DOI: 10.36347/sjmcr.2020.v08i07.020

Pages: 730-733

The C4 protein is part of the classical complement pathway which plays an important role in innate immunity and in the maintenance of immune complexes in the soluble phase. We report the observation of a 35 year old patient admitted to the respiratory diseases department for etiological assessment of diffuse bronchial dilatation foci (DDB) complicating repeated respiratory infections. After eliminating an acquired immunodeficiency, a balance of primary immune deficiency carried out, allowing to retain the diagnosis of a deficit in complement fraction C4 associated with a systemic lupus erythematosus. Complete C4 deficiency is very rare, can be revealed in adulthood by bacterial infections with encapsulated germs and predisposes to diseases with deposits of immune complexes. Requiring a diagnosis and an early management in order to avoid complications sometimes frightening, as was the case of our patient.