Clinical analysis of 52 patients with granular lymphocyte proliferative disorder (GLPD) showed frequent anemia in indolent T-cell GLPD in Japan.

We present here clinical and hematological findings of 52 cases of granular lymphocyte-proliferative disorder (GLPD), which contained 35 indolent T-cell lineage granular lymphocyte-proliferative disorder (T-GLPD), two atypical T-GLPD, 12 chronic NK-cell lymphocytosis (CNKL), and three aggressive NK-cell leukemia (ANKL). The median period of follow up was 24 months. Hemoglobin level <8.0 g/dL was recognized in 21 cases of indolent T-GLPD (60%), among which 15 patients met the criteria of pure red cell aplasia. Neutrophil counts <500/microL occurred only in two cases of T-GLPD (6%). Although the median age and male-to-female distribution were similar, very frequent anemia and rare neutrocytopenia in indolent T-GLPD in the present study keenly contrasted with previous reports. CD56 was positive in three of 29 indolent T-GLPD cases with CD4-CD8+ phenotype, in three of four CD4+CD8-, and in none of two CD4-CD8- cases. Therefore, although two atypical T-GLPD cases were CD56-positive, CD56 should not be a specific marker for aggressive T-GLPD. All CNKL patients had a chronic course with a stable granular lymphocyte count. All three ANKL patients presented high fever and hepatosplenomegaly, barely responded to chemotherapies and died within 6 months. The present analysis of 52 cases of GLPD in Japan showed that Japanese and Western cases of indolent T-GLPD clearly differ in their hematological complications.