Some prescription drugs may cause temporary hair shedding. Examples of such drugs include some of the medicines used for: gout, arthritis, depression, heart disease, high blood pressure, and anticoagulants[1]. High doses of vitamin A may also cause hair shedding. Chemotherapy and radiation treatment will cause hair loss because they both stop hair cells from dividing. Hairs become thin and break off as they exit the scalp[1]. The phenomenon typically occurs one to three weeks after the treatment. Patients can lose up to 90 percent of their scalp hair[1].

Hair loss may also be noted in people taking low protein diets. Hair loss may present in patients with diets insufficient in iron, especially manifested in women who have heavy menstrual periods or following major surgery. Women and men may have a genetic predisposition towards androgenic alopecia[1]. Since hormones both stimulate hair growth and cause hair loss, hormonal changes demonstrate a significant impact on hair loss[1]. Men generally have hair loss concentrated in a specific pattern from the front through to the crown. Women tend to have thinning throughout their head without being in any specific pattern[1]. This type of hair loss in both sexes is caused by the androgen dihydrotestosterone (DHT)[1]. Since everyone has DHT that is produced by their bodies and only selected people suffer from hair loss, another causative factor must be involved. The other factor is the possession of hair follicles that have a greater number of androgen receptors for the DHT to attach to; this is a critical component that is inherited[1].

SLE is a chronic autoimmune connective tissue disease that can affect any part of the body[2]. As occurs in other autoimmune diseases, the immune system attacks the body’s cells and tissue, resulting in inflammation and tissue damage[2]. SLE most often harms the heart, joints, skin, lungs, blood vessels, liver, kidneys, and nervous system[2]. The course of the disease is unpredictable, with periods of illness (called flares) alternating with remissions[2]. The disease occurs almost nine times more often in women than in men, especially between the ages of 15 and 50, and is more common in those of non-European descent[3,4]. SLE is treatable through addressing its symptoms, mainly with corticosteroids and immunosuppressants; however, there is currently no cure for the disease 3,4]. About 65% of people suffering SLE present with a dermatological issue at some point in their disease course. Most SLE immunologic studies have previously focused on testing the more common dermatological manifestations of SLE including the classic malar rash (or “butterfly rash”)[3–6]. Other studies had focused on studying the thick, red, scaly patches on the skin in discoid lupus patients[3–6]. Alopecia; and mouth, nasal, and vaginal ulcers are also common manifestations of SLE, but rarely studied from the immunological point of view[3–6]. In this report, we attempt to address this knowledge gap by focusing on testing some immunological markers and the antigen presenting cells that occur in alopecia in a patient with SLE. In our patient, we ruled out uncontrolled thyroid disease as a cause of alopecia (thyroid function was normal). We also discounted one of the most important causes for hair loss, a postpartum alopecia, due to the clinical timing of the hair loss

Some studies have found alterations of APCs in discoid lupus erythematous (DLE), however, no immunologic studies have been reported in hair loss in SLE. The most common cutaneous subtypes of DLE are chronic DLE (CDLE) and subacute DLE (SDLE). CDLE is the only type of DLE which heals with scarring, and is commonly associated with hair loss. It has been hypothesized that the inflammation in CDLE generally involves the bulb area of the follicles (where the stem cells exist), with possible damage leading to permanent loss of follicles[4]. This finding has been reported based on the fact that cytokeratin 15 (an epidermal stem cell marker) is diminished and/or has been found absent in the hair bulb in the scarring lesions in patients with cicatricial DLE.[4]. In SLE, broader involvement of the hair follicles is noted in alopecia; the broader involvement has been attributed to the more widespread perifollicular inflammatory cell infiltrate in SLE. As far as we can tell by reviewing the literature, almost no reports have focused on studying the presence of antigen presenting cells (APC) and their relationship with hair loss in SLE.

In SLE, hair loss has been a controversial diagnostic criterion; indeed, it was not included in the American Association of Rheumatologists (ARA) criteria for diagnosis. However the ARA accepts that non-scarring, diffuse hair loss has been frequently observed in SLE patients. In regard to the pattern of hair loss and its frequency, one of the largest studies reported evaluated 122 SLE cases during the course of active SLE disease[5]. They found that 104 patients experienced at least one hair loss event before or during the course of SLE. In eighteen of those patients, patch alopecia was also found[5]. The results suggest that non-scarring patch alopecia is an important pattern when testing patients for SLE[5]. Other authors had observed over the years that in lesions of DLE, the inflammation is usually more intense around the mid follicular level at the site where sebaceous glands are located[6]. The authors suggested that the sebaceous glands seem to be the first target in DLE, as is evident from significant, early histologic damage to the sebaceous glands (in the form of lymphocytic infiltration of the sebaceous glands, and the disruption of glandular structure)[6]. These findings are in agreement with ours. The authors suggest that it appears that the sebaceous glands are the first adnexal structures to disappear even before the hair follicles in DLE[6].

