A correlation of pregnancy term, disease activity, serum female hormones, and cytokines in uveitis.

BACKGROUND/AIMS: Pregnancy and the postpartum period are associated with the activity of autoimmune diseases including uveitis. Although the exact mechanism is unknown, hormones are reported to alter inflammatory cytokines and influence disease activity. The authors studied ocular inflammation, female hormones, and serum cytokine levels during and after pregnancy. METHODS: A prospective, observational case study was conducted. Four pregnant women in their first trimester with chronic non-infectious uveitis were followed monthly until 6 months after delivery. Serum female hormones (oestrogen, progesterone, prolactin) and various cytokines (IL-2, IL-4, IL-5, IL-6, IL-10, IFN-gamma, and TGF-beta) were measured by ELISA. RESULTS: The four patients had five full term pregnancies. Uveitis activity decreased after the first trimester but flared in the early postpartum period. Serum female hormones, highly elevated during pregnancy, drastically dropped post partum. Cytokine levels except TGF-beta were mostly undetectable. CONCLUSION: Female hormones and TGF-beta may contribute to the activity of uveitis during pregnancy and the postpartum period.

A multicentre randomised double masked clinical trial of a new formulation of topical cysteamine for the treatment of corneal cystine crystals in cystinosis.

AIM: To evaluate the safety and efficacy of a new topical cysteamine formulation, stable at room temperature, for the treatment of corneal cystine crystals in cystinosis. METHODS: 20 study subjects were enrolled in the safety study and 16 in the efficacy study. Both studies were randomised and double blind. The primary outcome for the safety study was the occurrence of predefined serious adverse reactions over 6 months and for the efficacy study the reduction of corneal cystine crystal score (CCCS) by 1.00 or more units on photographs graded by a reading centre using a standardised protocol. RESULTS: No study subject developed any serious adverse reactions. In the efficacy study, 47% of eyes receiving the standard formulation experienced a reduction in the CCCS of >/=1.00 after 1 year, while 7% of eyes on the new formulation experienced such a decrease (p=0.04). CONCLUSION: Although no serious adverse reactions were observed with either formulation, the new formulation was not as effective as the standard formulation.

Aqueous humor and plasma vascular endothelial growth factor in uveitis-associated cystoid macular edema.

PURPOSE: To determine the association between cystoid macular edema and vascular endothelial growth factor concentration in the aqueous humor and plasma of uveitis patients. METHODS: Cross-sectional study. Vascular endothelial growth factor concentrations were measured by enzyme-linked immunosorbent assay in the aqueous humor of 20 uveitis patients (9 with and 11 without cystoid macular edema), and in the plasma of 40 uveitis patients (20 with and 20 without cystoid macular edema) and 20 healthy volunteers. RESULTS: Mean aqueous humor vascular endothelial growth factor concentrations for uveitis patients with and without cystoid macular edema were 152.3 and 109.5 pg/ml, respectively, P =.044. Mean plasma vascular endothelial growth factor concentrations in uveitis patients with and without cystoid macular edema and in healthy volunteers were 32.2, 29.6, and 55.0 pg/ml, respectively. Uveitis patients had lower plasma vascular endothelial growth factor levels than did healthy volunteers, P =.0002. CONCLUSION: In uveitis patients, vascular endothelial growth factor concentration is increased in the aqueous humor of eyes with cystoid macular edema. It may be useful to investigate vascular endothelial growth factor antagonists as a treatment for uveitis-associated cystoid macular edema.

Pharmacokinetics and toxicity of intravitreal chemotherapy for primary intraocular lymphoma.

