METHODS: We analyzed the clinical and laboratory correlates of five patients who experienced infectious complications post rituximab use and needed supplemental immunoglobulin therapy.
RESULTS: Five patients were evaluated by our adult immune deficiency service in 2016-2017 who had received Rituximab, four of whom had Follicular Lymphoma and one had diffuse large B cell lymphoma. The median time since Rituximab therapy was 7.59 yrs. (IQR 6.5-9.6 yrs.). The median age at Rituximab treatment was 63yrs (IQR 44-66 yrs.). IgG levels at start of supplemental IgG therapy were <400mg/dl (median 282mg/dl). B cell immunophenotyping was obtained in 4/5 patients which showed decreased class switched memory B cells(CSMB) (CD27+M-D-), median: 0.25%,( normal range: 2.3-26.5%) absolute count :0.55 ( normal range: 7-61cells/mcL), despite adequate B cell reconstitution:median:229 cells/mcL ( normal range: 90-539 cells/mcL).
CONCLUSIONS: Decreased CSMB cells predict the need for continued need for replacement immunoglobulin therapy and could be considered as a prediction parameter. We plan to undertake a larger study of our lymphoma cohort.