*2.1. Clinical Characteristics of the Studied Groups*

The paraclinical characteristics of the studied groups are presented in Table 1. Classic biomarkers of lupus activity such as anti-ds DNA, UACR, C1q, C3 and C4 complement proteins were assessed. dsDNA was statistically significantly higher in LN and non-LN groups when compared with control group (*p* < 0.05), but it did not vary between SLE groups (*p* > 0.05). Urinary albumin: creatinine ratio was statistically significantly higher in LN group than in non-LN group (*p* < 0.05) or in control group (*p* < 0.05). C1q, C3 and C4 complement proteins were statistically significantly higher in LN group than in non-LN group (*p* < 0.05) or in control group (*p* < 0.05). Leucocytes and Hemoglobin were statistically significantly lower in SLE groups compared with the control group (*p* < 0.05), but without statistical variation between LN and non-LN subjects (*p* > 0.05). Albumin was statistically significantly lower in SLE groups, when compared with control (*p* < 0.05) and also in LN compared with non-LN group (*p* < 0.05). The estimated glomerular filtration rate was found to be lower in LN group than in non-LN group (*p* < 0.05) or in control group (*p* < 0.05). Renal tubular injury was evaluated by measuring the urinary levels of b2-microglobulin, that was found to be higher in LN group than in non-LN group

(*p* < 0.05) or in control group (*p* < 0.05). Inflammation was assessed by determination of erythrocyte sedimentation rate and C reactive protein, and we found high inflammation in SLE groups compared with control (*p* < 0.05), but no significant variation between SLE groups (*p* > 0.05).


SLEDAI—Systemic Lupus Erythematosus Disease Activity Index, BMI—body mass index; LDH lactatdehydrogenase; ASAT—aspartate aminotransferase; ALAT—alanyl aminotransferase; eGFR—estimated glomerular filtration rate; UACR—urinary albumin: creatinine ratio; ESR—erythrocyte sedimentation rate; CRP—C reactive protein; *p*—statistical significance.

The clinical manifestations of SLE in non-LN and LN groups and the associated comorbidities are presented in Table 2.


**Table 2.** Clinical characteristics of the SLE groups.
