Delayed-type Hypersensitivity Skin Test Research Articles

Genomic approach to identification of Mycobacterium bovis diagnostic antigens in cattle.

Differential delayed-type hypersensitivity skin testing with tuberculin purified protein derivatives from Mycobacterium bovis and M. avium is the standard for diagnosing bovine tuberculosis. However, improved tests based on defined, specific antigens are urgently needed. In the present study, a combination of bioinformatics, molecular biology, and bovine models of infection were used to screen mycobacterial proteins for their potential as diagnostic reagents which could be used in a whole-blood assay for diagnosis of tuberculosis. Initial screening of 28 proteins selected in silico and expressed as recombinants in Escherichia coli indicated that CFP-10, ESAT-6, TB27.4, TB16.2, TB15.8, and TB10.4 induced strong gamma interferon responses in experimentally infected cattle. A more thorough investigation over time in two groups of animals infected with a high (10(6) CFU) and a low (10(4) CFU) dose of M. bovis revealed that, for both groups, the strength of the in vitro response to individual antigens varied greatly over time. However, combining the results for ESAT-6, CFP-10, and TB27.4, possibly supplemented with TB10.4, gave sensitivities at different infection stages close to those obtained with M. bovis purified protein derivative. Importantly, while responsiveness to ESAT-6 and CFP-10 correlated strongly for individual samples, the same was not the case for ESAT-6 and TB27.4 responsiveness. The results suggest that combinations of specific antigens such as these have great potential in development of optimized diagnostic systems for bovine tuberculosis.

Effects of dietary n-6 and n-3 fatty acids and vitamin E on the immune response of healthy geriatric dogs

To determine the effect of dietary n-6 to n-3 fatty acid ratios and alpha-tocopheryl acetate concentration on immune functions andT cell subpopulations in healthy dogs. Thirty-two 7- to 10-year old female Beagles. For 17 weeks, dogs were fed food that contained low (1.4:1) or high (40:1) ratios of n-6 to n-3 fatty acids in combination with 3 concentrations of all rac-alpha-tocopheryl acetate (low, 17 mg/kg of food; medium, 101 mg/kg; high, 447 mg/kg). Dogs were inoculated twice with a keyhole limpet hemocyanin suspension at 13 and 15 weeks. After 12 weeks, dogs consuming low concentrations of alpha-tocopheryl acetate had lower percentages of CD8+ T cells, compared with dogs consuming medium or high alpha-tocopheryl acetate concentrations. Also, dogs consuming low alpha-tocopheryl acetate concentrations had higher CD4+ to CD8+ T cell ratios. On day 4 of week 15, the percentage of CD8+ T cells was highest in dogs fed medium concentrations of alpha-tocopheryl acetate, compared with other dogs; however, the CD4+ to CD8+ T cell ratio was higher only in dogs fed low concentrations of alpha-tocopheryl acetate with high concentrations of n-3 fatty acids. Dogs consuming low concentrations of n-3 fatty acids with medium concentrations of alpha-tocopheryl acetate had the largest delayed-type hypersensitivity (DTH) skin test response. An optimum amount of dietary alpha-tocopheryl acetate concentration, regardless of the dietary n-6 to n-3 fatty acid ratio, stimulates the CD8+ T cell population. Effects of an optimum amount of dietary alpha-tocopheryl acetate concentration on the DTH response are blunted by dietary n-3 fatty acids.

Optimism effects on cellular immunity: testing the affective and persistence models

Abstract Two models can explain effects of optimism on the immune system. The affective model proposes that optimists’ positive moods and confidence lead to physiological resilience unless coping efforts are not immediately successful and then lead to vulnerability due to disappointment. The persistence model proposes that optimists’ ongoing coping efforts improve prospects for adjustment and health because they continue to pursue goals but may take a physiological toll in the short term. Professional students (n=30) had delayed-type hypersensitivity skin tests under conditions of short-term (mental arithmetic) and long-term (examination) academic stress. Academic optimism was positively associated with skin test response when students did not do mental arithmetic but negatively associated when they did. Among optimism's five-factor model cognates, this effect could be attributed to its conscientiousness element, supporting the persistence model.

Metabolic aging and predicted longevity: results of a cross-sectional study in post-menopausal women.

