis. Tannic acid application has been effective in decreasing cat and mite allergen levels. No data have been available on tannic acid's effect on bird antigen.

OBJECTIVE

It is the purpose of this study to determine whether tannic acid reduces bird antigen in the home.

METHOD

Dust samples were collected from homes with bird antigen before and after application of tannic acid. Samples were assayed for bird antigen levels using a competitive inhibition ELISA. Pre- and post-bird antigen levels were compared using a paired t test to determine whether antigen was reduced significantly.

RESULTS

There was not a statistical difference between bird antigen levels before and after application of tannic acid as compared by paired t test (P = .09).

CONCLUSION

Tannic acid is not effective in decreasing bird antigen levels. In patients with hypersensitivity pneumonitis or allergic disease to birds, the bird should be removed from the home and environmental cleanup should be undertaken, but tannic acid application is not indicated.

Chronic sulfasalazine therapy in the treatment of delayed pressure urticaria and angioedema

BACKGROUND

Delayed pressure urticaria/angioedema can be profoundly disabling with painful and prolonged swelling of feet and hands as well as systemic symptoms of malaise and flu-like illness. Occupations requiring prolonged standing and forceful use of hands may be seriously compromised by this condition. The severe forms of the disease are usually unresponsive to antihistamines and nonsteroidal anti-inflammatory drugs, and patients frequently require corticosteroids for control of symptoms.

OBJECTIVE

It was the purpose of this report to evaluate the clinical utility of sulfasalazine for two patients with refractory delayed pressure urticaria.

METHODS

Sulfasalazine, starting at 500 mg/day (with weekly incremental dosing to a total of 4 g), was administered to two patients with disabling pressure urticaria and angioedema (symptomatic daily with normal activities) who had failed all other reported therapeutic options except corticosteroids.

RESULTS

Patient A required daily prednisone in excess of 30 mg (for more than 6 months) to control his painful angioedema sufficiently in order to continue working as a colorectal surgeon. Patient B also experienced daily symptoms for more than 1 year. Both patients tolerated sulfasalazine to a dose of 4 g/day without adverse reactions and achieved complete resolution of symptoms. Patient A continued to be well controlled 1 year after starting but must maintain a dose of 2 g or greater per day. Patient B reported excellent control 6 months after starting but was subsequently lost to follow-up.

CONCLUSION

Sulfasalazine, in doses used for inflammatory bowel disease, appears to be an effective alternative therapy for delayed pressure urticaria and angioedema in patients poorly controlled by traditional treatment and may act as a corticosteroid-sparing agent.

Mosquito bite anaphylaxis: immunotherapy with whole body extracts

BACKGROUND

Adverse reactions to mosquito bites have been recognized for some time. These usually consist of large local swellings and redness, generalized urticaria, angioedema and less easily definable responses such as nausea, dizziness, headaches, and lethargy.

METHODS

We report two patients who experienced systemic anaphylaxis from mosquito bites. Both were skin tested and given immunotherapy using whole body mosquito extracts.

RESULTS

Skin testing using whole body mosquito extracts was positive to Aedes aegypti at 1/1,000 weight/volume (wt/vol) in one patient and to Aedes aegypti at 1/100,000 wt/vol, and Culex pipiens at 1/10,000 wt/vol in the other. Skin testing of ten volunteers without a history of adverse reactions to mosquito bites was negative. Immunotherapy using these extracts resulted in resolution of adverse reactions to mosquito bites in one patient and a decrease in reactions in the other.

CONCLUSIONS

Immunotherapy with whole body mosquito extracts is a viable treatment option that can play a role in patients with mosquito bite-induced anaphylaxis. It may also result in severe side effects and one must determine the benefit versus risks for each individual patient.

Wheezing, hypoxia, and dyspnea in a 62-year-old woman

This patient presented with dyspnea, hypoxia, and generalized wheezing; however, her pulmonary function testing did not suggest asthma. Subsequent evaluations for conditions that may mimic asthma were not helpful. An invasive procedure (pulmonary angiogram) was required to diagnose pulmonary embolism, a potentially life threatening but treatable condition. The angiogram was performed despite nondiagnostic ventilation and perfusion scans because of a high index of suspicion for pulmonary embolism. In our patient, observation revealed episodes of sudden tachycardia, dyspnea, and increased wheezing which further raised our suspicion. Because pulmonary emboli can have such protean manifestations, it would be wise to consider pulmonary emboli in any patient with presumed asthma who has symptoms out of proportion to his or her pulmonary function testing and/or is not responding to treatment.

