Expression of the leukocyte-associated Ig-like receptor-1 on B lymphocytes from systemic lupus erythematosus patients

Abstract EN

Background The leukocyte-associated immunoglobulin (Ig)-like receptor-1 (LAIR-1) is a transmembrane molecule belonging to the Ig superfamily.

In B cells, LAIR-1 cross-linking leads to downregulation of Ig and cytokine production.

Aim of the work The aim of the present study was to assess the expression of LAIR-1 on peripheral blood B lymphocyte from systemic lupus erythematosus (SLE) patients, and its correlation with disease manifestations.

Patients and methods Twenty-two SLE female patients and 16 matched healthy controls were included in the study.

Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score was assessed.

The expression of LAIR-1 was determined by using flow cytometry.

Results The 22 SLE patients had a mean age of 25.59±4.22 years and disease duration of 5–24 months.

The mean SLEDAI was 8±1.5.

The percentage of CD19+ B lymphocytes lacking LAIR-1 was markedly increased in SLE patients (27.8 ±10.9%) compared with healthy controls (16.2±4.4%) (P<0.001).

The mean fluorescent intensity ratio (MFIR) of LAIR-1 expression on CD19+ B cells was strongly decreased in SLE patients (44.1±12.6) compared with healthy controls (58.9±7.7) (P<0.001).

The percentage of CD19+ LAIR-1− B cells significantly correlated with the complement (C4) (r=0.45, P=0.03) and the serum creatinine level (r=0.47, P=0.02), and negatively with the serum albumin level (r=−0.57, P=0.005).

The MFIR of LAIR-1 significantly correlated with the serum albumin level (r=0.74, P<0.001) and negatively correlated with the serum creatinine level (r=−0.43, P=0.041).

There was no significant association of LAIR− (%) or the MFIR with the clinical manifestations of the patients.

Conclusion Thisstudypointsout that thelackofLAIR-1expressiononBcells fromSLEpatientscould beatrigger for thedysregulationofantibody productioninSLE,andisassociatedwiththe degreeof renalaffectionasevidencedby thesignificant correlationwith serumcreatinine levels and negative correlation with the levels of serum albumin.