The first dendritic cells (DCs) to be discovered, in 1868 were the Langerhans cells of the human epidermis. It took however until the 1970s to demonstrate that these cells belong to the immune system. Simultaneously, in 1973, the pioneering work of Steinman and Cohn permitted the identification of DCs in lymphoid tissue and their functional relationship with Langerhans cells. Realization of the extraordinary capacity of DCs for antigen presentation set the stage for a, rising interest in their biology. Major advances in the early 1990s subsequently led to the ability to generate DCs in vitro from myeloid hematopoietic progenitors or from monocytes, and greatly facilitated their study. The initial unified model of DC life history held that immature DCs patrol peripheral tissues. Upon encounter with microbial and other unknown antigen products, the DCs undergo maturation as they migrate to lymphoid tissue, where they present antigen and activate naive T cells[7]. While most elements of this model still hold true, in particular the unique capacity of DCs to initiate adaptive immunity, many different and contrasting facets of DCs have since been discovered[8]. One aspect that has become clearly appreciated is the great diversity of DC subtypes, with considerable functional differences. Part of this heterogeneity is intrinsic (e.g. conventional versus plasmacytoid DCs), but a high degree of plasticity is also characteristic of the DC system. For instance, DCs can be instructed by the nature of the early signals they receive, with greatly divergent consequences on the immune response. Thus, in addition to their classic function to drive strong Th1-type adaptive responses, DCs can be polarized by microbial products towards a Th2- type response, or towards peripheral immune tolerance via the induction of regulatory T cells[9,10]. Today, DCs are thus positioned as the master regulators of immunity. Pharmacological intervention to exploit the full range of DC regulatory potential will undoubtedly lead to a variety of therapeutic applications either to boost, suppress or repolarize the immune system[12,13]. Another recently recognized important function of DCs is to link the innate and adaptive immune response. The link is illustrated by antiviral responses of plasmacytoid DCs[14], and by crosstalk between DCs and natural killer (NK) cells[15]. A major breakthrough in DC biology has been the recent unraveling of the mechanisms responsible for their regulatory functions, an advance made possible by the molecular cloning of genes expressed by DCs. Thus, it was realized that DCs are remarkably equipped with Pattern Recognition Receptors (PRRs), the innate sensors that recognize conserved molecular patterns on microbes and self-tissue. Outstanding PRRs are the C-type Lectin receptors and the toll-like receptors. The key role played by chemokines and their receptors in the migration patterns of DCs is now well established. Finally, an array of cytokines and corresponding receptors are known to be responsible for the crosstalk between DCs and a host of other cell types that will determine the net outcome of the immune response. Collectively, this rapidly-evolving knowledge allows for drug-discovery programs to design pharmacological compounds to agonize or antagonize DC molecules in a number of clinical settings.

The two major APCs found in normal skin include the Langherhans cells (mostly located in the epidermis), and dermal dendritic cells. However, our study revealed a large and well defined pool of APCs with positive staining for HAM 56, CD68, S-100 and CD1a around the BMZ and the sebaceous glands of the attached hair follicles. We propose that these APCs may play a role either as an effector cells, or interacting with other cells (in our case, APC interaction with CD4 T cells and complement may mediate the immune process in the hair loss process).