Venezuelan equine encephalitis-specific immunoglobulin responses: live attenuated TC-83 versus inactivated C-84 vaccine

Venezuelan equine encephalitis (VEE)-specific immunoglobulin responses to the two vaccines, TC-83 (a live attenuated vaccine) and C-84 (a formalin inactivated vaccine derived from the TC-83 strain of virus) were evaluated using an antigen and isotype-specific enzyme-linked immunoadsorbent assay (ELISA). The VEE-specific ELISA for IgG, IgG subclasses, IgA and IgM were developed and standardized using sera from vaccine-exposed and unexposed human subjects. Paired human sera (before and 28 days after immunization) were tested from laboratory workers vaccinated with either TC-83 (Group A: 20 paired sera from subjects receiving a single TC-83 vaccine and with no prior history of vaccination) or C-84 in varying schedules (Group B: 19 paired sera from subjects who had a distant vaccination history to TC-83 but no evidence of neutralizing antibody; Group C: 19 paired sera from subjects receiving their first C-84 vaccination and no prior documented history of vaccination; Group D: 15 paired sera from subjects receiving a C-84 booster vaccination with prior history of C-84 but no TC-83 exposure). Sera were all tested for viral neutralization in vitro using a Vero cell monolayer for culturing virus and establishing 80% plaque reduction for each serum tested. All pre-sera tested demonstrated no plaque reduction neutralization at a level of 80% for a dilution of 1:10. ELISA antibody titers for all pre-sera with no prior VEE exposure through vaccination or possible environmental factors were negative at a titer of 1:160 for IgM, 1:80 for IgG, IgA, and G subclasses.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved in vitro antigen-specific antibody synthesis in two patients with common variable immunodeficiency taking an oral cyclooxygenase and lipoxygenase inhibitor (ketoprofen)

In the process of performing a previously published study examining B cell function in 16 patients with common variable immunodeficiency (CVI)(J Allergy Clin Immunol 1991; 87:1138-49), we noted improved in vitro antibody (Ab) synthesis in a patient, H. B., while he was taking a cyclooxygenase and lipoxygenase inhibitor, ketoprofen. Addition of ketoprofen in vitro to B cells from patients with CVI resulted in improved proliferation and differentiation in four of five additional patients with CVI studied. One patient, besides H. B., M. K. B., whose B cells secreted increased amounts of antigen (Ag)-specific Ab in response to in vitro ketoprofen, underwent a trial of oral ketoprofen M. K. B., like H. B., demonstrated improved in vitro Ag-specific Ab production while she was taking oral ketoprofen. No increase in serum Ab levels was noted in either patient taking ketoprofen, but both patients remained infection free during the time of their ketoprofen trials (H. B., 9 months, and M. K. B., 36 months). No improvement in in vitro Ag-specific Ab synthesis was noted when H. B. and M. K. B. took oral cyclooxygenase inhibitors (naproxen or ibuprofen). Thus, additional study is warranted to examine the role of lipoxygenase products of arachidonic acid in the B cell dysfunction of CVI.

Abnormal response to a human B cell growth factor in patients with common variable immunodeficiency (CVI)

Patients with common variable immunodeficiency (CVI) generally fail to produce antigen-specific IgG. We have identified a lymphokine called high molecular weight B cell growth factor (HMW BCGF) that expands an IgG-producing subpopulation of B cells. The B cells from 15 of 16 patients with CVI evaluated in this study failed to proliferate to HMW BCGF, although they proliferated normally to another BCGF, low molecular weight BCGF (LMW BCGF). Nevertheless, 11 patients had more than normal numbers of B cells expressing HMW BCGF receptors. The HMW BCGF receptors on the B cells of three patients with CVI studied were the same molecular weight as the normal HMW BCGF receptor. Examination of B cells from four patients with CVI for intracellular signals produced in normal B cells after stimulation with HMW BCGF revealed that B cells from patients with CVI failed to developed significant increases in cyclic adenosine monophosphate or phosphoinositides after HMW BCGF stimulation. However, cytoplasmic phosphoinositides in the B cells from all four patients with CVI were already increased above what is observed in normal B cells before stimulation with HMW BCGF (either freshly isolated or Staphylococcus aureus Cowan I-activated B cell). Thus, the failure of B cells from patients with CVI to respond to HMW BCGF may be related to their abnormal activation in vivo. Since HMW BCGF expands a subpopulation of memory B cells, the inability of CVI B cells to respond to HMW BCGF may contribute to their abnormal secondary responses to antigens.

