Introduction: Systemic lupus erythematosus (SLE) is a chronic autoimmune multisystem disease. The aim of our study was to clarify the frequency of decreased serum immunoglobulin levels in SLE patients. There were evaluated 799 results of serum immunoglobulin levels gained from 157 patients fulfilling revised ACR criteria in the retrospective study.
Results: The immunoglobulin levels under the normal range were found in 29/157 (18.5 %) patients. The most frequent was isolated reduction of IgG 12/157 (7.6 %), two persons fulfilled criteria for selective IgA deficiency, and one case possible diagnosis of common variable immunodeficiency (CVID). Additionally we report two cases of SLE patients complicated by severe hypogammaglobulinaemia and infectious complications with necessity of long-term immunoglobulin substitution therapy. The diagnosis of CVID is highly probable in the first case. The second case presents sever drug-induced hypogammaglobulinaemia. This female with lymphoma history and multiorgan impairment due to acute SLE was treated with rituximab after convention therapy failure.
Conclusion: Humoral immunodeficiency may occur in SLE patients. The monitoring of serum immunoglobulin levels could be a routine in these patients. The CVID diagnosis is possible in patients suffering from recurrent sinopulmonary infections, especially in combination with absence of lupus activity. Rituximab therapy could cause long-term suppression of B lymphocytes with secondary humoral deficiency requiring immunoglobulin substitution therapy.