OBJECTIVE: To investigate the pharmacokinetics and toxicity of intravitreal chemotherapeutic agents in the rabbit eye for the potential treatment of primary intraocular lymphoma and other intraocular malignancies. METHODS: The ocular pharmacokinetics of intravitreal methotrexate sodium (400 microg) was studied in 10 New Zealand white rabbits, and a single-compartment, first-order elimination model was used to calculate the drug half-life. With the use of these data, a treatment schedule using serial injections of intravitreal methotrexate and single injections of fluorouracil and dexamethasone sodium phosphate was developed. This schedule was studied in 4 New Zealand white rabbits to explore the combined toxicity of these agents. RESULTS: Methotrexate vitreous levels, following a 400-microg intravitreal injection, remained therapeutic (>0.5 microM) in the rabbit eye for 48 to 72 hours. Intravitreal methotrexate, combined with fluorouracil and dexamethasone, showed no evidence of drug toxicity as determined by electroretinography and histopathologic examination. CONCLUSIONS: A treatment schedule for primary intraocular lymphoma consisting of methotrexate intravitreal injections every 48 to 72 hours provides therapeutic drug concentrations in the vitreous and, in combination with fluorouracil and dexamethasone, appears to be safe in the rabbit eye. CLINICAL RELEVANCE: Although responsive to conventional chemotherapy or radiotherapy, recurrence of ocular involvement with primary central nervous system lymphoma occurs in more than 50% of treated cases. Anecdotal reports of the use of intravitreal chemotherapy for primary intraocular lymphoma have been encouraging. However, animal data on the pharmacokinetics and toxicity of combined intravitreal agents for the treatment of this disease are lacking.

Apoptosis in cytomegalovirus retinitis associated with AIDS.

PURPOSE: To determine the role of apoptosis in the pathogenesis of cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome. METHODS: Forty-three eyes from patients with cytomegalovirus retinitis treated before the introduction of highly active anti-retroviral therapy were examined by routine histopathology and in situ techniques to detect apoptosis (TUNEL assay). Apoptosis was graded on a scale from 0 to 3+ by quantitating the number of TUNEL positive cells per case using a standard grading procedure. Statistical analysis describing the association between apoptosis grade and the proportions of eyes with active CMV infection, with choroidal inflammation and treated with the sustained-release intravitreal ganciclovir implant was performed using the Armitage procedure. RESULTS: Apoptosis in both CMV infected and uninfected retinal cells was detected in 28 of 41 eyes (68%); 13 (45%) with active and 15 (55%) with inactive cytomegalovirus retinitis. The degree of apoptosis was mild (1+) in 14 eyes, moderate (2+) in 6 eyes and severe (3+) in 8 eyes. Apoptosis was not identified in two eyes without CMVR. An increase in apoptosis grade was positively associated with active CMVR (p = 0.014). There was no significant association between apoptosis and choroidal inflammation. The presence and the severity of apoptosis was less in eyes treated with the sustained-release intravitreal ganciclovir implant compared to those treated with systemic anti-viral therapy, however, the difference was not statistically significant. CONCLUSIONS: Apoptosis contributes to retinal cell loss in eyes with cytomegalovirus retinitis associated with AIDS but did not correlate with the progressive loss of retinal cell function in patients with treated, inactive CMVR.

Correlation of visual acuity and ocular pigmentation with the 16-bp duplication in the HPS-1 gene of Hermansky-Pudlak syndrome, a form of albinism.

OBJECTIVE: Patients with the Hermansky-Pudlak syndrome (HPS), a form of albinism, were studied. The first purpose of this investigation was to determine if visual acuity was related to the presence or absence of the 16-bp duplication in the HPS-1 gene. The second was to study the correlation between the degree of ocular pigmentation and visual acuity within the two genetic groups described above. DESIGN: Cross-sectional study of a series of consecutive patients. PARTICIPANTS: Forty-nine patients with HPS with or without the 16-bp duplication in HPS-1. METHODS: Best corrected visual acuity (VA) using Early Treatment Diabetic Retinopathy Study (ETDRS) charts, photographic gradings of iris transillumination and of visibility of choroidal vessels in the macula (macular transparency). MAIN OUTCOME MEASURES: Association between VA and the presence or absence of the 16-bp duplication in HPS-1 and correlation between VA and the degree of iris transillumination (iris score) and macular transparency (fundus score), as determined by masked reading of photographs, with respect to the presence or absence of the 16-bp duplication in HPS-1 were the main outcome measures. RESULTS: The VA of the better eye did not differ between the two genetic groups (P = 0.322, two-sided t test). Spearman's rank correlation between VA and iris scores in 39 eyes of 20 patients with the duplication was not statistically significant (P = 0.698) but was statistically significant in 36 eyes of 19 patients without the duplication (P < 0.001). Among all patients, the correlation was statistically significant (r = -0.36 in RE and r = -0.51 in LE). Spearman's rank correlation between VA and fundus scores in 36 eyes of 19 patients with and 34 eyes in 18 patients with and without the duplication was statistically significant (P = 0.035 and P = 0.008, respectively). Among all patients, it was also statistically significant (r = -0.39 in RE and r = -0.45 in LE). CONCLUSIONS: The mean VA of the better eye did not differ in patients with the 16-bp duplication compared with those without the duplication. There were statistically significant associations between VA and the iris score and the fundus score except for the VA and iris scores in patients with the 16-bp duplication. However, because of the variability of VA, these associations were not large enough for useful prediction of VA based on the degree of ocular pigmentation.

