Klemens Stehr

A Comparative Efficacy Trial in Germany in Infants Who Received Either the Lederle/Takeda Acellular Pertussis Component DTP (DTaP) Vaccine, the Lederle Whole-Cell Component DTP Vaccine, or DT Vaccine

Background. The goal of the trial was to determine the efficacy of a multicomponent acellular pertussis vaccine against Bordetella illnesses in comparison with a whole-cell product and DT. Design. In a randomized, double-blind fashion, 2- to 4-month-old infants received 4 doses of either DTP or DTaP vaccine at 3, 4.5, 6, and 15 to 18 months of age. The controls received 3 doses (3, 4.5, 15 to 18 months of age) of DT vaccine. The DTP vaccine was Lederle adsorbed vaccine (licensed in the United States) and DTaP was Lederle/Takeda adsorbed vaccine. Follow-up for vaccine efficacy started 2 weeks after the third dose (DTP/DTaP) and at the same age (6.5 months) in DT recipients. Reactogenicity of all doses of all three vaccines was documented by standardized parent diary cards. In addition, all subjects were monitored for respiratory illnesses and serious adverse events by biweekly phone calls. Results. From May 1991 to January 1993, a total of 10 271 infants were enrolled: 8532 received either DTP or DTaP and 1739 received DT. Specific efficacy against B pertussisinfections with cough ≥7 days duration was 83% (95% confidence interval [CI]: 76–88) and 72% (95% CI: 62–79) for DTP and DTaP, respectively; results for DTP and DTaP based on ≥21 days of cough with either paroxysms, whoop or posttussive vomiting (PWV) were 93% (95% CI: 89–96) and 83% (95% CI: 76–88), respectively. For DTaP vaccine, efficacy was higher after the fourth dose as compared with its efficacy after the third dose (78% vs 62% for cough ≥7 days and 85% vs 76% for cough ≥21 days with PWV). For DTP vaccine, efficacy was less varied after the third and fourth dose (78% vs 85% for cough ≥7 days and 93% vs 93% for cough ≥21 days with PWV). In contrast with DTP, the DTaP vaccine had some efficacy against B parapertussisinfection (point estimate for cough ≥7 days: 31% [95% CI: −10–56]). All vaccines were generally well-tolerated. However, side reactions were significantly less after DTaP compared with DTP. Conclusions. Like other multicomponent acellular pertussis vaccines, the Lederle/Takeda DTaP vaccine demonstrated good efficacy against mild and typical pertussis due to B pertussisinfections. Interestingly, it also may have some efficacy againstB parapertussis. Based on the results of this trial, the vaccine was licensed in the United States in December 1996 for all 5 doses of the currently recommended immunization schedule in this country.

A search for serologic correlates of immunity to Bordetella pertussis cough illnesses.

In a pertussis vaccine efficacy trial in Germany we collected sera from vaccinees (DTaP or DTP) after the third and fourth doses of vaccine or at comparable time periods in DT vaccine recipients. In addition, sera were collected from a randomized sample of subjects in each vaccine group at approximately 3-month intervals from which antibody kinetic curves were constructed, which allowed us to estimate specific antibody values to pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin and fimbriae-2 at the time of exposure in the household setting. The imputed geometric mean antibody values to PT, pertactin and fimbriae-2 at the time of household exposure to Bordetella pertussis infection were higher (p < 0.07 or lower) in non-cases compared with cases. A multivariate (classification tree) analysis found that only pertactin and PT were significant in protection. Subjects with an imputed pertactin value of < 7 EU ml-1 had a 67% (18/27) chance of infection regardless of the PT value. If the pertactin value was > or = 7 EU ml-1 and the PT value > or = 66 EU ml-1 all subjects were non-cases. If the pertactin value was > or = 7 and the PT value was < 66 EU ml-1 the predicted probability of being a case was 31% (15/49). Logistic regression analysis also found that high versus low pertactin values were associated with illness prevention following household exposure. In the presence of antibody to pertactin, PT and fimbriae-2, the additional presence of antibody to FHA did not contribute to protection. Our data support historical data indicating that agglutinating antibodies are associated with protection and also recent serologic correlates data and clinical efficacy data which indicate that multicomponent vaccines containing pertactin and fimbriae have better efficacy than PT or PT/FHA vaccines.

