Assessment of lupus anticoagulant in anti-cardiolipin and/ or anti-β2GPI sero-positive patient: Clinicopathological perspective from a tertiary care lab in Pakistan

Objective: To assess the frequency of Lupus anticoagulant in patients seropositive for anti-cardiolipin and/or anti Beta-2 glycoprotein (anti-β2GPI) antibodies, and to explore potential clinicopathological correlations. Material and Methods: This Observational Cross-sectional study was conducted at the Department of Immunology, AFIP Rawalpindi from January 2022 to October 2024. A total of 108 samples seropositive for anti-cardiolipin and/or anti-β2GPI antibodies were selected and further investigated for Lupus anticoagulant. Patients were stratified into single, double and triple positivity based upon their aPL profile. Chi-square test were used to find significant association among these aPL profiles. Mann-Whitney U test was used to compare age in LA-positive and negative groups. p-value <0.05 was considered statistically significant. Results: Out of 108 samples analyzed, the LA positivity was observed in 13 (12%) patients and was significantly associated with younger age (median: 29 vs. 37 years, p = 0.041), but not with gender. Among cases positive for aCL IgG and aβ2GPI IgG (including dual positive cases),12 (11.1%) and 2 (1.9%) were LA-positive, respectively. No association was observed between individual antibody positivity and LA (p = 0.457 for aCL IgG; p = 0.221 for aβ2GPI IgG). Dual positivity for aCL IgG and aβ2GPI IgG did not significantly increase LA positivity, and triple positivity (aCL IgG + aβ2GPI IgG + LA) was rare (0.9%). Conclusion: To conclude, Lupus anticoagulant was detected in a subset of anti-cardiolipin and/or anti-β2GPI seropositive patients, with a significant association observed with younger age. Keywords: Antiphospholipid antibodies, Antiphospholipid Syndrome, Autoimmune disorder, Lupus anticoagulant.