Comprehensive immunization delivery in conjunction with influenza vaccination

All patients and employees presenting for influenza A and B vaccination were studied for the need for other immunizations or tests, based on criteria of the Immunization Practices Advisory Committee. More than 72% of patients and employees needed at least one other vaccine or test. During a 4 1/2-month period, 1,353 doses of influenza virus vaccine, bivalent, types A and B, were prescribed. Health care providers ordered doses of diphtheria and tetanus toxoids (adult) for 36.8% of these recipients, pneumococcal vaccine, polyvalent 23, for 42.1%, and a tuberculin skin test for 36.3%. Determinations of hepatitis B titers or hepatitis B vaccine doses were ordered for 140 individuals. Patients older than 60 years needed additional immunizations with greater frequency. Rates of delayed adverse reactions (35.9%) and subsequent self-medication (11.7%) were recorded. The systemic adverse reaction rate was 17.3%. Annual influenza vaccination programs are valuable public health opportunities to determine immunizations needed by patients who might not otherwise receive a comprehensive, individualized review of the status of their immunization protection.

Hypersensitivity to chromated catgut sutures: a case report and review of the literature

Chromated catgut sutures are used extensively in general surgical procedures. Although delayed hypersensitivity reactions to this material are difficult to diagnose post-operatively--ie, they may be interpreted as non-specific complications of surgery--the condition can be readily evaluated by patch testing with chromate or intracutaneous placement of the actual suture material. Multiple reports in the literature suggested that there was an increased frequency of post-operative adhesions, wound dehiscence, infection, and even intestinal obstruction along the line of suture material to which the patient had been sensitized during a previous surgery. Particularly with the widespread availability of fully synthetic suture materials, which appear to be less sensitizing, an increased awareness of chromate hypersensitivity in patients undergoing repeated surgical procedures may decrease the frequency of subsequent inflammatory post-operative complications. We report a patient with a history of multiple abdominal surgical procedures, eosinophilic cystitis surrounding the suture material, prolonged post-operative pain, and inflammatory masses at the sites of previous surgery associated with a positive delayed hypersensitivity skin reaction to patch test chromate and to intradermal chromic catgut.

The effects of triacetyloleandomycin and oleandomycin phosphate on the glucocorticoid receptor in cultured skin fibroblasts

Triacetyloleandomycin (TAO) has been described as a "steroid-sparing" drug in that poorly controlled asthmatic patients can be stabilized or improved with the addition of TAO despite decreasing dosages of steroids, specifically methylprednisolone (MP). It is not clear whether the beneficial effects of TAO are due to decreased MP clearance or are due to enhanced glucocorticoid effect peripherally. We tested the latter possibility by studying the interaction of TAO and oleandomycin phosphate (OLEO), the active metabolite of TAO in vivo, with glucocorticoid receptors in dispersed, intact cultured human skin fibroblasts. With the use of cells incubated with [3H]dexamethasone at 22 degrees C, we examined the competitive binding properties of TAO and OLEO (at varying concentrations) with and without MP as compared with several other steroids and MP alone. We also studied the effects on cellular glucocorticoid receptor number and affinity when TAO at a concentration of 4 X 10(-5) alone, at 10(-5) M in combination with a receptor saturating concentration of MP (5 X 10(-8) M), with MP alone, or with OLEO (10(-5) M) combined with MP was added to fibroblasts in the growth phase 1 wk before assay. TAO and OLEO did not compete for the binding of [3H]dexamethasone to the fibroblast glucocorticoid receptor, nor did they alter the binding properties of MP. With prolonged cellular exposure, TAO alone did not alter the number of glucocorticoid receptors (per cell) or their affinity for [3H]dexamethasone. Interestingly, prolonged exposure to saturating concentrations of MP alone decreased glucocorticoid receptor density; this effect was not altered by the presence of TAO or OLEO.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaphylaxis following psyllium ingestion

Psyllium is a hydrophilic agent found in many bulk laxative preparations. We report the occurrence of an anaphylactic reaction in a patient after ingestion of a psyllium-containing laxative. IgE mediation of the reaction was suggested by a positive immediate skin test to psyllium, positive passive transfer skin test, lack of skin response during passive transfer with heat treated serum, and an elevated IgE (RAST) to psyllium seed.

Antigen-stimulated human B cell clones are committed to the production of a single class of antibody in vitro

We have investigated the isotype(s) of antibody produced in vitro by antigen-stimulated human B cell clones. An analysis of the class(es) of antibody produced in multiple replicate cultures containing a mean of less than one precursor B cell per well was consistent with the hypothesis that individual B cell precursors produced a single class of antibody. This result was obtained by using cells isolated from either the peripheral blood or tonsils. Thus, under the culture conditions utilized, no intraclonal isotype switching was detected.

Antigen-stimulated human B cell clones are committed to the production of a single class of antibody in vitro

We have investigated the isotype(s) of antibody produced in vitro by antigen-stimulated human B cell clones. An analysis of the class(es) of antibody produced in multiple replicate cultures containing a mean of less than one precursor B cell per well was consistent with the hypothesis that individual B cell precursors produced a single class of antibody. This result was obtained by using cells isolated from either the peripheral blood or tonsils. Thus, under the culture conditions utilized, no intraclonal isotype switching was detected.