SAFE MYCOPHENOLATE INDUCTION AFTER COMPLETING RECOMMENDED VACCINATIONS IN LUPUS NEPHRITIS WITH SPLENIC HYPOPLASIA: A CASE REPORT

The spleen plays a role in immune function and helps prevent infectious diseases. Patients with post-splenectomy status and impaired splenic function, including splenic hypoplasia are susceptible to infections caused by encapsulated bacteria—Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type b (Hib). We hereby report a didactic case of lupus nephritis (LN) in a patient suffering from splenic hypoplasia, managed with immunosuppressive therapy after complete vaccinations.

Case report: The patient was a 36-year-old male with a 14-month history of bilateral arthralgia involving the shoulders, hands, knees, and ankles along with edema of the extremities and face for 6 months; and recurrent fever up to 39℃ for 2 months. Routine health screening revealed proteinuria, and he was referred to our hospital. Physical examination identified discoid rash on his right leg. Laboratory data revealed the following: slight anemia (hemoglobin, 11.9 g/dL); normal white blood cell and platelet counts; urine protein: 5.5 g/gCr; serum creatinine: 1.29 mg/dL; estimated glomerular filtration rate (using the 2021 CKD-EPI creatinine equation): 73.7 mL/min/1.73 m²; serum albumin: 1.9 g/dL; antinuclear antibody titer: 1:640 (speckled pattern); C3: 64 mg/dL; anti–double-stranded DNA (dsDNA) IgG: 162 IU/mL; anti-Sm antibody: 51.6 U/mL; and anticardiolipin IgG: 12 U/mL. He was diagnosed with systemic lupus erythematosus (SLE) in accordance with the 2019 EULAR/ACR classification criteria for SLE with a score of 28. Extrarenal SLE manifestations resolved within one month after treatment with hydroxychloroquine (HCQ) 200 mg daily and prednisolone (PSL) 50 mg daily. However, nephrotic syndrome (NS) failed to resolve completely, and low C3 levels persisted with elevated anti-dsDNA IgG titers. Renal biopsy revealed class IV+V LN. Addition of mycophenolate mofetil (MMF) to the treatment regimen was considered; however, computed tomography revealed splenic hypoplasia, raising concerns about an increased risk of fulminant infection with intensified immunosuppressive therapy. Hence, PSL was tapered to 40 mg, and the patient was administered a series of vaccinations over approximately four months, including the 13-valent pneumococcal conjugate vaccine, meningococcal polysaccharide diphtheria toxoid conjugate vaccine, Hib vaccine, 23-valent pneumococcal polysaccharide vaccine, and SARS-CoV-2 mRNA vaccine, prior to the initiation of MMF. During this period, he did not experience any SLE flares and C3 levels became normal. MMF was subsequently initiated and titrated from 500 to 2,000 mg daily. Two weeks later, complete remission of NS was achieved, accompanied by a decline in anti-dsDNA IgG titers.

Discussion: MMF in combination with HCQ and PSL is recommended for treating class IV/V LN. However, patients with splenic hypoplasia are susceptible to encapsulated bacterial infection and should receive the recommended vaccinations. MMF can increase the risk of fulminant infection while attenuating vaccine immunogenicity, hence we completed the vaccinations before initiating MMF. This report details a rare case of anatomically confirmed splenic hypoplasia coexisting with class IV+V LN and offers a practical template for balancing infection prevention with timely immunosuppression in patients with LN and splenic hypoplasia.