A randomized clinical trial of topical cysteamine disulfide (cystamine) versus free thiol (cysteamine) in the treatment of corneal cystine crystals in cystinosis.

In nephropathic cystinosis, corneal cystine crystals cause severe photophobia and corneal erosions. Topical cysteamine dissolves these crystals, but cannot be marketed because it rapidly oxidizes to the disulfide form, cystamine, at room temperature. Since cystamine itself could be used commercially, we compared the efficacy of cystamine and cysteamine with respect to cystine crystal dissolution in a randomized, double-masked clinical trial. One eye each of 14 patients with cystinosis was randomized to either cystamine or cysteamine, 0.5%, with 0.01% benzalkonium chloride; the companion eye was treated with the alternate preparation. Corneal crystals were photographed and a density score was assigned to each slide based on 13 standard slides. After 8-20 months, 6 patients showed significant reduction of the corneal crystal score in only one eye. In each case, the improved eye was the cysteamine-treated eye. Theoretically, cysteamine should dissolve both intracellular and extracellular crystals, whereas cystamine should dissolve only intracellular crystals because it must first be reduced to the free thiol by the cytoplasmic-reducing environment. Hence, the lack of efficacy of the disulfide cystamine suggests that some corneal cystine crystals in cystinosis patients are extracellular, and that another form of stable, topical cysteamine must be developed for cystinosis patients.

Biotransformation of halothane, enflurane, isoflurane, and desflurane to trifluoroacetylated liver proteins: association between protein acylation and hepatic injury.

In susceptible patients, halothane, enflurane, isoflurane, and desflurane can produce severe hepatic injury by an immune response directed against reactive anesthetic metabolites covalently bound to hepatic proteins. The incidence of hepatotoxicity appears to directly correlate with anesthetic metabolism catalyzed by cytochrome P450 2E1 to trifluoroacetylated hepatic proteins. In the present study, we examined whether the extent of acylation of hepatic proteins in rats by halothane, enflurane, isoflurane, and desflurane correlated with reported relative rates of metabolism. After pretreatment with the P450 2E1 inducer isoniazid, five groups of 10 rats breathed 1.25 minimum alveolar anesthetic concentration (MAC) of halothane, enflurane, isoflurane, or desflurane in oxygen, or oxygen alone, each for 8 h. Immunochemical analysis of livers harvested 18 h after anesthetic exposure showed tissue acylation (greatest to least) after exposure to halothane, enflurane, or isoflurane. Reactivity was not different between isoflurane as compared to desflurane or oxygen alone. An enzyme-linked immunosorbent assay showed halothane reactivity was significantly greater than that of enflurane, isoflurane, desflurane, or oxygen, and that enflurane reactivity was significantly greater than desflurane or oxygen. Sera from patients with a clinical diagnosis of halothane hepatitis showed antibody reactivity against hepatic proteins from rats exposed to halothane or enflurane. No reactivity was detected in rats exposed to isoflurane, desflurane, or oxygen alone. These results indicate that production of acylated proteins may be an important mediator of anesthetic-induced hepatotoxicity.

A comparison of enzyme immunoassays used to measure serum antibodies to components of Bordetella pertussis.

