The Potential Utility of Cerebral Fluid sLR11 and sIL-2R As a Marker for CNS Involvement of Malignant Lymphoma

Introduction: LR11 is a type I membrane protein that releases serum-soluble LR11 (sLR11) by proteolytic shedding. In the past, we reported that patients with acute leukemia and malignant lymphoma showed significantly increased serum sLR11 levels compared to those in normal controls. The diagnosis of central nervous system involvement of malignant lymphoma (CNS ML) is often difficult to diagnose by cytology. This study analyzed the potential utility of cerebral fluids (CFs) sLR11 and sIL-2R as diagnostic markers for CNS ML.

Materials and Methods: We enrolled patients suspected of CNS ML and administrated intrathecal anticancer drugs from 2017 to 2023. We analyzed CFs levels of sLR11 and sIL-2R, and cytological malignant grades. Then, we analyzed the relationship between changes in these CFs markers and clinical outcomes.

Results: We studied 26 patients (16 men and 10 women; mean age: 72 years old). The 20 patients were diagnosed as CNS ML in clinical conditions, and the other 6 patients were treated with prevention because of ML of the testis and adrenal glands. The sLR11 of CFs levels significantly and positively correlated with the sIL-2R of CFs levels (r = 0.6618, p = 0.0002) (Figure 1A). As shown in Figure 1B, in CNS invasion groups, only four patients showed class V in the cytology of CFs, the other patients showed negative results. There were no relations between the number of cell numbers and sLR11 and sIL-2R of CFs. As shown in Figure 2, the levels of sLR11 of CFs in diagnosis tended to be higher (p = 0.1831) in the CNS invasion group (36.5±30.0 ng/ml) than in the no-invasive group (23.9±5.8 ng/ml). The levels of sIL-2R of CFs in diagnosis were significantly higher (p = 0.0035) in the CNS invasion group (986.0±1274.3 U/ml) than in the no-invasive group (74.2±78.2 U/ml). The LR11 and sIL-2R of CFs post-treatment were lower in the remission group (n=9; 13.46±6.37 ng/ml, <50.0 U/ml) than non-remission group (n=5; 22.40±14.32 ng/ml, 78.4±41.1 U/ml), p = 0.2861, 0.0629 respectively.

Conclusions:Patients diagnosed with CNS ML showed high levels of sLR11 and sIL-2R of CFs. These two may be good markers for evaluating diagnosis and treatment effects. Further examination of a large number of cases is required to elucidate these mechanisms.