Systemic lupus erythematosus as a first presentation of common variable immunodeficiency associated with infrequent mannose-binding lectin gene polymorphisms.

The association of common variable immunodeficiency (CVID) and systemic lupus erythematosus (SLE) is infrequent. Mannose-binding lectin (MBL) has been shown to play a role in CVID and SLE. The purpose of this study is to describe two cases of CVID who presented as SLE and also evaluate the presence of MBL polymorphisms and MBL serum levels in those patients. In both patients, SLE was the first manifestation of CVID. In these patients the SLE immunological markers and disease activity disappeared after the development of CVID. They carried the very infrequent MBL haplotype 4Q-57Glu. One of them had a homozygous genotype, whereas the other patient was heterozygous and also presented the haplotype 4P-57Glu that had never been previously detected. Interestingly, this last patient was presenting frequent respiratory tract infections, developed bronchiectasis and had low levels of circulating MBL. These results may support the role of MBL in the development of autoimmunity in CVID. Further genetic studies are needed to clarify the role of the MBL polymorphisms in the development of autoimmunity in CVID.