John M. Zahradnik

Adenovirus infection in the immunocompromised patient

Illness associated adenovirus infection is described in 15 immunocompromised patients. Patients were immunocompromised by severe underlying disease, immunosuppressive or corticosteroid therapy or by age (prematurity). Evidence of adenovirus infection was obtained by either viral isolation or, in two cases, characteristic adenovirus inclusion bodies at postmortem study. All clinical illness was associated with high fever (temperature greater than 39 degrees C). Eighty per cent of the patients had severe systemic complaints including malaise, lethargy, fatigue and night sweats; a similar number of gastrointestinal symptoms. Pulmonary complaints were described in 11 of 15 cases and included cough (67 per cent) and tachypnea (53 per cent). Roentgenologic evidence of pneumonia was demonstrated in 12 of 15 patients (80 per cent). Elevation of serum hepatic enzyme levels (serum glutamic pyruvic transaminase (SGPT)) occurred in eight of 11 patients (73 per cent) and was moderate to severe (serum glutamic pyruvic transaminase greater than 450 IU/liter) in five of 11 (45 per cent). Nine patients died; seven after a rapid downhill course and two after a prolonged illness. Evidence of adenovirus infection microscopically by autopsy in the lung, liver or both is demonstrated in four patients with fulminant systemic illness. Adenovirus infection should be considered in the etiology of severe overwhelming illness in the immunocompromised host.

A Canarypox Vector Expressing Cytomegalovirus (CMV) Glycoprotein B Primes for Antibody Responses to a Live Attenuated CMV Vaccine (Towne)

To develop a vaccine against cytomegalovirus (CMV), a canarypox virus (ALVAC) expressing CMV glycoprotein (gB) was evaluated alone or in combination with a live, attenuated CMV vaccine (Towne). Three doses of 106.5 TCID50 of ALVAC-CMV(gB) induced very low neutralizing or ELISA antibodies in most seronegative adults. However, to determine whether ALVAC-CMV(gB) could prime for antibody responses, 20 seronegative adults randomly received either 106.8 TCID50 of ALVAC-CMV(gB) or 106.8 TCID50 of ALVAC-RG, expressing the rabies glycoprotein, administered at 0 and 1 month, with all subjects receiving a dose of 103.5 pfu of the Towne vaccine at 90 days. For subjects primed with ALVAC-CMV(gB), neutralizing titers and ELISA antibodies to CMV(gB) developed sooner, were much higher, and persisted longer than for subjects primed with ALVAC-RG. All vaccines were well tolerated. These results demonstrate that ALVAC-CMV(gB) primes the immune system and suggest a combined-vaccine strategy to induce potentially protective levels of neutralizing antibodies.

Safety and immunogenicity of Haemophilus influenzae type b polysaccharide and polysaccharide diphtheria toxoid conjugate vaccines in children 15 to 24 months of age.

To evaluate the safety and immunogenicity of the Haemophilus influenzae type b polysaccharide vaccine, PRP, and a new polysaccharide-diphtheria toxoid conjugate vaccine, PRP-D, a collaborative study was carried out in six centers in five states. Subjects were 585 infants 15 to 24 months of age. They were randomly assigned to receive a single dose of PRP or PRP-D vaccine. There were no significant differences in the rate of adverse reactions between the two vaccine groups. Minor local reactions occurred in 10.3% of PRP and 12.5% of PRP-D recipients, and fever in 27.4% of PRP and 23.8% of PRP-D recipients. All reactions resolved within 48 hours. Serum samples were obtained just before vaccination and after 1 month. Prevaccination antibody levels were similar for the PRP (0.035 micrograms/mL) and PRP-D (0.027 micrograms/mL) groups, with no differences in levels by age, sex, race, vaccine lot, or study site. Both groups had significant rises in geometric mean levels, but this difference was significantly greater for PRP-D (2.166 micrograms/mL) than for PRP (0.154 micrograms/mL). In addition, the percentage of responders as determined by three definitions (twofold titer rise, greater than 0.15 micrograms/mL, and greater than 1.0 micrograms/mL) was also significantly greater for PRP-D than PRP. In contrast to a marked age-related immunogenicity to PRP (P less than 0.001), there was no significant variation in immune response to PRP-D by age. PRP-D conjugate vaccine appears to be as safe and significantly more immunogenic than PRP vaccine for children vaccinated at 15 to 24 months of age.

