Nailfold Capillaroscopy in Lupus Nephritis Patients and its Relation to CD31 as a Vascular Endothelial Marker

Background: as a chronic autoimmune conditions, Systemic lupus erythematosus (SLE) primarily impacting women in reproductive age. lupus nephritis (LN), commonly arises early in the disease, often within the first 6 to 36 months, and may occasionally be present at the time of diagnosis. Nailfold capillaroscopy (NFC) is a non-invasive technique for assessing microcirculation and is useful in diagnosing various connective tissue disorders. CD31, also known as PECAM-1 (platelet endothelial cell adhesion molecule), is a vascular endothelial marker encoded by the PECAM1 gene on chromosome 17. Objective: Determination of CD31 as a Vascular endothelial marker in lupus nephritis patients and its correlation with peripheral circulation abnormalities in Nail fold capillaroscopy. Methods: This case-control study involved 90 patients: 45 with lupus nephritis and 45 lupus patients without nephritis . All participants underwent clinical assessments and serum CD31 level evaluation. Disease activity was measured using the SLEDAI. NFC was performed using a digital microscope at 500x magnification. Results: Serum CD31 levels were significantly higher in the lupus nephritis group compared to the non-nephritis group (p-value = 0.001). There was a statistically significant difference in capillary width (P-value = 0.001) and hemorrhage (P-value = 0.002), both of which were increased in the nephritis group. A positive correlation was found between nailfold capillaroscopic changes and CD31 levels, with more severe capillary abnormalities observed in patients with higher CD31 levels. . Conclusions: Serum CD31 levels could serve as a valuable marker for assessing disease activity and renal involvement in SLE patients. Abnormalities observed through nailfold capillaroscopy may indicate the degree of microvascular involvement and correlate with systemic organ manifestations in SLE. Keywords: Nailfold Capillaroscopy, CD31, Systemic Lupus Erythematosus (SLE), Lupus Nephritis.