To evaluate the comparability of immunoassays, the Center for Biologics Evaluation and Research organized an international collaborative study in which 33 laboratories participated. For a coded panel of 21 samples, each laboratory measured IgG antibodies to specific proteins of Bordetella pertussis using assay systems currently in place. Analyses were performed to evaluate the assay precision and the quantitative agreement among laboratories. Data from a subset of 12 laboratories are used to illustrate points relevant to the use of immunoassays in seven vaccine efficacy studies. Differences among the laboratories in assay precision for samples with known two-fold differences indicate that serological case definitions must take into consideration the characteristics of the assays and the concentration of antibody in the samples. Assays performed in different laboratories to assess vaccine immunogenicity may generate similar results but critical comparisons will probably require samples to be tested in the same laboratory at the same time.

Collaborative study for the evaluation of enzyme-linked immunosorbent assays used to measure human antibodies to Bordetella pertussis antigens.

Acellular pertussis vaccines are being evaluated in multiple clinical studies, and human immunogenicity data will likely be pivotal in the appraisal of vaccine responses between populations and the responses to different vaccine combinations. Antibody response to pertussis antigens is also used in the diagnosis of pertussis. An international study was designed to assess the comparability of data generated in different laboratories by enzyme-linked immunosorbent assays (ELISAs). Thirty-three participating laboratories were asked to quantitate specific antibody to pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), or fimbrial proteins (FIM) in 21 samples. Samples were to be assayed in triplicate in five independent assays by each ELISA routinely performed in the laboratory to assess intra-assay, interassay, and population variability. The mean sample values were used to compare quantitative results among the laboratories. Thirteen of the 32 laboratories which submitted evaluable data for an assay to measure antibodies to PT, 12 of 30 laboratories with assays for FHA, 10 of 17 laboratories with assays for PRN, and 6 of 13 laboratories with assays for FIM maintained a coefficient of variation below 20% for 75% of the samples tested. Assays that measure antibodies to FIM appear to be less precise than the other assays. Precision varied among laboratories that used similar methods. The relative values of intra- and interassay variabilities were not consistent for a given assay within a laboratory, indicating that the sources of these variability components may be unrelated. Precision and agreement appeared less reliable for samples with low antibody levels. Ranking and regression analyses suggest that some laboratories generated comparable quantitative results, although direct comparison or combination of results from different laboratories remains difficult to support. Calibration to the U.S. Reference Pertussis Antisera appears to have been successful at standardizing the results in some laboratories. Statistical analyses are affected by assay precision and are not necessarily reliable sole predictors of biologically relevant differences in quantitative results. If results from different laboratories must be compared, appropriate studies of precision and quantitative agreement should be conducted to support the specific comparisons.

Randomized, controlled phase I/II, trial of combination therapy with delavirdine (U-90152S) and conventional nucleosides in human immunodeficiency virus type 1-infected patients.

Delavirdine mesylate (DLV) is a potent nonnucleoside reverse transcriptase inhibitor with activity specific for human immunodeficiency virus type 1. In the present phase I/II study we evaluated the safety, toxicity, pharmacokinetics, and antiretroviral activities of two-drug and three-drug combinations of DLV and conventional doses of nucleoside analogs compared with those of both DLV monotherapy and two-drug nucleoside analog therapy. A total of 85 human immunodeficiency virus type 1 infected patients with CD4 counts of 100 to 300 cells per mm3 were enrolled in two periods: in the first period patients were randomized to receive either zidovudine (ZDV) plus didanosine (group 1) or ZDV plus didanosine plus escalating doses (400 to 1,200 mg/day) of DLV (group 2). In the second period, patients were randomized to receive either 1,200 mg of DLV alone per day (group 3) or ZDV plus 1,200 mg of DLV per day (group 4). DLV demonstrated good oral bioavailability at all five doses tested. The major toxicity was a transient mild rash which appeared in 44% of all DLV recipients. Overall, group 2 patients demonstrated more sustained improvements in CD4 counts, percent CD4 cells, branched DNA levels, p24 antigen levels, and virus titers in plasma than group 1, 3, or 4 patients. The magnitude of the response correlated with the intensity of prior nucleoside analog treatment, the non-syncytium-inducing or syncytium-inducing viral phenotype at baseline, and the presence of a wild-type codon at amino acid position 215 in the baseline reverse transcriptase genotype. Despite a transient rash, DLV therapy was well tolerated. Combination therapy with DLV and nucleoside analogs appears promising, with the three-drug combination appearing to be more potent that either two-drug combinations or monotherapy.

