Differentiation and clonality of lesional lymphocytes in pityriasis lichenoides chronica.
BACKGROUND
Pityriasis lichenoides chronica (PLC) and pityriasis lichenoides et varioliformis acuta (PLEVA) are benign T-cell diseases that share several overlapping clinicopathologic features, leading many to believe that they exist as a spectrum rather than as single entities. Previous molecular studies have shown that PLEVA is a clonal lymphoproliferative disorder. To further characterize the immunohistologic features of PLC and to determine whether PLC demonstrates clonality, we studied 6 cases of PLC using a frozen section-immunoperoxidase technique and polymerase chain reaction/denaturing gradient gel electrophoresis.


METHODS
All 6 cases showed a mild to moderate superficial and deep perivascular infiltrate composed predominantly of CD4(+) T cells, admixed with Langerhans cells and macrophages; most were associated with an HLA-DR(+) epidermis. Three of 6 cases involved monoclonal T-cell receptor gamma (TCR gamma) gene rearrangements detected by V gamma 1-8/J gamma 1-2 and V gamma 9/J gamma 1-2 primers.


CONCLUSIONS
Our findings enhance existing data showing that PLC shares many immunohistologic features with PLEVA and indicating that PLC is frequently a clonal T-cell disease. This provides further evidence that PLC and PLEVA are interrelated processes within the larger group of T-cell lymphoproliferative disorders.
Shieh
S
S
Department of Internal Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
Mikkola
D L
DL
Wood
G S
GS
D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D005260:Female; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007801:Langerhans Cells / Q000276:immunology / Q000473:pathology; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D017514:Pityriasis Lichenoides / Q000276:immunology* / Q000473:pathology; D016133:Polymerase Chain Reaction; D012867:Skin / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology
D015703:Antigens, CD; D006684:HLA-DR Antigens