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North American Journal of Medical Sciences 2011 May, Volume 3. No. 5.
Case Report
OPEN ACCESS
Activation of the signaling cascade in response to
T lymphocyte receptor stimulation and prostanoids in
a case of cutaneous lupus
Ana Maria Abreu-Velez, M.D. Ph.D.1, Graham Smith, Jr., M.D. 2, Michael S. Howard, M.D.1
1
Georgia Dermatopathology Associates, Atlanta, Georgia, USA.
Diagnostic and Medical Clinic/Dermatology, Mobile, Alabama, USA.
2
Citation: Abreu-Velez AM, Smith G, Howard MS. Activation of the signaling cascade in response to T lymphocyte
receptor stimulation and prostanoids in a case of cutaneous lupus. North Am J Med Sci 2011; 3: 251-254.
Doi: 10.4297/najms.2011.3251
Availability: www.najms.org
ISSN: 1947 – 2714
Abstract
Context: Discoid lupus erythematosus is a chronic inflammatory skin disorder presenting with scarring lesions that occur
predominately on sun exposed areas of the face and scalp. Case Report: A 22-year-old male was evaluated after presenting
with reddish-purple, atrophic and erythematous plaques on the scalp, with loss of hair within the plaques. Biopsies for
hematoxylin and eosin examination, direct immunofluorescence and immunohistochemistry analysis were performed. The
hematoxylin and eosin staining demonstrated classic features of cutaneous lupus. Direct immunofluorescence revealed
strong deposits of immunoglobulins IgG and IgM, fibrinogen and Complement/C3, present in 1) a shaggy pattern at the
epidermal basement membrane zone, and 2) focal pericytoplasmic and perinuclear staining within epidermal keratynocytes.
Immunohistochemisty staining revealed strongly positive staining with antibodies to cyclooxygenase-2,
Zeta-chain-associated protein kinase 70, and HLA-DPDQDR in areas where the inflammatory infiltrate was predominant, as
well as around dermal blood vessels and within the dermal extracellular matrix. Conclusions: Noting the autoimmune nature
of lupus and its strong inflammatory component, we present a patient with active discoid lupus erythematosus and strong
expression of Zeta-chain-associated protein kinase 70, cyclo-oxygenase-2, and HLA-DPDQDR in the inflammatory areas.
We suggest that these molecules may play a significant role in the immune response of discoid cutaneous lupus, possibly
including 1) the biosynthesis of the prostanoids and 2) activation of the signaling cascade in response to T-lymphocyte
receptor stimulation.
Keywords: Zap 70, COX-2, HLA-DPDQDR, discoid lupus erythematosus, autoantibodies, prostanoids.
Correspondence to: Ana Maria Abreu-Velez, MD., PhD., Georgia Dermatopathology Associates, 1534 North Decatur Rd.
NE; Suite 206, Atlanta, GA 30307-1000, USA. Tel.: (404) 371-0077, Fax: (404) 371-1900, Email: abreuvelez@yahoo.com.
erythematosus, lupus erythematosus tumidus, lupus
profundus, neonatal lupus erythematosus, chilblain lupus
erythematosus, drug-induced lupus erythematosus,
systemic lupus erythematosus, and hypertrophic LE, among
others [1, 2]. Multiple models have been suggested for the
pathogenesis of DLE. Ultraviolet radiation is thought to
increase local mediators of inflammation, and stimulate
local cytokine release. The cytokine release could in turn
modify selectins, adhesion molecules, chemokines and
prostanoids [3]. In addition, it has been suggested that the
cytokines help to recruit and activate T lymphocytes,
Introduction
In the classic presentation of discoid lupus erythematosus
(DLE), erythematous, scaly patches and plaques develop
which leave postinflammatory pigmentary changes and
white scars [1, 2]. The disease lesions may be localized or
widespread. DLE predominantly affects the cheeks, nose
and ears, but sometimes involves the upper back, frontal
neck, and dorsal hands. LE is classified as an autoimmune
disease, as it is associated with antibodies directed against
components of cell nuclei. [1, 2]. There are multiple types
of cutaneous LE, including DLE,
subacute lupus
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North American Journal of Medical Sciences 2011 May, Volume 3. No. 5.
classic dendritic cells, and plasmocytoid dendritic cells [3].
Based on these factors, we investigated the possible
presence of selected molecules in the skin biopsies of a
patient affected by DLE.
staining of stratum spinosum keratinocytes); IgM (-); IgE
(-); complement/C1q (+, linear at the BMZ);
complement/C3 (++, mild staining on dermal vascular
walls); albumin (+++, pericytoplasmic and perinuclear
staining of stratum spinosum keratinocytes, and mild linear
staining along the BMZ) and fibrinogen (+++, linear pattern
along the BMZ) (Figure 1).