Metabolism of compound A by renal cysteine-S-conjugate beta-lyase is not the mechanism of compound A-induced renal injury in the rat.

Compound A [CF2 = C(CF3)OCH2F], a vinyl ether produced by CO2 absorbents acting on sevoflurane, can produce corticomedullary junction necrosis (injury to the outer stripe of the outer medullary layer, i.e., corticomedullary junction) in rats. Several halogenated alkenes produce a histologically similar corticomedullary necrosis by converting glutathione conjugates of these alkenes to halothionoacetyl halides. To test whether this mechanism explained the nephrotoxicity of Compound A, we blocked three metabolic steps which would lead to formation of a halothionoacetyl halide: 1) we depleted glutathione by administering dl-buthionine-S, R-sulfoximine (BSO); 2) we blocked cysteine S-conjugate formation by administering acivicin (AT-125); and 3) we inhibited subsequent metabolism by renal cysteine conjugate beta-lyase to the nephrotoxic halothionoacetyl halides by administering aminooxyacetic acid (AOAA). These treatments were given alone or in combination to separate groups of 10 or 20 Wistar rats before their exposure to Compound A. We hypothesized that blocking these metabolic steps should decrease the injury produced by breathing 150 ppm of Compound A for 3 h. However, we found either no change or an increase in renal injury, suggesting that this pathway mediates detoxification rather than toxicity. Our findings suggest that the cysteine-S-conjugate-mediated pathway is not the mechanism of Compound A nephrotoxicity and, therefore, observed interspecies differences in the activity of this activating pathway may not be relevant in the prediction of the nephrotoxic potential of Compound A in clinical practice.

Comparison of 13 acellular pertussis vaccines: overview and serologic response.

OBJECTIVE: To compare the immunogenicity of a licensed conventional whole-cell (WCL) and 13 diphtheria-tetanus-acellular pertussis (DTaP) vaccines that differed in source, method of manufacture, and included antigens; all vaccines included diphtheria and tetanus toxoids. METHODS: Healthy infants were enrolled through six university-based vaccine and treatment evaluation units and were randomized to receive one of the study vaccines at 2, 4, and 6 months of age. Sera were obtained before the first immunization and 1 month after the third immunization and were analyzed for antibody to pertussis toxin (PT), filamentous hemagglutinin, fimbriae, pertactin, and diphtheria and tetanus toxins. Chinese hamster ovary cell toxin neutralization assays were performed, and levels of agglutinating antibodies were determined. RESULTS: Of 2342 infants enrolled, 1942 contributed usable preimmunization and postimmunization serum specimens. Each vaccine produced significant increases in antibodies directed against the included antigens; postimmunization antibody titers differed significantly among the DTaP vaccines. For each evaluated antigen, the majority of DTaP vaccines produced antibody responses that equaled or exceeded those produced by WCL. For some antigens (eg, PT), mean antibody levels by vaccine correlated poorly with the quantity of antigen included in each vaccine; for others (eg., fimbriae), there was a close correlation. CONCLUSION: Although serologic correlates of pertussis immunity are not defined, it is clear that DTaP vaccines can stimulate immune responses that exceed those of licensed whole-cell vaccine with respect to the measured antibodies. Particularly for PT, immunogenicity seems to depend on factors in addition to antigen concentration, possibly including antigen derivation and formulation. No DTaP was most or least immunogenic with respect to all included antigens.

Comparison of 13 acellular pertussis vaccines: adverse reactions.