The extent to which general characteristics of metabolic aging contribute to differences in life span among individuals remains uncertain. The objective of this study was to examine the association of age-related physiological and metabolic variables with predicted longevity in postmenopausal women. Subjects were 33 healthy women aged 55-65 years. Total and resting energy expenditure, body temperature, immune function as assessed by a delayed-type hypersensitivity skin test (DTH), lipid profile, and reported dietary intake were measured. There were no significant associations between longevity, energy expenditure, body temperature, lipid profile, or dietary intake. However, there was a significant association of predicted longevity with DTH (partial r=0.44, p=0.023). These results suggest that immune function may predict familial differences in longevity, while energy expenditure, body temperature, lipid profile, and dietary intake are unrelated. Although the small sample size may have limited the ability to detect metabolic effects on longevity in this study, the general approach may be broadly applicable to examinations of metabolic aging in humans.

Enhanced humoral immune response correlates with improved disease-free and overall survival in American Joint Committee on Cancer stage II melanoma patients receiving adjuvant polyvalent vaccine.

Although the improved overall survival (OS) of patients who receive Canvaxin (CancerVax Corp, Carlsbad, CA) polyvalent vaccine (PV) immunotherapy for metastatic melanoma has been correlated with cellular and humoral immune responses, the mechanisms of vaccine immunotherapy for early-stage melanoma are unclear. Specific immune responses to tumor-associated antigens might correlate with disease-free survival (DFS) and OS in patients receiving adjuvant PV therapy for primary melanoma. Eighty-three patients received PV plus bacille Calmette-Guérin after wide excision of American Joint Committee on Cancer stage II melanoma. Humoral and cellular responses during the first 12 weeks of adjuvant immunotherapy were assessed by serum antibody titers to a tumor-associated 90-kd glycoprotein antigen (TA90) expressed by PV, and by delayed-type hypersensitivity (DTH) skin testing with PV (PV-DTH). At a median follow-up period of 46.6 months (range, 10.7 to 93.6 months), an increased PV-DTH response seemed to be associated with improved 5-year DFS (54% v 20%) and 5-year OS (75% v 60%), but the correlations were not statistically significant. Anti-TA90 immunoglobulin (Ig) M levels > or = 1:800 were significantly correlated with improved 5-year DFS and improved 5-year OS, and multivariate analysis identified anti-TA90 IgM as an independent prognostic factor for OS and DFS. These findings suggest that an increased IgM response in patients receiving PV therapy for stage II melanoma is associated with decreased recurrence and improved survival.

Delayed type hypersensitivity response to recall antigens does not accurately reflect immune competence in advanced stage breast cancer patients.

The development of delayed-type hypersensitivity (DTH) response to recall antigens has long been utilized as a measure of immune competence. It is assumed that because patients with advanced stage cancers exhibit multiple immune system defects they may not be responsive to immunization. We pre-selected patients with advanced HER-2/neu (HER2) overexpressing breast and ovarian cancers for enrolment into a phase I trial designed to evaluate the immunogenicity of a HER2 peptide vaccine based on the patient's immune competence as assessed by DTH skin testing to common recall antigens (Multitest CMI, Institut Merieux, Lyon, France). At the time of a positive DTH response to tetanus toxoid (tt) peripheral blood was obtained to measure T cell responses to tt. Of 53 patients evaluated, 38 (72%) were not anergic. Among the 15 (28%) who were, seven patients with advanced stage breast cancer were re-tested a median of 26 days (range 12-150 days) after receiving a tt bopster vaccination. Five of the seven had positive DTH responses when re-challenged with tt and six had peripheral blood tetanus specific T cell response with stimulation index >2.0. Thus, the majority of patients studied with advanced stage breast or ovarian cancer were able to mount a DTH response to common recall antigens. Moreover, a negative response by DTH testing to a battery of common recall antigens was not a reflection of the breast cancer patient's ability to mount a cell-mediated immune response to a vaccinated antigen, tt.

Intracutaneous DNA vaccination with the E8 gene of cottontail rabbit papillomavirus induces protective immunity against virus challenge in rabbits.