Another unexpected finding was the presence of CD117/c-kit and MCT around the same sebaceous glands. Human mast cell tryptases (MCT) comprise a family of trypsin-like neutral serine proteases that are predominantly expressed in mast cells[16]. The mast cells play an active role in many diverse diseases. The CD117/c-kit antibody labels the transmembrane tyrosine kinase receptor CD117/c-kit, located in hematopoietic stem cells, melanocytes, mast cells, Cajal cells, germ cells, basal cells of the skin, and mammary ductal epithelia[16]. The proto-oncogene c-kit, localized to human chromosome 4, encodes a transmembrane receptor, CD117/c-kit, belonging to the class III receptor tyrosine kinase family, which includes the receptor for colony-stimulating factor 1, and the platelet-derived growth factor receptors type A and B[16]. Other authors have analyzed the relationship between the level of CD117/c-kit in peripheral blood mononuclear cells (PBMCs) and clinical activity in SLE[8]. The authors compared the c-kit expression in PBMCs in 47 patients with SLE and 21 healthy volunteers. They showed that the expression of c-kit messenger ribonucleic acid (mRNA) in PBMCs of SLE patients was increased, as determined by reverse transcription-polymerase chain reaction (RT-PCR). In addition, the c-kit receptor (CDll7) was measured in their PBMCs by flow cytometry and was found to be increased in the patients with SLE[17]. Based on their results and on those of our study, we believe that the C-kit receptor, IgE, and mast cells, in addition to APCs, complement and immunoglobulins may all be of pathophysiologic importance in active skin lesions in SLE patients with alopecia. Further we detected some overexpression of CIV, which is a major constituent of the BMZ. HAM56 is another APC marker and also demonstrated positive staining around the BMZ, and around the sebaceous glands. The HAM56 antibody labels human skin macrophages, tingible body and interdigitating macrophages within lymph nodes, and deep tissue macrophages. We also noted strongly positive CD4 staining in the cells around the BMZ and sebaceous glands. The CD4 protein is a transmembrane glycoprotein, and is expressed on normal thymocytes, T-helper cells, the majority of mature peripheral T cells, and a small subset of suppressor or cytotoxic T cells. The HLA-DP, DQ and DR staining were also weakly present in some cells around the superficial dermal vessels. The HLA antibody reacts with the alpha and beta-chains of all products of the DP, DQ and DR sub regions. These antigens belong to the histocompatibility (HLA) complex class II, or MHC class II. The antibody principally labels B cells, interdigitating reticulum cells, Langerhans cells and many non-Langerhans macrophages. It has been accepted that APCs play critical roles in establishing and maintaining peripheral tolerance. As described in most cases of lupus erythematosus, we observed the presence of strong autoreactivity to the BMZ (lupus-band)[18]. In addition, we were able to identify reactivity to the BMZ of the sebaceous glands, including staining with the anti-human IgE antibody. We also detected over expression of ICAM-1/CD54 in several vessels, both in the papillary as well as in the reticular dermis, as previously noted by others[19]. The presence of IgE has been previously described in patients affected by SLE directed to the kidney BMZ[19,20]. The presence of these antibodies has been demonstrated to have a strong prognostic significance in the renal disease process, and light and electron microscopy showed more severe pathological changes in those with IgE positivity than in patients who were IgE negative[11,12]. However, the significance of IgE, MCT and C-kit at the BMZ of the skin and sebaceous glands in SLE is not presently characterized.

Alopecia can be divided into non-scarring and scarring forms. Non-scarring alopecia, unlike scarring alopecia, leads to hair loss without destroying hair follicles. The most common types of non-scarring hair loss are male and female androgenetic alopecia, telogen effluvium and alopecia areata. This group includes also some less common variations: hair pulling alopecia, trichotillomania, alopecia syphilitica, and mycosis of the scalp.

The control group consisted of 21 healthy volunteers without hair loss, 17 of whom were female and 4 were male. The age of the patients in the control group ranged from 21 to 63 years. A careful history based on the author’s own inquiry was taken in all patients, consisting of personal data, age of the patient at the onset of hair loss, the duration and pattern of hair loss (patchy, diffuse), the presence of key factors in determining the cause of hair loss, such as past medical history, stress, lifestyle, improper hair care, medications and family history of alopecia, as well as any details concerning the applied treatment and its efficacy.

During the clinical study, the scalp, hair and skin of the patients were examined, noting signs of seborrhea and the coexistence of hirsutism. The degree of alopecia in men with MAGA was determined based on the 7-point Hamilton-Norwood scale, while in women with FAGA, the determination was based on the 3-point Ludwig classification. In all patients and in the control group, the serum concentrations of dihydrotestosterone were evaluated.

Despite the fact that every type of alopecia has many characteristic features, their differentiation is sometimes difficult and the results are unclear. So far no reliable diagnostic tools have been developed which would be useful both for evaluating and monitoring the response of therapy in different types of alopecia. Typically, interview data, clinical assessment, laboratory tests, and helper methods such as the pull test, trichogram and trichoscopy, as well as histopathological examination of vertical and horizontal sections, are useful methods in the differentiation of hair diseases. Histopathological examination of the scalp often allows a diagnosis to be made, however, recommendations for its implementation should be carefully considered because of its invasive nature.

