Serum IgG, IgA, and IgM responses to pertussis toxin, filamentous hemagglutinin, and agglutinogens 2 and 3 after infection with Bordetella pertussis and immunization with whole-cell pertussis vaccine.

Class antibody responses to pertussis toxin (PT), filamentous hemagglutinin (FHA), and agglutinogens 2 and 3 (Agg 2/3) were studied in 114 patients with pertussis, 49 family contacts of patients with pertussis, and 139 infants attending vaccination clinics. IgG responses to FHA and PT were similar in patients with pertussis and in infants immunized three times with whole-cell pertussis vaccine. IgA responses to FHA and PT were greater in patients with pertussis than in vaccines, and a serum log10 titer of IgA to PT greater than 1.9 was a useful discriminant of Bordetella pertussis infection. When compared with patients with pertussis, vaccinees had a greater IgG response to Agg 2/3 and an equivalent IgA response to Agg 2/3. Serologic responses to FHA, PT, and Agg 2/3 were common in family contacts but were smaller than the responses in patients with pertussis. Initial titers of IgG to FHA and IgA to FHA were significantly higher (P less than .005 and P less than .05, respectively) in family contacts aged 3-10 y than in patients with pertussis in an identical age group.

Human serum antibody responses to Bordetella pertussis infection and pertussis vaccination.

We used an immunoblotting technique to compare the serum antibody responses to pertussis toxin (PT), filamentous hemagglutinin (FHA), a 69-kilodalton (kDa) adenylate cyclase-associated protein (69 KD protein), and Bordetella pertussis outer membrane proteins (OMPs) following either B. pertussis infection or immunization with whole-cell pertussis vaccine. Infection and vaccination induced nearly equally intense antibody responses to PT and to FHA, but vaccination induced stronger antibody responses to the 69 KD protein and to many OMPs. The importance of serum antibody responses to the 69 KD protein and to B. pertussis OMPs other than PT and FHA in conferring immunity to pertussis after vaccination is unknown. Serum antibody responses to PT following either infection or vaccination were almost exclusively to the 28-kDa enzymatic subunit (S1) and only rarely and weakly to the lesser molecular weight binding subunits (S2-S5).

Severe hypoxaemia in pertussis.

Overnight tape recordings of breathing movements, airflow, and arterial oxygen saturation from six infants aged 3 weeks to 7 months, who had cyanotic episodes associated with pertussis, were compared with recordings from 12 age matched healthy controls. In all patients clinically apparent apnoeic episodes were associated with the rapid onset and progression of central cyanosis. When overnight recordings were compared, patients with pertussis had a greater frequency of apnoeic pauses (particularly those greater than or equal to 12.0 seconds duration) and a greater frequency of episodes of hypoxaemia (oxygen saturation less than or equal to 80% for greater than or equal to 0.5 seconds) associated with apnoeic pauses. In addition to episodes of hypoxaemia associated with a prolonged absence of breathing movements, patients with pertussis had frequent dips in oxygen saturation in association with continued breathing movements with and without continued inspiratory airflow. These episodes of hypoxaemia during continued breathing movements were more common in patients with pertussis. These findings suggest that episodes of abnormal apnoea accompanied by evidence of a mismatch between ventilation and perfusion of the lungs may produce the rapid onset of severe hypoxaemia in infants with pertussis.

Failure of penicillin prophylaxis in laboratory acquired leptospirosis.

A laboratory technician developed leptospirosis following accidental inoculation, despite prompt administration of parenteral penicillin by an accepted regimen of post-exposure prophylaxis. Another technician was similarly exposed and was given doxycycline; no illness or serological conversion followed. The implications of these cases are discussed and recommendations made for post-exposure chemoprophylaxis with doxycycline.

Effect of whooping cough in infancy on subsequent lung function and bronchial reactivity.

Thirty-six children younger than 1 yr of age hospitalized for whooping cough approximately 9 yr previously (cases) were compared with 36 control children of the same age and sex. Subjects were sampled from participants in an earlier large field study of the long-term sequelae of whooping cough. Respiratory symptoms were more common in cases, although the differences were not statistically significant. Cases were significantly more likely either to be atopic or to have a family history of wheezing illness. There were no significant differences between cases and control subjects in lung function indices derived from maximal expiratory flow volume loops or from single-breath nitrogen washout tests or in bronchial reactivity as judged by the histamine challenge PC20. The evidence from both the present and the earlier study indicates that whooping cough is unlikely to be a causal factor in later respiratory illnesses and symptoms and that no deficit in lung function can be detected in later childhood. The disease may, however, occur more frequently or be more easily recognized in children with environmental or constitutional factors that predispose to respiratory morbidity.

Reading attainment and physical development after whooping cough.

Anthropometric measurements were made on 360 primary school children with a history of whooping cough and on 711 controls. Altogether 245 (68%) cases and 469 (66%) controls had taken tests of reading attainment and a smaller number had taken tests of intelligence. No significant differences were found between cases and controls in any of the anthropometric measurements nor in reading age or intelligence quotient after controlling for social class and parental smoking. Whooping cough is, in general, unlikely to cause subsequent deficiency in physical or mental development.