A 37-year-old Caucasian female, ex-smoker, was admitted for persistent mild chest pain fol­lowing hemoptysis which occurred 3 weeks previ­ously. She had been receiving angiotensin convert­ing enzyme (ACE) inhibitor therapy for systemic hypertension for 5 years. She was not obese and had never used oral contraceptives. There was no family history of thrombosis and investigation for family thrombophilia was not performed.

She was afebrile, with a heart rate of 100 beats min^-1, blood pressure 130/80 mmHg, and respira­tory rate 18 breaths min^-1. An electrocardiogram, routine laboratory findings and arterial blood-gas analysis gave normal results. Blood sedimentation rate and leukocyte count were increased (80 mm h^-1 and 12.6 x 10⁹/L, respectively).

Chest X-ray examination and computerized tomography (CT) (Figure 1, Figures 2a and 2b) showed bilateral nodular infiltrates in the lower lung lobes. The D-dimer level, measured several times by an immunoturbidometric method (Dade-Behring, Deerfield, IL, USA), was <250 ug L^-1 (normal <250). Perfusion lung scans showed a sub-segmental perfusion defect in the laterobasal part of the right lung, and a postero-basal hypoperfusion zone in the left lung. The ventilation scan was not available, and the perfusion scan was interpreted as non diagnostic. Antinuclear antibodies (ANA), antineutrophil cytoplasmic antibodies (ANCA) and antiphospholipid antibodies were not present. The sputum smear was negative for Mycobacteria.

Bronchoscopy showed some old blood in the trachea, starting from bronchus number eight of the right lower pulmonary lobe, from where an aspirate was taken for cytological and bacterial analyses. After this aspiration, bronchial hyperemia was evi­dent but there were no signs of infiltration. The as­pirate was negative for malignant cells and patho­logic bacterial flora.

To clarify the nature of the bilateral nodular lung infiltrates, open lung biopsy was performed, without perioperative antithrombotic prophylaxis. A macroscopically, well bordered, ovoid hemor­rhagic nodule was removed. On histological exam­ination, recent hemorrhagic pulmonary infarction with subocclusive and occlusive thrombosis of pul­monary arterioles was noted (Figures 3a and 3b). Two days after the lung biopsy, she had sharp chest pain and a chest radiograph revealed a triangular shadow in the right middle lung field (Figure 4). Arterial blood gas analysis showed PaO₂: 9.1 kPa (standard value 11.45 kPa), and a D-dimer level of 1820 ug L^-1. The perfusion lung scan showed a massive defect in the middle and lower parts of the right and segmental defects in basal part of the left lung. Compression ultrasonography of lower limb veins gave negative results for the presence of deep venous thrombosis (DVT). Hematological investigation revealed presence of a thrombophilic state. Genetic analysis showed a heterozygous FII G20210A mutation (see Methodology Description below). Activities of protein C, protein S and an-tithrombin III were normal. The polymerase chain reaction (PCR), analysis for factor V Leiden mu­tation was negative, and anticardiolipin antibodies were not elevated.

Intravenous heparin was introduced, followed by warfarin, keeping the international rate (INR) of prothrombin time at 2-3. The patient's clinical state gradually improved, and over 2 years of follow-up she had no new thrombotic episodes.

Methodology Description. The fragment of the factor II gene was amplified by PCR on whole blood, followed by digestion with HindIII (New England BioLabs, Ipswich, MA, USA) endonu-clease. The digestion products were analyzed by electrophoresis on 10% polyacrylamide gels fol­lowed by silver staining of the gels. We used the following modification of the PCR according to Poort et al. [5]: PCR reactions were performed in a 25 |iL final volume containing 50 mM KCl, 100 mM Tris-HCl, pH 9.0, 0.1% Triton X-100, 200 mM dNTPs, 5 mM MgCl2, 10 pmol of forward and re­verse primers and 1 |iL of whole blood. The ther­mal cycle profile was: five cycles consisting of 3 min. at 98°C and 3 min. at 55°C, to assure complete denaturation of DNA. One unit Taq polymerase (Applied Biosystems, Foster City, CA, USA) was added at 50°C and after 5 min., 35 cycles consist­ing of denaturation at 94°C for 1 min., annealing at 56°C for 1 min. and polymerization at 72°C for 1 min. were applied. Final extension of the PCR products was at 72°C for 10 min. The PCR reac­tions were performed in Mastercycler gradient ap­paratus (Eppendorf, Hamburg, Germany).