With the intention of preventing the recurrent respiratory infections associated with antibody deficiency, IV Ig was administered to eight subjects. The dose varied from 150 mg/kg/mo in six subjects to 400 mg/kg/mo in two subjects. All had IgGSC deficiency, IgG3, IgG4, combined IgG3 plus IgG4, and one patient had IgG3 plus IgG1. Their ILD was documented by BAL and physiologically (subjects 1 and 2), radiologically (subject 21 with bronchiectasis and chronic postinfectious pneumonitis), or histologically (subjects 5 and 6 with LIP, and subjects 7, 9, and 15 with UIP, nonspecific interstitial pneumonitis [NSIP], and—descriptive diagnosis—with interstitial pneumonitis with few scattered granulomas without vasculitis but with antiproteinase-3 antibody, homogeneous antinuclear antibody, and antiribonucleoprotein, respectively). The immune treatment lasted 4 months in subjects 6, 7, 15, and 21; 4 years in subject 9; and 10 to 12 years in subjects 1, 2, and 5. On the average, per patients’ rating, the recurrent respiratory infections decreased by 75% in frequency, duration, and severity; dyspnea on exertion (Borg scale) improved by 50 to 75%; while the rate of hospitalizations decreased by 68%. Unanimously, the subjects claimed that IV Ig increased their general well-being. All subjects improved radiologically, as illustrated in Figures 1234
and, with the exception of a mentally retarded subject who could not perform pulmonary function tests reliably, physiologically as well (Fig 5
). No isotype deficiency was reversed when the isotypes were measured 6 weeks after IV Ig administration. In four subjects receiving 4 months of treatment (subjects 6, 7, 15, and 21), the physiologic and radiologic improvement lasted at least 12 months (Fig 1). Subject 1 had repeated episodes of respiratory infection with clear chest radiograph, CT scan, or Ga scan, which were associated with acute, reversible restriction. These episodes (occult pneumonia?) together with the intercritical, mild restrictive abnormality improved during his many years of treatment with IV Ig (Fig 5). One of the two subjects with LIP, subject 5 (Fig 2) acquired a severe abdominal infection, followed by sepsis and ARDS after 10 years of IV Ig; a few months later, this subject died receiving mechanical ventilation. The autopsy showed chronic diffuse alveolar damage but no evidence of LIP (Fig 6
). Subject 15 died during an episode of acute respiratory infection; autopsy revealed interstitial fibrosis and bronchopneumonia but no granulomas.