The cottontail rabbit papillomavirus (CRPV)-rabbit model has been used in several studies for testing prophylactic and therapeutic papillomavirus vaccines. Earlier observations had shown that the CRPV nonstructural genes E1, E2, and E6 induced strong to partial protective immunity against CRPV infection. In this study, we found that CRPV E8 immunization eliminated virus-induced papillomas in EIII/JC inbred rabbits (100%) and provided partial protection (55%) against virus challenge in outbred New Zealand White rabbits. CRPV-E8 is a small open reading frame, coding for a 50-amino-acid protein, that is colinear with the CRPV E6 gene and has features similar to those of the bovine papillomavirus and human papillomavirus E5 genes. Papillomas that grew on E8-vaccinated outbred rabbits were significantly smaller than those on vector-vaccinated rabbits (P < 0.01; t test). Delayed-type hypersensitivity skin tests showed that some of the E8-vaccinated rabbits had positive responses to E8-specific peptides.

Phase I Trial of a B7-1 (CD80) Gene Modified Autologous Tumor Cell Vaccine in Combination With Systemic Interleukin-2 in Patients With Metastatic Renal Cell Carcinoma

A reason that the immune system may fail to reject tumors is that T cells encounter tumor antigen derived peptides on the surface of tumor cells in a tolerizing rather than activating context since tumor cells do not express T cell co-stimulatory molecules such as B7-1 (CD80). In preclinical models over expression of B7-1 on the surface of tumor cells has been shown to activate T cells which kill tumor cells. We conducted a phase I clinical trial testing this approach in patients with metastatic renal cell carcinoma. Resected tumors from 15 patients were disaggregated and adapted to tissue culture, transduced with the B7-1 gene and injected subcutaneously as a vaccine. The dose of the vaccine was escalated in 3 separate cohorts of patients, and systemic interleukin-2 (IL-2) was administered as an adjuvant designed to enhance the proliferation of the vaccine activated T cells. Of the 15 patients 9 had measurable disease, 2 had a partial response and 2 had stable disease. Perivascular T cell infiltrates at autologous tumor delayed type hypersensitivity skin test sites developed in 3 of the 4 patients with stable disease or partial response. Although the patients experienced the usual and expected toxicity from the IL-2, there was no significant toxicity observed with the vaccine. The B7-1 gene modified autologous tumor cell vaccine is safe and can be combined with systemic IL-2 with acceptable toxicity. Immunological and clinical responses were observed in some of the patients. A phase II trial is reasonable to determine the efficacy of this approach.

Delayed-type hypersensitivity in volunteers immunized with a synthetic multi-antigen peptide vaccine (PfCS-MAP1NYU) against Plasmodium falciparum sporozoites

During the testing of the safety and immunogenicity of an adjuvanted, synthetic Plasmodium falciparum CS multiple antigen peptide (MAP) vaccine, we investigated the potential for using cutaneous delayed-type hypersensitivity (DTH) reactions as a correlate of immune response. We evaluated 27 of our volunteers for DTH reactions to intradermal inoculation (0.02 ml) of several concentrations of the MAP vaccine and adjuvant control solutions. Induration was measured 2 days after skin tests were applied. Nine of 14 vaccinees (64%) with serum, high-titered anti-MAP antibody developed positive DTH (≥5 mm induration), that first appeared by 29 days after immunization and persisted for at least 3–6 months after 1–2 more immunizations. In contrast, DTH responses were negative in eight of eight vaccinees with no or low antibody titers, and in five of five non-immunized volunteers. Biopsies of positive DTH skin test sites were histologically compatible with a DTH reaction. We conclude that the presence of T cell functional activity reflected by a positive DTH skin test response to the MAP antigen serves as another marker for vaccine immunogenicity.

Immunotherapy of solid cancer using dendritic cells pulsed with the HLA-A24-restricted peptide of carcinoembryonic antigen.

