A case of PLL diagnosed with: High serum IgG, BAL showing 45% plasma cells and 18% lympocytes, CD19(+), IgG/albumin ratio 13 times higher and IL-6/albumin ratio29 times higher in BAL than serum. The PCR on the DNA extracted from the surgical specimen showed rearrangement of the immunoglobulin heavy chain gene. The gene discussed is IL6; the disease is prolymphocytic leukemia.