Case Report
A 22-year-old African American male presented with
reddish-purple atrophic plaques and erythematous patches
on the scalp, with lesional hair loss. The clinical lesions
were consistent with a presentation of discoid lupus
erythematosus (DLE). He denied systemic symptoms of
arthralgia, arthropathy, myalgia, fatigue, Raynaud's
phenomenon and gastrointestinal complaints. Lesions were
present on the head, mainly on the cheeks, but also on the
trunk.. Laboratory data revealed a normal complete blood
count, and a normal erythrocyte sedimentation rate. Serum
electrolytes, blood urea nitrogen, creatinine, and liver
function tests, as well as urinalysis and chest radiograms
were within normal limits. The antiphospholipid,
anti-Smith, anti-double stranded DNA, anti-histone,
anti-ribonuclease-sensitive antigen, extractable nuclear
antigen, small nuclear antigen, ribonucleoproteins, U1, U2,
anti-SS-A and anti-SS-B antibodies were all negative.
Complement was normal. Biopsies of the lesions were
performed, with subsequent hematoxylin and eosin (H&E)
staining, multicolor direct immunofluorescence (DIF) and
immunohistochemistry (IHC); these techniques were
performed as previously described [4-7]. Selected IHC
antibodies included 1) Zeta-chain-associated protein
kinase 70 (ZAP-70), which plays a critical role in the
initiation of T-lymphocyte signaling, and 2)
prostaglandin-endoperoxide synthase 2, also known as
cyclo-oxygenase-2 (COX-2).
Immunohistochemistry staining (IHC)
The IHC staining revealed strong positivities to
HLA-DPDQDR and ZAP-70 in most of the dermal
inflammatory infiltrate, primarily around dermal blood
vessels and within the extracellular matrix. The antibody
to COX-2 was also overexpressed around the dermal
vessels, and within the dermal extracellular matrix in focal
areas surrounding inflammatory cells (Figure 1). To our
surprise, the antibodies for linker for activation of T cells
(LAT), CD34, BAX and CD35 displayed normal staining
patterns, vis-à-vis their respective negative controls.
We focused our studies on 1) several molecules involved
in triggering the signaling cascade in response to T-cell
receptor stimulation, 2) molecules expressed on
antigen-presenting cells and 3) enzymes that play a role in
biosynthesis of prostanoids.
Hematoxylin and eosin staining (H&E)
Examination of the H&E tissue sections demonstrated mild
epidermal hyperkeratosis with focal follicular plugging. A
mild interface infiltrate of lymphocytes, histiocytes and
plasma cells was noted. Rouleaux of erythrocytes were
noted in multiple superficial dermal blood vessels (Figure
1). Within the dermis, a superficial and deep, perivascular
and periadnexal infiltrate of lymphocytes, histiocytes and
plasma cells were observed. Neutrophils and eosinophils
were rare, and dermal mucin was not appreciated (Figure
1). The histologic features were consisted with discoid
lupus erythematosus (DLE).
Fig. 1 a. H&E section demonstrating prominent follicular
plugging (blue arrow).b. Erythrocytes sludging in dermal blood
vessels and forming linear stacks of erythrocytes called rouleaux
(blue arrows). c. Same as b, at higher magnification. d. Positive
PAS staining along the BMZ (basement membrane zone) (blue
arrow). e. DIF showing positive staining along the epidermal
BMZ utilizing FITC conjugated anti-human fibrinogen (yellow
arrow); the white arrow highlights cytoplasmic and perinuclear
Direct immunofluorescence staining (DIF)
DIF displayed positive (+++) deposits of FITC conjugated
IgG, present as pericytoplasmic and perinuclear staining
within the stratum spinosum of the keratinocytes, and in a
linear pattern along the basement membrane zone (BMZ).
Additional antibody staining supported a diagnosis of
discoid lupus, i.e., IgA (+, pericytoplasmic and perinuclear
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North American Journal of Medical Sciences 2011 May, Volume 3. No. 5.
reactivity within epidermal keratinocytes. F. DIF showing
positive epidermal staining with FITC conjugated anti-IgG
(yellow staining; dark blue arrow). Epidermal keratinocyte nuclei
are conterstained with Dapi (light blue). g, DIF showing positive
staining along the epidermal BMZ utilizing FITC conjugated
anti-human fibrinogen (yellow arrow); the white arrow highlights
BMZ reactivity, and the yellow arrow shows vascular reactivity
h. DIF showing positive staining with FITC conjugated
vomplement/C3 against superficial dermal blood vessels (yellow
staining; dark blue arrow). i. IHC demonstrating positive staining
against COX-2 in the dermal inflammatory infiltrate, and also in
the dermal extracellular matrix (brown staining; blue arrows). j.
IHC highlighting positive staining against HLA-DPDQDR in the
dermal inflammatory infiltrate (brown staining; blue arrow). k and
l, IHCs showing positive staining against ZAP-70 in the dermal
inflammatory infiltrate(brown staining; blue arrows).
expressed in T cells and natural killer cells, but is also
detectable in mast cells and basophils [9, 10]. ZAP-70 is
further expressed in normal pre-B lymphocytes, but not in
mature B lymphocytes [10, 11]. It has been previously
demonstrated that T cells from SLE patients exhibit
defective functions of CD4 (+) T cells; these T cells can in
turn be responsible for improper activation of B cells, and
resultant antibody biosynthesis against host antigens.