Clinical characteristics of illness caused by Bordetella parapertussis compared with illness caused by Bordetella pertussis

In conjunction with a pertussis vaccine efficacy trial in Germany, nasopharyngeal specimens were collected from May, 1992, to March, 1993, from patients with cough illnesses. Clinical data were obtained by initial and follow-up questionnaires. Bordetella parapertussis was isolated from 38 patients (mean age, 3.5 years; 68% girls). Clinical characteristics in these cases were compared with those of 76 patients (matched by age and sex) with illness caused by Bordetella pertussis during the same period. Findings were: (B. pertussis/B. parapertussis): cough > 4 weeks 57%/37% (P = 0.06); whoop 80%/59% (P = 0.07); whoop > 2 weeks 26%/18% (P = 0.05); paroxysms 90%/83% (P = 0.5); body temperature > or = 38 degrees C 9%/0% (P = 0.17); vomiting 47%/42% (P = 0.69); and mean leukocyte and lymphocyte counts 12,500/mm3 and 7600/mm3 (P < 0.0001) and 7800/mm3 and 3500/mm3 (P < 0.0001), respectively. Illness caused by B. parapertussis was typical of pertussis but less severe than that caused by B. pertussis. In contrast with B. pertussis infection, lymphocytosis is not a characteristic of B. parapertussis infection. This is most likely a result of the lack of production of lymphocytosis-promoting factor toxin by B. parapertussis.

The acute lymphoblastic leukaemia cell line SEM with t(4;11) chromosomal rearrangement is biphenotypic and responsive to interleukin-7

Summary A cell line, designated SEM, was established from the peripheral blood of a 5‐year‐old girl in relapse with acute lymphoblastic leukaemia (ALL). Both the lymphoblasts of the patient and the cells of the cell line SEM showed the t(4:11) chromosomal rearrangement. The analysis of the immunophenotype of the SEM cell line revealed the B‐cell differentiation antigens CD19, CD22 and CDw75 in the absence of CD20. CD24 and immunoglobulin expression. Besides B‐lineage antigens. SEM cells were positive for the myeloid antigens CD13, CD15, CD33 and CDw65. Immunogenotypic analysis of SEM cells showed a monoclonal rearrangement of immunoglobulin heavy‐chain (IgH), T‐cell receptor (TCR) γ and δ genes. Addition of interleukin (IL)‐7 promoted the growth of the patients lymphoblasts in culture and enhanced the proliferation of SEM cells. The SEM cells also express messenger RNA (mRNA) for the IL‐7 receptor (IL‐7R), but no evidence for autocrine production of IL‐7 by the cell line was found. Addition of IL‐4, tumour necrosis factor (TNF)‐α, interferon (IFN)‐α, or IFN‐γ resulted in a profound inhibition of SEM growth. Thus, these cytokines may have important growth regulatory activities for biphenotypic leukaemic ALL cells.

Clinical Validation of a Polymerase Chain Reaction Assay for the Diagnosis of Pertussis by Comparison With Serology, Culture, and Symptoms During a Large Pertussis Vaccine Efficacy Trial

