Human homozygous type I plasminogen deficiency and ligneous conjunctivitis

On the basis of a questionnaire sent to the ophthalmology departments of ho spitals throughout Germany, 10 patients with ligneous conjunctivitis or pse udomembranous disease, ranging in age from 1 to 71 years were identified. A ll 10 patients had severely reduced plasminogen levels. Genetic analysis re vealed homozygous type T plasminogen deficiency (which had not previously b een described in humans) in 7 patients and compound heterozygous plasminoge n deficiency in 1 patient. Clear differentiation was not possible in 2 pati ents. Most of the parents had heterozygous plasminogen deficiency. None of the patients had experienced any episodes of thrombosis. Additionally, the following observations were made: 1) Levels of polymorphonuclear (PMN)-elas tase protein were markedly elevated in 6 of 6 patients and 10 of 11 parents tested, and levels were higher in homozygotes than in heterozygotes. 2) He reditary factor XII deficiency was found in 3 of 6 patients tested. 3) Cl-i nhibitor was elevated in 2 of 4 patients, prekallikrein was elevated in 1 o f 4 patients, and plasminogen activator inhibitor type 1 was elevated in 1 of 4 patients. Infusions of lys-plasminogen concentrate induced pronounced fibrinolytic activity as indicated by high levels of D-dimer, increases in plasmin-antiplasmin complex and decreases in polymorphonuclear elastase. Cl -inhibitor, prekallikrein and PAI-I normalized after repeated infusions of lys-plasminogen. In contrast to dysplasminogenemia, severe type I plasminog en deficiency might be seen as a problem of extravascular space, in particu lar of the mucous membranes, possibly triggered by mechanically induced or inflammatory lesions of the vessels supplying the tissue.