Effect of a multitarget therapy with prednisolone, mycophenolate mofetil, and tacrolimus in a patient with type B insulin resistance syndrome complicated by lupus nephritis.

Type B insulin resistance syndrome (TBIR) is a rare autoimmune disease characterised by autoantibodies targeting insulin receptors. TBIR is often complicated by systemic lupus erythematosus (SLE). We describe the case of a 59-year-old Japanese man with TBIR complicated with lupus nephritis (LN), who presented with nephrotic syndrome and severe hypoglycaemia. Treatment with prednisolone (PSL), mycophenolate mofetil (MMF), and tacrolimus (TAC) resulted in improved SLE activity and glucose intolerance with the reduction of anti-insulin receptor autoantibodies. To the best of our knowledge, this is the first reported case of TBIR complicated with LN that was successfully treated using multitarget therapy with PSL, MMF, and TAC.