To systematically review the available evidence to evaluate (1) the prevalence and degree of leukopenia, lymphopenia, and neutropenia in patients with systemic lupus erythematosus (SLE), (2) whether these conditions carry a major infection risk for patients, and (3) whether a treatment with colony stimulating factors (CSF) can be an effective and safe option in SLE patients with leukopenia.
MedLine and Embase were searched by including MeSH terms, text words, and subheadings "systemic lupus erythematosus," "leukopenia" (first search), and "colony stimulating factor" (second search). Inclusion and exclusion criteria were a priori defined and two reviewers screened the retrieved articles for selection criteria; data from the included studies were recorded in ad hoc standard forms; the results were synthesized and transported to evidence tables.
A total of 17 articles were included in the systematic literature review: nine articles were retrieved for the first research question and 11 for the second while no articles satisfied the inclusion criteria for the third research question. The prevalence of leukopenia is reported in 22-41.8% of cases and lymphopenia is reported cumulatively from 15% to 82% of the patients while neutropenia is described in 20-40% of the patients. There is no evidence of a significant association between overall reduction of white blood cells and infection occurrence while some studies found a strong association between low lymphocytes/neutrophils count and the risk of major infections. Only case reports and case series have been found to investigate the safety of CSF in SLE patients.
The results of this systematic literature review are inconclusive for many aspects related to the original research questions and highlight the need for further studies. Indeed, the strength of the evidence is not sufficiently robust to draw specific recommendations on how to balance between the need to treat the patient with SLE with immunosuppressive drugs and the risk of severe infections.