Carcinoembryonic antigen (CEA), an oncofetal glycoprotein overexpressed in most gastrointestinal and lung cancers, is a candidate molecule for cancer immunotherapy. Recently, a CEA-derived 9-mer peptide, CEA652 (TYACFVSNL), has been identified as the epitope of cytotoxic T lymphocytes restricted with human leukocyte antigen (HLA)-A24, which is present in 60% of the Japanese population and in some Caucasians. The authors performed a clinical study of a vaccine using autologous dendritic cells (DCs) pulsed with CEA652 and adjuvant cytokines, natural human interferon alpha (nhuIFN-alpha), and natural human tumor necrosis factor alpha (nhuTNF-alpha), for the treatment of patients with CEA-expressing advanced metastatic malignancies. Ten HLA-A24 patients with advanced digestive tract or lung cancer were enrolled in the study to assess toxicity, tolerability and immune responses to the vaccine. DCs were generated from plastic adherent monocytes of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (PBMCs) in the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4). Generated DCs showing an immature phenotype were loaded with CEA652 and injected into patients intradermally and subcutaneously with 50% of the dose administered by each route every 2 weeks for a total of ten vaccinations. The total dose of administered DCs ranged from 2.7x10(7)cells to 1.6x10(8)cells. Adjuvant cytokines, i.e., 1x10(6) U/body of nhuIFN-alpha and nhuTNF-alpha, were administered to patients twice a week during the vaccination period. No severe toxicity directly attributable to the treatment was observed, and the vaccine was well tolerated. In the delayed-type hypersensitivity (DTH) skin test, two patients showed a positive skin response to peptide-pulsed DCs after vaccination, although none of the patients tested positive prior to vaccination. In the two patients who showed a positive skin response disease remained stable for 6 and 9 months respectively. These results suggest that active immunization using DCs pulsed with CEA652 peptide in combination with the administration of adjuvant cytokines is a safe and feasible treatment procedure.

In vivo and in vitro diagnosis of Mycobacterium bovis infection.

The intradermal delayed type hypersensitivity (DTH) skin test, using purified protein derivative from culture of M. bovis or M. avium, is the most frequently used test for diagnosis of tuberculosis or detection of M. bovis infection in cattle. Many improvements have been made to the original tuberculin test, and molecular approaches to identify and clone antigens may lead to improved specificity and sensitivity of DTH skin tests. Recent advances in technology have allowed the development of new in vitro techniques, such as antibody-based, cell-mediated immunity-based and nucleic acid-based diagnostics, which allow more rapid diagnosis than bacteriological culture. The choice of diagnostic technique should consider both the population being investigated (e.g. apparently healthy animals or a herd with a high prevalence of clinical infection) and the aim of the testing (e.g. the screening of healthy animals or confirmation of infection in animals strongly suspected to be infected). Moreover, any evaluation of a diagnostic test must use a carefully selected control population which is representative of the population to be tested in terms of relative proportions of infected and non-infected animals.

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.

QS-21 promotes an adjuvant effect allowing for reduced antigen dose during HIV-1 envelope subunit immmunization in humans

Three separate studies were undertaken in HIV-1 uninfected persons to determine if the adjuvant QS-21 improves the magnitude or kinetics of immune responses induced by recombinant soluble gp120 HIV-1 MN protein (rsgp120) immunization. The QS-21 was administered at two doses (50 and 100 μg), either alone or in combination with aluminum hydroxide (600 μg). At the highest doses of rsgp120 (100, 300, and 600 μg), QS-21 exerted no significant effect on either binding or neutralizing antibody titers. Antibody binding and neutralizing responses fell dramatically when rsgp120, formulated with alum alone, was given at low doses (3 and 30 μg). In contrast, antibody responses similar in titer to those in the high dose antigen groups were induced with the low dose rsgp120 formulated with QS-21. In addition, the lymphocyte proliferation and delayed type hypersensitivity skin testing were superior in the QS-21 recipients compared with the alum recipients at the low antigen doses. Moderate to severe pain was observed in majority of the volunteers receiving QS-21 formulations, and vasovagal episodes and hypertension were not infrequent. Thus, the use of QS-21 may provide a means to reduce the dose of a soluble protein immunogen.

Vaccination with a CDR2 BV6S2/6S5 peptide in adjuvant induces peptide-specific T-cell responses in patients with multiple sclerosis

Earlier studies from several groups including ours have documented that patients with multiple sclerosis (MS) have over-expression of activated T-cells from specific TCR V beta families, including BV6S2/S5 (Kotzin et al. [1991] Proc. Natl. Acad. Sci. USA 88:9161--9165; Gold et al. [1997] J. Neuroimmunol. 76:29--38). It has also been established in the rat EAE model that peptide vaccines to the over-expressed V beta 8.2 TCR can prevent MBP induced disease (Vandenbark et al. [1989] Nature 341:541--544). In the current clinical study, 10 patients were vaccinated with 300 microg of BV6S2/6S5 peptide emulsified in incomplete Freund's adjuvant (IFA) and monitored for safety and immunogenicity in a 48-week multicenter, open-label trial. The peptide vaccine was well tolerated and no serious adverse events were observed. Vaccinations induced cell-mediated immunity to the immunizing peptide in eight of 10 patients as demonstrated by lymphocyte proliferation assay (LPA) and delayed-type hypersensitivity (DTH) skin test responses. In summary, these results demonstrate that immunization with TCR BV6S2/6S5 peptide vaccine in MS patients is safe and immunogenic, and supports a larger double-blind placebo controlled trial to determine the clinical efficacy of this approach.