Objective. To assess the diagnostic sensitivity and specificity of a Bordetella pertussispolymerase chain reaction (PCR) assay using nasopharyngeal (NP) specimens from subjects with cough illnesses participating in a large pertussis vaccine efficacy trial. Design. From 1991 to 1994, we conducted a large pertussis vaccine efficacy trial in Germany to determine the efficacy of the Lederle/Takeda acellular pertussis component diphtheria-tetanus toxoids in comparison with the Lederle whole-cell component diphtheria-tetanus toxoids vaccine. In the final year of the follow-up period of this trial, a second NP specimen for PCR, in addition to a culture specimen and blood for specific serology (enzyme-linked immunosorbent assay), was collected by use of a Dacron swab in subjects or family members with cough illnesses ≥7 days duration or in subjects with exposure to a cough illness in a household member to establish a diagnosis ofB pertussis infection. Oligonucleotide primers (pTp1 and pTp2) that amplify a 191-bp-sized DNA fragment from the pertussis toxin operon, which is specific for B pertussis, were used. The PCR-amplified products were visualized by dot blot analysis followed by hybridization with a digoxigenin labeled probe and rated as 1+, 2+, or 3+ in comparison with positive controls representing ∼1 to 10, 11 to 50, and >50 B pertussis organisms, respectively. In the present analysis, we compare PCR findings with those of serology, culture, positive household contact, and clinical characteristics of cough illnesses. Results. Of 392 subjects with NP specimens obtained for PCR, 376 also had NP specimens collected for culture and 282 had serum specimens. PCR and culture were positive in 86 (22%) and 23 (6%) subjects, respectively. Of the positive PCR specimens, 40 were rated 3+, 32 were rated 2+, and 14 were rated 1+; 3+ positive specimens were more prevalent among DT recipients compared with pertussis vaccine recipients. Illnesses in subjects with 3+ positive PCR results were more typical of pertussis than were those in subjects with 2+ and 1+ positive results with a mean duration of cough of 48 days versus 43 and 42 days, respectively; presence of paroxysms, whoop or vomiting in 38% versus 17% and 10%, respectively; and a clinical diagnosis of definite or probable pertussis by the investigators of 26% versus 7% and 4%, respectively. Using serologic evidence of infection as the standard, sensitivity of PCR was 61%, and specificity was 88%. For 3+ positive PCR results, the respective values were 42% and 97%. Conclusion. Our findings demonstrate that PCR is more sensitive than conventional culture for the diagnosis of pertussis. They also demonstrate a high specificity of PCR when serology with or without other confirmative criteria (culture and household contact) is used as the reference. Analysis of semiquantitative PCR results revealed that subjects with a 3+ PCR more frequently experienced typical illness compared with patients with 1+ or 2+ PCR. Although specific serologic study remains a necessity in pertussis research its modification for diagnosis in the clinical setting results in low sensitivity and specificity. Therefore, because PCR is more sensitive than culture and is easy to perform, it is a useful addition in the clinical setting.

Comparative study of Lederle/Takeda acellular and Lederle whole-cell pertussis-component diphtheria-tetanus-pertussis vaccines in infants in Germany

In preparation for a large efficacy trial in Germany, a pilot study was initiated in December 1990. In this study 149 infants were enrolled; with double-blind randomization 75 received Lederle/Takeda acellular pertussis component diphtheria-tetanus-pertussis vaccine (APDT) and 74 received Lederle whole-cell pertussis component diphtheria-tetanus-pertussis vaccine (DTP). The mean age at first dose was 3.5 months, and the second and third doses followed at 6-week intervals. Reactions were relatively mild with both vaccines; in general they were less frequent following APDT. The IgG antibody responses to lymphocytosis promoting factor (LPF) and fimbriae-2 were similar in both groups whereas the responses to pertactin and filamentous haemagglutinin (FHA) were greater in APDT recipients. DTP recipients had greater responses to tetanus and diphtheria toxoids. When age of first dose was examined (8-12 weeks versus 16-20 weeks), it was found that young age had a suppressive effect on antibody responses in DTP but not APDT recipients to LPF toxoid, pertactin, fimbriae-2, and tetanus and diphtheria toxoids. High values of transplacentally acquired antibody lessened the response to LPF toxoid and tetanus toxoid in DTP recipients and to tetanus toxoid in APDT vaccinees. The IgG immune response to LPF toxoid, FHA and fimbriae-2 was found to be more uniform in APDT recipients than in DTP vaccinees. An IgA antibody response to fimbriae-2 was noted in 13% of DTP recipients but in no APDT vaccinees. The broad immunogenicity and mild reactogenicity of this APDT vaccine justifies its use in the German efficacy trial.

