CD123 POSITIVE PLASMACYTOID DENDRITIC CELLS & CUTANEOUS LUPUS ERYTHEMATOSUS (LE)

CD123 POSITIVE PLASMACYTOID
DENDRITIC CELLS & CUTANEOUS
LUPUS ERYTHEMATOSUS (LE)

Ms Nandini Roy (3rd Year Medical Student)1
Dr. Garima Gupta (Specialist Registrar Histopathologist)2
Dr. Rathi Ramakrishnan (Consultant Histopathologist)2
Imperial College School of Medicine1 &
Imperial College Healthcare NHS Trust2

INTRODUCTION
   Cutaneous LE – an autoimmune inflammatory dermatosis
    affecting skin & subcutaneous tissue

   Histologically- B & T cells, macrophages in perivascular &
    adnexal area with interface dermatitis

   Plasmacytoid dendritic cells (PDCs) are often associated
    with LE producing interferons and CD123 antigen and are
    linked to symptoms

   Identification of PDCs – ? diagnosis value

AIMS AND OBJECTIVES
   To review cutaneous LE at our centre

   To assess diagnostic value of CD123 staining
    PDCs in CLE

MATERIALS AND METHODS
   CLE diagnosed at Charing Cross Hospital
    between 2013 & 2017 were reviewed with respect
    to histology & immunofluorescence (IMF)

   Immunohistochemistry (IHC) to CD123 was
    performed & semi-quantitative criteria were
    developed for assessing staining intensity &
    patterns of distribution

SEMI-QUANTITATIVE    CRITERIA FOR
ASSESSMENT

              Intensity of staining

       Weak                           Strong

• 1+                        • 2+

SEMI-QUANTITATIVE     CRITERIA FOR
ASSESSMENT

               Number of clusters

    1+                  2+               3+

•1-2 cluster      •3-5 cluster      •> 5 clusters
 involvement       involvement

SEMI-QUANTITATIVE        CRITERIA FOR
ASSESSMENT

               Overall score generated

          ≤3                             ≥4

• Low expression              • High expression

H&E STAINED SECTIONS OF CLE

                                       Section showing moderate
   Section showing moderate
                                     perifollicular and perivascular
perifollicular lymphoid infiltrate
                                           lymphoid infiltrate

RESULTS: POSITIVITY BASED ON STAINING
INTENSITY

   A total of 81 cases of
    CLE were identified

   72/81(88%) cases stained
    for CD123

 45/72 (62%) – 2+             Staining

 27/72 (38%) – 1+
                                          Strong(2+)

                                          Weak(1+)

RESULTS: PROPORTION OF CELLS

                                               3+
   26/72(36%) – 3+                            2+
                                               1+

   20/72 (28%) – 2+

   26/72(36%) – 1+

     1+             2+               3+

•1-2 cluster   • 3-5 cluster   •> 5 clusters
 involvement     involvement

CD123 STAINING
1+ distribution with weak staining   2+ distribution with strong staining

3+ distribution with strong staining

RESULTS: OVERALL SCORE/EXPRESSION

   28/72 (39%): Low    Expression
    expression

   44/72 (61%): High
    expression                       Low
                                     High

RESULTS
   CD123 positive PDCs were distributed in
    perivascular, perifollicular, superficial dermal
    and deep subcutis

   Predominantly noted in perivascular 56/72(78%)

RESULTS: CASES WITH IMF DATA

   IMF available in 34/81
    cases (42%). 47/81
    (58%) no IMF

   12/34 (35%) cases -
    positive for IgG and C3,
    22/34 (65%) – IMF
    negative

                               Positive
   19/22 (86%) with           Negative
    negative IMF were
    positive for CD123

KEY POINTS

   High concordance between histologically
    diagnosed CLE and CD123 staining;

   Predominantly high overall score (61%)

   Good diagnostic utility: CD123 staining present
    even in cases lacking IMF to support histological
    diagnosis (81% (38/47))

   Helps in the distinction of lupus from other
    neoplastic lymphoid proliferations

REFERENCES
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