Distinct Human T Cell Repertoires Mediate Immediate and Delayed-Type Hypersensitivity to theTrichophytonAntigen, Tri r 2

The 29-kDa subtilase homologue, Tri r 2, derived from the dermatophyte fungus Trichophyton rubrum, exhibits unique immunologic characteristics in its ability to elicit immediate (IH) and delayed-type (DTH) hypersensitivity skin tests in different individuals. Thus, Tri r 2 provides a model for comparing the T cell repertoire in subjects with distinct immune responses to a single Ag. Recombinant Tri r 2 produced as a GST fusion protein in Escherichia coli stimulated strong in vitro lymphoproliferative responses in 10 IH and 10 DTH responders. Patterns of T cell epitope recognition were compared between skin test groups using 28 overlapping peptides (each in 12 replicate wells) derived from Tri r 2 to stimulate T lymphocyte proliferation in vitro. Peptide 5 (P5; aa 41-60) induced the strongest response in DTH subjects and showed the largest difference between DTH and IH responders in proliferation (mean standardized index, 2.22 and 0.82, respectively; p = 0.0047) and number of positive wells (81 vs 12). Responses to P5 were associated with diverse HLA haplotypes. These results showed that P5 contains an immunodominant epitope specifically associated with DTH and that this peptide is recognized in a permissive manner. Cross-validated linear discriminant analysis using T cell proliferative responses to two regions of Tri r 2 (aa 51-90 and 231-270) gave a 95% predictive accuracy for classification of subjects into IH or DTH groups. We conclude that different immune responses to Trichophyton are mediated by distinct T cell repertoires between individuals with IH and DTH reactions to Tri r 2.

Epstein-Barr virus reactivation associated with diminished cell-mediated immunity in antarctic expeditioners.

Epstein-Barr virus (EBV) reactivation and cell-mediated immune (CMI) responses were followed in 16 Antarctic expeditioners during winter-over isolation at 2 Australian National Antarctic Research Expedition stations. Delayed-type hypersensitivity (DTH) skin testing was used as an indicator of the CMI response, that was evaluated 2 times before winter isolation and 3 times during isolation. At all 5 evaluation times, 8 or more of the 16 subjects had a diminished CMI response. Diminished DTH was observed on every test occasion in 4/16 subjects; only 2/16 subjects exhibited normal DTH responses for all 5 tests. A polymerase chain reaction (PCR) assay was used to detect EBV DNA in saliva specimens collected before, during, and after the winter isolation. EBV DNA was present in 17% (111/642) of the saliva specimens; all 16 subjects shed EBV in their saliva on at least 1 occasion. The probability of EBV shedding increased (P = 0.013) from 6% before or after winter isolation to 13% during the winter period. EBV appeared in saliva during the winter isolation more frequently (P < 0.0005) when DTH response was diminished than when DTH was normal. The findings indicate that the psychosocial, physical, and other stresses associated with working and living in physical isolation during the Antarctic winter result in diminished CMI and an accompanying increased reactivation and shedding of latent viruses.

Immune Reconstitution in the HAART Era, Part 2: Implications for Practice

As discussed in Part 1 of this series, HIV infection alters the function of the immune system. These alterations include declines in CD4-positive lymphocyte counts, disturbances in the function of the CD4-positive lymphocyte, diminished delayed-type hypersensitivity (DTH) skin test responses and cell-mediated immune responses, phenotypic changes in lymphocytes, and changes in cytoxic T-lymphocyte and natural killer cell function. Although highly active antiretroviral therapy (HAART) has dramatically improved CD4-positive lymphocyte counts and quality of life, there have been unforeseen consequences of immune reconstitution. For example, cytomegalovirus (CMV) and hepatitis C flares have been observed in HAART-treated patients coinfected with HIV and CMV and hepatitis C (HCV). Part 2 of this series will examine the clinical consequences of immune reconstitution in persons with HIV infection.

Search for evidence of a Th2 profile in HIV+ patients.

