AB0558 PREVALENCE OF LATENT TUBERCULOSIS INFECTION AND ITS ASSOCIATIONS WITH CLINICAL AND SEROLOGICAL PARAMETERS IN SYSTEMIC LUPUS ERYTHEMATOSUS

Abstract

BackgroundSystemic Lupus Erythematosus (SLE) and Tuberculosis are complicatedly related and studies have shown increased risk of TB in SLE. Studies of Latent TB and SLE are inadequate. This study intended to assess the prevalence of latent TB and its association with disease parameters in SLE.ObjectivesTo assess the prevalence of latent TB in patients with SLE. To investigate the demographics and clinical characteristics in patients with SLE and concomitant latent TB compared to those without.MethodsThis is a single center cross sectional study. 124 adult patients with SLE without past h/o TB were recruited. SLE demography, disease activity indices, autoantibody profile and steroid use were noted. Presence of Latent TB infection was assessed in all patients based on the IFN-g release assay (TB-IGRA). Based on the results of IGRA, SLE cases were divided into 2 groups-IGRA positive and IGRA negative. The collected parameters were compared between the 2 groups.ResultsAmong 124 patients, 19 had latent TB resulting in a point prevalence of 15.4 %. The average disease duration was 4.3 years in IGRA positive and 4.6 in IGRA negative group(p>0.05). Among antibody profile, though no statistical significance among the groups, proportion of antibodies like anti Ku, Ro 60, Ro 52 and La were numerically higher in the IGRA positive group (21.1%, 42.1%, 42.1% and 21.1% respectively) when compared to the IGRA negative group (11.5%, 28.8%, 28.1% and 7.7% respectively). Likewise, anti nucleosome, histone, U1RNP, PCNA, aCLA IgG and IgM, beta 2 GPI IgG and LAC were numerically higher in IGRA negative group (42.3%, 40.4%, 43.3%, 8.7%, 23%, 18.3%, 28.8%, 14.4%) when compared to IGRA positive group (31.6%, 21.1%, 31.6%, 0, 15.8%, 5.3%, 15.8%, 5.3%). Mean clinical SLEDAI was 2.37 ±5.1 in IGRA positive and 3.5 ±5.77 in IGRA negative group. Among clinical features, 1 person in IGRA positive and none in the IGRA negative group had current gastrointestinal involvement. Comparison of other organ manifestations yielded no statistically significant difference in the 2 groups at this point. Serology revealed greater proportion of C4 in IGRA negative as compared to the positive group(p<0.042).ConclusionPrevalence of latent TB in SLE cases was 15.4%. Although comparison of demographic, clinical and autoantibody profile did not yield any statistically significant differences, the early turnover from this pilot study mandates further evaluation with larger sample size.Table 1.Comparison of clinical and laboratory parameters between IGRA positive and IGRA negative SLE casesIGRA POSITIVE(n=19)IGRA NEGATIVE(n=105)p VALUEAge(Mean± SD)31.79±9.729.26 ±10.80.199Female Sex n(%)19(100)101(97.1)0.312Anti P0 antibody n(%)3(15.8)14(13.5)0.827Anti Ribo P antibody n(%)2(10.5)13(12.5)0.761Age of disease onset(Mean± SD)25.58± 10.624.62± 10.570.285Disease duration(Mean± SD)4.33 ±4.024.6± 3.530.438Treatment duration(Mean± SD)3.84± 4.124.03± 3.420.439Clinical SLEDAI(Mean± SD)2.37 ±5.13.5 ±5.770.306SLICC ACR DI(Mean± SD)0.105±0.320.231± 0.660.666Current CNS involvement1(5.3)4(3.8)0.781Current renal involvement3(15.8)26(25)0.367Current hematological involvement1(5.3)14(13.5)0.272Current GI involvement1(5.3)00.052Current steroid dose(Mean± SD)11.32± 11.6513.03 ± 11.60.400Serum C3(Mean± SD)0.79 ±0.320.89± 0.470.477Serum C4(Mean± SD)0.19± 0.0720.1635± 0.130.413Anti dsDNA (Mean± SD)458± 400.8379.5± 400.50.454Low C3 n(%)9(52.9)37(38.9)0.108Low C4 n(%)2(11.8)35(36.8)0.042Elevated Antidsdna n(%)6(35.3)37(38.9)3.343Disclosure of InterestsNone declared