This protocol addresses adults over 18 years of age who are nonsmokers or former smokers, carry a genetic variant consistent with severe AATD, and have a serum AAT concentration below the protective threshold (< 57 mg/dL or < 11 µM). Pulmonary function testing shows proven functional loss above the physiological level. Patients with selective IgA deficiency are excluded from this protocol.
There is broad consensus that serum AAT below 57 mg/dL (< 11 µM) falls beneath the protective level. When this low concentration is combined with a confirmed severe genetic variant and pulmonary function evidence of airflow limitation — in a patient who is a nonsmoker or former smoker over 18 — the indication for treatment is met.
The established approach involves intravenous replacement therapy using a purified, plasma-derived preparation — a specific intervention class that directly targets the underlying protein deficiency. This is the mainstay of treatment in this population.
The complete regimen — including the precise administration schedule, monitoring parameters, and the full structured algorithm — is set out in the protocol below.
There seems to be a consensus that intravenous AAT replacement therapy is indicated in nonsmokers or former smokers over 18 years of age with a genetic variant consistent with severe AATD, a low serum AAT concentration (< 11 µmol/L or < 57 mg/dL), and evidence of airflow limitation on pulmonary function testing.
Supported by robust data in the literature, we recommend AAT replacement for any patient over 18 years of age with severe AATD; that is, serum concentrations below the protective level (< 57 mg · dL−1 or serum AAT < 11 µM), with proven functional loss above the physiological level (even if lung function is still normal or if there is mild, moderate or severe airflow obstruction).
Its administration is contraindicated in patients with selective IgA deficiencies, because of the possibility of severe anaphylaxis.
Intravenous replacement therapy with purified AAT is the mainstay of treatment for AATD, although lung volume reduction surgery and lung transplantation are of real value in selected cases.
In 1989, US Food and Drug Administration approved AAT purified from human plasma for intravenous administration, at a dose of 60 mg/kg, administered weekly.
Serum AAT concentrations above 11 µmol/L or 57 mg/dL are considered protective and should be used as a parameter to determine the effectiveness of replacement therapy.
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