Androgenetic alopecia is the most common type of non-scarring hair disorder. Excessive hair loss has been found to have a significantly deleterious effect on the appearance of a patient, often causing distress and social conflict as well as aggravating their quality of life.

In the opinion of some authors, androgens are the most important hormones regulating human hair growth, apart from nutritional deficiency and thyroid disease [71, 72]. There are few studies assessing the correlation between androgenetic alopecia and DHT concentrations in serum samples from the patient. On the basis of studies performed on 52 patients of both sexes with early androgenetic alopecia, Sreekumar et al. [73] found no increase in androgen concentrations (DHT and T), but did note the presence of a significantly elevated ratio of DHT/T. However, Vierhapper et al. [74] report that the level of DHT is significantly higher in men with MAGA, and its determination is necessary before anti-androgen treatment. In the present study, the androgen values exceeded the norm, both in patients with androgenetic alopecia, and also in the control group.

Among investigated women with androgenetic alopecia, increased values of DHT were most commonly observed. However, increased levels of DHT did not correlate with the progression of hair loss. The literature reports that although the severity of hair loss may vary, regardless of age, the severity of alopecia is not significant in most cases [34, 35, 41]. Many authors [20, 36, 37, 75] note the frequent occurrence of this form of hair loss in immediate family members. In the present study, more than half of the patients reported the occurrence of androgenetic alopecia in their mothers, but this was not statistically significant. In some women with FAGA, the coexistence of seborrhea was found, which is also confirmed by other authors [37, 49, 53]. The literature highlights the frequent presence of hirsutism in patients with FAGA, which is also the cause of hyperandrogenism [10, 49, 55, 63, 76]. However, all patients demonstrated the Ferriman-Gallweya criteria, which did not allow for hirsutism recognition [63, 77]. The mean age of the group of men with androgenetic alopecia was 25 years. More than half of the respondents with MAGA reported a similar pattern of hair loss in their father or the mother, which may support the theory of a genetic link for this form of hair loss [3, 27–29]. All investigated men reported a history of hormonal disorders. However, 2 patients were taking formulations with carbohydrate-protein containing, among other things, creatine, which causes muscle growth. All patients were either classified as being in stage II, IIIa or IV of hair loss by the Hamilton-Norwood scale. Changes in the nature of acne vulgaris were seen in almost half of the patients.

The results of the present study are consistent those of other authors [56, 78–80], who consider that the level of androgens in women with FAGA may be increased or normal. A retrospective study published in 2009 performed on 228 women with symptoms of hyperandrogenism, also showed higher levels of androstenedione, DHEA and testosterone present in saliva. The SHBG levels were also lower, although their mean values were lower than those in women experiencing hirsutism. An analysis of the results indicated a strong positive correlation of hirsutism with markedly increased hormone levels, particularly testosterone and negative with SHBG. Average total testosterone levels were similar in patients with hirsutism and FAGA [49].

It is noteworthy that biochemical markers of hyperandrogenism can be seen in women with an absence of clinical features. Orme et al. note a complete lack of correlation between FAGA and elevated androgen levels [81]. Schmidt et al. [82] also report no increased androgen levels in patients with FAGA: the level of estrogen was usually within normal limits. A recent Riedel-Baima and Riedel [83] study assessing the concentrations of free and total testosterone, DHEAS, SHBG in 20 women with FAGA also shows a normal range of concentrations of these hormones to be present. Estradiol to free testosterone ratio levels and estradiol to DHEAS ratio levels were found to be significantly lower in FAGA patients compared to the control group. Estradiol to free testosterone ratio levels in women with FAGA were almost always less than 10. Futterweit et al. and Derksen et al. [55, 84] emphasize that the finding of significantly elevated levels of testosterone and DHEAS may indicate the presence of androgen-secreting tumors or of other diseases which require a precise gynecological and endocrinal diagnosis. According to Price [76], the results of routine hormonal tests performed on women with FAGA are often not much valuable.

According to Stanczyk [85], the determination of the DHT level in serum is not helpful in assessing the prevalence of hyperandrogenism. However, its metabolites, such as sulfate and glucuronide, androstenedione, appear to be clinically relevant markers in the recognition of hirsutism, acne and androgenic alopecia.

