[Epidemiology of adult asthma (Socio-economic effects) (author's transl)]

A study of the prevalence of adult asthma (subjects over 18 years of age) has been carried out in the Puy-de-Dôme area over the past two years by means of a questionnaire sent out to all the doctors in the area. 1,130 asthmatics have been inventoried to this day (547 males and 583 females). A study of the geographical distribution carried out in terms of demographic data on thhe present time, but is certainly underestimated. Correspondence analysis shows up the influence of age on the severity of the attacks. Frequency calculation and the cumulated frequency of the answers to the question concerning the date of the onset of asthma, leads to the conclusion that there will probably be an important increase of cases of late asthma in the next few years. The socio-economic and professional (sick leave, change of job) effects of this type of asthma in adults are analysed.

[Immunological approach to asthmatic disease (author's transl)]

Research into the environmental factors in the aetiological diagnosis of asthma is a fundamental measure which must direct complementary test and therapy. Extrinsic asthma is mostly found in young people, with atopic antecedents. Immunological study is based on the clinical history and skin tests (IgE dosage, in vitro tests and provocation tests are difficult to apply in epidemiology due to their high cost). In children 3/4 of asthma cases are extrinsic. Differential diagnosis is especially a problem with rhinitis. There is only a small percentage of cases of non atopic extrinsic asthma which can bring other immunological mechanisms into play. So-called intrinsic asthma (late onset asthma, with continuous dyspnea, corticodependent) is mostly observed in adults. The age has an influence on the severity of the attacks, the curve of asthma with permanent dyspnea being a function increasing with age, whereas that of less severe asthma is a function decreasing with age. The role of extrinsic factors does not seem important in this category of asthmatics (10 to 25% according to the statistics). Immunofluorescence studies of the bronchial mucosa show up the possibility of local immunological reactions, whether specific or not (frequent presence of the C3 complement). This means that the immunologist can, in many cases of asthma, help the epidemiologist to define and to understand the physiological mechanisms of the disease.

Diagnostic and therapeutic problems associated with hereditary deficiency of the C1 esterase inhibitor

Six patients in a family with a history of hereditary angioedema reported swelling of the extremities and recurrent abdominal pain occurring spontaneously or after trauma. Attacks of oedema involving the airways, the greatest danger with this disorder, were present only in one case. This autosomal dominant disease is due to deficient activity of the inhibitor of the first component of complement. Low levels of C4, and absence of C1 esterase inhibitor confirm the diagnosis. Two asymptomatic cases with the appropriate biochemical abnormality are reported in this study. For short term prophylaxis of attacks (before surgery expecially), fresh frozen plasma is used, or better still, C1 esterase inhibitor. For long term prophylaxis of attacks antifibrinolytic and hormonal drugs are used: in two cases, the authors obtained good results with methyltestosterone after failure of tranexamic acid.

[Applications of bidimensional immunoelectrophoresis to hypersensitivity pneumonia by inhalation of organic antigens. Its interest in relation to the classical immunodiffusion and immunoelectrophoresis methods (author's transl)]

Bidimensional electrophoresis is of most interest for the diagnosis of extrinsic allergic alveolitis. In fact, this detecting method is more specific than classical immunoelectrophoresis. Thus patients showing with the classical methods precipitation lines with one or several antigens do not present everytime the corresponding clinical signs. These positive but false reactions cannot in any case appear with bidimensionnal electrophoresis. Generally, the patient showing at least two precipitation lines opposite one antigen in bidimensional electrophoresis always followed by an increase of IgG, does also present the clinical signs of the disease.

[Pulmonary reactions to non-infective antigenic contaminants]

There are different categories of non-infectious antigenic contaminants capable of provoking pulmonary reactions: thermophilic actinomycetales, fungi, vegetable particles, protein antigens, arthropods, drugs; their identification is based on their isolation, culture, and the study of their biochemical composition. The pulmonary reactions depend on the size and number of antigenic particles inhaled and by the underlying background. The immunological mechanisms brought into play a complex Arthus's phenomenon: in addition to the IgGs, the IgEs and the different factors of complement intervene; the recent acquisitions of immunomorphology enable better comprehension of the histogenesis of the pulmonary granuloma. The diagnosis of extrinsic allergic alveolitis is founded on well defined criteria of clinical, radiological, respiratory functional, immunological and histophthological order. These conditions are met with in agricultural, industrial and urban environments or are related to iatrogenic diseases. Many problems still remain obscure with regards to the pathogenesis and integration within the framework of immunological pneumonia of various conditions, and especially certain sarcoidosis.

The pattern of fetal haemoglobin disappearance after birth

Haemoglobin F (Hb F) levels were determined in 209 full-term newborn babies or infants of different ages ranging from birth to 11 months. A follow-up study of the disappearance of Hb F after birth was carried out on 25 premature babies; they were followed periodically from birth until 8 months. The results obtained in both samples show that Hb F levels remain constant after birth for periods varying from about 15 d in at term babies to about 40 d in premature babies; a linear decrease follows in both cases. The initial plateau is a finding contrary to what has been reported. A possible model for the phenomenon is discussed in terms of haemoglobin genes and ontogenetic differentiation.