Other authors found that ZAP-70 protein content in SLE
CD4 (+) T cells may be reciprocally correlated with SLE
disease activity [9, 11].
In our patient, we also found positive staining for
prostaglandin-endoperoxide synthase 2, also known as
cyclo-oxygenase 2 (COX-2). The COX-2 molecule
represents a key enzyme in biosynthesis of the prostanoids
(prostaglandins, prostacyclins and thromboxanes). COX-2
acts both as a dioxygenase, and a peroxidase. Overall, the
cyclo-oxygenase (COX) enzymes, COX-1 and COX-2,
play critical roles in the biosynthesis of prostaglandins
from arachidonic acid [11]. Thus, are two isozymes of
COX: a constitutive COX-1 and an inducible COX-2,
which differ in their regulation of expression and tissue
distribution. The human COX-1 protein is constituitively
expressed in most tissues, and functions in the
maintenance of tissue homeostasis. Human COX-2 shows
86-89% amino acid sequence identity with mouse, rat,
sheep, bovine, horse and rabbit COX-2 proteins,
respectively. Human COX-2 is expressed in a limited
number of cell types and regulated by specific stimulatory
events, suggesting that it contributes to prostanoid
biosynthesis involved in inflammation and mitogenesis [3].
Human COX-2 is encoded by the PTGS2 gene. Moreover,
nonsteroidal anti-inflammatory drugs are effective in
decreasing the inflammatory response, by blocking both
COX isoenzymes [12]. In addition, previous authors have
investigated the role of COX isozymes in the functioning
of cell types involved in the lupus autoimmune response.
These authors examined the therapeutic effect of COX-2
inhibitors in mice prone to spontaneously developing SLE
[12, 13]. In their results, treatment with COX-2 inhibitors
resulted in 1) decreased autoantibody production and 2)
inhibition of the T cell response to the major lupus
autoantigen, nucleosome, and its pathophysiologic
presentation by antigen-presenting cells. Surprisingly, a
significant increase in survival occurred only in mice
receiving intermittent therapy with the lowest dose of
celecoxib [12, 13]. The authors concluded that the major
players in the lupus pathogenic autoimmune response,
namely, hyperactive T cells, B cells, dendritic cells, and
macrophages, depend on an increased expression and
activity of COX-2 in target organs.
Discussion
DLE is an autoimmune disease. The presence of ZAP-70,
HLA-DPDQDR and COX-2 in skin biopsies from patients
affected by this disease has never been reported in the
medical literature [1, 2]. Of interest, our staining results
for another cell signaling molecule, the linker for
activation of T cells (LAT) were negative. LAT is a
transmembrane adaptor protein that plays an essential role
in T cell receptor (TCR) signal transduction pathways.
LAT is phosphorylated on multiple tyrosine residues upon
TCR engagement, recruits several important signaling
proteins to the cell membrane, and functions as a scaffold
for the assembly of numerous signaling complexes. In this
study we confirmed the diagnosis of DLE by H&E
staining, and established the typical BMZ lupus band by
DIF. In addition, we demonstrated pericytoplasmic and
perinuclear reactivity within epidermal keratinocytes with
selected antibodies.
The primary function of the HLA-DP, DQ and DR
molecules is to present antigenic peptides, mostly of an
exogenous nature, to T lymphocytes. HLA molecules are
associated with a variety of autoimmune and
non-autoimmune diseases, and aid in restricting the
antibody response to certain antigens. HLA-DP, DQ and
DR molecules are expressed on antigen-presenting cells
such as B lymphocytes, monocytes and dendritic cells, but
can also be detected on cytototoxic/suppressor T
lymphocytes and activated granulocytes. HLA class II
expression can also be induced on cells and tissues such as
fibroblasts and endothelial cells as a result of activation by
certain cytokines such as γ-interferon, tumor necrosis
factor and interleukin-10 [3]. We have also demonstrated
that HLA-DPDQDR is highly expressed in tumid lupus [3,
4]. As shown in this study, other authors have found that in
Japanese patients affected by DLE and systemic lupus
erythematosus (SLE), the HLA-DRB1*1501 carrier
phenotype has a statistically significant association with
these disorders [8].
We conclude that in our patient with active DLE, strong
expressions of ZAP-70, COX-2 and HLA-DPDQDR are
present in the inflammatory areas. These markers could
play significant roles in this autoimmune disorder,
specifically in the maintenance and regulation of specific
stimulatory events affecting the biosynthesis of
prostanoids involved in inflammation and mitogenesis.
We also tested for the presence of ZAP-70, a tyrosine
kinase of the Syk family. The ZAP-70 protein plays a
critical role in triggering the signaling cascade in response
to T-cell receptor stimulation [8-10]. ZAP-70 is primarily
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North American Journal of Medical Sciences 2011 May, Volume 3. No. 5.
Further studies are warranted to investigate these
possibilities, and also to assess the therapeutic efficacy of
ZAP-70 and COX-2 inhibitors in lupus erythematosus.
8.
Acknowledgments
The authors thanks Jonathan S. Jones HT (ASCP) for his
excellent technical work. All work was performed with
funds from Georgia Dermatopathology Associates (GDA).
9.
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