SP-A binds alpha1-antitrypsin in vitro and reduces the association rate constant for neutrophil elastase.

Background: Alpha1-antitrypsin and surfactant protein-A (SP-A) are major lung defense proteins. With the hypothesis that SP-A could bind alpha1-antitrypsin, we designed a series of in vitro experiments aimed at investigating the nature and consequences of such an interaction.

Methods And Results: At an alpha1-antitrypsin:SP-A molar ratio of 1:1, the interaction resulted in a calcium-dependent decrease of 84.

Complement receptor 1 gene polymorphisms in sarcoidosis.

Sarcoidosis is likely to result from exposure of genetically susceptible hosts to environmental agents. Erythrocyte (E) complement receptor 1 (CR1) is a membrane protein mediating the transport of immune complexes (ICs) to phagocytes, and at least three polymorphisms on the CR1 gene are related to erythrocyte surface density of CR1 molecules, in turn related to the rate of IC clearance from circulation. We hypothesized that sarcoidosis could be associated with increased frequency of the CR1 gene alleles coding for reduced CR1/E ratio.