Dihydrotestosterone has the most powerful androgen action and seems to play an extremely important role in the pathogenesis of androgenetic alopecia. However, based on the present findings and opinions of many other authors [6, 18, 27–29, 41, 42], the individual, genetically-based sensitivity of hair follicles to DHT concentrations and their varied response to the action of androgens seem to be the most significant factors.

SS is diagnosed predominantly in post-menopausal women with the female to male ratio reaching 9:1 (Nazmul-Hossain et al., 2011), suggesting a role for ovarian sex hormones in the pathogenesis of SS. However, not all postmenopausal women develop SS, indicating a contribution of other factors such as genetic background to the onset of SS.

To investigate the early events of the disease and the contribution of sex hormones and genetic predisposition background, our laboratory has been using the NOD.B10.H2b mouse model of SS. We have previously reported that a decrease in the concentration of sex hormones following ovariectomy (OVX) in these genetically predisposed mice resulted in lacrimal gland lymphocytic infiltration, consisting of T cells and B cells, followed by epithelial cell death (Mostafa et al., 2012). We also found that treatment with physiological doses of dihydrotestosterone (DHT) or 17β-estradiol (E2) at the time of OVX prevented these changes.

The lymphocytic infiltration observed in the lacrimal glands could affect cytokine levels and promote autoantibody production, leading to lacrimal gland epithelial cell death and loss of epithelial function in these animals. Several cytokines have been proposed to play a role in the pathogenesis of this disease. Thus, it has been reported that cytokine homeostasis is disrupted in the plasma of SS patients with significantly increased concentration of pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) (Szodoray et al., 2004). Moreover, increased expression of IL-1β, TNF-α, IFN-γ, and the anti-inflammatory cytokine IL-10 was also reported in lacrimal and submandibular glands of NOD mice (Hayashi, 2011). Furthermore, IL-10 produced by activated T cells, B cells and monocytes/macrophages has been identified as a critical cytokine, whose overproduction has been implicated in promoting the development of autoimmune lacrimal gland disease either directly or by suppression of Th1 responses (Jabs et al., 2001; Fiorentino et al., 1989; Moore et al., 1993). Increased expression and levels of IL-4 and interferon-γ (IFN-γ) have also been found in the salivary glands of patients affected by SS (Mitsiasis et al., 2002).

Although several cytokines have been observed to be upregulated in patients with SS, patients are usually diagnosed 5–10 years into disease progression. Therefore, the time frame where cytokine upregulation occurs as the disease progresses has not been elucidated.

While the levels and expressions of cytokines in the lacrimal glands of OVX NOD.B10.H2b mice increased significantly over time, the lacrimal glands of OVX C57BL/10 showed a very small but significant increase only in the expression of IL-1β and IL-4 at 7, 21, and 30 days after surgery. These symptoms observed are probably in response to the surgical procedures and suggest that these animals are most likely able to recover from the initial inflammation without developing the disease. Consequently, these findings support our hypothesis that, in addition to a decrease in the circulating levels of sex hormones, a predisposed genetic background seems to be necessary for a more severe and pronounced response and for the development of SS.

To ensure that the difference in genetic background of these two strains of mice studied did not influence the observed findings, we compared the gene expression profile between the sham-operated NOD.B10.H2band the sham-operated C57BL/10 mice, using a cDNA microarray. We found that 87% of the genes studied were similarly expressed. This high similarity in gene expression between these strains suggest that the differences in gene expression observed between the OVX groups from both strains in these studies are due to the effect of genetic predisposition to SS, not to the difference in their genetic background. A successful OVX in these animals was confirmed by vaginal smears and ovarian hormone concentration as previously described (Mostafa et al., 2012).

Our present investigation showed that the increase in levels and expressions of pro-inflammatory cytokines IL-1β, TNF-α, IL-4, and IL-10 in the lacrimal glands of OVX NOD.B10.H2b mice correlates with the time frame of lymphocytic infiltration previously reported. Therefore, this overall increase in cytokine production is most likely due to the previously reported increase in CD4+ cell count in the lacrimal glands of the OVX NOD.B10.H2b mice.

