| Abstract: | Lung function studies were performed in 23 patients with the syndrome of essential mixed cryoglobulinemia. Signs of exposure to hepatitis B virus were present in nine (HBV+) and absent in 14 (HBV?). Pulmonary symptoms were generally absent or moderate except in three patients who presented with either asthma, hemoptysis or pleurisy together with the other manifestations of the disease. On the contrary, tests indicative of small airways disease, such as forced end-expiratory flow (FEF0.75-0.85VC) and maximal expiratory flow at low lung volume (Vmax0.75VC) were markedly altered (61.9 per cent and 40.4 per cent of the expected values, respectively). Other lung function tests, such as residual volume (RV), airway resistance (Raw), FEF0.25-0.75VC, maximal expiratory flow at 50 per cent vital capacity (VC)(Vmax0.50VC) showed smaller deviations from normal, whereas vital capacity (VC), total lung capacity (TLC), forced expiratory volume in 1 second (FEV1), FEV1:VC, RV:TLC and intrathoracic gas volume (ITGV) were within the normal limits. Nine of 14 of the HBV? patients showed impairment of gas exchange, measured as alveoloarterial oxygen gradient D(A-a)O2, which, on the contrary, was always within normal limits in the nine HBV+ patients. The difference between the two groups was significant (28.4 mm Hg and 18.6 mm Hg, respectively, p < 0.025). Roentgenographic signs of interstitial lung involvement were present in 18 of 23 patients. Lung scan showed, in all instances in which it was performed, inhomogeneities of regional lung perfusion; they were, however, minimal in nearly half of the cases. The present data indicate that lung involvement is frequent in essential mixed cryoglobulinemia, that it should be recognized in addition to the other features of the disease and that it seems to be more pronounced in the HBV? patients. Indirect evidence suggests that circulating immune complexes may play a role in the genesis of the lung abnormalities observed in these patients. |
