Unusual Phenotype (Leu 7⁺, OKT4⁺, OKMl⁺) Expressed by Cells from a Patient with an Abnormal Expansion of Granular Lymphocytes

Abstract

We report the case of a 70-year-old female with a lymphocytosis which was casually detected during a routine examination. Immunological studies revealed the expansion of granular lymphocytes (GL) with the following, previously undescribed phenotype: Leu 7⁺, OKT3⁺ , OKT4⁺, OKT8^-, OKM1⁺ . These cells were tested for their functional activities and found to exert neither helper nor suppressor functions in in vitro tests. Cytotoxic activities demonstrated a strong ADCC and a markedly reduced NK function. 1 year later the clinical course has remained good without any treatment and we suggest that this case should be classified as an abnormal expansion of GL, despite the OKT4 positivity of the cells. Our data point out the importance of a careful immunological study of cells from these rare patients and suggest the existence of a normal GL population expressing the OKT4 phenotype, which is possibly expanded in this patient.

Deficiency of Lymphocyte Lectin-Dependent Cytotoxicity in Myelodysplastic Syndromes

“…Despite the reduction in NK activity, our data de monstrated an increase in Leu7+, CD16+ and CDllb+ subsets, commonly related to NK activity [26][27][28][29][30], A normal or increased NK-related phenotype with absolute or relative functional defects has been reported previously in hematological disorders [31][32][33], Using the SCCA we have clearly demonstrated that the defect in NK activity is due to an impairment of both target binding cells and N K active cells.…”

Large granular lymphocyte/natural killer cell proliferative disease: Clinical and laboratory heterogeneity

“…LGL from cases 1, 2 and 5 , for instance, possess immunological features quite similar to those of a subset of normal HNK-I positive leucocytes that express pan-T antigens (such as Leu 1) but lack Leu 11 and NK activity (20). Case 3, furthermore, is a proliferation of HNK-I and OKT4 positive LGL similar to 2 other reported cases (21,22), and represents an expansion of the LGL subset bearing the Leu3/OKT4 antigen (20,23). Case 4's LGLs displayed a peculiar phenotype, with concurrent expression of both the T4 and T8 antigens in HNK-1, OKM1, N901, and FcR positive LGL.…”

Multiple Cranial Neuritis Associated with Large Granular Lymphocytosis

“…LGLs have a cytotoxic/suppressor phenotype (CD8+), and the helper/inducer phenotype (CD4+) seen in our case is rare [3][4][5][6][7][8][9].…”