Growth-Inhibiting Antibody Responses of Humans Vaccinated with Recombinant Outer Surface Protein A or Infected with Borrelia buvgdorferi or Both

Serial serum samples from a 2-year human trial of outer surface protein (Osp) A vaccine were analyzed by Borrelia burgdorferi growth-inhibition assay (GIA) and anti-OspA ELISA to assess the antibody responses of vaccine recipients and subjects with Lyme disease. Although 74% of OspA recipients had a reciprocal GIA titer >/=64 after 3 vaccinations, none of the placebo recipients, even those with Lyme disease, had a GIA titer this high. The correlation between GIA and ELISA titers after 3 doses of vaccine was.84; however, more vaccine recipients had an elevated ELISA titer paired with low GIA titer than had a low ELISA titer with a high GIA titer. OspA-vaccine recipients who acquired Lyme disease had significantly lower serum GIA and ELISA titers after 3 immunizations than did age- and sex-matched OspA recipients without Lyme disease. Thus, vaccinated subjects had antibodies to native antigen on viable cells, and antibody assays with this specificity may predict protection of vaccinees against infection.

AUGMENTED ANTIBODY (Ab) RESPONSES IN INFANTS ADMINISTERED A NEW HAEMOPHILUS INFLUENZAE TYPE B CAPSULAR POLYSACCHARIDE (PRP) DIPHTHERIA TOXOID CONJUGATE VACCINE (PRP-D)

PRP-D, a hapten-carrier conjugate containing 20μg PRP/0.5cc, has previously been shown to be highly immunogenic in adults and young children (<18 mo.) given 2 doses. Ab responses in sera taken 1 mo. post-vac were evaluated in 90 infants administered PRP-D, PRP, or placebo at ages 3, 5 & 7 months. No significant adverse reactions occurred. Anti-PRP responses for the vaccinees shown (Farr assay with SK standard) developed in 14%, 53%,& 100% of PRP-D vaccinees respectively, following the first three doses as compared to 0, 7%, and 60% in PRP vaccinees respectively. A sequential increase in the mean anti-PRP titer was see in the PRP-D group and final mean titers were 5-fold greater than that following PRP:This new PRP-D conjugate vaccine appears to have resulted in an enhanced response since the seroconversion rate and Ab titers were higher than those seen following PRP.

512 HEMOPHILUS INFLUENZAE TYPE B(HIB) POLYSACCHARIDE VACCINE: SAFETY AND IMMUNOGENICITY OF PRP AND PRP-D CONJUGATE VACCINES IN CHILDREN 16|[ndash]|24 MONTHS

A multicenter study of the relative safety and immunogenicity of the purified heat-sized Hib polysaccharide (PRP) and conjugate (PRP-D) vaccines was conducted in 475 children 16-24 months of age. No serious reactions occurred in either group. Except for fewer febrile reactions in the PRP-D group (p<.05), other reactions were similar for both vaccines.Immune responses were measured by KIA (ug)ml and are summarized below:Although PRP is soon to be licensed for use in older children, PRP-D is at least as safe and significantly more immunogenic.

1134 STUDIES OF SAFETY AND IMMUNOGENICITY OF HAEMOPHILUS INFLUENZAE TYPE B POLYSACCHARIDE DIPHTHERIA TOXOID CONJUGATE VACCINE (PRP-D) IN CHILDREN 7–14 MONTHS OF AGE

In a multicenter study, 502 normal infants ages 7-14 months were randomized to receive either 2 doses of PRP-D intramuscularly containing 20 ug PRP (80%) or placebo (20%) 6-10 weeks apart. Serum samples were obtained from 25% prior to each injection and 1 month post second dose and tested by Farr-type radioimmunoassay for anti-PRP antibody. Reaction data are available from 400 subjects. The incidence of local erythema at the injection site was 2.4% and irritability 3% in both groups. Two PRP-D recipients had temperatures greater than 1022(R). Among 120 children tested for antibody, 99% of PRP-D recipients demonstrated a two fold or greater rise in anti-PRP compared with 5% of placebo recipients. Median anti-PRP levels in the two groups were 7.0 and 0.012 ug/ml respectively. After 2 doses of PRP-D, 95% had ≥ 0.15 ug/ml antibody protein/ml and 90% had > 1 ug/ml. This study confirms prior observations in 9-14 month olds that PRP-D can induce primary and booster antibody responses in infants over 7 months compatible with protection against H. influenzae b disease.

