Alpha-1-antitrypsin deficiency (AATD) is a hereditary disease. Clinical manifestations include pulmonary emphysema, hepatic cirrhosis, and more rarely, ANCA-positive panniculitis or vasculitis.1 Few instances of its association with other genetic deficits have been reported in the literature.

We report the case of a 36-year-old man with no toxic habits and a history of atrial fibrillation, treated with oral anticoagulants, referred to the pulmonology department for genetic counselling after the detection of a family member as an AATD index case (father with SZ genotype). Genetic studies were performed, and the patient was diagnosed with type SZ AATD, with serum protein levels of 46.4mg/dl. Spirometry and high-resolution computed tomography were normal. In subsequent follow-up visits, he began to present repeated bronchial infections, so a full study of primary immunodeficiencies was performed. In this study, very low levels of mannose-binding lectin (MBL) were detected on ELISA (normal range>1000ng/ml, deficit considered<500ng/ml and severe deficit<100ng/ml): the initial result was 7.54ng/ml, and a subsequent test found 72.807ng/ml. Other primary immunodeficiency results, including immunoglobulin serum levels, were normal (IgG 1186mg/dl; IgA 362.80mg/dl; IgM 75.60mg/dl).

Alpha-1-antitrypsin (AAT) is a glycoprotein1 synthesized mainly in the liver. Its principal function is to inhibit neutrophil elastase and other proteases, and its anti-inflammatory, anti-microbial and immunomodulatory properties have been characterized in recent years. AAT deficiency is caused by a mutation on the long arm of chromosome 14. Lectin is a protein synthesized in the liver which is found in different types of biological fluids, and is considered by some authors as an acute-phase reactant.2 MBL is involved in the activation of the lectin complement system, which has been established as the third activation pathway.3 MBL deficiency is caused by a mutation on the long arm of chromosome 10. Low serum levels of MBL are associated with an increased risk of various infections in children. In adults, this deficiency may be associated with concomitant diseases or immunodeficiencies.4 MBL deficiency has been associated with predisposition to a large number of diseases (autoimmune diseases, in particular), but it generally has more clinical significance when it coexists with another immunodeficiency state.5 Curiously, the association of MBL deficiency and AATD in the same patient has not been described previously.

The clinical presentations of AATD vary widely, so disease registries and studies are needed to better determine its natural history. Taking into account the prevalence of both deficiencies in the general population, its association in our patient may be a random event. Nevertheless, these immunodeficiencies may need to be ruled out in AATD patients, since they could modify the clinical manifestation and management of the disease, as occurs with other immunodeficiency states.