Hypersensitivity dermatoses are common in human immunodeficiency virus-positive (HIV+) patients, particularly as the disease progresses. Studies have shown that a switch to T-helper 2 (Th2) might represent a turning point in HIV. This study investigated whether increases in the number of skin mast cells, immunoglobulin E (IgE) serum levels, and eosinophilia, involved in the Th2 response in allergic disease, might also be present in HIV+ patients. If so, these alterations might explain one of the mechanisms of skin hypersensitivity in these patients. Forty-five skin biopsies from the normal skin of the upper arm of HIV+ patients and 15 controls were included in the study. HIV+ individuals were classified into three equal categories according to their immunologic status: Category I (< 200/microL), Category II (200-499/microL), and Category III (> 500/microL). Anti-tryptase antibody was employed in tissue sections to show mast cells; IgE serum levels and eosinophils in peripheral blood count were investigated; delayed-type hypersensitivity (DTH) skin tests (candidin, trichophytin, and PPD 2U) were evaluated. Normal cutaneous mast cell and eosinophil counts were the same in all categories and in the control group, but increased IgE levels (P < 0. 01) and DTH skin test anergy (P < 0.006) were observed among acquired immunodeficiency syndrome (AIDS) patients. The density of skin mast cells in HIV infection was not modified in the course of the disease. Mast cells do not seem to be primarily responsible for triggering hypersensitivity dermatoses among AIDS patients, although data in support of the Th2 response, as seen in increased IgE serum levels and DTH anergy, are present.

Extracorporeal photochemotherapy does not suppress T- or B-cell responses to novel or recall antigens

Background: Extracorporeal photopheresis (ExP) is an effective therapy for several conditions including cutaneous T-cell lymphoma, scleroderma, and allograft rejection. Experimental animal models suggest that ExP may induce antigen-specific immunosuppression. Objective: Our purpose was to determine the effect of photopheresis on humoral and cell-mediated immunity in human subjects. Methods: Recall and primary immune responses of patients with scleroderma receiving monthly ExP treatments were assessed by delayed type hypersensitivity skin tests, T-cell proliferative responses after immunizations with tetanus toxoid and keyhole limpet hemocyanin, and serum antibody titers against common viral pathogens. Results: After 6 months of ExP, viral antibody titers and delayed type hypersensitivity responses were not significantly different from baseline values in all 7 patients tested. T-cell responses to tetanus toxoid remained normal in 3 of 3 patients tested for a minimum of 6 months after booster immunization. Immunization with the protein antigen keyhole limpet hemocyanin after initiation of ExP therapy resulted in sustained T-cell proliferative responses up to 6 months in 3 of 3 patients. Conclusion: These results, along with the observation of no increased incidence of opportunistic infections or neoplasms, suggest that ExP is not broadly immunosuppressive and does not prevent primary responses to vaccination or other antigenic challenges. (J Am Acad Dermatol 1999;41:980-6.)

GM‐CSF as a systemic adjuvant in a phase II prostate cancer vaccine trial

BACKGROUND Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF; Leukine® [sargramostim], Immunex Corp., Seattle, WA) was administered to a subgroup of 44 patients in a phase II clinical trial for prostate cancer using DC pulsed with HLA-A2-specific prostate-specific membrane antigen (PSMA) peptides. Our purpose was to determine if GM-CSF caused any enhancement of patients' immune responses, including enhancement of clinical response to the DC-peptide treatment. This report compares the clinical responses to DC-peptide infusions with and without systemic GM-CSF treatment. METHODS GM-CSF was administered by subcutaneous injection at a dose of 75 μg/m2/day for 7 days with each of six infusion cycles. Prefilled syringes were supplied to the patients for self-administration. RESULTS One complete and 8 partial responders were identified among 44 patients who received GM-CSF, as compared to 2 complete and 17 partial responders among 51 patients who did not receive GM-CSF. For patients who received GM-CSF and were tested by delayed-type hypersensitivity (DTH) skin test, 3 cases of improved immune response were identified, compared to 5 cases of improvement in patients who did not receive GM-CSF. The main GM-CSF side effects reported were local reactions at the site of injection, fatigue, pain, and fever. Most reported side effects were of mild severity, with some cases of moderate severity leading to discontinuation of GM-CSF. CONCLUSIONS Our results suggest GM-CSF as employed in this trial did not detectably enhance clinical response to DC-peptide infusions, or significantly enhance the measured immune response. Prostate 39:291–297, 1999. © 1999 Wiley-Liss, Inc.