Several studies have suggested that cytokines play a central role in the progression of SS. However, the mechanisms by which increase in cytokine expression and concentration eventually lead to the pathogenesis of SS remain unknown. Increased levels and/or expression of IL-1β, TNF-α, IL-4, IL-10, and IFN-γ have been reported in the serum, saliva, and/or salivary glands of patients diagnosed with SS, and also in mouse models used for the study of this disease (Hayashi, 2011; Szodoray et al., 2004; Mitsiasis et al., 2002). Some of the potential mechanisms that could lead to apoptosis of epithelial cells in the lacrimal glands of OVX NOD.B10.H2b mice include the activation of the transcription factor NF-κ B by TNF-α and IL-1β, which in turn can further increase lymphocytic infiltration and cause apoptosis by transcribing various inflammatory and pro-apoptotic genes (Dong et at., 2010; Buhrmann et al., 2011).

In addition, lacrimal epithelial cells may also secrete TNF-α and IL-1β, indicating that the epithelial cells may become active participants in the progression of the disease (Zoukhri, 2006).

Another possible mechanism for apoptosis could be the direct influence of specific cytokines, since it has been reported that TNF-α and INF-γ directly induce apoptosis in salivary glands of SS patients (Kamachi et al., 2002), and that the exogenous addition of IL-1β or TNF-α leads to impaired lacrimal gland secretion in MRL/lpr mice (Zoukhri et al., 2002).

On the other hand, IL-4, a T-helper type 2 cytokine (Th2), has been shown to promote the survival and proliferation of B lymphocytes, production of autoantibodies and has been accepted as a regulatory molecule for immunoglobulin isotype switching (Singh, 2003). Consequently, IL-4 could serve as an additional participant in the pathogenesis of SS that involves humoral immunity and antibody production. In our study we observed a significant increase in IL-4 in the lacrimal glands of OVX NOD.B10.H2b mice, suggesting that IL-4 could have a direct influence on SS disease progression in the NOD.B10.H2b mouse model, and that IL-4 might also play a central role in the disease mechanism in patients diagnosed with SS.

A highly significant increase in mRNA and protein IL-10 was observed at only 21 and 30 days after OVX in the lacrimal glands of NOD.B10.H2b mice. IL-10 is a cytokine originally identified as anti-inflammatory and immunosuppressive due to its properties of suppressing the Th1 cell response. However, immunostimulatory effects of IL-10 have also been reported (Jabs et al., 2001). Studies using patients diagnosed with SS have reported that anti-inflammatory cytokines, with exception of IL-10, were found at very low concentration or remain undetectable in the salivary glands, suggesting that IL-10 may play a role in the human disease pathogenesis (Hayashi, 2011).

IFN-γ may also play an additional role in the pathophysiology of SS in the lacrimal glands of NOD.B10.H2b mice, since it has been reported that IFN-γ and IFN-γ receptor knockout mice, NOD.IFN-γ−/− and NOD.IFN-γR−/− mice respectively, do not exhibit increased acinar cell apoptosis in salivary and lacrimal glands at 20 weeks of age, nor do they show the abnormal salivary protein expression that is observed in the disease-prone NOD/Lt mice (Cha et al., 2004). In the present study, IFN-γ mRNA and protein levels were not detected, probably due to the early time frame under which these experiments were conducted. The exact time frame of increase in IFN-γ in our NOD.B10.H2b mouse model remains to be elucidated.

Serum anti-Ro/SSA and anti-La/SSB autoantibodies are known as hallmarks of SS. Our experiments showed the presence of only anti-Ro/SSA autoantibodies in the serum of our ovariectomized mouse model. This finding concurs with previous reports in which the anti-Ro/SSA has been detected more frequently in patients with SS than the anti-La/SSB (Yoshimi et al., 2012). Moreover, while anti-Ro/SSA can be found either by itself or in combination with anti-La/SSB, it is very rare to find anti-La/SSB exclusively (Hernandez-Molina et al., 2011; Tzioufas et al., 2012).

We also observed that the increase in the anti-Ro/SSA autoantibodies in the serum occurs at later experimental times, which overlap with the later increase in IL-10 in the lacrimal gland of these mice. IL-10 is a promoter of the Th2 response, which might further increase the autoantibody production as the disease progresses. Although the exact role of these autoantibodies remains unknown, anti-Ro/SSA and anti-La/SSB serum autoantibodies have been correlated with more severe exocrine dysfunction of the salivary glands, longer disease duration, and younger age of diagnosis in patients with SS (Tzioufas et al., 2012). The increase in serum levels of anti-Ro/SSA observed in our experiments coincides with the increase in acinar cell apoptosis, lymphocytic infiltration (Mostafa et al., 2012), and cytokine levels and expression in the lacrimal glands.