0799: Serum Laboratory Parameters of Hemophagocytic Lymphohistiocytosis Syndrome in Patients with Autoimmune Rheumatic Diseases Infected with SARS-CoV-2: A Retrospective Comparative Study

Omar Alsaed, Samar Al emadi, Karima Becetti, Eman Satti, Hadil Ashour, Yousef Alrimawi, Miral H.Gharib, Mohamad Alkahlout, Rawan Saleh, Basem Awadh and Mohammed Hammoudeh, Hamad Medical Corporation, Doha, Qatar

Background/Purpose: The serum features of the cytokine storm induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are similar to those of hemophagocytic lymphohistiocytosis syndrome (HLH) which can be secondary to both SARS-CoV-2 infection as well as some autoimmune rheumatic diseases (ARDs). Whether patients with ARDs are at higher risk for hypercytokinemia induced by SARS-CoV-2 infection is unknown. The aim of this study is to compare the risk of cytokine storm during SARS-CoV-2 infection between patients with ARDs and those without using serum parameters of the H-score.

Methods: Patients with ARDs infected with SARS-CoV-2 were identified from the electronic medical records (EMR) of Hamad Medical Corporation, one of the participating centers in the COVID-19 Global Rheumatology Alliance Registry. Cases were age and sex matched (1:3) to controls who were non-ARD patients infected with SARS-CoV-2. HLH serum parameters included in the H-score; hemoglobin, white blood cells, platelets, ferritin, triglyceride, aspartate transaminase and fibrinogen were electronically captured from EMR within 18 days after a confirmed SARS-CoV-2 infection by a positive nasopharyngeal polymerase chain reaction swab test. The serum cut-offs as defined by the H-Score tool were used to calculate the final score. To explore the crude differences in serum HLH markers, other items of the H-Score; "known underlying immunosuppression", "evidence of hepatosplenomegaly" and "HLH features in bone marrow aspirate" were recorded as zero. Independent Samples t-test was used to compare the mean H-Score between study groups.

Results: The study included 203 cases and 551 controls with a mean (SD) age of 45.3 (11.7) and 44 (12.5) years, respectively, p = 0.191. Majority of patients were female in both groups (122 [60.1%] vs. 297 [53.9%], p = 0.129).

The most common ARDs was rheumatoid arthritis in 86 cases (42.4%), followed by spondyloarthropathy in 33 (16.1%) and systemic lupus erythematosus in 31 (15.7%). Of these cases, 67% were on conventional synthetic disease modifying anti-rheumatic drugs (Cs-DMARDs), 15.8% on biological DMARDs and 4.9% on rituximab. About 83% of the ARDs group were in remission or low disease activity while 13% were in moderate or high disease activity.

The mean (SD) H-Score was significantly higher in ARDs group compared to controls (63.9 [25.4] vs. 58.9 [23.1], p = 0.038). The difference in H-Score between the study groups was more substantial when "known underlying immunosuppression" item was considered for ARDs group (81.9 [25.4] vs. 58.9 [23.1], p < 0.001).

Conclusion: Based on the serum markers of the H-Score tool used to estimate the risk of HLH, patients with ARDs have higher scores compared to patients without ARDs during SARS-CoV-2 infection. This might indicate that patients with ARDs are at higher risk for a cytokine storm induced by this infection. A study is needed to clinically correlate the H-score to infection outcomes and highlight the implications of these findings.

Disclosures: O. Alsaed, None; S. Al emadi, None; K. Becetti, None; E. Satti, None; H. Ashour, None; Y. Alrimawi, None; M. H.Gharib, None; M. Alkahlout, None; R. Saleh, None; B. Awadh, None; M. Hammoudeh, None.