OBJECTIVE: To compare the reactogenicity of a licensed conventional whole-cell (WCL) and 13 acellular pertussis vaccines that differed in the source, manufacture, and quantity of included antigens; all vaccines included diphtheria and tetanus toxoids. METHODS: Healthy infants were enrolled through six university-based vaccine and treatment evaluation units and were randomized to receive one of the study vaccines at 2, 4, and 6 months of age. Parents recorded the occurrence of fever, redness, swelling, pain, fussiness, drowsiness, anorexia, and use of antipyretics for 2 weeks after each inoculation; nurses interviewed parents on the third day and at each succeeding visit; long-term follow-up information was collected from parents and medical records 1 year after the third immunization. RESULTS: Of 2200 vaccinated infants, 2189 contributed reaction data after 6375 vaccinations. For every acellular vaccine, every monitored reaction except vomiting occurred at a significantly lower frequency and severity than was seen with WCL. The groups receiving acellular pertussis vaccines differed significantly with respect to redness, swelling, pain, and vomiting, but not with respect to fussiness, antipyretic use, drowsiness, or anorexia. CONCLUSION: Although there were differences among the acellular vaccines, none was consistently the most or least reactogenic; all were associated with substantially fewer and less severe adverse reactions than a standard commercial whole-cell vaccine. Selection of acellular vaccines for further development and for introduction into efficacy trials can give priority to assessments of immunogenicity and purity, with comparative reactogenicity a secondary consideration.

A randomized comparison of reactogenicity and immunogenicity of two whole-cell pertussis vaccines.

OBJECTIVE: To compare prospectively the reactogenicity and immunogenicity of two licensed whole-cell pertussis vaccines. METHODS: We conducted a prospective, randomized, double-blinded assessment of two licensed whole-cell pertussis vaccines with diphtheria and tetanus toxoids that were included in a multicenter trial evaluating 13 acellular pertussis vaccines. Infants were immunized at 2, 4, and 6 months of age with a single lot of Lederle (309 infants) or Massachusetts Public Health Biologic Laboratories (MPHBL; 94 infants) vaccine. RESULTS: The group receiving the Lederle vaccine demonstrated significantly higher antibody titers to pertussis toxin by enzyme-linked immunosorbent assay (ELISA) and by the Chinese hamster ovary cell pertussis toxin neutralization assay, and to fimbrial antigens by ELISA, as well as higher mean agglutinin titers. In contrast, the group receiving the MPHBL vaccine demonstrated higher ELISA antibody levels to filamentous hemagglutinin and pertactin. Similar differences were observed in the proportions of vaccinees seroconverting to these antigens. Rates of systemic and local reactions were relatively low for both vaccines. Although the Lederle product had substantially lower reactogenicity in this study than previously reported for that vaccine, the MPHBL vaccine was significantly less reactogenic in nearly all clinical categories. CONCLUSION: The two whole-cell vaccines demonstrated statistically significant differences in postimmunization antibody levels to all six evaluated pertussis antigens. Whether these statistically significant differences in antibody levels have clinical relevance is not clear. Rates of nearly all local and systemic reactions were significantly lower among the MPHBL group than the Lederle group. Licensed whole-cell diphtheria-tetanus-pertussis vaccines produced by different manufacturers cannot be assumed to be similar in reactogenicity or immunogenicity.

Description and evaluation of serologic assays used in a multicenter trial of acellular pertussis vaccines.

OBJECTIVE: To describe and evaluate the assays used to measure the antibody responses in infants to 13 experimental acellular pertussis vaccines and 2 licensed whole-cell pertussis vaccines. METHODS: During a 53-week period, preimmunization and postimmunization sera were assayed for immunoglobulin G antibodies to pertussis toxin, filamentous hemagglutinin, pertactin, and a mixture of type 2 and type 3 fimbriae by enzyme-linked immunosorbent assay (ELISA), for whole-cell agglutinins (AGG), and for pertussis toxin-neutralizing antibodies by the Chinese hamster ovary cell assay. All ELISA reagents were characterized to assure antigen and isotype specificity of the assays. Intralaboratory reproducibility and temporal stability were evaluated by analysis of results of control sera and by assessment of the response to the control whole-cell vaccine. Interlaboratory reproducibility was assessed by repeating the assays on preimmunization and postimmunization sera for 10% of the infants in a second laboratory. RESULTS: For control sera having antibody concentrations at least four times the minimum level of detection, the coefficients of variation within and between the ELISAs consistently were less than 20%. Trend analysis indicated that none of the assays drifted by more than 20% during the study period, and no significant drift was seen in the response to the control whole-cell vaccine. Results from the two laboratories correlated well; correlation coefficients were .93 or greater for the four ELISAs, .79 for the Chinese hamster ovary cell assay, and .82 for the AGG assay. For four of the six assays, there was either no difference or a modest (< 15%) difference in the geometric mean values for sera tested in both laboratories. Larger quantitative differences were observed for the AGG (45% difference) and pertactin (61% difference) assays. CONCLUSION: Assay reproducibility and stability indicate that the standardized methods can be transferred between laboratories, and that the results accrued during a 1-year period for the 15 vaccines can be compared.

