Patients with membranous nephropathy becoming ill with a cold is indeed quite dangerous. This is because, firstly, a cold often leads to the relapse or aggravation of membranous nephropathy, causing changes in the condition of the disease. Secondly, patients with membranous nephropathy often use corticosteroids and immunosuppressants to control the disease, and a major side effect of these medications is that they suppress the body's immune capability, making infections more likely to occur. Once an infection sets in, it can lead to septic shock and the inflammation of multiple organs, with potentially life-threatening consequences for some patients.