Serologic Response and Antibody-Titer Decay in Adults with Pertussis

Pertussis is a frequent and significant illness in adults. Because acellular pertussis vaccines for use in adolescents and adults have now been developed, it is important to compare serologic responses in adults after infection with serologic responses in adults after vaccination. We measured IgG and IgA antibodies to 4 Bordetella pertussis antigens at approximately 6-month intervals for 28 months in 11 adults with pertussis. After reaching peak levels, titers of antibody to pertussis toxin decreased more than did titers of antibodies to filamentous hemagglutinin, pertactin, and fimbriae type 1 and type 2. Although studies of adults who have been vaccinated with acellular pertussis vaccines have had shorter follow-up periods than studies of adults with pertussis infection, the antibody decay patterns are similar in both groups.

Clinical and laboratory diagnosis of pertussis in the regions of a large vaccine efficacy trial in Germany.

As a support service for a pertussis vaccine efficacy trial, a central diagnostic laboratory was established. Physicians in the geographic areas of the planned study were encouraged to send nasopharyngeal specimens from children and household contacts with cough illnesses whether or not the illnesses were typical of pertussis. From April, 1991, to February, 1992, 3629 specimens were received and in 601 instances (16.6%) Bordetella pertussis was isolated. Only 3.3% of patients with positive cultures had received pertussis vaccine whereas 16.1% of culture-negative patients had received vaccine (P > 0.0001). Fever was more common (12.2%) in patients with negative cultures compared with those with positive cultures (5.4%) (P > 0.0001). B. pertussis isolation rates fell markedly after 21 days of cough. Significantly more patients with negative cultures compared with those with positive cultures had been treated with erythromycin (8.5 vs. 2.9%; P > 0.0001). Patients with cough for greater than 4 weeks and specimen collection within 2 weeks of cough onset had a B. pertussis isolation rate of 59%. Similarly if whoop occurred under the same circumstances the isolation rate was 80%. In this study 25.5% of patients with culture confirmed pertussis had illnesses with cough of less than 21 days duration. This finding suggests to us that a pertussis case definition in efficacy trials that requires cough of 21 days is excessively restrictive.

Comparison of immunogenicity and reactogenicity of a measles, mumps and rubella (MMR) vaccine in German children vaccinated at 9-11, 12-14 or 15-17 months of age.

Children aged 9-11, 12-14 or 15-17 months, respectively were vaccinated with a measles, mumps and rubella (MMR) vaccine and serum antibody responses and reactogenicity were compared. The data of 118 children could be analysed (group 1=9-11 months, n=46; group 2=12-14 months, n=29, group 3, 15-17 months, n=43). The only significant difference observed was for seroconversion against measles virus between group 1 and group 3 (84.8% vs 100%, p=0.012). No serious adverse events were reported. Local side reactions were mild, infrequent and independent of age. Immunisation against MMR is safe and effective even when administered before the currently recommended age of 12 months.

Polymerase chain reaction identification of Bordetella pertussis infections in vaccinees and family members in a pertussis vaccine efficacy trial in Germany.

The polymerase chain reaction (PCR) was recently added to conventional culture and serology for the diagnosis of Bordetella pertussis infection in a large vaccine efficacy trial in Germany. In vaccinees or family members who had illnesses with cough, two nasopharyngeal swabs (calcium alginate for culture and Dacron for PCR) were taken and initial and follow-up clinical data were obtained. PCR was done using oligonucleotide primers PTp1 and PTp2 which amplify a 191-base pair DNA fragment of pertussis toxin operon. From December, 1993, to May, 1994, 555 pairs of swabs were processed; 28 grew B. pertussis and 9 grew B. parapertussis. Twenty