RESPONSE OF IgG SUBCLASS DEFICIENT PATIENTS TO H. INFLUENZA TYPE b POLYRIBOSE PHOSPHATE (PRP) DIPHTHERIA TOXOID CONJUGATE (PRP-D) VACCINE

The efficacy of PRP-D vaccine in young infants has been documented in previous studies. We now report the response of patients with IgG subclass deficiency (GSD) to a single immunization with PRP-D. Patients with GSD ranging in age from 6 to 10 years were given a single i.m. dose of 20 μg PRP-D. Total serum anti-PRP antibody levels were determined using a modified Farr assay and radiolabeled PRP. Four patients with GSD and no major abnormalities in B- and T-cell subsets or in vitro mitogen stimulation had a mean preimmunization anti-PRP level of 1.61 μg/ml which rose to 22.6 μg/ml 3-4 weeks after immunization. The mean increase in anti-PRP for 3 patients with IgG2 deficiency was 18.8 μg/ml. Two patients with IgA and IgG2 deficiency responded with post-immunization anti-PRP levels of 10.8 and 40 μg/ml. Both of these patients failed to respond to immunization with a polyvalent pneumococcal polysaccharide (PS) vaccine. One patient with isolated IgG3 deficiency responded normally to diphtheria and tetanus toxoid, to 3 of 4 pneumococcal serotypes tested, and had a rise of anti-PRP antibody from 0.6 to 28.4 μg/ml. A fifth patient with common variable immunodeficiency had no response to immunization with any of the above vaccines. These data suggest that protein conjugate vaccines may lead to effective immunization of patients with defective PS antigen processing.

MUCOSAL AND SERUM ANTIBODY (Ab) RESPONSES TO PARENTERAL IMMUNIZATION OF 1-YR-OLD INFANTS WITH H. INFLUENZAE B CAPSULAR (PRP) ANTIGEN CONJUGATED TO A DIPH IHERIA PROTEIN CARRIER

Seventeen healthy infants age 9-15 mos received a 2-injection sequence of a PRP oligosaccharide conjugate vaccine. Sera and samples of nasal mucus obtained using saline washes (NW) were taken before the 1° and 2° injections and 1 mo and 6 mos after the 2°. A rise in total serum anti-PRP Ab [determined by radio-antigen binding (RAB)] occurred in 15 of 17. NW anti-PRP Ab developed in 6 of 17 as detected by RAB and in 8 of 17 as detected by an Ig class-specific immunosorbent assay (ELISA); these ELIS.A responses occurred as IgG (7 of 17), IgM (5 of 17), and IgA (4 of 17). Ab responses in NW were related to the magnitude of the serum Ab response: in 8 infants with post-2° serum Ab of <2 μg/ml, NW responses were detected in 0 of 8 by RAB and 1 of 8 by ELISA; in 9 infants with serum Ab >2 μg/ml, NW responses were detected in 6 of 9 by RAB and 7 of 9 by ELISA. At 6 mos after 2° injection, anti-PRP Ab was still detectable in NW in 6 of 16 subjects. Thus, a mucosal Ab component may contribute to the protective potential of conjugate vaccines.

HAEMOPHILUS INFLUENZAE TYPE B (Hib) CAPSULAR ANTIGEN (PRP) CONJUGATE VACCINE INDUCES ANTI-PRP ANTIBODY (Ab) IN CHILDREN FOLLOWING Hib INFECTIONS

PRP vaccine is a poor immunogen when administered to some children following Hib infection or their sibs. To date, we have immunized 18 patients (mean age 19 mos., range 7-45 mos; 14 meningitis) with PRP-diphtheria toxoid conjugate vaccine (PRP-D) containing 20 μg PRP. Children were inoculated 1-8 mos. (15 ≤ 2 mos.) post illness with 1 or 2 doses of PRP-D. Serum was obtained for anti-PRP Ab (radioantigen binding assay at Connaught Laboratories) prior to and 1 month post vaccine. Serology is available on 13 patients, 6 of whom were Ab negative ( < 0.012 μg/ml) pre-vac (4 were ≤ 16 mos. when immunized). Anti-PRP rises developed in 11/13 patients and 5/6 pre-vac Ab negative patients. The pre- and post-geometric mean titers were 0.13 and 2.0 μg/ml, respectively (p < 0.001 for log transformed data). One patient (pre-vac Ab neg), a non-responder to routine PRP given at 24 mos., developed 0.28 ug/ml anti-PRP Ab following PRP-D at 26 mos. Anti-PRP Ab developed in 3/3 sibs, (8, 11, and 24 mos.), 2 of whom were Ab negative pre-vac.Our data indicate that young children who may not have developed anti-PRP within 1 or 2 mos. of Hib infection usually respond to 1 or more doses of PRP-D and suggest that children at increased risk for Hib disease will likely respond to PRP conjugate vaccines.