Simultaneous administration of Haemophilus influenzae type b vaccine with acellular or whole-cell pertussis vaccine: effects on reactogenicity and immune responses to pertussis vaccines.

OBJECTIVE: To evaluate the effect of simultaneous Haemophilus influenzae type b conjugate (Hib) vaccination on the safety and immunogenicity of selected acellular (DTaP) and whole-cell (DTP) pertussis vaccines with diphtheria and tetanus toxoids combined. METHODS: Enrollment of infants into a large multicenter study of the safety and immunogenicity of 13 DTaP and 2 DTP vaccines was partially completed when the first Hib vaccine, HbOC (Haemophilus b oligosaccharide conjugate vaccine), was licensed for use in infants. Thereafter, at each immunization most infants received HbOC simultaneously with DTaP (or DTP), administered in opposite thighs. Postvaccination geometric mean titers or concentrations (GMTs) of pertussis antibodies as measured by six different assays were compared pairwise among groups of infants receiving 0, 1, 2, or 3 simultaneous HbOC immunizations. The incidence of reactions was compared between infants who received only DTaP or DTP and those who received HbOC simultaneously. RESULTS: Comparison of postvaccination GMTs was possible among groups of infants receiving different numbers of simultaneous immunizations for 10 of the 13 DTaP and both DTP vaccines. Increased HbOC exposure had no consistent dose-response effect on antibody titers for DTaP or DTP vaccines in any assay. Significant differences between groups in postvaccination GMTs were observed with 4 DTaP vaccines in 1 to 2 assays each; the GMTs were higher with increasing HbOC exposure for 2 DTaP vaccines and lower for 2 others. There was no significant increase in reactions with simultaneous HbOC and DTaP immunization. CONCLUSIONS: Based on these retrospective analyses, there did not seem to be an interference in pertussis immunogenicity or alteration in reactogenicity associated with the simultaneous administration of HbOC and DTaP. These findings are encouraging with respect to the development of DTaP-Hib combination vaccines.

The effect of maternal antibody on the serologic response and the incidence of adverse reactions after primary immunization with acellular and whole-cell pertussis vaccines combined with diphtheria and tetanus toxoids.

OBJECTIVE: To evaluate the effect of maternally derived antibody on the immunogenicity and reactogenicity of acellular (DTaP) or whole-cell (DTP) pertussis vaccine with diphtheria and tetanus toxoids combined. METHODS: A total of 2342 infants were randomized to receive one of 13 DTaP or 2 DTP vaccines at 2, 4, and 6 months of age. The correlation between preimmunization and postimmunization antibody after three doses of vaccine and the relation between preimmunization antibody and adverse reactions after the first immunization were modeled by linear regression. RESULTS: After DTP but not DTaP, higher levels of preexisting antibody were associated with substantial (28% to 56%) reductions in the subsequent antibody response to pertussis toxin (PT). For other pertussis antibodies, modest inverse correlations were seen between preexisting antibody concentrations and most postimmunization antibody responses (resulting in 8% to 18% reductions in postimmunization antibody) for both DTP and DTaP. There was no consistent association in any DTP or DTaP group between adverse reactions and preimmunization antibody levels. CONCLUSION: The PT antibody response to DTaP, unlike DTP, is not adversely affected by preexisting antibody to PT. Inhibitory effects with respect to other antibodies, seen with both DTP and DTaP, were relatively modest. Our data suggest that the use of acellular pertussis vaccines in adults, which could confer higher levels of antibody in women before pregnancy, would be unlikely to adversely affect pertussis antibody responses after DTaP among infants born to mothers with high antibody levels.

Effect of gender, race, and parental education on immunogenicity and reported reactogenicity of acellular and whole-cell pertussis vaccines.

OBJECTIVE: To determine whether gender, race (black or white), or level of parental education influenced serologic responses or reporting of clinical reactions after immunization with acellular (DTaP) or whole-cell (DTP) pertussis vaccine with diphtheria and tetanus toxoids combined. METHODS: Healthy infants were prospectively randomized to receive one of 13 DTaP, Lederle DTP, or another DTP. Parents recorded the occurrence of adverse reactions for 2 weeks after each inoculation. Sera obtained before the first immunization and 1 month after the third immunization were analyzed for antibody to pertussis toxin, filamentous hemagglutinin, fimbriae, and pertactin (PRN). Chinese hamster ovary cell pertussis toxin neutralization assays were performed, and levels of agglutinating antibodies determined. RESULTS: Prevaccination antibody levels did not differ by race, gender, or parental education. Postimmunization geometric mean titers (GMTs) were strongly and consistently associated with race. For both DTaP and DTP and for every included antigen, postimmunization GMTs were about twice as high for black as for white infants. Among DTaP recipients, these differences were significant for pertussis toxin, Chinese hamster ovary cell pertussis toxin neutralization assay, filamentous hemagglutinin, PRN, and agglutinins; among the much smaller sample of WCL recipients, the differences achieved or approached statistical significance for agglutinins, PRN, and fimbriae. These findings were confirmed by regression analyses that controlled for gender, parental education, study site, and preimmunization antibody level. Reported reactions were not correlated with parental education level and showed no material correlation with gender. Black infants were reported to have had more pain than white infants after receiving WCL and DTaP and were reported to be more fussy after receiving WCL. CONCLUSIONS: The consistently higher postimmunization GMTs among black infants seems to be a real finding for which we have no explanation; the infants did not significantly differ by race in vaccine assignment, preimmunization antibody levels, age at immunization, or interval from immunization to phlebotomy. These observations should be confirmed and further evaluated in future pertussis vaccine trials. Reported differences by race in pain and fussiness after receiving WCL might reflect chance, differences by race in the occurrence of reactions, or differences by race in the reporting of reactions.

Relationships between functional assays and enzyme immunoassays as measurements of responses to acellular and whole-cell pertussis vaccines.

OBJECTIVE: To examine the relationships between functional assays and antigen-specific enzyme immunoassays in sera from a multicenter trial of 13 different experimental acellular pertussis vaccines and 2 licensed whole-cell vaccines, and to determine whether correlations previously observed among assays of specimens from pertussis patients and whole-cell vaccinees would apply to specimens from infants immunized with purified components in acellular vaccines. METHODS: Postimmunization sera were assayed for immunoglobulin G antibodies to pertussis toxin (PT), filamentous hemagglutinin, pertactin (PRN), and a mixture of types 2 and 3 fimbriae (FIM) by enzyme-linked immunosorbent assay, for whole-cell agglutinins (AGGs) and for PT-neutralizing antibodies by the Chinese hamster ovary (CHO) cell assay. Assay results were compared for individual sera, as well as for geometric mean antibody concentrations or titers (GMTs) calculated by vaccine or overall. RESULTS: For the 15 vaccines, the PT GMTs were highly correlated with the CHO assay GMTs (r = .92), and the FIM GMTs were highly correlated with the AGG GMTs (r = .96). For individual postvaccination sera, there was a significant correlation between the CHO titers and levels of antibody to PT whether the 15 vaccines were considered separately (.59 < or = r < or = .85) or combined (r = .81). For individual sera from infants immunized with the two whole-cell vaccines or any of the four acellular vaccines containing FIM, a strong correlation between AGG titer and FIM antibody was observed whether the vaccines were considered separately (.83 < or = r < or = .91) or together (r = .86). One vaccine without detectable FIM produced a measurable AGG response; for this vaccine, a moderate but significant correlation (R = .58) between PRN antibody and AGG titer was observed. CONCLUSION: These data indicate that appropriate antigen-specific enzyme-linked immunosorbent assays will furnish results similar to those provided by the CHO and AGG assays in the evaluation of the immunogenicity of component vaccines. Antibodies to FIM seem to include the most important AGGs; however, there is evidence that agglutination by PRN antibody may be detected in the absence of antibody to FIM.